Recent Advances in Structural Engineering—Vol. 4

This study examines the seismic activity about Koyna Concrete Gravity Dam, a structure essential for managing water resources, producing hydroelectric power, and preventing flooding. The dam, built in 1963, was tested by a 6.5 magnitude earthquake in 1967, prompting the construction of concrete buttresses for reinforcement. Despite these precautions, the dam’s seismic susceptibility remains an issue. This study will use advanced finite element modeling and historical ground motion data from the 1967 earthquake to better understand the dam’s dynamic response to seismic loading. The analysis looks at static and dynamic loading conditions, illustrating how the dam behaves during normal and seismic events. The modal analysis results are highly consistent with prior investigations, demonstrating credible modeling with percentage variances in time periods and natural frequencies ranging from 0% to 1.59%. Crest displacement study shows large movements during seismic events, with maximum displacements of 3.568 cm upstream and 3.161 cm downstream. Stress distribution visualizations indicate crucial structural evaluation locations, with stress values varying by up to 3.62% from previous analyses. These findings provide important insights into the dam’s performance during seismic events, aiding continuing efforts to improve its safety and reliability. By addressing its seismic susceptibility and guiding future risk assessment and mitigation techniques, our research supports the continued integrity and longevity of vital infrastructure in seismically active areas.

Highway bridges are crucial elements of essential infrastructure, enabling continuous transportation, emergency response, and evacuation routes, particularly in seismic-prone regions. Despite significant progress in understanding the seismic behavior of concrete bridges, the impact of irregularity on bridge failure remains a notable concern. This study conducts a comprehensive literature review of reinforced concrete (RC) bridge structures that failed due to diverse irregularities, encompassing both structural and geometrical factors, under seismic conditions. The literature review incorporates historical data of bridge failures attributed to seismic events, with a specific focus on cases where irregular span and geometry arrangements were identified as contributing factors. This review provides insights into how these irregularities influence the seismic performance of bridge structures, ultimately contributing to overall sustainability and performance enhancement. The study aims to assist designers and policymakers in determining the permissible extent of various types of irregularities. By clarifying the relationship between various irregularities and recorded bridge failure cases, this study contributes to the development of guidelines and strategies for mitigating seismic risks in bridge design and construction. Ultimately, the findings of this study have practical implications for enhancing the resilience and safety of highway bridges in seismic-prone regions.

Highway bridges are critical in facilitating transportation and ensuring emergency response effectiveness, particularly in earthquake-prone regions. While extensive research has been conducted on the seismic behavior of concrete bridges, uncertainties persist regarding the impact of in-span hinges on irregular bridge configurations commonly encountered in real-world scenarios. This research examines the seismic behavior of reinforced concrete slab bridges with different span irregularities. The seismic response of bridges with different span configurations is systematically analyzed through numerical simulations and analytical investigations. Key parameters, including the length ratio between left and right spans, are varied to assess their influence on bridge performance during seismic events. The study quantifies structural responses such as displacements, stresses, reactions, and moments, providing valuable insights into the structural behavior and vulnerabilities of irregular bridge configurations. The results highlight the significance of considering span irregularities in bridge design and retrofitting practices to enhance seismic resilience. Moreover, optimal length ratios between spans are identified to mitigate potential damage and improve overall structural performance. These findings aid in creating efficient design principles and retrofit methods to improve the earthquake resilience of highway bridges irregular span configurations.

The construction industry is known for its distinct range of materials, techniques, and methods which can significantly influence a structure’s performance and overall cost. Among the vast number of existing structural systems, the most adopted types are reinforced concrete (RC), steel, and composite structural systems. Designers must judiciously select from a multitude of structural systems to optimize strength, stiffness, stability, sustainability, and cost-effectiveness in their projects. This study aims to compare the seismic performance and cost-effectiveness of RC, steel, and composite systems. Additionally, a parametric study on composite systems explores variations in parameters such as number of stories, concrete grade, reinforcement grade, soil type, and seismic zone factor. Seismic analysis employs response spectrum analysis, while statistical analysis utilizes one-factor-at-a-time (OFAT) analysis. The results are presented in terms of base shear, displacement, and cost. This study aims to help architects, designers, decision-makers, and industry professionals make informed decisions that match project specifications, performance requirements, and financial constraints. The research highlights the crucial need for a thorough and tailored approach in selecting structural systems, focusing on cost-effectiveness. It emphasizes the significance of giving equal consideration to both factors when making decisions.

High-rise structures are particularly vulnerable to seismic events, often experiencing structural deformation, resonance amplification, and damage to non-structural elements during earthquakes. The balance between a structure’s flexibility and stiffness plays a crucial role in its seismic response. According to Indian seismic design standards, incorporating shear walls is critical for maintaining the stiffness and overall stability of high-rise structures. Furthermore, the Indian code stresses the strong column–weak beam concept, underlining the necessity for durable columns in high-rise structural frameworks. This study aims to identify the optimal ratio of shear wall area to floor area (A_sw/A_f) and column area to floor area (A_c/A_f) in reinforced concrete (RC) high-rise structures. Through response spectrum analysis in compliance with IS 1893:2016, different combinations of A_sw/A_f and A_c/A_f ratios are evaluated for structures with five, ten, and fifteen stories. The results are presented in terms of story drift and base shear. The outcomes provide practical insights for architects, engineers, and decision-makers, helping them optimize the allocation of shear walls and column areas relative to floor space. Ultimately, this research supports the enhancement of seismic performance in tall structures, ensuring their safety and functionality under earthquake loading scenarios.

The demand for high-speed rail transit systems has significantly increased since last decade. A high-speed train is a form of transportation that is convenient and environmentally good as it is a mass rapid transit system. However, fast train speeds bring into consideration some of the new engineering challenges that were unknown before. One of the most important problems is a substantial increase in the amount of rail-generated ground vibrations that can occur when the train speed surpasses the velocity of Rayleigh surface waves in the supporting ground. These vibrations may cause severe damage to the supporting ground. Hence, great attention should be taken while designing such structural systems. Advanced numerical analysis is a great tool for determining the performance of a system subjected to dynamic rail loading. The present study deals with the linear time history analysis of stratified embankment subjected to high-speed rail loading using the concepts of the finite element method (FEM). The results are shown here in terms of total translation and Von-Mises stresses in the pavement and embankment. Also, the effects of change in the rail load direction are studied and illustrated. The study of the fundamentals of dynamic impulsive loading induced due to the moving rail load by understanding the advanced numerical methods like Eigenvalue analysis and time history analysis for evaluating the response of the structure.

The implementation of a response-oriented design, particularly the direct displacement-based design (DDBD), offers notable advantages in the era of building structures. This design paradigm revolves around determining the structural capacity to withstand earthquake loading following specific requirements. Present study includes a 15-storey reinforced concrete (RC) frame building that is meticulously modelled utilising the DDBD approach, considering fixed-based and incorporating soil–structure interaction (SSI) effects as crucial boundary conditions for life safety performance. Nonlinear p–y springs and elastic springs to capture soil nonlinearity are integrated into the design. The frames undergo thorough nonlinear static pushover analysis (NSPA) analysis to elucidate their nonlinear behaviour. Subsequent seismic fragility assessment obtained the building’s probability of occurrence in varying collapse states, ranging from slight to complete. Notably, including SSI effects in the DDBD approach yields heightened structural responses and increased design requirements with 5% lesser seismic vulnerability compared to the RC frame without considering SSI.

The complexity of seismic structure response arises from the nonlinear soil behavior during earthquakes. Typically, seismic structural design disregards soil flexibility, assuming a fixed base. This study aims to explore and elucidate various methods for incorporating soil flexibility into the interaction between soil and structure, particularly focusing on its impact on the superstructure's response. The study entails analyzing a vertically geometrically irregular ten-storey building with four bays supported by a raft foundation, considering both fixed and flexible bases for soil–structure interaction, and comparing the outcomes with those of a conventional building. Three soil types, hard, soft, and medium hard, are utilized in this study of soil–structure interaction. Soil flexibility is integrated into analysis through the Winkler approach and the elastic continuum theory. SAP 2000 v24 is utilized for model development. The impact of SSI on structural parameters, namely base shear, natural time period, and lateral displacement, is examined also discussed. It is validated that the structure's response is altered not solely by its dynamic and seismic excitation features also by the external environment surrounding its base, encompassing interaction among the foundation, structure, and soil.

Since the early twentieth century, tall building design has evolved with a focus on realism, material efficiency, and constructability, allowing for taller structures. Advances in materials, software, and structural systems have driven this progress, emphasizing a balance between architectural expression, safety, serviceability, and efficiency. Current trends favor composite structures to handle lateral loads like wind and earthquakes. This study analyzes framed-tube, braced-tube, and outrigger systems for 60-story buildings situated within Seismic Zone III, characterized by medium soil using dynamic analysis with response spectrum method and gust factor for wind load calculations.

Diagrid structures are outside structures comprising diagonal struts and connections around the perimeter and an internal core. These diagonal elements support gravity and lateral loads through axial action. The structural efficiency of diagrids allows for the elimination of interior and corner columns, giving the floor plan more freedom. In many industrialized nations worldwide, diagonal structures are becoming prominent structural systems, but their significance has not yet grown in India. This chapter presents reviews of combinations of dampers and diagrid structural systems in reinforced concrete (RC) buildings. Dampers are additional energy dissipation devices researched with diagonal grid systems, recognized for their high lateral performance and diagonal grids. The research focuses on studies that examine the combined effect of structures and dampers in RC buildings. The chapter investigates how dampers improve the seismic performance of diagrid RC structures by damping vibrations, lateral stiffness, natural frequency, and lateral displacement and explores the performance of various types of dampers, including friction, tuned mass, and viscous dampers, in diagrid remote control systems.

The seismic performance and structural response of buildings are crucial considerations in earthquake-prone regions. This research chapter focuses on the dynamic analysis of a G + 10 building located in an area susceptible to the devastating effects of earthquakes in the Turkey–Syria region. The study aims to evaluate the building's behavior and seismic performance under the specific conditions of a seismic event, considering critical factors that could potentially lead to structural failure. The research methodology begins with a comprehensive seismic hazard assessment. This assessment involves analyzing historical seismic data, studying geological surveys, and considering regional tectonic characteristics to estimate ground motion parameters. By understanding the potential for seismic activity in the region, more accurate predictions of earthquake-induced ground motions can be made. The G + 10 building under investigation is accurately modeled, taking into account its architectural and structural elements, material properties, and foundation conditions. This meticulous modeling ensures a realistic representation of the building's behavior under earthquake-induced loads. The structural analysis is conducted using dynamic analysis methods, such as response spectrum analysis or time history analysis, which are widely accepted techniques for evaluating the dynamic response of structures. To simulate the effects of seismic events, design earthquakes are selected based on their representative ground motion characteristics derived from the seismic hazard assessment. These earthquakes serve as input ground motions for the dynamic analysis. The selected ground motions are applied to the building model as dynamic loadings, representing the forces and accelerations experienced during the earthquake events. Through the dynamic analysis, the building’s response is evaluated in terms of displacements, accelerations, and member forces. This assessment helps identify critical locations within the structure that may be prone to excessive displacements or forces, indicating potential vulnerabilities or areas of concern. By understanding the areas of weakness, appropriate measures can be taken to mitigate the risks and improve the building's seismic performance. The findings from this research provide valuable insights into the structural response and seismic performance of the G + 10 building in the Turkey–Syria earthquake scenario. The identification of critical locations within the structure helps inform decision-making processes related to structural design, retrofitting strategies, and risk mitigation measures. Ultimately, this research contributes to the development of more resilient structures capable of withstanding the devastating effects of earthquakes, thus enhancing the safety and sustainability of buildings in earthquake-prone regions.

Diagrid structures, known for their structural efficiency and esthetic appeal, offer significant advantages in tall building design by distributing loads efficiently and reducing the need for internal columns. However, their application in tilted buildings presents unique challenges due to asymmetrical loading and lateral forces. To address these challenges, hybrid diagrid systems combine the benefits of diagrid structures with additional structural elements, such as traditional columns or shear walls, strategically placed to enhance stability and structural performance. By integrating these systems, designers can achieve optimal structural efficiency, stability, and architectural expression in tall tilted buildings. Using E-tabs software, the 36-story tall buildings are analyzed using diagrid and hybrid diagrid structural systems under lateral loads. The parameters such as time period, story drift, lateral displacement, and load distribution are compared.

This paper considers study of lab-based model treating greywater. The model combines electrocoagulation and filtration technologies for greywater treatment and its optimization so as to alleviate water scarcity. Greywater is a non-potable water that can be re-cycled and re-used. The research work explores utilization of hybrid electrocoagulation and filtration technologies. It conducts and optimizes impact tests on anode and cathode in continuous manner. For this purpose, combinations of aluminium (Al) and copper (Cu) are considered. The electrodes are arranged in 2 sequences. These are Al:Cu:Al:Cu and Cu:Al:Cu:Al. The study discovered that when cathode and anode were separated at 20 mm distance for Al:Cu:Al:Cu arrangement, 94.20% of COD was found to be removed. The specific energy was observed to be 1.95 kWh/m³ and the operating cost was optimized to 18.50 INR. In addition, Al:Cu:Al:Cu consumes less energy than that of Cu:Al:Cu:Al, resulting in higher current efficiency. The study also shows that the hybrid electrode has high removal efficiency while running at a lower voltage for both Al:Cu:Al:Cu and Cu:Al:Cu:Al indicating the effectiveness of model for greywater treatment obtained from multi storied buildings.

The seismic resilience of RC structures is critical in earthquake-prone regions. Utilizing advanced numerical modeling and dynamic analysis, the study compares the performance of the bracing systems under a range of seismic loads. The impact of the different bracing methods on seismic parameters such as overturning moment, maximum story drift, story displacement, and story shear was examined using the response spectrum method. The preferred usage of this system is by means of the shear walls which assist in consolidating the structure. Due to the high cost of the shear wall installation, the analysis of the residential building with steel bracings of varying combinations and the resultant displacement of the frame model was carried out. The findings indicate that combining different bracing configurations can significantly improve the overall seismic response, reducing inter-story drifts and mitigating potential structural failures. This research provides valuable insights for structural engineers and contributes to developing more resilient RC frame buildings capable of withstanding severe seismic events.

A crucial factor in building design process is damping. With the intention of maximizing stability of an earthquake-resistant structure, dampers are important. There are various different types of dampers in use, including tuned mass dampers, rubber isolators, magnetic dampers, and friction dampers. Rubber dampers have been shown to be useful in decreasing seismic forces and enhancing structural stability, although their application in India is still somewhat limited. A number of variables, including exorbitant expenses, a lack of knowledge, and a dearth of field research and development. Therefore, in the current study, an asymmetric G + 40 story RCC building is subjected to the following conditions: Medium soil with soil type II and seismic zone III. To investigate response of the structure, a Rubber Isolator Damper is utilized. First, the construction was identified as the General Building when it was assessed without a damper. Later, Rubber isolator damper will be used for analysis of structure. Various dynamics variables something like seismic displacement, shear force at base, storey drift and modal mass participations were evaluated.

Generally, foundations are designed for the settlement with respect to soil bearing capacity. In the case of a slender high-rise building, transmission tower, buildings in hilly areas are constructed on a sliding surface, high-rise structures are constructed on earthquake sensitive zone and high wind speed zone, affected with uplift and overturning forces. It is needed to provide some remedial measures, like vertically anchored foundation elements to resist the uplift and overturning forces considering soil-structure interaction effects. This study aims to examine how earthquake vibrations affect the behaviour of foundational reinforced concrete structures built on various soil types, both with and without anchor elements. On a ten-storey thin building, a couple of nonlinear time history analyses were conducted while taking into account the earthquake motions in Bhuj and Chamoli. The buildings were supported on Dense Sand and Gravels, Dry salty clay, Sandy clay and Lomy Sand having shear modulus (G’) 70 N/mm², 35 N/mm², 25 N/mm² and 10 N/mm², respectively. Based on nonlinear time history analysis, the results indicate that the anchor element foundation reduces the structure’s period and storey drifts. It also has substantial effects on base shear and global displacement. Result indicates reduction in uplift and overturning forces and foundation settlements.

This study provides a comprehensive review of recent developments in the understanding of Soil–Structure Interaction (SSI) and Structure–Soil–Structure Interaction (SSSI) effects on the seismic behavior of buildings. It analyzes numerical, analytical, and experimental studies, focusing on soil–structure and adjacent building interaction performance. Numerical methods like Finite Element Method (FEM), Boundary Element Method (BEM), and hybrid approaches enable complex nonlinear analyses. Experimental methods offer validation data. The review highlights the importance of building arrangement, soil properties, and adjacent structures in SSSI effects. Knowledge gaps and future research directions are identified, including further experimental testing, and incorporating SSI and SSSI into seismic design codes. The findings provide insights for earthquake-resistant design, seismic risk assessment, and hazard reduction strategies. This review contributes to understanding complex soil–structure interactions and their implications for seismic performance, offering a foundation for future research and practical applications in earthquake engineering. The study also explores the evolution of SSI and SSSI concepts, tracing their historical development and the gradual recognition of their significance in seismic analysis.

Each country has their unique seismic code. Code revisions reflect a country’s progress in earthquake engineering. In this present study, G + 30 multi-storeyed commercial buildings of steel–concrete composite and steel are analysed. Both the buildings are analysed by Equivalent Static Analysis (ESA) method and Response Spectrum Analysis (RSA) method. E-tabs software is used for the analysis. In this study, analysis results of three seismic codes (i.e. IS 1893–2002, 2016, Draft 2023) in terms of the Base shear, Maximum top displacement and Maximum storey drift are compared. The study of the draft IS 1893–2023 reveals a consistent shift towards safer and more precise methodologies for designing buildings in India.