Proceedings of the 4th International Conference on Sustainability in Civil Engineering

The development of modern society heavily relies on existing infrastructures. In particular, transport infrastructures are crucial to moving people and goods around the world, thus materializing globalization. In recent years, awareness has been raised on the necessity to maintain the existing infrastructures and aspects such as sustainability are nowadays the top priorities of infrastructures’ stakeholders. Accordingly, the future infrastructures will be those already existing and properly maintained rather than new ones to be built to replace them. The success of this huge compromise on maintaining existing infrastructure depends on the development of more accurate, efficient, cost-effective and sustainable tools and technologies to support all the lifecycle management. The present work provides an overview of some relevant efforts that are being conducted worldwide in this regard, highlighting the current trends of technological development, identifying some existing opportunities, and anticipating some of the most relevant tools that will be used in the near future to support transport infrastructures’ management.

In a horizontal ground-source heat pump system, thermal properties of the material backfilling the ground heat exchanger are the key factor that affects the performance of the system. The aim of this study is to evaluate the feasibility of steel-making slag-based controlled low-strength materials (CLSM) as a heat transfer medium for horizontal ground-source heat pump systems. Firstly, the engineering properties of CLSM mixtures were evaluated with different steel-making slag contents and steel-making slag types. Secondly, the effects of the GWT level drop on the thermal–hydraulic properties of different backfill materials and the performance of the system was investigated using a numerical analysis model of COMSOL Multiphysics based on measured water retention characteristics. The in-door thermal response test was conducted to validate the numerical analysis model and access the heat exchange rate of spiral-coil GHE backfilled with CLSM and natural sand. Finally, to access and compare the beneficial use of the CLSM over the typical soil, an economic analysis of 50 case studies for the horizontal GHE was performed. The results indicate that the suggested steel-making slag-based CLSM satisfied all requirements of common backfill material. Furthermore, using ground steel-making slag to replace the sand in the CLSM mixture can enhance the thermal conductivity up to 2.35 W/(mK), which is double that of the conventional grout (bentonite). Another advantage of CLSM is a high air-entry value, which can limit the influence of the GWT drop. Finally, as expected, the GHE backfilled with the CLSM shows a better economic performance compared to that of the GHE backfilled with an ordinary soil owing to its high heat transfer performance.

Corrosion of steel rebar’s in reinforced concrete (RC) structures, known as main cause reducing their service life, could be significantly accelerated in maritime regions where environmental chlorine ions (Cl−) content is very high. The crucial phrase of corrosion phenomenon, initial corrosion phrase concerning the penetration of Cl− through concrete cover, depends deeply on the surface chlorine ions content (Cs). The Cs data should be gathered from in-situ structures. For this motivation, in this paper, experimental investigation on Cs is performed. The surface chlorine ions (Cs) content of RC structure is obtained by extrapolating experimental data gathered from in-situ RC samples in the tide zones of sea island regions of Khanh Hoa (Viet Nam). Then, using these estimated Cs at different ages, it is possible to establish empiric evolution of surface chlorine ions content versus the concrete age. Unlikely to constant value of Cs versus concrete age as practical routine, results of this paper show non-negligible time-dependence of Cs. And, based on experimental results in this paper, prediction of service life of constructions is performed by durability method. It is concluded that service life estimated by durability method is 4 times smaller than design working life of studied structures.

In Vietnam, the amount of generated construction waste is rapidly increasing along with economic and social development. According to a report from the World Bank, the amount of treated construction waste was 1.8 million tons in 2018, but the amount of untreated construction waste was considerably larger. If the construction waste is not recycled, it will become a huge environmental problem. According to the World Bank, the Vietnamese government envisions a construction waste recycle rate of 60% by 2025, most of which will be used as leveling material, roadbed material and non-fired brick. To improve the recycle rate of construction waste, a measurement for disseminating the use of low-quality recycled aggregate (recycled aggregate class L) in concrete is necessary. In this study, by mixing low-quality recycled and normal aggregates in a suitable replacement ratio, a relative quality index method was used for evaluating the concrete’s performance. Accordingly, a mix proportion of concrete using low-quality recycled aggregate can be designed that satisfies Vietnam’s required performance.

Incorporating recycled asphalt mixture with reclaimed asphalt pavement (RAP) is becoming popular because of its economic and environmental benefits. However, using high RAP contents is often prone to cracking. To address the problem, recycling agents (rejuvenators) are often used to reduce the hardness of the mixture and, therefore, improve the cracking resistance. In this paper, two types of petroleum-based rejuvenators (aromatic extracts—A rejuvenator) and vegetable-based (V rejuvenator) are used at different contents (0%, 4%, 8%, and 12% by the weight of recycled bitumen). IDEAL-CT test (ASTM D8225) is used to evaluate the impact of these rejuvenators on the cracking resistance of asphalt mixtures. Laboratory test results indicated that the use of the rejuvenators improves the cracking resistance of asphalt mixtures, in which using petroleum-based rejuvenator is more effective against cracking than vegetable-based rejuvenator.

The solution of using organic and inorganic chemical agents to strengthen soil for base, subbase or surface layers in road pavement has been applied for a long time in the world. In Vietnam, the method has been initially researched, but still very limited in practical application. Chemical waste from the paper industry has been studied and used around the world as a soil stabilizer in construction. The paper presents the research results from the use of lignosulfonate, which is derived from the waste of paper production process, collected from the paper factory located in Ky Son District, Hoa Binh Province, as the soil stabilizer, namely DBS-06, to strengthen the soil used as base, subbase or surface layers in road pavement. The research also proved that the DBS-06 agent is not only a good achievement on technical or economic sides, but also a fruitful outcome for environmental problem treatment in the paper industry.

Chloride ions penetration in reinforced concrete (RC) structures causes serious problems linked to steel rebar corrosion, especially in maritime regions in Vietnam where environmental chloride ions content is much higher than standard value regarding corrosion problems. In this study, experimental investigation to determine durability capacity of HPC, regarding chlorine ion penetration, is performed in different conditions of chloride ion content in environmental water: laboratory condition, Ha Long Bay and Khanh Hoa region. Different doses of silica fume additive (5%, 10% and 15% replacing cement in concrete) are consequently examined on three HPC grades (C50, C60 and C70). Service life or durability capacity by mean of rapid chloride ions permeability measures, according to ASTM C1202 standard, at 365 days are analyzed. Experimental results show that 15% of silica fume additive replacing cement is the best dose to reduce chloride ions penetration for all studied maritime regions in Vietnam. Among three grades of HPC, C70 is more suitable in high environmental chlorine ions content regions and capable to stand against chlorine ions penetration much more than C50 and C60 HPC.

Recycled concrete aggregates (RCA) is one of the most prevalent construction waste products what is regularly used in the road construction industry. Besides many advantages, substances leaching from RCA are emphasised as the most involving the environmental problem. The research investigated metals leaching characteristics from RCA by carrying out a detailed experimental method with many influential factors to grasp the most influencing factors on the metal leaching regime. Research outcomes disclosed that the integrated influences of factors are changed to RCA, while individual metals released are also influenced following to varied ways. Liquid-to-solid ratios (L/S) significantly affect leaching metals from RCA controlling saturated conditions, facilitating high metal concentrations in the leachate. Interestingly, the larger degree of compaction leading to increasing density of materials displayed the highest negative influence on metal leachability, suggesting that the metal release can considerably decrease, especially when the RCA is used for the sub-base road layers with a high degree of compaction. However, the use of recycled construction materials under field conditions should be further studied as there is an increasing concern of metal leaching from RCA with respect to recreational and drinking water thresholds.

This study investigated the impact of dog-boned and crimped shape memory alloy (SMA) fibers on the volumetric strain and moduli of concrete. The SMA fibers were produced via cold drawing and shaping through crimping or heating. Cyclic compression tests were conducted on plain and 1.0–1.5% fiber content concrete under heating and non-heating conditions. Results showed that adding SMA fibers decreases volumetric strain and increases ductility of concrete. However, heating led to an increase in volumetric strain due to recovery stress. The presence of SMA fibers also increased secant and tangent moduli, with dog-boned fibers proving more effective than crimped fibers. The recovery stress caused a factor of 2 and 1.6 increase in secant and tangent moduli, respectively, enhancing the stiffness of the SMA fiber-reinforced concrete. The study provides valuable insights into the potential use of SMA fibers in improving the ductility and stiffness of reinforced concrete structures.

The controlling function plays a vital role in successfully managing public construction works. Several studies have focused on the area of construction project management, but the results have rarely emphasized investigating controlling behaviors, which are critical factor for measuring management effectiveness within public construction works. To fulfill this research objective, a regression research design was performed based on data from questionnaires answered by professionals involved in public construction works in Vietnam. The structural equation modeling (SEM) technique with partial least-squares estimation (PLS) was applied to analyze the data. The results confirmed six behavioral dimensions (i.e., legal monitoring (CT1), plan monitoring (CT2), evaluating (CT3), corrective action (CT4), inspection implementation (CT5), and punishing action (CT6)) to asses controlling function. The behaviors related to legal monitoring (CT1) and corrective action (CT4) were revealed to have significant impacts on management performance (ME). In addition, corrective action (CT4) was found to mediate between evaluating (CT3) and plan monitoring (CT2); while punishing action (CT6) was noted as the mediator of inspection implementation (CT5).

The culture within project organizations has been acknowledged as a determinant of successful organizations. Previous works in this domain has emphasized the development of organizational culture models.However, little attention has been paid to determining the relationships between culture and cost performance within construction project organizations. This study aimed to address this gap. Project organizational culture artifacts were employed in a developed model and validated using a data survey conducted on 199 completed construction projects. Through a principal component factor analysis and the structural equation model (SEM) technique, the cultural behaviors were organized into a framework of four-factor culture dimensions. The findings reveal that commitment orientation and shared understanding contribute to improved cost performance. In addition, commitment orientation plays the role of mediator of the potential effects of the leadership orientation and supportive orientation culture on cost performance. The findings of this study reinforce the cultural effects and provide a useful project management tool that can contribute to the successful management of construction project organizations.

In recent years, air transport passenger (pax) demand through Noi Bai International Airport (NBIA) has increased rapidly, requiring us to have a plan to supplement, upgrade and expand NBIA accordingly. Recently, the several airport experts have proposed to build the second airport in Hanoi area which is different from the accepted airport planning in 2019 by ADP Ingénierie Company (ADPi). Our forecasting using logarithmic function with parameters in form of time functions for regression method to predict the pax demand for Hanoi then propose the options to upgrade NBIA and build the second airport in Hanoi area.

Road construction projects require a large amount of resources, labor, and equipment, which has significant negative effects on sustainability, such as carbon emissions, resource depletion, and forced labor. This paper aims to conduct a review of current policies and regulations concerning the sustainability of road construction projects. According to the results, policies are primarily aimed at achieving economic and environmental objectives, while social issues are barely considered. Accordingly, a systematic strategy is developed to assess the sustainability performance of road construction projects in Vietnam. The strategy sets a foundation for comparing systematically projects toward sustainable development. Additionally, supporting activities, such as improving stakeholder understanding, enforcing mandatory requirements, and ensuring consistency of laws, are proposed to adopt the proposed strategy.

The role of the private sector in the successful implementation of PPPs projects is critical; however, little effort has been made to explore the constraints of implementing PPPs. The purpose of this study is first to explore the current situation of PPPs in Vietnam and then to investigate the point of view and assessment of the private sector on the constraints of PPPs implementation. Methods included semi-structured interviews and content analysis of the findings of the semi-structured interviews carried out with PPPs practitioners of senior management level. The complete picture of current PPPs implementation practice in infrastructure in Vietnam was then obtained. The findings include three main categories: “legal and regulatory issues”, “institutional and capacity issues”, and “financial issues”. These results offer a better understanding of current PPP practice projects in Vietnam and are expected to help the public sector and lawmakers to develop strategies and improve the efficiency of the process of applying PPP in Vietnam.

LiDAR technology has been a few developments in recent years, but they are applied to the recently released Matrice M300 which can use many different types of cameras. In this study, the authors conducted a survey to assess the accuracy of Lidar UAV technology on Matrice 300 flying devices with Lidar camera L1 in different terrain projects. From there, make comments on the accuracy of this technology and its applicability in topographic surveying in Vietnam.

Highway overtopping due to floods is one of the critical causes of road damage in Central Vietnam because of the potential for rapid soil erosion and mass wasting resulting in partial or complete failure of the roadway embankment. This paper focuses on feature analysis of the hydraulic characteristics of water flowing over an embankment providing a basis for understanding the erosion process. The effectiveness and application conditions of several modern methods to protect road embankments from overtopping flow are also presented.

Cable stayed bridges are often chosen because of its long span and esthetics. However, this type of structure requires high level of corrosion protection of stay cable and components. Improved continuously since the mid-1970s, Freyssinet stay cable technology is the world reference in terms of fatigue resistance, protection against corrosion, ease of inspection and replaceability. High strength galvanized strand is selected to use along with active adjustable anchorage at girder level and saddle at tower to allow each strand goes through saddle and keep their protective HDPE sheath. Fatigue test of stay cable system is carried out as projects reference. Strand can resist 300 MPa stress amplitude at 45% of ultimate strength for 2 million cycles. Thank to high friction between strand and saddle that made by UHPC, unbalanced force between two sides of bridge will be assured not only during construction but also in service stage. This type of stay cable and friction saddle allow to minimize work of maintenance in time of service. The pylon is also more compact because of no space require for cable anchorage inside. Internal Hydraulic Dampers (IHD) is also used to limit vibration of stay cable due to traffic and wind and rain effect. To get accurate require tensile force in stay cable, iso-tension technology is used by special equipment. This is the first cable stayed bridge with friction saddle in Vietnam.

Vietnam is in the top five countries most vulnerable to climate change. Vietnam is ranked fourth among countries worldwide with the highest number of people exposed to flood risk. Floods often cause damage to the transportation infrastructure in Vietnam. The assessment of flood risk in road networks should be considered as the problem of multi-index evaluation. Vulnerability analysis of roads that are exposed to flood is an important part of risk assessment and management. Thus, index weight evaluation is the critical issue when quantifying flood vulnerability. In the present paper, the causes and major factors influencing the road flooding in the Red River Delta were investigated. Both subjective and objective weights are studied. In addition, the methodology for determining the weighting factors will be presented in detail.

Despite the numerous studies on local scour at piers conducted, very few of them applied pier local scour formulas based on field data, but mainly on the laboratory experimental data. Consequently, the scour depth is often biased larger than the actual one. This paper proposes a formula (UTCwp20-University of Transport and Communications for wide pier 2020) for piers 3 m wider (b or D) and field data set or live-bed scour from 68 publications in the USA, China and Russia, and recorded the best results compared to eight published formulas using the same data set.

The corrugated steel webs are used to allow without continuous stiffeners for the steel and composite bridges. This structure has many advantages compared to steel girder with flat web. A corrugated web steel bridge, corrugated steel webs increase the stability of the girder web, increase the torsional stiffness and reduce the weight of the steel girder. It is many beneficial qualities, such as lower dead-load, increased shear buckling strength and so on. In this article, the advantages and applicability of corrugated steel ribs are presented. The comparison between the behaviors of flat steel I-girder and corrugated web steel I-girder is performed to clearly see the effect of the corrugated webs.

Due to the demand for the construction of a high-speed railway HSR system in Vietnam, a study on the selection of suitable technology is an important task. Currently, two train technologies, i.e., electronic multiple unit (EMU) and push–pull train (PP) are the most feasible options that can be applied in Vietnam. The EMU or PP has its advantages and scope of application. Additionally, the different train technology leads to a difference in related infrastructure, especially bridges, one of the most common structures in HSR lines. Nowadays, the determination of the concordance of bridge span structures considering dynamic effects on HSR routes of trains at the speed over 200 km/h is of interest not only in Vietnam but also in the world. In many recent HSR projects, the applications of box girder bridges become more and more popular. However, one of the major disadvantages of box girders is the large cross-sectional height, which makes the box girder much more expensive in comparison with simple common girders. Hence, this work analyzes the dynamic behavior of several simple girders. Thereafter, the dynamic outcome is compared with that of the box girder bridge with the aim to evaluate the applicability of beams for superstructure railway bridges. Finally, the recommendation of suitable train technology for HSR lines in Vietnam is provided.

An essential element of a pavement management system is a means to monitor pavement surface roughness, distress, and other properties. Most pavement management activities include the use of devices that measure longitudinal profile for assessment of surface roughness. The International Roughness Index (IRI) has become one of the major road roughness indexes that is most commonly used. In Japan, a time-stable and user-friendly compact mobile road profiler (MRP) known as STAMPER II has been developed. This system enables frequent, inexpensive, and regular road surface roughness monitoring. In this paper, some results of the first IRI measurement using STAMPER II in the joint research project between Taisei Rotec Corporation and University of Transport and Communications are introduced. The studies also show the applicability and effectiveness of using mobile road profiler STAMPER II for surface roughness monitoring and pavement management in Vietnam.

Submarine landslide-induced tsunami, which is caused by earthquakes or volcano eruptions, seriously affects humans’ lives and properties. To date, this is a challenging topic for numerical hydrodynamic researchers due to the unpredictable submarine landslide sources. Several researchers assumed the submarine landslide source as the impermeable soil layer and its movement as an elliptic shape. In this paper, the underwater soil surface is porous, water can pass through and then the submarine landslide source becomes a permeable soil layer. The submarine landslide is simulated correctly using the nonlinear shallow water equations (NSWE) and the hybrid finite volume/finite difference (FV/FD) method. To generate tsunami, the time-varying water depths and the porosity inside the submarine landslide are included as the source terms in the two-layer extended Boussinesq equations to generate waves. A high-order FD method is applied to discretize the two-layer Boussinesq equations in time and space. The numerical simulations of submarine landslide-induced tsunami for two-layer case are investigated in a specific porosity. The two-layer and one-layer results are compared and explained by real dynamical phenomena.

The paper considers the configuration of protected port structures and the port gate position as required to ensure the port water area protection from wind waves as well as to provide sufficient water exchange. The object of research is the projected Gelendzhik yacht port located in the Gelendzhik Bay on the north-eastern coast of the Black Sea. Two configurations of protected port structures are compared herein. The wave propagation and water exchange we studied using numerical and physical modeling. The first configuration features the port gates open southeastward. This results in wind waves penetrating the port water area and being capable of forming wave beats which are dangerous for the mooring yachts. The second configuration, a more enclosed one, features the port gates open northeastward. In this case, there is a problem associated with the peculiarities of the wind-wave mode of the area, i.e., the existence of unusually strong offshore winds or “bora”. The paper proposes using SWAN to predict the waves generated by the “bora”. It allows estimating the waves from above. The closeness of the second configuration ensures the protection of the port water area even in “bora” conditions. The port area water exchange differs slightly in the two cases and seems satisfactory. The paper recommends the second configuration based on the results of the presented research.

The sloping revetment and the crest configurations appear to have important effect on wave reflection, especially the presence of crown walls may cause higher reflected wave and might modify the cross-shore current, and eventually affect the sea dike toe scour during storms. In this paper, the degree of wave reflection as well as the distribution of reflected wave are investigated through a series of fix-bed flume model experiments. Based on previous studies, a new spatial autocorrelation function that described the distribution of reflection coefficient in the vicinity of sea-dike structure, has been developed for sloping dike in the north of Vietnam.

Vietnam’s south central coast, from the Quang Ngai province to the Binh Thuan province, is characterized by many asymmetrical inlets with a protruding rocky headland on one side and an elongated sand spit on the other side. The rocky headlands can be located in the North, such as at De Gi inlet and the Tam Quan inlet, or in the South, such as at the My A inlet and the Da Nong inlet. Under certain hydrodynamic conditions, a large-scale flow circulation may emerge at these inlets due to the asymmetrical topography. However, the formation mechanisms and hydrodynamic parameters that drive the evolution of a large-scale flow circulation of asymmetrical sand spit inlet have not been clarified. This paper describes simulated flow patterns at De Gi inlet in the Binh Dinh province under various wave and tide conditions. The findings, based on numerical simulation results, will reveal the mechanism of large-scale flow circulations and their relationship to the physical characteristics of sand spit inlets on Vietnam's South Central Coast.

The mathematical model of two-dimensional vertical flow is commonly constructed using the classic average method by taking the integral from the right to the left riverbank of the three-dimensional Reynolds averaged Navier–Stokes equations. Hence, average quantities obtained from this approach are not generalized in comparison to ones estimated by the dual approach. This paper presents a dual approach to establish the two-dimensional vertical flow equations. The setup model will be more complex than the classic one because the integration can be done locally several times. In this paper, the author performed twice integrals: (i) the first integration is from the right riverbank to the intermediate vertical surface layer between the right bank and the left bank, and then (ii) the second integration is from the right bank to the left bank. The improved two-dimensional vertical flow model received from this dual approach allows the calculation of flow characteristics more accurate than the classical method. In other words, it provides some flexible parameters to adjust based on the field or experimental data.

In the modern life, marine structures such as projects for exploiting inland waterways, navigational channels, and transportation types are developing more and more. The research of materials technology for these projects on channels is not only fast but also requires high precision. As a result, aids to navigation play an important role in maritime safety for all marine routes of Vietnam. One of them is buoys which have been improving significantly not only in Vietnam but also around the world. The purpose of this article is given the new improving aids to navigation in modern life. Instead of using steel buoys, new technology buoys will be used for Vietnam maritime channels with the priority of long age and convenient for authorities. At present, new technology buoys latest replacement of steel buoys to low-maintenance quality PE buoys have been installed at Mekong River Commission–Lao PDR, Cambodia, and Vietnam RWS (Lighthouse Authorities)–The Netherlands Port Of Rotterdam–The Netherlands, Maritime Office–Poland DAB VLOOT–Belgium, Nigerian Inland Waterways Administration and Nigerian Port Authorities–Nigeria Australian Maritime Safety Authority–Australia Arabian Maritime and Navigation Aids Services–Oman. In fact, new technology buoys are polyethylene buoys which are rotational molding by a pre-determined quantity of polyethylene powder pre-compounded of required color. Thus, in process of manufacturing PE buoys, rotational molding is a method for manufacturing hollow plastic products with all dimension and shape.

The vibration impact test method has been studied very interestingly and is applied to check and evaluate the health status of the pile types of a port structure. The data collection technique for building a theoretical dynamic analysis model depends not only on the influence of the boundary conditions of the passing pile foundation and its load but also on the size of the berth by the scale and port structure classification. The paper reviews and analyzes the research influence of this issue. The paper also presents a simple formula to determine the natural design frequency of the segment of the pile-type port structure through the natural frequency of a typical transverse frame in Vietnam. Calculating the natural design frequency of a typical horizontal frame diagram is simple and quick, even if the original design document has no design records. From this, it is possible to determine the design natural vibration frequency of the whole berth segment and predict the frequency range measured if the pile-type port structure usually works.

Submerged coral reefs develop unique topographic profiles over time. Moving landward from the offshore, they are recognized by a very steep slope with a transition at the algal ridge or reef crest to a large, gentle, or concave region attached to the shore. The water depth of the reef flat is relatively small and often exposed during low tides, in the range of a few to tens meters. The mechanism of wave transformation from offshore to the reef crest and reef flat is complicated. The main distinction in the wave propagation in these geometric profiles is caused by a sudden change of reef topography, from hundreds of meters in deep water depth to a few meters of shallow flat shelves. When waves propagate from deep water to reefs with steep foreshore, the mean sea level (MSL) will significantly increase and be associated with the increased wave crest elevation. Predicting the wave propagation, water setup, and wave crest elevation is crucial in analyzing and designing structures on nearby islands, such as determining the scale of wave height effects, overtopping discharge, etc. This paper predicts the water setup and the increase of wave crests above MSL based on a physical model in a wave flume. The remarkable result shows that the water surface elevation above water level can even reach approximately a wave height offshore due to the resonant phenomenon of wave amplitudes at the shoreline…

The importance of vegetation in coastal environments is becoming more widely acknowledged. The intricate structure of roots, stems, and canopies of vegetation allows it to absorb external disturbances such as waves and currents. Even though several physical models have been performed, they mostly address the attenuation of regular waves. The influence of wave parameters on vegetation-induced wave height attenuation is not well explored. At the Delft University of Technology, a laboratory mimicking the processes of wave reduction through cylinders was performed. Various tests were carried out, including regular, irregular, broken, and non-broken waves. Moreover, a model imitating the test was built in a non-hydrostatic wave-flow model SWASH, using experimental data to calibrate and validate. The results suggest that the wave attenuation processes inside vegetation strongly depend on the wave characteristic. The numerical model captured very well the processes of the wave height reduction measured in the physical tests. Thus, the rate of wave attenuation was studied as a function of the number of wavelengths and the Ursell number.

Surf zone is an extremely dynamic region which is important to other wave hydrodynamic processes such as non-linear wave interaction, infra-gravity wave formation, wave set-up and decisive in coastal protection work design. This paper presents study on wave characteristics in the surf zone over fringing reef with steep beach slope under monochromatic wave condition conducted in a wave flume at Thuyloi University. Based on cine-photography analysis breaker type, breaker location, breaker wave height, breaker depth and the total surf zone width is determined and discussed. The results show that the relative reef flat submergence (d/H0 in which d denotes flat depth, H0 denotes incoming regular wave height) strongly influences on the breaking properties, albeit, the influence of beach slope is of minimal for the case of ten-meter flat width and beach slope m = 3.

Managing water resources efficiently, ensuring water quality, and avoiding water resource degradation from adverse effects of climate change and natural disasters are keys to ensuring water security for coastal regions. To propose a comprehensive sustainable approach to address water security challenges, relevant stakeholders need to understand the water-related system, i.e., how and why the system is evolving and how climate change and human interventions may impact that evolution. Therefore, hydraulic engineers, modelers, and managers need expert local knowledge, proof, and some predictive tools. This paper introduces a new framework, summarizes, and describes different mathematical models to simulate, analyze, and understand the changes in the water resources systems, particularly focusing on eco-morphodynamics. The techniques discussed range from analytical, conceptual, and dynamic system models and the Monte Carlo method to detailed 2D and 3D numerical models. The principal types of these techniques and some practical examples illustrating how these models can be applied in the water resources engineering field are discussed.

The channel for large vessel to Hau River was completed in January 2016 for vessels of 10,000 DWT full load and 20,000 DWT half load to Can Tho Port. The large vessels from the East Sea to Can Tho port must go through Duyen Hai harbour, then go into Kenh Tat channel, and then go to Quan Chanh Ba channel to enter the Hau River then to Can Tho port. A new segment channel length of 23.9 km consists of three sub-segments such as Offshore, Kenh Tat, and Quan Chanh Bo channels. Kenh Tat channel is a new dredging channel connecting the navigation channel in Quan Chanh Bo channel to the east sea of Vietnam with length of 7.7 km. Duyen Hai harbour was built in 2016, and the harbour basin was protected by two breakwaters. These infrastructures induced an extremely complicated hydrodynamic regime. In this study, the hydrodynamic features were depicted by the numerical model and the result indicated that the hydrodynamic characteristics in the new segment channel to Quan Chanh Bo and Kenh Tat channels depend on the tide and river flows in Dinh An, Kenh Tat estuaries of Hau River and Cung Hau estuary of Tien River.

The Bona beach, one of the beautiful sandy beaches along the eastern Giens double tombolo, is experiencing with severe coastal erosion which menaces its existence as well as many seaside properties on it. Submerged breakwaters (SBWs) are applied to this beach for the purpose of halting or at least limiting coastal erosion, stabilize the shoreline and to promote beach expansion by the formation of salient. SBWs are designated as the most rational measure for beach protection because of a number of outstanding advantages such as not destroying the landscape, not interfering the seaward vision, not reducing beach amenity and minimizing the negative impacts on the surrounding marine environment. These esthetic features are very necessary to maintain the tourist values of sandy beaches. In this study, the one-line numerical model of LITLINE is used to uncover the impact of SBWs on morphological evolution. The numerical results confirm that SBWs have certain effectiveness in protecting the Bona beach in different wave conditions.

The coastal erosion in the Vietnamese Mekong Delta (VMD) has become a serious problem for many years. Many solutions have been proposed to protect the coasts in many regions. The most popular constructions are pile–rock breakwaters. These structures consist of two rows of centrifugal piles which infilled rock. The wave flume experiments have been applied to build an experimental formula to evaluate wave reduction efficiency of breakwaters. But, there are some limitations of experimental situations, especially in case breakwater width is changed. Therefore, this paper focuses to (1) study the wave reduction ability of pile–rock breakwaters and (2) conduct wave flume experiments which take into account the change of breakwater width to determine the variation of wave spectra in front of and behind breakwaters. Results of experiments show that pile–rock breakwaters performed effectively because the wave transmission coefficients for emerged and submerged breakwaters are both low. Thus, the authors propose an experimental formula to determine the wave transmission coefficient and to be basement to design pile–rock breakwaters in the future.

Among thousands of atolls in the East Sea, some consists of sandy cores emerging from the reef flats. Extreme wind and waves may exert impacts seriously attacking these cores which are usually very small in the area compared to the reef flats. Therefore, the paper explores wave characteristics and how they propagate on the platform of a representative atoll. We conducted experiments in a 50-m-long wave flume at Thuyloi University, Ha Noi, Vietnam. In general, the period of wave spectral Tm−1,0 would be from one to three times longer than the Tp of deep-water waves. Furthermore, an empirical formula was derived to predict Tm−1, 0.

The Mekong River Delta has faced many impacts of climate change, sea level rise, and extreme climate. Besides, the exploitation and use of water resources and sand and gravel lead to serious riverbank and coastal erosion. In recent years, many innovative technologies of coastal protection have been applied to protect coastal erosion. In this paper, based on the results of two field investigations from the coast of Tien Giang province to Ca Mau province, a review of coastal protection also points out some advantages and disadvantages. The results indicated that the applied coastal protection technologies need to be further improved to limit the process of coastal erosion in the Mekong River Delta.

In case of a wellbore drilled in poro-thermo-elastic rock, the process of wellbore drilling will result in thermic, hydraulic and mechanical phenomena which occur simultaneously and interact with each other. This study presents the analysis of the stress state around the wellbore located in the saturated rock at depth based on a fully coupling thermo-hydro-mechanical behavior model of the rock mass by the finite element method. Two scenarios related to thermal condition at well wall are taken into account, i.e., the drilling fluid temperature is inferior or superior to the temperature of the rock mass corresponding to the cases of “cooling” and “heating” the wellbore. The obtained results indicate that the thermic, hydraulic and mechanical phenomena in interaction with each other occurring in the material produce a large change in the stress state around the wellbore through the cases of cooling and heating. Effect of some thermic and hydraulic parameters of the rock mass on the stress state around the wellbore is also highlighted in this work.

In 1972, expanded polystyrene (EPS) geofoam was first utilized as a lightweight fill material for constructing roads in Oslo, Norway. The use of EPS geofoam in civil engineering has been applied widely for over four decades in various countries throughout the world. Especially, the EPS construction method was applied to reduce the deformation of soft ground for the highway embankment. In this study, numerical modeling of the EPS geofoam embankment using the Finite Element Method (FEM) through Plaxis 2D software was carried out. In the analyses, the hardening soil model (HS) was also used to model the grounds and EPS geofoam. Additionally, the interface elements were used to simulate the slippage between the blocks of EPS geofoam with two distinct densities, i.e., 0.2 and 0.35 kN/m3. The analyzed results indicated that EPS geofoam is an effective method to diminish the settlement influence of highway embankments on soft ground.

This study investigates slope protection using vegetation in the area of soil with high disintegration characteristics. The investigated site was a downstream slope (1:2.5) of a dam at the Song Trau lake, Thuan Bac district, Ninh Thuan province. A grass seed mat was employed to cover the slope surface, which could help to activate the development of grass. Eroded soil and the developing height of grass were recorded during watering time with the volume of water, which was calculated from precipitation conditions at the site. In addition, three small-scale flumes (0.5 × 0.5 × 1.5 m) were made to cultivate grass with different slope angles (1:1, 1:1.5, and 1:2.5) using the same grass seed mat. The erosing rainfall intensity was employed at 50 mm/2 h, 80 mm/2 h, 100 mm/2 h, and 150 mm/2 h. Results showed that the eroded soil weight after using the grass seed mat reduced 8 times as much as that before using the mat. The developing rate of grass in the site was the same as in the flumes, which was 1 cm/day in average. Finally, the soil strength was increased after the development of grass. In particular, cohesion and friction angle of soil were increased to 56% and 43%, respectively.

This paper presents a study on mitigating the impacts of rockfall on the Hoang Sa road, a coastal route to Son Tra peninsula, Da Nang city. Son Tra peninsula is very well-known for tourist attraction places. The Hoang Sa road is located in mountainous terrain. Rockfall events had occurred along this highway several times in the past. As a result, it affected the tourism sector and damaged the road infrastructure in Da Nang city. In this study, UAV was used to investigate the rockfall-prone area. According to the field survey, there were many large tectonic fractures and unstable blocks on the rock cliff along the Hoang Sa road. This paper focused on the mechanism of rockfall in a high-risk rockfall area on the Hoang Sa road and determined a suitable barrier location and height using parameters such as run-out distance, bounce height, velocity, and kinetic energy of the falling rock blocks with the RocFall software. The numerical analysis indicated that the appropriate barrier location and height for this area were at 14.5 and 5 m, with a kinetic energy of 590 kJ.

During the TBM construction, volume loss occurs and should be well controlled. This is considered the most critical tunneling factor affecting the movement and ground surface settlement. The empirical method with analytical equations or numerical methods is based essentially on that factor for evaluating the surface settlement trough. This factor, however, depends on different TBM parameters and operation experiences and is sometimes difficult to estimate accurately. Through an assessment of the monitoring data acquired during the construction of metro line 1, Ben Thanh—Suoi Tien of Ho Chi Minh City, this paper proposes an analytical equation for evaluating the volume loss factor based on some basic TBM parameters. A good correlation between the calculation results using this new equation and the in situ monitoring data proves the efficiency of the mathematical model for future prediction in Ho Chi Minh City for example.

The most concerns during the underground metro construction by TBM method is the ground movement and surface settlement which may cause the damages to the surrounded buildings. The maximum surface settlement should then be monitored and controlled by setting the different alarming levels. The prediction of the maximum surface settlement is in the critical important. Analytical or numerical method could be used for the evaluation of the value. In this paper, throughout the acquired monitoring data of the maximum surface settlement during the construction of the Ben Thanh-Suoi Tien, underground metro section of Ho Chi Minh City, an analytical prediction equation was proposed. A very good correlation between the calculation results using this new equation and the site monitoring data proves the efficiency of the mathematical model for future prediction in very similar condition. The influences of different operation parameters are then discussed.

Expanded polystyrene (EPS) geofoam has been applied widely to diminish consolidation settlement of highway embankments on soft ground for over four decades in various countries throughout the world. With the advantage of being a lightweight fill material, whose weight is only 1–2% compared with rock or concrete with the same volume but can withstand relatively large compressive stresses, is molded into standard-sized blocks in the factory. However, the EPS geofoam is quite new and has not been widely used in Vietnam. In this study, an experimental study was conducted to compare an EPS embankment on the soft ground with a soil embankment through full-scale field measurements at Ba Ria-Vung Tau Province, Vietnam. The study results indicated that the settlement of EPS embankment is significantly reduced comparing with that of the soil embankment.

This study introduced a solution to renovate a caisson-type gravity quay wall by grouting and deepening and investigated its dynamic behavior using the geo-centrifuge test. The experiments were conducted for both existing and renovated quay walls. During the tests, the acceleration and caisson displacements were recorded. The results indicated that both models increased acceleration from the base to the surface. However, the increase in the renovated quay wall was lower than that of the existing case. The deformed shape of the caissons was different between the two cases. In the case of renovated quay wall, the caisson slipped horizontally, while in the existing case, it rotated to the seaside. The displacements of the caisson significantly decreased after renovation, implying that damage resistance increased.

Landslide hazards are geological disasters caused by heavy rainfall and debris flow, mainly occurring in mountainous regions. This paper presents remedy solutions for a deep-seated landslide on Road No. 155, section Km 12 + 667.85–Km 12 + 711.57, near a new Mong Sen bridge in Sapa town, Lao Cai province. In October 2020, two deep-seated landslides occurred in this area with some serious cracks. The landslide area was divided into two zones: zones 1 and 2, and up to date, these two zones have still been under reinforcement. While these two zones were reinforced with the retaining structure, soil nails, and grounded anchor system, a landslide (named Zone 3) happened in the area between Zones 1 and 2, where soil erosion and water erosion appeared serious because of heavy rainfall and cutting slopes. In this study, geological investigations, laboratory tests, topographical features, hydrological features, and stability analysis (Geo-Slope/W software) were studied and analyzed to understand the failure mechanism. Then, mitigation solutions such as the retaining wall with the ground anchors, drainage pipe, and soil nails were proposed for the reinforcement. The analysis results showed that the sliding surface of the entire landslide body and the behavior of the new cut slope, with and without reinforcement structures, were based on the numerical analysis by Geo-Slope/W software.

The lowering of the river bed elevation near bridge piers caused by the flow washing away the material flowing downstream is known as local scour. Accurate estimation of maximum local scour depth around piers is essential for the safe and efficient design of bridge foundations. To estimate local scour depths around single piers, prevailing methods rely on empirical formulae developed mostly from laboratory studies. To improve the predictability of the HEC-18 scour model, this paper presents the modified equation for prediction of local scour depth around circular piers in non-cohesive soil condition, developed by using field scale data and nonlinear regression. This modified equation already has a determination coefficient (R2) calculated to be 0.95.

Determining the relationship between rainfall intensity–duration–frequency (IDF) is primarily required for the design and management of any city’s drainage system worldwide. In recent years, Ho Chi Minh City has had to face to climate problems such as growth in the extreme rainfall events which resulted in rising serious floods and inundation. This city’s drainage system and flood defense structures were designed based on outdated input criteria, which may no longer be suitable for recent situation. This paper presents updated information on the rainfall IDF curve for Ho Chi Minh City. Moreover, the reasonable rainfall intensity formula-based IDF curves for frequencies of 2, 5, 10, 50 and 100 years are proposed. The results are able to support the local government in designing or upgrading drainage systems.

Soil is a vital component for supporting life on Earth and is substantially responsible for the operation of any ecological system. Soil erosion is a global problem because it has resulted in the destruction of agricultural land. Raindrops contacting the soil surface may cause soil separation. This process may be identified by assessing the rainfall kinetic energy (KE). Since direct measurements of KE are challenging, statistical formulas are often employed as an alternative option to estimate the KE using rainfall intensity (RI), which significantly influences soil erosion and is very simple to detect. In this study, we collected a rainfall dataset using a laser-based device (OTT Parsivel2 optical disdrometer) between June 2020 and December 2021 in Sangju City (Korea) to analyze the property of KE-RI relationship. A total of 37 rainfall events were selected and used for the formation of KE-RI equations. We derived three KE–RI equations in each group based on the three different rainfall intensity groups. Power-law, linear, and polynomial models were used to link KE to RI, and the best correlation between KE and RI was determined using a power-law form.

Precipitation information with high accuracy plays a crucial role in hydrology and water resources management. With the advance in technology, satellite precipitation products (SPPs) provide an unprecedented opportunity for monitoring the spatial and temporal variation of precipitation from space. However, SPPs still present a low performance with high uncertainty. To overcome this problem, the current study aims to produce a new reanalysis of precipitation data by integrating information from observation data with multiple SPPs over South Korea under the aid of a fast and high-performance machine learning-based, namely a light gradient boosting machine. In addition, other statistical merging methods were also carried out to highlight the robustness of the machine learning-based algorithm. To examine the accuracy of merging precipitation products, observed data from 64 automated synoptic observation system rain gauge stations were collected and compared with merging precipitation products. A high agreement between merging precipitation data generated from the machine learning-based approach with observation was witnessed through several continuous criteria and categorical indicators. The results from this study point out that light gradient boosting machine not only has the capability in merging multi-sources precipitation but also it could provide extraordinary rainfall information for the region of interest, especially in areas with low observed station density.

This paper presents multiple statistical methods consisting of cumulative deviations (Cd), Bayesian (Ba), Worsley’s likelihood ratio (Wo), and von Neumann’s ratio (vN) tests that can be applied to the homogeneity analysis of precipitation series. Vinh Phuc province, an adjacent area of the economic triangle named Ha Noi—Hai Phong—Ha Long in North Vietnam, is used for demonstrating the methods. The series of daily rainfall in the long period between 1/1/1975 and 31/12/2021 at eight meteorological locations in the province are applied. The results depict that the Cd, Ba, and Wo value changes in the permitted range. In detail, the Cd value ranges from 0.23 to 4.34, while the Ba value changes between 0.17 and 2.63, and the vN value varies from 0.16 to 3.51. The Wo showed that almost rainfall series at the studied locations are homogeneity, with the Wo value ranging from 0.13 to 2.66. The series of rainfall at almost locations illustrates homogeneity, and thus, these data can be used for assessing rainfall variability, trend analysis, and for input data in relevant calculations. The Cd, Ba, and vN tests showed similar homogeneity results.

Impacts of enhanced vegetation index (EVI) on the monitoring of surface water from the MODIS imagery are presented for the lowland region of the Mekong River consisting of the Tonle Sap Lake and its tributaries, the Tonle Sap channel, the Mekong River from Kraite to Tan Chau, and the Bassac River. Records of 839 MODIS images and daily water elevation at ten locations in the domain of interest are collected in the period from 2000 to 2019. A wavelet-based filter algorithm is applied for detecting the water surface. Using the relation between observed water elevation and surface water area and extent, a sensitivity analysis of EVI is performed to determine and classify the non-flood, mixture, and flood pixels in MODIS images. The results showed that the EVI affects significantly correlation coefficients. A value of 0.95 is obtained for the magnitude of the correlation coefficient at most studied locations when appropriate values of 0.30 and 0.45 are used for classifying non-flood, mixture, and flood pixels in MODIS images. Spatio-temporal variation of surface water area and extent associated with different flow conditions is also discussed.

Bathymetric data generates nautical charts, seafloor profiles, biological oceanography, etc. Water depth is collected using active sensors like sonar, lidar, or using passive multispectral imagery. Determining the bathymetry for a large area using sonar and LiDAR is very expensive. At the same time, a multispectral satellite can effectively determine the water depth and cost savings, especially for shallow water areas. In the coastal region, the nature of the bottom is very dynamic, and water is primarily turbid, which degrades the accuracy of satellite-derived bathymetry assessment. This study focuses on extracting water depth in Hai Phong’s coastal region (Viet Nam) by applying the ratio transform algorithm on Landsat-8 satellite imagery bands. The result shows a good correlation between the algorithm-derived and the sounding values.

This study presents a method to estimate the trend of natural drought. The trend was evaluated based on the natural drought index from 1981 to 2016. Total of 6 types of Mann-Kendal models and regression models was utilized to explore the trend of natural drought for whole South Korea. The spatial characteristic of natural drought was analyzed with zonal statistical model. Various spatial statistics such as mean, variance, and extreme was investigated to find the spatial change at each zone. In addition, diverging temporal scale monthly, seasonally, and annually trend of drought was analyzed. Results show monthly temporal scale of mean zonal NDI values which is increasing or trend drought decreasing. Because the smaller NDI values, the more severe drought is. The variance zonal drought is increasing. The extreme drought is increasing in 1- and 6-months temporal scales of NDI. In the west season (summer), drought has an increasing trend. For annual temporal scale, drought has an increasing trend in the North-East of South Korea. In short, the integrated approach of regression model and geo-statistical model gives the comprehensive estimate of natural drought at various temporal scales.

The Vietnamese Mekong Delta (VMD) plays an extremely important and central role in the country's food security. The influences of the upstream dam's development, sea-level rise, and complicated tidal regime in the dry season have caused barriers and constraints for local agricultural activities in VMD. Once these causes combined climate change, the salinity intensity is more severe, and intrusion length is likely further in seven Mekong estuaries. The purpose of this study to propose mitigation and adaptation measures for saltwater intrusion (SI) for sustainable agricultural development in the Mekong estuary areas. The relationship between Q ~ S and Q ~ L has been built to predict the S and L along five of seven branches. Also, the boundary between freshwater—brackish—saltwater zone also was proposed for planning the land use and water use. Moreover, the location of salinity monitoring stations, as well as the kinds of saltwater control works, is also discussed to serve the operation of saline control works based on analysis of field measurement data. The study will be very meaningful for local farmers to select crops that are adaptable with the different saltwater values or change land use and cultivation models for higher yields.

Traditionally, the optimization of civil engineering structures is conducted by a deterministic approach based on global safety coefficients recommended by the dimensioning codes, such as the Algerian seismic code and the Eurocodes. These coefficients are applied to take into account the uncertainties related to live loads in order to protect the structures against unpredictable variations in the mechanical performance of the materials. In reality, the use of these safety factors still do not lead to an optimal solution, as they can lead to an over-dimensioning of the structure when it does not lead to a lack of robustness. This approach gives to the dimensioning a reliability without having to perform a reliability analysis. The use of these coefficients aims to introduce a sufficient margin of safety in order to increase the safety of the structure design and to reduce the role of the uncertainties on the performances of the optimized structure. This research aims to evaluate the partial safety factors associated with the internal tensile stress developed in the upper beam of a tank, as well as its resistance. The evaluation of the partial safety factors is presented with a semi-probabilistic calculation. Two random variables were considered, the live load, as well as the compressive strength of concrete, modeled by distribution normal laws. In addition, the target reliability index is taken in a range of performance of the civil engineering structure.

In the present study, the significance of the quality indicators of “Fosuk” type driving masses used for the monolithic construction of the walls of the steel foundry ladles used in steel production was determined by rank correlation method. Six quality indicators of driving masses were studied: linear changes, open porosity, compressive strength, beginning of deformation, 4% deformation and 40% deformation. The three most significant indicators of driving masses “Fosuk” type have been determined. A multi-criteria optimization was performed, using a genetic optimization algorithm, the set of fifty Pareto-optimal solutions (Pareto-front) were found in the two-dimensional space of the control parameters within their range limits. A multi-criteria analysis was done by using fractional-rational generalized functions of usefulness in order to determine the optimal content of clay substances (Al2O3) and the temperature of heat treatment of the inner lining of the steel foundry ladles.

Solutions of precast components and prefabricated construction are increasingly widely used for civil and industrial construction with the advantage of fast-track and material-saving implementation, good quality components which are less damaged by subjective factors and weather. A S-VRO foam core slab is a flat reinforced concrete slab with a hollow foam core in the middle which reduces the weight of the slab, but still maintains the same stiffness beneficial to fast-track and material-saving implementation, long-span structure, heat and sound insulation increase. The combination of the prefabricated S-VRO slab and prefabricated column components opens the new way for Vietnam's construction industry in the future, promisingly brings high quality construction works in extremely short time. This research paper will study advantages and disadvantages of the construction process using precast concrete columns combined with prefabricated S-VRO compared to conventional construction methods.

Textile-reinforced concrete (TRC), which is known as a combination of textiles or fibers embedded in fine-grained concrete and concrete, is a form of reinforced concrete. Recently, TRC is becoming more and more interesting because of many advantages, such as good mechanical properties, durability to external agents and performance at failure. In addition, the TRC applications in structures results in lightweight, high speed of execution, flexibility and durability. Besides, the combination of TRC and high-performance concrete (HPC) can improve significantly the flexural behavior of this composite structure. The cohesive interface between fine-grained concrete and concrete is one of the key factors affecting the flexural behavior of the material. In this study, numerical simulations of three-point bending tests were carried out at different rigidities of the interface to examine the flexural performance. The results show that the flexural behavior of TRC depends strongly on the strength of textile layer. In addition, the contact between two layers of materials should be increased to avoid premature failure such as fiber slip or premature detachment. Furthermore, good bonding enhances the flexural strength, thus enhances the properties of the reinforcing material.

The purpose of this work is to present an innovative method of structural integrity assessment dedicated to steel bridges. According to the European Commission, at least 30% of steel bridges are more than 100 years, and most of them were not designed to support today’s increased traffic intensity. However, this cyclic solicitation gives rise to fatigue induced damage of vital bridge elements that ultimately may lead to their failure. The structural integrity assessment of these elements by fracture mechanics requires the mechanical properties of the material aged by environmental and mechanical conditions. However, destructive sampling for conventional testing is seldom not viable. A patented technology based on the statistical fractographic analysis of the surface of a millimetric fractured punch test specimen opens new perspectives to address this issue. It provides the fracture properties (toughness, cohesive strength…) of a material in a “quasi-nondestructive” manner, and it can be combined with the determination of the elastoplastic properties through the analysis of the force versus displacement response of the punch test specimen. Such a procedure provides a full characterization of the residual mechanical properties of an aged material that can then be used as input data for predictive fracture mechanics-based models of residual lifetime. We believe that such original approach may help local authorities involved in assessment of fatigue-prone bridges to take appropriate decisions.

Urban development has recently got the attention of the supervisor and inspector of construction. The researcher must find a method to assess the structural situation. The cables of the cable-stayed bridge are simplistically modeled to evaluate the cable tension that have been defined in this report, through the Euler beam theory of the cables with viscous damping. Owing to simplified assumptions of boundary conditions, the tension of cables and viscous damping coefficient has been found through measured frequencies. The proposed method is experimented with by a cable of the Phu My cable-stayed bridge over the Saigon River in Vietnam.

In this paper, the seismic response of a container crane subjected to near-field ground motion was studied via using a shake table testing on a 1/20 scale container crane. The 1/20 scale model was designed and manufactured based on the theory of similitude laws. Three independent quantities as geometric length, acceleration, and elastic modulus were selected as fundamental parameters to design the 1/20 scale model. Two near-field ground motions were chosen as input ground motions to investigate the seismic response of the 1/20 scale container crane at the Seismic Research and Test Center, Pusan National University, Yangsan Campus. The results show that the maximum moment occurs on the location of the top of the lower seaside leg.

The lifetime of a reinforced concrete (RC) storage tank depends strongly on the aggressiveness degree of its environment (presence of chlorides and carbon dioxide). The aggressiveness of these agents leads to corrosion of steel reinforcements. To understand the evolution in time of this corrosion pathology, the engineer uses corrosion models in deterministic calculation of RC structures. However, this deterministic approach, using average values of input variables, leads to an unreliable representation of the reality. Similarly, the loads applied to the structure are not always perfectly known. It is why the civil engineer uses probabilistic analysis to take into account the uncertainties marring these parameters. This paper is dedicated to mechanical reliability analysis of the RC tank upper beam, taking into account pitting corrosion and uniform corrosion of its steel reinforcements. The influence of chloride ion concentration and carbon dioxide content on the evolution of corrosion is studied in order to determine the evolution, as a function of time, of the residual section of its steel reinforcements. The reliability analysis is performed with the Monte Carlo method.

Establishing a displacement model of a cable-stayed bridge plays an important role in the operating process of structures in order to assess the structural health conditions, detect damages to structures, and suggest recommendations for maintenance. This paper studies to application of Artificial Neural Network (ANN) for establishing the displacement models along to X, Y, and Z directions of the center main span point of a cable-stayed bridge. The strategy of the building displacement model includes three steps. Firstly, Structural Health Monitoring systems (SHMs) data of a cable-stayed bridge were acquired in long-term monitoring which includes Global Navigation Satellite System (GNSS) displacement data in 3D of the center main span point, air-temperature data, windspeed, and stress data. The acquired data were de-noised and then assessed the correlation between the GNSS displacement data and other influencing factors such as air-temperature, windspeed, and stress data. Secondly, the displacement models were established by applying the ANN method for the long-term monitoring data. Finally, the establishing models were then assessed for their precision by some criterions such as Root Mean Square Error (RMSE), the determination coefficient (R2), and making comparisons between the real GNSS measurement data and the predicting data. The results show that the displacement models have high precision and reliability with the RMSE less than ± 3 mm and R2 over 0.96.

Real-time GNSS data plays a crucial role in structural health monitoring and early warning in bridge displacement monitoring. Outliers in the range of observations may lead to wrong assessments and maintenance plans. However, outliers are un-avoiding in GNSS time series data caused by various reasons and need to remove for further steps of analysis. The paper studies the ability to filter outliers of two algorithms, including moving average and moving median with different sizes of moving windows. At the same time, the paper also compares the sensitivity of both algorithms with the same set of data and moving windows. The study uses real-time displacement data from P5U GNSS devices of the CHC navigation brand in Dachongyong Bridge, Naning province, China. The results show that these two algorithms can be applied for filtering outliers, and the sensitivity is compared together as well.

The GNSS–RTK technique has been studied and applied to monitor the displacement of buildings in structural health monitoring systems (SHMs), especially with large-scale works such as super high-rises or bridges with long spans and special construction structures. Monitoring data obtained, including short-term and long-term (continuous), can be used to study, analyze the health status of the structure, detect damage, and predict future structural displacements. In port construction monitoring or maritime safety, the structural displacement or stability monitoring system has also been researched and initially applied by authors. However, the studies are still local, focusing on a few specific objects in a short observation period, not to mention the automatic warning of the risk level. In other words, people must also continuously monitor the data to detect risks when detected promptly. The article delves into the experiment of automatic safety warning monitoring of harbor works with whistles/lights or messages to solve the above problems. This is a new solution suitable for the 4.0 technology revolution era. Primarily, it is a valuable solution to monitor, evaluate/diagnose the stability of the port structure in case the construction is different from the design, in terms of operation and maintenance, to develop the port sustainably, safely, and effectively and minimize environmental impact.

Digital twin (DT) is one of the most modern and promising technologies in realizing smart manufacturing and implementing Industry 4.0. DT offers opportunity to integrate the physical world with digital world with a seamless data source. Civil engineering industry, in general, is facing many challenges in the process of digital transformation to improve efficiency and technology to meet the current growth rate of the economy. DT technology has the potential to transform and improve the exploitation and management of infrastructure in civil engineering, especially in the service phase. Based on DT model, managers and maintenance operators can test different scenarios, improve efficiency, and make accurate decisions in maintenance of the structure, leading to reduction of management and other regular monitoring costs, as well as accurate prediction of risks during the lifespan of the infrastructure. This study presents advances in digital twin implementations in structural health monitoring. This presents the opportunities and challenges of the digital twin in structural health monitoring with current technologies and future directions.

Recently, one of the most significant study areas in civil engineering has been the application of machine learning (ML) to structural damage identification. Traditional statistical pattern recognition methods, such as artificial neural networks (ANNs), are limited to detecting minor damage to bridges. Deep learning algorithms (DLs) extract complicated high-level abstractions, such as data representations, through a hierarchical learning process. Based on comparatively simpler subtractions created at the preceding level of the hierarchy, complex abstractions are learnt at some level. Similar to standard deep learning algorithms, convolutional neural networks (CNNs) are feed-forward ANNs with alternating convolutional and subsampling layers. The main idea is to use the time-series data from the output-only approach as inputs to the one-dimensional convolutional neural network (1DCNN) processing system. A significant benefit is that 1DCNNs have recently been proposed to provide instant monitoring performance at the forefront of structural condition monitoring. The proposed method is validated with the reference data of the Z24 bridge to classify the damage scenario. The results show that the proposed 1DCNN methods exhibit structural defects with excellent accuracy.

Cracks are one of the causes of the decline in the bearing capacity of beams. Crack studies often use the natural frequencies as a parameter to identify the occurrence and growth of cracks. However, for a small crack, the natural frequency does not change significantly, and thus, it is not useful for the early damage identification. In this study, the shape change of the power spectral density (PSD) is proposed as a novel feature more sensitive to cracking. This feature is represented by the centroids of the PSD (C-PSD) of the beam under moving load with different levels of cuts.

Morphology and topographic factors are closely related to soil and rock characteristics, tectonic activities, and endogenous and exogenous processes such as flash floods, landslides, and rocks. The aim of this paper is to present the application possibility of the FARO Focus 3D S350 Terrestrial Laser Scanner (TLS) in building 3D models in the potential case study of landslides and rocks—the Na Chi commune, Xin Man district, Ha Giang province. The FARO Focus 3D S350 TLS uses the phase-shift technology to determine the distance, the measuring range of 350 m, the measurement speed of up to 976,000 points/second, and the accuracy of ± 2 mm. The results show that the FARO Focus 3D S350 TLS fully meets the accuracy and is highly applicable for building the 3D point-cloud models in the landslide and rock areas. This research will be useful to local managers as well as geologists.

The risk management is quite important for the highway bridge projects due to the complicate structures and technologies influenced by site conditions, environment, service condition, etc. The risks in these projects are sometime unavoidable, so the identification and prediction of risk are required to ensure the high requirements of safety, quality, longevity and to optimize the management and maintenance activities. Technical risks of bridge in Vietnam have identified and analyzed by some authors with initially proposing of effective models and solutions to control and limit the risks. However, the risk factors in bridge projects are comparatively fuzzy, random and complicatedly connected to each other. Hence, there are some disadvantages of these proposed models and methods in solving the complex and multi-risk problems and the prediction has not been well done. In this paper, an Artificial Intelligence model for technical risk identification and prediction in highway bridge projects will be constructed based on the previous investigation results during the bridge construction and operation in Vietnam, the ensemble methods with Random Forest algorithm will be discussed and be used to obtain better risk predictive performance, and then, the application for real projects is intended.

Nowadays, ancient buildings with cultural and historical value are in danger of being completely destroyed by natural disasters, climate change, and even war. It isn’t easy to restore buildings of this type without the necessary databases. Therefore, generating 3D models is the most convenient method to establish databases of constructions for maintenance and preservation purposes. Hence, this study aims to integrate terrestrial laser scanning technology and unmanned aerial vehicles (UAV) in establishing a 3D model where all the detailed information about the ancient building can be stored for the preservation of the unique intangible cultural values of each country.

It has been observed that cracks, the most common sign of deterioration happing on the pavement, are difficult to detect at an early stage. Although the U-net-based model has detected well-established cracks, it shows some limitations when working with low-quality pavement images that are automatically captured by moving pavement-inspection vehicles. In this study, the attention technique is applied to the U-net model to enhance the results of pavement crack detection under some difficult pavement image conditions. Attention gates (AGs) are deployed at the skip connections of the U-net model to remove irrelevant regions by setting attention weights for each image part. This procedure helps the U-net model learn how to eliminate extraneous regions in the input image. Therefore, the technique minimizes the computational resources by ignoring wasted irrelevant operations and enhances crack segmentation results. The proposed model is verified using a real-life image packet of pavement. The performance of the attention U-net model illustrates better outcomes compared to the ones from the U-net model.

In recent years Building Information Modeling (BIM) has been introduced and gradually adopted in the Vietnamese construction field. It has received simultaneously the increasing attention of stakeholders in construction projects because BIM could bring benefits to the stakeholders. However, the adoption of BIM, in reality, has faced many difficulties and has not achieved the desired results. This paper aims to explore the factors that hinder BIM adoption in the Vietnamese construction field. To achieve the aim, interviews were carried out to collect qualitative data from six practitioners in the Vietnamese construction sector. After that, the deductive content analysis technique was employed to analyze the data. The results indicate that the hindrances to the adoption of BIM in Vietnam are in four main groups including legal, technology and information security, financial, and perspective and culture. Stakeholders can utilize these research findings to make decisions to help the adoption of BIM become more favorable.

In today's world, innovation is not only the application of new technologies, but also the continuous improvement of existing technologies based on new scientific and technological achievements. The article presents the efforts of the authors in researching to improve the technology of road surface survey by specialized road surface survey vehicles, which have been widely used in Vietnam in recent years. On the basis of the road surface image dataset collected during previous surveys, the authors have applied machine learning algorithms to build models to automatically detect pavement cracks on the collected images instead of conventional method of manual detection. Initial efforts using machine learning techniques such as: support vector machines (SVMs), machine learning, especially the combination learning algorithm Boosting (Adaboost) and deep learning (DL) had demonstrated the feasibility of the new solution alternative to manual analysis. The next research at a higher challenging level, a deep architecture using convolutional neural network (CNN) for crack segmentation on gray scale images has been developed for much better improvement of the current technology in terms of pavement crack detection.

Cargo handling equipment (CHE) plays an essential role in ensuring the proficiency and effectiveness of a container terminal. This study aims to examine the performance of CHEs using the overall equipment effectiveness technique (OEE) based on specific data obtained from questionnaires collected from 159 respondents working in container terminals in Vietnam. The findings reveal that the performance of the quay cranes group (HS1) and the performance of the lift on/off vehicles group (HS3) contribute to improving the OEE. In addition, the performance of the lift on/off vehicles group (HS3) acts as a mediator of the potential effects of the performance of the yard cranes group (HS2), while the performance of the quay cranes group (HS1) and the performance of lift on/off vehicles group (HS3) acts as mediators of the potential effects of the performance of yard tractors group (HS4). The CHEs’ OEE in Vietnam container terminals is generally estimated below design capacity due to their old technologies and poor management mechanism. Therefore, the study findings provide evidence to propose some strategies to improve the CHEs’ performance, thereby enhancing container terminals’ performance in Vietnam.

This paper presents a method to assess pedestrian safety, the traffic conflict technique was used to detail potential hazards or collisions with pedestrians at crosswalks. We use two parameters of this technique to describe the conflict process including the time to conflict (TTC) and post-encroachment time (PET), which have been proven effective in the evaluation of pedestrian traffic safety. In addition, the conflicting data will be classified through the K-means classification algorithm to identify the danger level of the conflicting points and areas, thereby proposing the appropriate solution to minimize conflict areas, which have a high risk to traffic safety.

In Vietnam, school traffic accident is an urgent problem that needs mitigation solutions. Schools such as primary and secondary schools are located in the roadside of streets/roads, national highways, and provincial roads. School children who usually walk, ride a bicycle, or taken by their parents by motorbikes going to school are considered as vulnerable road users. Meanwhile, solutions for traffic organization and traffic safety in these areas have not really ensured traffic safety. Motor vehicles often use high speed through schools, causing traffic safety problems. On that basis, this paper conducts observations and evaluates the speed of motor vehicles when passing through the school areas. Three sites (schools) with different levels of roadside activities in Pleiku city, Vietnam, were selected for observation and analysis. An image processing method is used for collecting speed data. It is found that there is a relationship between the free-flow speed of vehicles and roadside activities. The results of the paper help to provide solutions for improving traffic safety for school children.

The COVID-19 pandemic caused by the SARS-CoV-2 virus has appeared in Vietnam since January 2020. The pandemic has spread to all 63 provinces and cities in Vietnam. In this paper, based on the volume of freight and passenger transport of inland waterway transport (IWT) in 2020 and 2021, the impact of COVID-19 was investigated. The result indicated that the passenger transport deceased from 8.3% in 2020 and 27% in 2021 where the total volume of freight increased 19% in 2020 but decreased 6% in 2021. To promote the inland waterway transport, several recovery solutions for IWT are proposed and conditions for implement are also presented.

Since early 2020, the acute pneumonia pandemic caused by a novel corona virus (COVID-19) has left negative impacts on every sphere of human life, economy, and society globally. The pandemic also took a heavy toll on the business sector; however, its impacts on each industry and field of enterprises in Vietnam varied greatly by the nature, scope, and characteristics of their production and business activities. Road transport enterprises, whose business models are apparently associated with the travel needs of passengers and freight transport, are directly and deeply affected. Among good results, one interesting finding in this research had been clarified: although transport enterprises have experienced many difficulties over the past period, they are very determined to maintain their business with better awareness of risks and adaptability.