4th International Conference "Coordinating Engineering for Sustainability and Resilience" & Midterm Conference of CircularB “Implementation of Circular Economy in the Built Environment”

Field investigations after recent large earthquakes have confirmed that several structures were severely damaged and collapsed not only by the earthquake, but also by the subsequent tsunami, landslide, or fault displacement. Effect of material degradation due to chloride attack on structural performance should be considered when structures are located in a harsh environment. In addition, climate change has produced typhoons and hurricanes with extreme intensity in recent years. Sea-level rise could cause severe storm surges and tsunamis, and global warming is accelerating the deterioration of structures. When structures are exposed to these different types of hazards, it can be difficult to ensure their safety and additional performance indicators such as risk and resilience are needed. Several lessons were learned about the importance of investigating individual structures from the perspective of ensuring network functionality. A probabilistic life-cycle framework for quantifying the loss of functionality of road networks including bridges is needed. A risk-based decision-making approach at the network level is required to identify the dominant hazard and the vulnerable structures that require strengthening and retrofitting. After a catastrophic event, the functionality of transportation networks can be significantly degraded, resulting in catastrophic economic impacts. To quantify the promptness of recovery, it has become common to use the concept of resilience. In addition, the economic, environmental, and social impacts of disaster waste management systems need to be examined in terms of sustainability. Consequences related to resilience and sustainability need to be investigated and implemented in the risk assessment of road networks under multiple hazards. Life-cycle design and assessment methodologies can incorporate risk, resilience, sustainability and multiple hazards, learning from the lessons of past disasters. This keynote paper provides an overview of measures to ensure the functionality of individual and spatially distributed structures under multiple hazards from the perspectives of reliability, risk, resilience and sustainability.

Constructions should be able to remain stable for their designed lifetime, from 50 to 100 years, even more. As climate change intensifies, extreme weather events such as temperature variation, humidity, heavy rainfall, floods, and windstorms become more frequent and more severe. These events pose a significant threat to conventional building designs and infrastructures. Consequently, there is a growing demand for climate-resilient constructions that can withstand extreme weather conditions. Protecting infrastructure and buildings to cope with these threats is a complex challenge. Building materials, design, and construction techniques need to be adapted to ensure the durability and safety of structures in the face of changing climatic conditions. The safety margins and robustness of constructions for undesired events in technical regulations and standards should therefore be continuously re-evaluated so that the designed level of reliability is maintained. To control by design, alternatively to traditional prescriptive design codes, where the building must conform to a set of given requirements that results in a hard-to-quantify performance, a Performance-Based Design (PBD) method might apply to explicitly define and achieve the desired structural performance. Based on the review and analysis of dedicated literature and research reports related to this complex problem, potential technical solutions are discussed. Also, two real study cases, one caused by extreme wind and the other by extreme drifted snow, are presented.

This study describes a framework for optimizing environmental sustainability, climate resilience, and cost in post-hazard transport asset recovery. Particular focus is given to the environmental impact assessment component and its conceptual integration with resilience metrics. After describing the workflow adopted in the complete framework, the environmental impact modelling assumptions, system boundaries, and life cycle inventories for materials, on-site activities and transportation are detailed. Carbon equivalent emissions are evaluated for various restoration tasks for a bridge subjected to nine flood scenarios and represented through a sustainability index. A baseline environmental impact analysis is initially conducted, considering conventional materials, construction techniques, and procedures for each restoration task. Additional sensitivity studies are carried out to evaluate the influence of low-carbon solutions and task duration on carbon emissions. These are weighted based on the probability of the bridge being in a specific damage state. The results demonstrate that low-carbon solutions can provide carbon savings to varying degrees depending on the hazard intensity. Normalised sustainability, resilience, and cost metrics are combined into a unique global index, which can be adopted to prioritise the recovery of the asset. Suggestions on adopting circularity indicators and waste hierarchy levels into such frameworks are also given.

Bridge structures are key components of transport networks, enabling connections between important centres and regions of countries. Their operability and functionality loss due to long-term deterioration or extreme hazards could cause crucial social and economic impacts. Assessment of bridge resilience against these hazards is needed to predict functionality, optimal management, sustainable development, and decision-making in maintenance and post-conflict restoration measures. Nevertheless, no studies exist to date to optimize resilience metrics for aged bridges subjected to human-induced stressors, considering indirect losses due to disruption of the transport network. This is a capability gap that gave the motivation for this research paper. The study covers functionality-related resilience metrics of damaged bridges, associated with direct losses in terms of repair cost, and socio-economic metrics due to the inoperability of the logistic route. The application of a framework for resilience assessment was illustrated with an example of the case study of the post-conflict restoration of Ukrainian aged bridge structures, which experienced extensive war-induced destruction. This research presents a novel application of resilience framework for assets, subjected to war-induced stressors, considering both direct and indirect losses, and introduces cost and safety-based resilience indexes.

Traffic safety, particularly among young adults, is a critical public health concern that necessitates a deeper understanding of the factors influencing driving behaviors and compliance with traffic regulations. This study, conducted at the German Jordanian University in Amman, Jordan, aimed to elucidate these factors by evaluating the traffic awareness and behaviors of a diverse group comprising students, academic staff, and other university employees. Employing a survey methodology, the research engaged over 500 individuals, yielding 300 responses. This survey revealed notable trends, for example, a significant portion of drivers exhibited non-compliance with speed limits and seatbelt usage, coupled with prevalent mobile phone usage while driving. A concerning observation was that the majority of respondents who had experienced one or two accidents fell within the 18–19 age range. The study also highlighted the perception of social media as the most effective medium for traffic awareness campaigns, in contrast to television, which was deemed the least effective. These findings underscore a pressing need for comprehensive traffic safety education, especially among younger drivers. The results advocate for the integration of Traffic Awareness as a mandatory module within university curricula, ensuring a structured and consistent approach to instilling the importance of traffic safety measures. Such an initiative could significantly contribute to reducing traffic-related incidents and fostering a culture of responsible driving within the university community.

The paper investigates the response of the pavement of a road sector analyzed to the traffic load that was determined numerically by using Abaqus numerical modelling software. This tool offers advanced analysis options in comparison with the normative road structure dimensioning tool. Thus, in contrast to the current use road structure dimensioning program, the FEM software allows the definition of the interfaces between layers and switch loads from static load to moving load, based on the determination of the resilient stresses and deformations in road structures by using the classical linear elastic multilayer model. The aim of this study was to determine whether the road pavement with deficiencies of adhesion between asphalt layers can take over the calculated traffic load considered in the study, or the proportion of design traffic load that can be taken over. That would allow an assessment of the service operation life of the road pavement and, implicitly, of the possibility of its yielding before the end of the perspective period considered.

This research is a Parametric study that investigates the temperature and thermal stress distributions in Roller Compacted Concrete (RCC) dams. The analysis used in this study involved the RCC placement temperature, the Modulus of Elasticity, tensile strain capacity, the placement schedule of RCC layers, the number of layers, and the thickness of each layer. The Metolong Dam Project in the South African state of Lesotho is used in this research as a case study, in addition to ANSYS, a well-known computer code. The sensitivity of each of the parameters listed above is investigated, and the results are presented in tables and graphs. Conclusions are drawn to better understand the effect of each parameter on the temperature distribution and thermal stress in the RCC dams.

Cold-formed steel composite floors are lightweight systems whose application increased in the last few decades. According to the design guidelines, the frequency of floor systems should be more than 4 Hz while in the case of light steel floors, the natural frequency of the system should be in the high frequency range above 8 Hz. The main focus of this paper is to investigate the vibration performance of an innovative lightweight composite floor system called LWT-FLOOR. The LWT-FLOOR system is composed of spot-welded built-up cold-formed steel elements that are connected to a lightweight concrete slab. Based on laboratory tests material properties of all components of the system are obtained and the finite element model of cold-formed steel concrete composite floor is created to investigate its vibration behaviour. Numerical analyses were conducted in Abaqus/CAE, where after mesh density verification, the influence of the degree of shear connection, spot weld density, concrete type and class, steel channels cross-section thickness and the arrangement and diameter of the shear connector were analysed. The results show that the flexural rigidity of the system and vibration characteristics can be improved by changing those parameters, especially by changing steel channel cross-section characteristics and support conditions from nominally pinned to nominally rigid.

Steel and composite shear wall systems are used for vertical stabilisation of buildings and have been widely investigated in recent decades. Such systems provide excellent shear strength and ductility while allowing material savings due to optimal material usage and an increase in construction speed. A double-skin cold-formed steel shear wall filled with concrete is an innovative composite shear wall that is composed of cold-formed corrugated steel sheets and intermediate fasteners filled with concrete which is in turn bounded by a steel frame. Steel sheets are connected onto a concrete core with the help of intermediate fasteners behaving as shear connectors forming a sandwich Steel–Concrete–Steel panel. Compared to reinforced concrete shear walls, this type of wall has enhanced strength and ductility due to steel confinement while allowing for a reduction in construction time. The numerical simulation of double-skin cold-formed steel shear walls filled with concrete has been studied in this paper. The numerical parametric simulations are conducted in ABAQUS/CAE, where the influence of steel sheet thicknesses, concrete strength and the arrangement and diameter of the shear connectors were analysed. The wall shear capacities for all parameters were compared and the results provide suggestions for future investigations.

In recent decades, economic growth and globalization have spurred increased demand for efficient storage systems, leading to the extensive production of industrial racks from cold-formed steel profiles. Technological advances and research have significantly enhanced the optimization and mechanical efficiency of these profiles. However, older structures often require reassessment and strengthening to meet current and future load-bearing requirements, especially when systems are continuously in use and interventions must be minimized in terms of time and complexity. This paper investigates two strengthening solutions designed to improve the structural performance under various loading conditions, using experimental research to assess and understand the behavior of reinforced profiles. It presents a comparative analysis of the axial compression behavior of the base upright profiles of steel storage racks, each 1 m in length. A specific open cross-section with perforations was utilized, and a total of 13 specimens were tested: 5 unreinforced, 3 with ‘2L-shaped profiles’ for method 1, and 5 with ‘1C-shaped profile’ for method 2. For the strengthened profiles, both methods were secured inside the original profile using M8 bolts. The results demonstrate a 25% improvement in compression resistance capacity for method 2 and 4% for method 1, underscoring the effectiveness of these interventions.

Structural engineers are always struggling with the unpredictable complexities of the extreme vibration due to natural or human induced loads. It is not possible to eliminate the vibration from structures entirely what so ever. Therefore, in order to keep the structures safe and healthy, the vibration needs to be mitigated and that can be done by adopting passive, active or semi-active type control systems. Those aforementioned technologies come with a price, hence, it is not so straightforward to decide which technology should be adopted. The passive vibration systems (e.g. tuned mass damper, base-isolator) can be found both in many old and new structures due to their feasibility and simplicity. On the other hand, many modern structures are adopting active and semi-active control systems (e.g. dampers) as an alternative to achieve better control on structure. Both the active and semi-active control systems are more expensive than passive control systems but they offer better control on structures. In order to understand the discussed issue, herein, a comparative study has been performed to evaluated their performances. A detail comparison among passive, active and semi-active control alternatives have been conducted. The outcome shows that the passive control systems can be suitable where deformations are and the other alternatives would be beneficial where large deformations are expected.

As construction material, wood represents a response to concerns over the environmental impact caused by steel and concrete. A good performance of timber structural members must be demonstrated in fire. To perform numerical simulations of timber structures under elevated temperatures, EN1995-1-2 provides effective thermal properties of wood for computing the temperature distribution. These properties have been determined considering the standard time-temperature curve. The aim of the exploratory research is to verify to what extent these properties may be considered also for natural fires, by adapting the real exposure conditions within the numerical simulations. In the tests performed at the University of Liège, timber samples were subjected on one side to heat fluxes of different intensities, including decreasing phases. Time-temperature curves inside the samples were recorded by thermo-couples inserted at different distances from the exposed side. Using SAFIR software, dedicated to the analysis of structures under elevated temperatures, the temperature distribution within the samples was calculated considering thermal properties provided by EN1995-1-2. The comparison with the experimental results emphasized that the correspondence is not satisfactory for all cases.

One of the effective ways to increase the efficiency of the circular economy is the reuse of existing structures and parts of buildings or extending the life cycle of existing buildings. Assessing the technical condition of existing systems is the basis for reliable and safe operation, both of structures and buildings as a whole. The paper analyses the history and development of Ukrainian standards (codes). It compares methods for evaluating the technical condition of existing structures presented in Ukrainian standards with those shown in the international standard for assessing existing members. Over the past 30 years, Ukraine has actively developed methods for assessing the technical condition of existing steel, reinforced concrete and composite structures. The basis of the results of the analyzed works is theoretical, experimental, and full-scale studies of existing structures. Much work is devoted to assessing the reliability of existing and damaged building structures. Methods of reliability theory have been applied to evaluate enclosure structures, for which a new term - thermal reliability of enclosure structures - has been introduced. Based on the analysis of codes and research, recommendations have been prepared for implementing sustainable practices into European standards.

With rapid development of 3D scanning technologies and implementation of digital twinning and reverse engineering in the construction industry, it became possible for finite element simulations to facilitate analysis of measured geometries when it is needed. A new approach to generate 3D solid models using advanced techniques in the field of 3D scanning is introduced in this paper. Constructing three-dimensional (3D) finite element (FE) models with measured geometry of structures or structural elements can be technically difficult. To date, there is no robust automated approach to translate the data obtained from 3D scans directly into a model for FE analysis. This paper provides an overview on current applications of 3D scanning, and a case study that addresses the issue of processing three-dimensional point clouds that are generated from 3D scans of steel links. Another objective of this paper is to present a simple and practical procedure to convert point clouds into solid models that can be further used in FE analysis. Five distinct 3D scanning technologies were selected for the measurement of replaceable steel links to generate solid models based on the measured geometry. For the specific application addressed in this paper, the blue laser scanner with measuring arm has shown the most satisfactory results in terms of efficiency.

When an RC (reinforced concrete) structure is prone to a very high temperature, the structure severely deteriorates; the reasons for this are: a) the degradation in the products of the cement hydration, b) the production of vapor’s pressure, and c) the incompatible change in the volumes of the components of concrete when the temperature is higher than 500 °C. Nevertheless, the structures damaged severely by excessive heat can be greatly able to re-have their original performance and qualities back if they are strengthened in shear with laminated CFRP (a short form for carbon fiber-reinforcement polymers) composites. However, the efficiency of this method is menaced because of two setbacks: 1) delamination, and 2) anchorage. This method aimed to examine its efficacy in reinforcing-in-flexural concrete beams, whether mainly or additionally, prior to and post being exposed to very high temperatures. In this paper, the study parameters were: 1) the CFRP sheet’s length of CFRP; and 2) the exposed temperature. Also, the researchers took into consideration to monitor: the structure’s behavior, the ultimate capacity of loading, the correspondent-to-loading deflections, toughness, and elastic stiffness. This research paper found that using internally installed sheets of CFRP for flexural strengthening proved to be highly efficient in damaged-by-heat RC beams.

Floating offshore wind turbines (FOWTs) demonstrate very promising potential in unlocking the plentiful wind resource in deep-water oceans. Meanwhile, the combination of the harsh marine environment and strong dynamics complicate the long-term deterioration of FOWT-supporting towers, specifically the escalating corrosion fatigue (C-F) coupled deterioration in critical connections. Unlike traditional engineering structures, an interoperable control is available in FOWTs, such as the pitching, yawing and torque controllers, which can mitigate structural oscillation and loads. With the recent advances in smart sensing, a better prognosis of current and future deterioration can be guaranteed with increasingly accessible data. Thus, a refined adaptive control strategy is hence deemed essential based on the site-specific data, to curb the operation and maintenance (O&M) costs of FOWT towers based on the structural condition. The present work elaborates on the influence of various adaptive controlling strategies of FOWTs on the C-F deterioration of supporting towers, lending itself to preliminary references for balanced trade-offs between power generation and structural reliability. Multi-physics simulations of FOWTs are initially carried out to establish fatigue stress spectra from site-specific wind-wave distribution, using various types of control strategies. Structural reliability assessment is then conducted by incorporating the spectra into a time-variant C-F deterioration model in which the ambient corrosivity is accounted for. The result suggests a compelling C-F deterioration faced by FOWT towers due to strong wind-wave loads, high corrosivity and improved structural flexibility. More critically, the finding underscores the apparent influence of controlling strategies on the C-F deterioration of FOWT structures, especially under certain regimes of wind velocities. In addition, preliminary but innovative perspectives are elucidated on the delicate balance and conflict between generation efficiency and structural reliability.

This paper presents the development of a benchmark vertical farm that could potentially enable the sustainable development of urban and rural areas. The investigation seeks to tackle global issues linked to sustainability development goals such as zero hunger, affordable clean energy, industry innovation and infrastructure, amongst others. Vertical farms enable plant-friendly environments in urban skyscrapers through agricultural techniques, often identified as consuming large amounts of energy. These facilities could be fully embedded into urban planning as clean energy sources such as solar and wind are fully utilised. This paper scrutinises the potential for wind energy utilisation in a vertical farm with different planting corridor widths. The study also seeks to clarify the potential for energy harvesting by identifying suitable micro wind turbines installed in the façade and roof. The vertical farm prototype is elliptical and has a total height of 108 m, 80 m width, and 60 m chord. This paper studied the prototype with corridor widths of 3 m, 4 m, 5 m, and 6 m, respectively. The maximum inlet wind speed was defined as 20 m/s, and the atmospheric boundary layer condition was applied to simulate an urban wind environment and observe the aerodynamics of the farm. The results showed that the benchmark building with a corridor of 5m-width has the best potential for wind energy harvesting, particularly when the wind turbines are located on the roof.

This study consists of a sensitivity analysis of photovoltaic/thermal (PV/T) collectors, liquid thermal storage, and battery systems applied for the offices of a school building near Montreal, Canada to enhance building performance and resiliency to power outages during winter operation. The analysis was applied for 3 days in January with mixed solar conditions by varying the sizing of each of the components to achieve at least 8 h of self-sufficiency, the average length of power outages. It was found the optimal sizing for the studied system, while minimizing component costs, is to dimensions PV/T collectors to meet the base heating load, while maximizing thermal storage, and diminishing battery capacity to meet the base heat pump electricity consumption. For the case study, the optimal configuration was 27 PV/T, a 908 L thermal storage tank, and 10 kWh of battery capacity, to consistently achieve over 8 h of self-sufficiency in mixed sunny and cloudy winter conditions.

Universities are among the largest public sectors and energy consumers in many countries worldwide. They are considered crucial places to learn about opportunities to adopt sustainable and renewable energy to meet global greenhouse gas emission targets and incentivize economic growth. In this study, different energy efficiency strategies on university campuses were analyzed to investigate the level of engagement in practical actions at universities and the reduction of the environmental impacts of this sector. The results show that energy actions on university campuses are fewer and focused on plans for renewing energy systems and reducing energy consumption in buildings. Only a small portion of universities’ energy consumption comes from renewable sources. There is a need for more empirical studies on the description of actions and their impacts on the sustainability of campuses, in addition to the need to better understand and study the connections between energy use and energy efficiency in university campuses. An integrated approach to different energy strategies, in parallel with the knowledge of available technologies and the commitment of university stakeholders, in partnership with government support and energy concessionaires, is essential to improve energy performance and reduce the energy footprint of the universities.

In this study, a hybrid energy system was implemented to fulfill the electricity requirements of the trams operating in Kayseri province. The tram's annual electricity consumption data was acquired on a monthly basis from the local electricity company in Kayseri. Utilizing the obtained data, energy and cost simulations were conducted employing the Homer-Pro program. The primary objective of this investigation is to enhance sustainability while satisfying electricity demands with minimal carbon emissions. Consequently, the established hybrid energy system incorporates renewable energy sources, specifically wind, solar, and biomass energy, with the inclusion of batteries for energy storage. Furthermore, generators and converters are integrated for energy conversion purposes. The study encompasses a detailed cost analysis to identify the most economically efficient hybrid energy system, determined through optimization studies. Through this research, it is anticipated that the implementation of such a system will significantly diminish carbon emissions in Kayseri, contributing to a substantial increase in sustainability.

The paper evaluates the disassembly capability and reuse potential of steel-timber shear connections. Experiments involving double shear configurations with coach screws of three diameters are detailed. Monotonic tests were first performed for each configuration to evaluate the stiffness, strength, and ductility. Counterparts were then tested under ten loading-unloading cycles, to 40% of the capacity obtained from the monotonic tests, to evaluate stiffness degradation characteristics, screw deformations, and cross-laminated timber (CLT) panel damage. After disassembly and measurements, the specimens were reassembled and tested up to failure. The measurements indicated that the secant stiffness enhances after the first loading cycle and is then largely constant to the tenth cycle. After disassembly, the screws had permanent deformations, and the timber panels indicated limited damage during the cyclic loading. The reassembled specimens had similar stiffness, strength, ductility, and failure modes as the monotonic test specimens. Based on test measurements, both the steel profile and the CLT panels have full structural reusability. The test results can be used as a measure for quantification of the structural reuse potential through an index that can be incorporated into established building circularity indicators.

The technique known as glued-in rods (GiR) presents an appealing option for effectively connecting structural timber members. The utilization of fibre reinforced polymer (FRP) rods offers additional advantages, such as reduced weight, improved corrosion resistance and lower thermal conductivity. Studies examining the behaviour of GiR connections with Basalt FRP (BFRP) rods are limited, and there is currently a lack of guidance for their fabrication and design. This paper presents an experimental study on the performance of glulam timber beams bonded with glued-in BFRP rods. Epoxy adhesive was used to glue the BFRP rods into the cross-sections of glulam, forming the connections. The experimental programme includes four types of connections, investigating two configurations for the glued-in rods (Designs D1 and D2) and two rod diameters (8 mm and 10 mm). Testing was conducted with four replicates for each connection type, resulting in a total of 16 tests. To assess the moment capacity of connections, a four-point bending set-up with a 2300 mm span, was applied. The response in terms of load-displacement response was monitored and the failure mechanisms were assessed. The predominant observed failure mode was bar pull-out and tensile splitting of timber. D1 connections with 10 mm bars demonstrated superior performance in both moment capacity and maximum displacement at failure.

This paper presents experimental investigations into the feasibility of disassembling and reusing exterior lightweight infill walls. The work stems as necessary steps towards the advancement of circular economy principles in future constructions. The experiment employed the single-shear test method commonly used to assess the shear strength of steel connections. The test samples consisted of cold-formed steel plates attached to hot-rolled steel plates, connected by screws. The cold-formed steel plate represents the track, a component of exterior lightweight infill walls, while the hot-rolled steel plate represents the beams of the primary structural frame. In total, twenty-one specimens were made: nine were tested after screwing, nine were tested after unscrewing and re-screwing, and three were tested after unscrewing, re-screwing, unscrewing, and re-screwing. The unscrewing step demonstrates the disassembly of the infill walls, while the re-screwing demonstrates their reuse. The experimental results revealed that the average peak strengths of the samples with different connections exhibited negligible differences. This can be attributed to the interaction between the screws and the connected cold-formed steel and hot-rolled steel plates, a mechanism further discussed in this paper. The test outcomes imply that exterior lightweight infill walls can be disassembled from the primary structural frame’s beams after the infill walls’ service life, and subsequently reused in the construction of other exterior lightweight infill walls. The study also demonstrated that more specimens should be tested to confirm the observation.

Spatial systems like shells, arches and shelters can often be used as temporary structures to accommodate short to medium expositions, events, or emergencies. This has historically allowed them to be designed for multiple uses. Recent advancements in computer graphics, algorithmic design, and advanced manufacturing have accelerated their development and opened new scope for applications, by exploiting new capabilities and opportunities for material-efficient designs and constructions. The authors aim to develop combined systems approaches to the design of resilient, de-constructible constructions for the built environment. This work presents the recent advancements in the development of discrete shell systems developed at the AS_Lab between the Politecnico di Milan and the University of Leeds, using biogenic materials such as wood which are inherently sustainable. Coupling geometry design and segmentation with ad-hoc connection systems, demountable systems have been developed, which are materially efficient, digitally designed, and fabricated, and can, in some instances, be robotically assembled. The study presents the conceptual design and fabrication of three prototypes, which have been realized to accelerate the transition to industry 4.0 while posing the focus on a circular future.

Improving the thermal properties of materials used in buildings is crucial to reducing energy demand and consumption. This study investigated the use of textile fiber waste in cement-based composites for construction applications. Mechanical and thermal characterizations were carried out to assess the behavior of cement mortars with different percentages of two types of textile fibers after 7 and 28 days of water hardening. The results show that the incorporation of fibers can significantly improve the thermal insulation capacity of buildings by reducing the thermal conductivity of cement mortar by up to 52%. In addition, the use of textile fibers can improve the mechanical strength of the cement mortar, especially with a high fiber content and a longer curing time.

Urban system transformation in view of sustainability is fundamental for efficient adaptation and mitigation of challenges faced by cities. Sustainable urban transitions, under the umbrella of circular economy, are key to effectively addressing future challenging scenarios and their impacts. The adoption of nature-based solutions (NBS) for circular resource management can provide beneficial ecosystem services to the urban built environment while promoting the conservation and reuse of resources within the urban cycle. The Circular City framework outlined the use of NBS to tackle challenges related to urban circularity. One such challenge is ‘Building system recovery’, which involves the regeneration of the built environment. By implementing NBS, the lifespan of building systems, construction materials, buildings, as well as open spaces can be extended. This is achieved by reducing exposure to weathering from external agents, thereby reducing the rate of infrastructure renovations, retrofitting and replacements. Moreover, strategies that prioritize resource savings, greener environments, and water-sensitive systems can increase resilience by providing critical ecosystem functions such as stormwater management, greywater treatment and mitigation of the urban heat island effect. Building upon the Circular City framework, this contribution presents NBS units and interventions at different urban scales – materials, components, systems – aiming at addressing the circularity challenge of ‘Building system recovery’. This is followed by a comprehensive analysis of input and output resource streams for strengthening circularity solutions in cities. This contribution describes state-of-the-art circularity frameworks aiming at supporting decision-makers and practitioners, while providing guidance tools for involving all relevant stakeholders, thereby supporting multifunctional implementation of NBS for inclusive and resilient circular cities.

Increasing urbanization trends led to growing concerns regarding human health risks linked to long-time exposure to poor indoor air quality. Volatile Organic Compounds (VOCs), e.g., formaldehyde and benzene, are the most significant pollutants in indoor environments due to the high number of sources contributing to increase their concentration. Vertical Greening Systems (VGSs) have been proven as space-efficient nature-based solutions (NBS) using the ability of ornamental plants in removing VOCs. Growing media and rhizosphere community often play a pivotal role in removing indoor VOCs, especially in active biofilters. Although horticultural substrates are often overlooked in VGSs’ applications, an increasing number of studies focus on: (i) investigating sustainable opportunities provided by organic materials to produce alternative growing media; and, (ii) exploring compositions of substrates to maximize VGSs phytoremediation efficiency. This work presents preliminary results on the influence of almond shells as an alternative growing medium for VGSs on the removal efficiency of formaldehyde. For that, a VGS module with almond shells as substrate and a single species of ornamental plant was placed in a sealed chamber – specially designed to recirculate the air contaminated by formaldehyde through the module acting as an active biofilter. The system produced a clear reduction of the formaldehyde concentration, and the plants developed correctly with the substrate. Green building-integrated systems are multifunctional NBS which address challenges such as human wellbeing and circularity at local scale. Using organic growing media to improve the biofiltration capability of these systems is a promising alternative towards successful implementation in the built environment.

The concept of the circular economy has rapidly gained traction as a transformative approach to sustainable resource management. Central to this paradigm is the emphasis on recycling and repurposing waste materials to ensure their maximum re-utility and minimal environmental side-impact. Over the myriad of waste materials, end-of-life (ELT) tires have emerged as a particularly significant resource, which has been underestimated in the past. However, the advent of advanced recycling technologies has illuminated the latent value embedded within these tires. From their rubber granules and steel components to fibrous materials and carbon black, each element holds potential for repurposing. Notably, the construction industry has been identified as a prime sector for the integration of these recycled materials, offering both durability and sustainability in building processes. Guided by the principles of the circular economy, this paper embarks on a comprehensive journey through the full lifecycle analysis of ELT tires. It delves into the intricacies of the recycling and utilization processes, shedding light on the myriad of potential value they present. Furthermore, a meticulous assessment and review are conducted on the contribution of these recycled tire by-products to the construction industry. The study revealed that recycling tires can result in a reduction in carbon emissions and provide substantial economic benefits. Specifically, for truck tires, the economic benefits can amount to 32.37 €, and the GHG emissions produced during the recycling process are minimal, only 1.13 kg of CO2 equivalent for truck tires.

By integrating living organisms and their intelligent capabilities at the heart of the design process, design evolves towards a creation in harmony with the surrounding nature. Therefore, the designer is led to reconsider the way they design sustainable solutions, capable not only of integrating but also of acting as living entities within their ecosystem. This approach promotes continuous interaction with the environment, fostering mutual enrichment where design and nature mutually enhance each other. Designers have the ability to reintegrate nature into the creation of materials and collaborate with natural resources. This reintegration fosters mutual positive impacts between natural and human systems. Such interactions lead designers to envision proactive scenarios for future habitats, merging scientific knowledge to co-evolve with nature. The design thus becomes a catalyst for transforming the design paradigm towards interconnectedness harmonious with the environment. In this context, it involves co-creation with living organisms from a perspective of bio-integrity rather than anthropocentrism, contributing to the regeneration of natural systems, restoration of human health, and preservation of biodiversity. While this approach presents a forward-thinking perspective, our empirical study seeks to demonstrate its potential implications in our daily lives and the real world. We have attempted to explore various methods and tests to incorporate the microorganism Ulva algae into the process of developing a living construction material, with the aim of promoting a locally regenerative approach.

In Circular Economy Management, various stakeholders play different roles that contribute to the value chain within the circular economy. These stakeholders need to be tracked and motivated to contribute to a circular economy. In addition, real estate developers as well as facility managers have a growing interest in both, the expansion of the value chain within the building as well as associated with facility services within the optimized building operation. The research approach is drawing upon real estate development projects as case studies. It maps the different stakeholders and analyses their role in the value creation. A range of new value creation stakeholders were identified and analysed to which extend their role is defined in traditional business models. The key benefits for owners and real estate investors comes from the adaptability to changing market demands, re-use and repurpose, low impact on urban ecology and biodiversity, innovative new real estate products among others. This study shows the benefits of encouraging stakeholders to actively participate in the co-creation and co-innovation of circular solutions. This involves identifying different stakeholders in the design and development of strategies, policies, and projects related to the circular economy. By defining their new role, diverse business models, as well as innovative and effective solutions can be developed.

This study examines the importance and adoption of circular economy (CE) principles within the construction industry by focusing on stakeholders’ opinions on key CE strategies across different building life cycle stages. The study draws insights from the perceptions of European-based stakeholders who actively participated in the CircularB Workshop 1 Part 2, entitled Creating a Roadmap towards Circularity in the Built Environment - State-of-the-Art. The research comprises two parts. In the first part, a structured survey was employed to systematically collect opinions on the levels of awareness and variations among the adoption and importance of selected CE implementation strategies within the construction sector. The second part engaged stakeholders in a dynamic creative thinking activity, posing seven targeted questions allowing participants to offer multiple answers for each query. Overall, the study sheds light on the multifaceted challenges and opportunities inherent in fostering CE within the construction domain by highlighting the significance of recognising and addressing systemic barriers within the CE framework, the importance of product design for disassembly, and the efficient production of reusable and recyclable materials. Furthermore, it emphasises the necessity to motivate industry stakeholders to participate actively in the transition to a CE, bridging the gap between theory and practice frameworks and increasing the engagement of policymakers and governments.

Building Information Modelling (BIM) is a digitalisation tool that is widely adopted in construction industry. It is a three-dimensional digital replica of asset(s) such as buildings, which contain architectural information and building details (e.g. dimensions, materials, parts, and components). It has evolved from 2D CAD models (or blueprints) in the past to 3D CAD models embedded with information layers (e.g., construction time sequence or 4D-BIM), resulting in automation in construction. BIM has now been essential in various countries; for example, new UK BIM standards require asset owners to keep and maintain building information. BIM adopts an interoperable concept that can benefit the whole life-cycle assessment (LCA) and circularity of the built environments. Its applications extend to six dimensions (6D) where time sequence, cost and carbon footprint can now be reported in real time. These attributes are essential to stakeholders and critically help reduce any unexpected consumption and waste over the life cycle of a project. This study builds on the development of 6D BIM of an existing building to enrich circular value chains and stakeholder engagement. This paper highlights the development of 6D BIM, and, subsequently, the stakeholder interviews to address challenges, barriers, benefits, and effectiveness of 6D-BIM applications for stakeholder engagements across circular value chains. Snowballing sampling method has been used to identify stakeholder interviews to obtain new insights into the digital valorisation for stakeholder engagement. The outcome of this study will exhibit new insights and practical paradigms for BIM applications in built environments.

Urban Resilience refers to the ability of a city to absorb, adapt and transform in the face of a disturbance. Such a concept is increasing in importance as the continuous growth of cities leads them to face new uncertainties, challenges and often significant disruptions. Most extant literature focuses on the development of frameworks and indices that measure urban resilience. However, due to the inherent complexity of the concept as well as to the variety of research perspectives, the existence of several frameworks is quite confusing. Also, such frameworks fail to reveal how different urban factors affect resilience and the way it acts on the urban scale. The study aims to contribute to address such limits by investigating the main urban characteristics affecting resilience. Using a Resource-based view (RBV) perspective, the research develops a theoretical framework which links resources of urban systems (economic, social and environmental), urban abilities (leadership and governance, preparedness, cooperation and infrastructures and resources), and resilience capacities (absorptive, adaptive and transformative). The theoretical framework is then empirically tested through an online survey sent to a sample of urban stakeholders, namely, policy makers, emergency services, public organizations, academics, experts, infrastructure employees, public and private associations and organizations. The empirical analysis provides scholars with knowledge on the main factors that affect resilience and enables policy makers to better understand the way urban resilience arises based on the interrelationship between urban resources and capabilities.

Circular economy principles remain relatively new tendencies in Albanian economy sectors, with some attempts throughout recent years, and until now, little research has been done in this aspect, especially in the construction sector. As the construction sector is connected with other sectors of the economy, its development or slowdown affects the indicators of other sectors. Moreover, this sector possesses numerous challenges, as special attention is needed on the impact that the momentum of construction and the expansion of the real estate market can have on the stability of the financial sector. Integrating the circular economy into the construction sector means understanding the role of stakeholders, their interactions, and the influences they can exert on the process itself, by adding value in each step of this chain process. By categorizing different groups of stakeholders and analyzing their activity regarding the circular economy approach in the construction sector in Albania, this paper presents a clear overview of what has been done until now, the consequences and benefits of these attempts, and also what can be improved in the future. The stakeholders’ theoretical analysis has shown that the relation between different stakeholders presents difficulties in cooperation, although these groups aim towards mutual objectives and goals. In this context, Albanian economy presents difficulties, as this approach is widely influenced not only by political decisions, but also by cultural and financial matters, making it more challenging to make progress.

The efficient assessment of circularity in buildings requires a comprehensive consideration of diverse elements such as material selection, design principles, construction methods, operational effectiveness, and end-of-life management. However, the absence of a consistent methodology poses a significant challenge in circularity assessment, as extant evaluation techniques either offer a broad perspective on circularity or concentrate on specific components. The lack of clarity in the variations and ranges of circularity indicators further hampers the ability to thoroughly evaluate a building’s performance, leading to a preference for a qualitative approach. This study aims to overcome the challenges associated with the development of circularity assessment indices by proposing a generic framework for index generation, providing guidance to tool developers and decision-makers in understanding the rationale behind circularity indices within the building environment literature. To achieve this goal, the study conducts a literature review elucidating common methods employed in developing circularity indicators and indices as well as the aggregation methods encompassing both qualitative and quantitative indicators, emphasizing how their weights are determined and utilized in the aggregation process. This critical review offers insights into current practices, identifies challenges, and fosters a deeper understanding of the inherent complexities in circularity assessment. Ultimately, this study contributes to the advancement of methodologies for evaluating and enhancing circularity in building, addressing a vital aspect of sustainable construction practices.

The built environment is responsible for around 50% of the total extraction of raw materials and 25% of all waste in the European Union, which comprises numerous materials that still have the potential for reuse and recycling. Due to the planet’s finite reserves, transitioning towards a circular approach in the built environment to achieve sustainability, particularly at the building design stage, is inevitable. At this level, the role of indicators as the primary measurement tools is essential to assess the circularity in the built environment and guide the implementation of circular economy (CE) principles into the design and construction of buildings and infrastructure. This study aims to analyse international and European policies and standards and extract and present the remarkable and relevant existing circularity indicators at the building design level. Subsequently, a categorised list of the most employed indicators to measure building design-level circularity is discussed. To achieve this goal, a bibliographic-analytical approach is used to analyse the prevalence and alignment of several sustainability and circularity criteria in international policies and standards at the building design level. Finally, the indicators are classified into seven categories: Material and Resources, Energy resources, Water resources, Waste Management, Environment, social and economic indicators. In conclusion, suggestions for further research that have the potential to facilitate the design processes of engineers, architects, and stakeholders are presented. The outcomes of this research can significantly contribute to creating a more circular and, consequently, sustainable built environment.

The transition towards a Circular Economy (CE) stands as a pivotal strategy in reshaping our prevailing consumption patterns towards more sustainable resource management. Within this context, the European Union places a strong emphasis on elevating recycling and renovation rates while reducing dependence on primary resources, with a particular focus on the construction industry. Material and Building Passports have emerged as potential tools to facilitate this transition. They play a multifaceted role in CE, serving to raise awareness of the building’s performance, functioning as digital repositories of extensive data, and acting as consulting instruments for stakeholders involved in renovation actions, energy management, and building operation. However, a universally accepted definition of these tools remains elusive, and diverse interpretations persist. To contribute to a deeper understanding of these tools, this study embarks on a comprehensive review, tracing their evolutionary journey and delving into the potentialities and synergies they offer in fostering circularity throughout the life cycle of buildings. It also examines the barriers hindering their full-scale development and adoption, including the lack of standardization and legislative measures, financial constraints, issues of stakeholder involvement and responsibility, as well as challenges associated with data accessibility.

The concept of circular economy (CE) nowadays garners considerable attention as strategy for resource management and waste reduction. The principles of circular economy have emerged as a promising framework for minimizing environmental impacts while maximizing resource efficiency across the entire life cycle of a building. To effectively assess and monitor the progress towards circularity in buildings, the development and implementation of appropriate key performance indicators (KPIs) are crucial. This paper provides a comprehensive overview of circular economy KPIs in the building sector, aiming at supporting industry professionals, policymakers, and researchers in understanding and implementing effective measurement and evaluation frameworks. The study identified several indicators related to circular buildings and categorized them based on building types and layers. The study findings indicate lack of robustness to comprehensively evaluate the circularity and socio-economic impacts of circular practices that highlight the need for more comprehensive and universally accepted KPIs. Such indicators could guide stakeholders, enabling them to assess progress towards circularity, identify areas for improvement, inform their decisions, and actively promote the transition towards more circular building practices.

The study aims to propose the integration of Axiomatic Design (AD) and Design Structure Matrix (DSM) methods to support the implementation of building reversibility within circular building design (CBD). In CBD, strategies for building reversibility have been formulated, but available tools mainly support design evaluation in the late stages. On the other side, in engineering design, methods to support reversibility in early design stages are available. AD and DSM are two matrix-based product modelling methods that are used in the analysis and modelling of relations in complex systems from the concept design. AD guides the designers in modelling the relationships between functional elements and physical components in a structured manner from the early design stages. DSM provides a method for modelling physical relationships among the physical components and groups them into modules. Despite the potential benefits of using these matrix-based design methods, previous studies on building reversibility within CBD have not yet explored this proposition. The study intends to place the theoretical premises for the application of AD combined with DSM within CBD for building reversibility. The study applies theory-oriented research by exploring, collecting, and evaluating relevant information from different theoretical and practical sources to formulate propositions on building reversibility within CBD. Propositions will be tested in future real-world applications while detecting challenges and limitations to assess effectiveness in supporting building reversibility within CBD.

Our research focuses on the reutilization of construction materials and how we could foster growth in this sector. It deals with the specific case of the re-use sector around Strasbourg, France, providing a comprehensive overview of the local landscape. Indeed, the research was conducted in partnership with the School of Architecture of Strasbourg, the City of Strasbourg, and an engineering consultant called “BOMA” specialized in circular building. This project is supported by the “Campus des Métiers et des Qualifications Eco-construction et Efficacité Energétique Grand Est”, the Grand Est Region, the “Région Académique Grand Est” and the “Banque des Territoires”. To encourage innovative programs around circular economy, we gave particular attention to analysing feedbacks from pilot projects. In addition to the interview with key local stakeholders, a literature review focusing on assessment of circularity in buildings was carried out. Through a methodology developed in a separate scientific paper, we selected 10 key indicators adapted to the area to measure the circularity of a building, focusing mostly on social, environmental, and economical aspects of the project. Thanks to these indicators, a digital tool was developed to calculate the relevant data concerning the circularity of the project, creating analysed feedback of the construction. Five of those indicators have been implemented in this tool, although suggestions have been made to cover more topics. Moreover, in the future, there is the possibility for it to be transformed into a decision-making tool in order to boost the structuration of the re-use sector around Strasbourg.

One of the major motivations behind the effort for the transition from linear models to circular ones in the building sector is related to the need for the minimization of resources depletion. Water holds a prominent position among those resources. The building sector is responsible for appreciable water consumption and, hence, represents an important field for improvements. While in the case of new buildings several options are available for the relevant systems and strategies, when existing buildings are considered, the limitations are multiplied in the context of decisions already made and materialized. However, the existing building stock is a massive contributor to the total impact of the built environment and must be considered as well. In this work, three buildings’ environmental performance assessment methods (BREEAM, DGNB, LEED) and, specifically, their versions for existing buildings in use (residential and non-residential), are examined regarding the way water-related parameters are implemented in the evaluation that they perform. The factors reviewed are those associated with water regarded as a resource (water consumption, (re-)use of rainwater, management issues etc.) and not the ones referring to flood risks and to energy demand (hot water). The analysis’ main focus lies in the criteria used by each method, the main strategies highlighted as advantageous, and issues related to the integration of those evaluation axes into each system. Initially, main features of the three methods are presented (assessment structure, scoring process, etc.). Among others, differences and similarities in the adopted approaches (three evaluation methods, various building uses) are highlighted and discussed.

Various models of Circular Economy (CE) principles have been developed in various sectors. This paper tries to give an overview of the main existing models found in literature. It explains the origins and evaluates the purpose by classifying the underlying definitions. It then compares the different models, explains the limitations and concludes with resulting principles for real estate applications. It takes a closer look at existing circular economy principles and which circular economy principles can be applied for space and infrastructure. The research approach is based on an extensive literature review of existing CE models and underlying principles in the built environment. A stepwise analysis is applied to each model. A collection of CE models is presented that helps to complete our understanding of the opportunities and limitations of CE strategies. This study analyses the existing CE models in a comprehensive manner. By comparing the different origins is manages to explain the opportunities and limitations of the different models. Providing the knowledge results in a better understanding of current CE strategies is a valuable addition to our current understanding of CE business models in real estate management.

Cities face the challenge of addressing urban vacancies due to market volatility, rapid shifts in needs, demand, user preferences, or issues related to financing, planning, or delays in building approvals common in cities like Zürich. The study delves into a transformative shift in the Swiss real estate market, emphasizing the integration of circular economy principles, impact investments, and digitalization. The research approach is mainly descriptive, drawing upon case studies of temporary use urban projects. It incorporates a review coupled with the application of design thinking in the development of a digitalization model. In Zürich, the temporary use of vacant buildings is predominantly as office space showing a limited multi-scalar impact. In contrast, in vacant sites, Nature-based Solutions interventions demonstrated high multi-scalar impacts, enhancing biodiversity, air quality, and resident well-being, and aligning with circular economy principles. Meanwhile, various flexible uses of vacant sites indicated moderate impact, promoting innovation and new business models. A digitalization model is proposed to re-purpose these sites in circular rather than linear economy. The research underscores the importance of temporary, flexible uses on vacant site as platforms for testing new multi-scalar impact investment ideas and establishing the financial profitability of nature-based solutions in urban contexts. The study highlights the potential of temporary urban land use to promote swift urban transformations, balancing financial returns with ecological impacts for advancing circular economy.

The urban circular economy is a highly effective approach to both waste management and the utilization of resources. Many cities have already adopted best practices based on circular economy principles. However, implementing such practices requires multi-stakeholder engagement, new business models, and collaboration between cities. Some successful strategies exist, ranging from urban agriculture and waste-to-energy to sharing economies, industrial symbiosis, and sustainable mobility, as well as eco-design, waste prevention, and the extension of product life. By adopting circular economy practices, cities can support economic growth, reduce environmental impact, and create social benefits, thereby moving towards a more sustainable future. In this regard, this study aims to analyze circular economy practices at the urban circularity level, by assessing their impacts on economic growth, environmental sustainability, and social benefits. To achieve this goal, a literature review is conducted to identify the most widely adopted circular strategies in cities. Comprehensive data collection, encompassing quantitative and qualitative measures, including economic indicators, environmental metrics, social assessments, and stakeholder feedback on the implementation process. Then the case study of Amsterdam is selected to demonstrate how urban circularity can be effective in achieving a balance between economic growth, environmental sustainability, and social benefits. Finally, this study also provides insights into the potential of urban circularity as an effective tool for sustainable urban development.

The circular economy has emerged as a powerful solution to address environmental and socio-economic challenges in urban areas. As cities continue to grow and face increasing resource demands, adopting sustainable practices becomes critical to promote resource efficiency and improve the well-being of urban communities. This study aims to assess the effectiveness and feasibility of circular economy strategies at the urban scale, focusing on urban design and resource management. By examining successful case studies from four cities, valuable insights will gained into implementing circular economy practices in urban planning, such as waste management, renewable energy, and sustainable architecture. The comparative analysis of these cases will allow an assessment of the different approaches taken by each city and their impact on the sustainability and resilience of urban environments. This study aims to inspire and guide future urban development and promote sustainability and resilience in European cities by highlighting successful examples of circular economy implementation. Ultimately, this study aims to provide a comprehensive understanding of the role of circular economy principles in urban environments, highlighting their potential to promote sustainability and resilience. Through four study cases, this study will illustrate The tangible outcomes and real-world implications of adopting circular economy practices in urban landscapes.

The concept of circular economy has become an important topic nowadays. This paper provides a brief literature review that introduces sustainability and the circular economy by presenting their origins and their conceptual definitions. In accordance with the above-mentioned, the standards applied in Serbia are enumerated. In April 2020, the Roadmap for Circular Economy in Serbia, the first document that initiated a dialogue between decisionmakers, industry representatives, academia and civil society in order to define the goals, future steps and a time frame for the transition from a traditional linear model to the circular economy, was adopted. In November 2020, Serbia accepted the conditions of the European Union for linking the European Green Deal with the strategic development of the region by signing the Green Agenda for the Western Balkans. Furthermore, Serbia has a Digital Platform for the Circular Economy that provides support to companies through business models, examples of good practice and tools, in order to more easily apply the circular business model, and reduce the carbon footprint in production processes and products. Although the implementation of the circular economy is at the very beginning, there are already several examples of good practice in Serbia, in terms of sustainable building materials.

To better understand the full impact of building materials and buildings over their lifetime and beyond, Lifecycle Assessment (LCA) studies have been an area of interest and a growing body of knowledge. Moreover, recent studies emphasize the critical importance of the end-of-life (EoL) scenario, particularly for wood-based construction, and highlight its potential for further decarbonization through circular strategies. However, there is a significant knowledge gap in the LCA literature regarding mitigation strategies specific to affordable housing options, despite the urgent and undeniable need for these typologies worldwide. This study contributes to filling this gap by conducting a materials-level, whole-building LCA of a prototype affordable single-family house built in 2020 using a business-as-usual wood-frame construction method. Besides the conventional as-built scenario, this study developed five hypothetical scenarios that evaluated the influence of different EoL options (recycling or energy recovery), enhanced circular strategies (reduce and reuse), and substitution of non-renewable materials with circular materials for insulation (wood fiber) and finishing (clay plaster), with the aim of identifying further opportunities and limitations for decarbonizing such a typology and construction method. The results of this study consistently indicated that the order of priority should be to (1) ensure appropriate end-of-life for metals and wood-based materials. (2) Replace non-renewable materials with renewable wood or earth-based materials. (3) Improve material reuse and construction waste diversion rates. The results of the study could support decision-making processes for the design and construction of low-impact affordable single-family homes and the development and implementation of affordable housing policies and regulations.

The sustainable built environment concept has recently gained enormous attention from academic and industrial organizations. The growth in climate-related disasters and pandemics, continuing difficulties in the energy sector, and consumer awareness regarding resources’ conservation and sustainability are considered the driving factors influencing participants toward supporting sustainable engineering applications. Furthermore, numerous professional standards and requirements for implementing and rating sustainable practices have been generated, such as life cycle assessment (LCA), cost analysis, project development (i.e., from planning through construction up to demolition), recycling, material preservation, and utilizing reusable materials. The LCA is a great method for examining and integrating a wide variety of environmental elements to provide a comprehensive picture of system sustainability. The research presented in this study covered significant environmental elements that are essential to deciding between two or more choices and improving the system. This research compared the OPC and AABC based on CO2 emissions. The results showed that the AABC produces positive sustainability outcomes in terms of CO2 emissions. The AABC emits substantially less CO2 than the OPC, indicating that it is preferable for greenhouse buildings.

Significant changes in the strategic goals of the construction sector at the global level have been visible in recent years. By implementing the fundamental principles of sustainable development and circular economy, the modern construction industry tries to contribute to a healthier environment by reducing CO2 emissions, minimizing waste landfills, and preserving non-renewable natural resources. The possibilities of reusing prefabricated concrete elements of existing buildings instead of their traditional recycling on a material level or disposing of them in landfills are analyzed in this paper. Special attention in the research was placed on the carbonation of prefabricated reinforced concrete elements of buildings, as it is one of the most frequent processes that accelerate the deterioration of RC structures. Long-term carbonation processes inevitably result in reinforcement corrosion and accompanying damage to the concrete cover, therefore some constrains for the further use of prefabricated RC building elements must be precisely defined. In this study, the potential use of prefab RC building elements was determined by calculating the depth of carbonation while taking into account the age of buildings and environmental conditions (relative air humidity, position of prefab element). Depending on the thickness of the carbonized concrete and the type and intensity of damage to the reinforcement and concrete, various variants for further use of the dismantled prefabricated RC building elements were proposed (reuse without restrictions, use in the interior of new buildings, use in less demanding facilities, reuse after application of a protective coating, replacement of the protective cover and reuse etc.).

Global environmental awareness pushes the building sector to achieve carbon neutrality and find low embodied impact solutions. The European Union has set a 2050 goal and is regulating the whole carbon life cycle (embodied and operational) as part of the Energy Performance of Buildings Directive (EPBD). In this scope, low-tech geo-bio-based materials can have an important role in reducing the embodied environmental impacts and carbon in buildings. Due to their low processing production, these materials fit in a circular approach since they can be easily recycled or returned to the natural environment at a minimal environmental cost. However, the lack of quantitative data on the life cycle environmental performance of some non-conventional techniques can hinder their use since professionals cannot compare the benefits of such versus conventional practice and comply with future EPBD requirements. This paper aims to contribute to the topic by presenting results on the life cycle environmental performance of earthen materials and bio-based insulation products versus conventional solutions based on data from Environmental Product Declarations or studies following the EN15804 standard. The results show that earthen materials can reduce the potential environmental impacts by about 50% versus conventional mansory walls. At the same time, bio-based insulation solutions offer the advantage of lowering operational carbon emissions and stocking carbon (e.g. straw has a Global Warming Potential performance about three times better than Expanded Polystyrene). The benefits of using earthen and bio-based materials are also discussed for the different building life-cycle stages, focusing on the possibility of reusing/recycling these materials in a closed-loop approach.

The consistent growth of the construction sector during the last decades has generated massive waste that severely impacts the environment. Globally, construction activities generate around 30% of the overall waste annually, and the numbers are expected to increase due to population growth projections and the need for infrastructure developments. As a matter of fact, the causes of waste can be grouped into seven categories namely, design-related, procurement-related, human-related, handling and storage, site conditions, management-related, and due to other external factors, such as the effect of weather and accidents. In addition, construction waste types are influenced by project type, size, and construction method. To mitigate the impacts of construction waste, a plethora of practices have been recommended, including innovations for procurement, design, and construction. The present study scrutinises potential opportunities for minimising construction waste and proposes future sustainability enhancement related to construction activities. A pivotal contribution of this study is the creation of a matrix that links the identified causes of construction waste with sustainability practices, offering a comprehensive insight for effectively reducing waste and enhancing the sustainability of construction activities.

In an effort to mitigate climate change, the construction industry is moving toward a more responsible approach regarding production and design methods. The environmental impact of a structure must be reduced from the design phase by using reliable design approaches and choosing the production and construction processes that minimise as much as possible the carbon footprint. The purlins are components of the roof structure and their scope is to transfer the roof loads to the rafters. An efficient design of purlins is generally achieved by using cold-formed steel Z-shaped profiles. Z purlins span continuously over the rafters to reduce material use through a more favourable bending moment distribution. To ensure continuity of the bending moment along the length of the structure, the purlins form overlapped connections on the supports. The focus of this research paper is to assess through the Life Cycle Assessment methodology how the design influences the environmental impact of overlapped purlins. The paper assesses the impact of higher-grade steels versus more traditionally used steel grades. Furthermore, the adoption of steel manufactured using a high content of scrap steel and energy obtained from renewable sources facilitate the reduction of the carbon footprint of the element. Using advanced finite element models, previously validated against experimental results, the purlin systems were designed to support both gravity and pressure loads.

Global concerns about environmental sustainability have escalated in the last three decades, forcing industries to critically examine their practices and their contribution to the overall ecological footprint. The construction sector has become a significant contributor to environmental deterioration due to its extensive energy consumption, raw material extraction, and waste generation. One of the ways to reduce the environmental impact of the construction sector is to decrease the embodied carbon footprint of buildings using the three R approaches – reduce, reuse, recycle and by using renewable construction materials. The paper focusses on the evaluation of the behaviour of steel-intensive façade systems from an environmental impact perspective. The research presented in the paper shows a comparative Life-Cycle Assessment (LCA) of industrial buildings that have envelopes consisting of liner tray cladding systems and sandwich panel cladding systems. The results of this comparison show that when different envelope solutions are considered, the highest potential benefits (8–25% higher) occur for structures that have liner tray cladding systems and the highest loads (11–19% higher) appear for structures that have sandwich panel cladding systems. Moreover, the potential for repeated reuse in the case of claddings based on steel liner trays is superior to the potential for repeated reuse of sandwich panels, helping to reduce the environmental impact of the cladding system even after its second life cycle.

The lightweight structures play a crucial role in mitigating the environmental impact of buildings throughout their lifespan. There is an interest in exploring various agricultural by-products as effective aggregates for filling framed timber structures. Natural fibers, such as hemp shives, are gaining attention for their environmental benefits, including biodegradability, renewability, recyclability, composability, and their potential to reduce greenhouse gas emissions. By harnessing these natural fibers, it is possible to reduce emissions associated with the most popular wall structures. Moreover, this approach reduces agricultural waste and facilitates integration into a circular economy model. This study delves into the effects of bio-composites created from hemp shives, combined with starch, gypsum, and a geopolymer binder, in fabricating lightweight timber structures. These lightweight structures are compared among themselves and conventionally used wall structures, assuming one square meter of wall with a specific U-value as the comparative unit. Results from a life cycle assessment revealed that these innovative lightweight timber wall structures yield CO2 emissions ranging from −13.94 to 82.89 kg of CO2 equivalent per square meter. In contrast, compared to traditional brick wall constructions, these structures offer substantial savings, potentially reducing emissions by up to 149.38 kg of CO2 equivalent per square meter. This research underscores the promising environmental advantages of utilizing natural fiber-based bio-composites in constructing lightweight timber structures, emphasizing their potential to reduce carbon footprints in building construction significantly.

Wind energy is one of the most widely distributed renewable energy sources. Generally, wind turbines have an expected lifetime of 20–25 years after which decommissioning is expected. Life cycle assessments show that optimal recycling at the end of life is of economic and environmental interest and is in line with the principles of a circular economy. Despite these benefits, current recycling processes cannot guarantee high-end material quality, but the reuse of parts of wind turbines as construction elements in buildings and infrastructures has been demonstrated to be a suitable option. This study presents an overview of wind power installations in Europe, emphasizing the typology of farms, onshore and offshore, and trends of the wind industry that promote an increase in the size and power of wind turbines. The study aims to make it clear how the different types of materials used in wind turbines, such as steel, iron, aluminium, copper, polymers, glass and carbon fibres, change according to the development of the technology. Moreover, examples of reusing wind turbine components in cities and buildings are collected and illustrated to provide a panorama of the potential for the reuse of these components in the concept of a circular economy in the construction sector.

There is a vast building stock of existing buildings and the exchange rate is low (up to 0.2% per year). Therefore, there is a very strong need to deal with the existing building stock in respect to circularity. The effect of (new) regulations and standards on this volume for refurbishment and recycling of building materials is therefore crucial to meet the targets of CO2 reduction by increasing aspects of circularity overall to support environmental sustainability. The influence of standards towards the harmonization of technical requirements for refurbishment of existing buildings is therefore essential for wider implementation and acceptance in the market. There is, however, a gap identified between existing relevant standardization efforts and research in the field of refurbishment in the context of circularity. The effect of newly released standards and regulation will be analysed and identified barriers are discussed such as the generation and dissemination process of these standards.

European Member States are required to promote initiatives and programs to shift their traditional linear economy into circular economy. The paper shows the Italian initiatives towards circular economy in the built environment, across different application level (national and local) and different drivers (top-down and bottom-up). The method of investigation regards an on-field research based on direct dialogue with various stakeholders of construction sector in the national context. The results show the current barriers to circular material flows and the successful initiatives in Italy. Firstly, the top-down strategies are reported, as well as existing standards, national regulations and local policy. Secondly, the bottom-up strategies are shown, stressing the local stakeholders involvement. Based on the discussion, potential improvements are highlighted to align the current Italian initiatives with the broader European Commission circular economy objectives, considering also the best practices developed in other European countries.

The Waste Framework Directive (WFD) proposes a Waste Hierarchy (WH), a list of waste management strategies ordered from the most to the least preferable and often illustrated as an inverted pyramid. Waste prevention is at the top of this pyramid, followed by preparing for reuse, recycling, and then other recovery activities such as waste to energy. At the bottom of this hierarchy, the waste management strategy to be avoided is waste disposal at landfills.Although this hierarchy establishes a logical framework for waste management policies, case-by-case assessment shows many exceptions to the rules implicit in this structure. Indeed, depending on the materials and constructive solutions, the order proposed by the WFD can be modified by considering a detailed LCA. On the other hand, when performed on an element level, the results of LCA may not be viable to inform policymakers on the best course of action towards a more sustainable built environment. This paper proposes a multi-level approach – at a material, element and building level – combining the waste hierarchy with the 9R framework. Assessments of building refurbishment at the building or element level can yield vastly different results, which may be relevant when addressing questions posed by each type of stakeholder according to their scope of action.

One of the main issues with applying Circular Economy (CE) principles to the construction sector sits at the End-of-Life (EoL) of buildings. How to recover the materials and then how to reintroduce them into the economy are fundamental problems that lack immediate solutions. The status quo in the EoL of buildings has always been demolition followed by deposition at a landfill (linear economy), thus, to change this approach, there is the need to replace demolition with deconstruction. This causes new problems, as buildings vary greatly, there is a need for pre-demolition audits, that can report on the recoverable materials, potential generated waste and plan the deconstruction intervention. Here, new problems arise, such as the lack of methodologies to intervene or skilled labour that makes deconstruction possible. However, at that point, even when materials are recovered there is the problem of how to reintroduce those materials back into the market. Here, digital platforms can bridge that gap, making it possible for the recovered materials to be posted in a marketplace where the designers of new buildings (or building renovations) can access the circular materials available to introduce into their designs. Thus, this paper aims to present a possible solution to the problem of introducing CE into the built environment, proposing pre-demolition audits, digital platforms, and labour upskilling as enablers for a greener future.

The simultaneous evolution of the construction sector towards the circular economy and digitalization is widely recognized and endorsed by both policy initiatives and academic discourse. In this dynamic landscape, research efforts are focused on creating automated tools and models to facilitate the implementation and monitoring of circularity in buildings, thereby enhancing efficiency and effectiveness of decision-making processes. Building Information Modelling (BIM) stands out for its acknowledged capabilities in data storage and process automation, making it a compelling platform for achieving these objectives. This paper aims to establish a conceptual framework that addresses the challenge of developing BIM-supported tools and models for promoting circularity in buildings. The primary goal of the proposed framework is to assist tool developers and professionals in the construction sector, providing them with a systematic approach to integrate circularity aspects into BIM for efficient and automated assessment processes. To achieve this, the study critically analyzes five existing BIM-based circularity tools and models from previous studies, elucidating the key stages and providing detailed steps for their development. The paper concludes by emphasizing the main barriers hindering the development and automation of circularity tools within the BIM framework. This comprehensive exploration contributes to the ongoing discourse on sustainable construction practices, offering valuable insights for practitioners, researchers, and policymakers striving to advance the integration of circular and digital principles in the construction industry.

There is a growing emphasis in current global construction sector for the incorporating of sustainability ideas into design and construction practices. This present paper investigates the considerable impact of using Building Information Modelling (BIM) techniques to address sustainability and financial concerns in a residential project in the Kingdom of Saudi Arabia (KSA). We propose to further embedding BIM 3D modelling and the development of alternative design scenarios for optimising Life Cycle Cost (LCC) and Life Cycle Assessment (LCA). Four scenarios are assessed using Green Building Studio (GBS) for whole-building analysis, and specific design units are assessed using One Click LCA, which is integrated into Revit. The significance of the study relies on merging of BIM and LCC to improve the sustainability of residential developments at the KSA. It also intends to optimise resource efficiency, reduce environmental impact, and increase cost-effectiveness throughout the whole life cycle of residential structures by using simulation approaches. The findings will benefit industry stakeholders by encouraging sustainable practises that inform decision-making processes in the context of Saudi residential development.

Humanity in our days is fighting with climate change effects and the depletion of natural resources. In this direction, the adoption of sustainable and circular practices is considered vital and in most cases is prescribed by regulations. The construction sector is responsible for massive amounts of energy consumed during the extraction of raw materials, the production of building materials, the construction phase, the operating phase of the buildings, and also during their demolition and end-of-life. The latter one already gathers the scientific community’s interest with the efforts being focused on efficient Construction and Demolition Waste (CDW) management solutions. Meanwhile, Building Information Modelling (BIM), as a storage medium of information about all building components, offers various advantages on a building’s optimum design and operation, allowing information exchange among all involved stakeholders. Although many studies demonstrate the effectiveness of BIMs in reducing construction waste for new buildings, there is not extensive research on how BIMs can contribute to CDW reduction for an existing building. In this review study, the existing studies addressing BIM integration on CDW management are analyzed, pointing out the advantages that this strategy offers on reducing CDW and managing them efficiently, increasing reuse and recycle rates, and promoting circularity. The main challenges this approach presents, mainly attributed to the difficulty of gathering the required information with the appropriate accuracy about an existing building, are extensively discussed, along with future research needs, necessary for a further enhancement of this technique.

The construction industry is one of the most resource-intensive industries and one of the largest contributors to greenhouse gas emissions and waste production. Building information modelling (BIM) can help architects and engineers design more energy-efficient buildings with less waste, contractors build more efficiently with fewer errors, and facility managers operate buildings more sustainably while reducing maintenance costs. In addition to the well-established benefits of using BIM in construction projects, adopting an openBIM workflow can further streamline the permitting process, making it more efficient and transparent. Digital building permits (DBPs) are intended to further improve process efficiency by digitalizing and automating conformity and code compliance checking processes of obtaining building permits. Further, by integrating sustainability concepts, DBPs have the potential to revolutionize city planning and urban development by enabling more sustainable construction practices and reducing the environmental impact. This study explores the relationship between BIM and DBP in the context of sustainability presenting the current ongoing activities and implementation challenges and proposes a series of solutions.

The construction industry is undergoing a significant transformation driven by digitalization and an unwavering commitment to implementing circular economy (CE) principles and sustainability into its core practices. Emerging digital technologies (DTs), such as Material Passports (MPs), Building Information Modelling (BIM) Artificial Intelligence (AI) and Scanning technologies, Blockchain technology (BCT), the Internet of Things (IoT) stand out as pivotal tools capable of expediting the transition towards CE implementation in buildings. This study highlights the significant potential of six DTs to support CE application throughout the building lifecycle. Furthermore, it delves into the potential synergies among these diverse DTs, highlighting the additional benefits that collaboration can bring across different lifecycle stages of a building project. Particular emphasis is placed on the integration of MPs with other DTs, showing promise in assessing resource availability, volumes, and flows. This integration optimizes waste reduction and recycling plans, contributing to more precise selective and smart deconstruction planning. The combined use of DTs offers substantial benefits to stakeholders, enabling them to make informed decisions regarding maintenance and understand the current quality of specific materials. Through these means, the study aims to provide a comprehensive overview of the array of DTs propelling circular building practices. It also explores emerging trends in this dynamic field, scrutinizing the effectiveness of adopting these technologies throughout the building life cycle stages, and anticipating potential challenges these technologies may face.

The characteristics of supply chains in the construction industry give rise to several information and collaboration system needs, such as system affordability and adaptability. The presence of several companies from a variety of industries in supply chains for the construction industry sets them apart. Information sharing and system integration therefore require cooperation and trust. In the manufacturing industry, a lot of efforts are being made to create tools, technologies, and strategies that would allow supply chain actors to communicate with one another and work together. However, it is more challenging to establish a solid environment for inventory and data management in the construction industry. The Internet and information technology are now being used in the construction industry to strengthen cross-organizational relationships. The employment of these tools in this industry is occasionally hampered by limitations like security worries, a lack of managerial commitment, high costs, and deployment rigidity. Additionally, a dynamic configuration of supply chains is required to integrate with more adaptable business models, increase internationalization, and enhance coordination. For this reason, this study primarily explores the inventory and supply chain tools currently in use in the construction industry and evaluates their functionality from a business and consumer perspective. Other areas of study are based on either inventory management for circular buildings or cross-organizational cooperation, and they include secure data storage, information exchange among stakeholders, and their modification. In the end, it aims to emphasize the key problems with data and inventory management in the construction industry, as well as inform about the potential technology solutions to make a guidance of academic and industry specialists within this study.