The multi-span suspension bridge, a novel bridge system, has emerged as an economically viable alternative for sea-crossing bridges with extensive spans. However, as bridge length increases, the complex correlation between support excitation becomes apparent due to the coherency effect in the underlying soil and the seismic wave-passage effect, termed Multi-Support Excitation (MSE). This study focuses on the seismic responses of Multi-span Suspension Bridge (MSB) under MSE, taking into account incoherence and wave-passage effects. The study conducts a time history analysis of “Cheon-Sa Bridge” to investigate the responses of girder and pylons under three different types of homogenous soil conditions: soft, medium, and firm, with three different apparent wave velocities of 600 m/s, 900 m/s, and 1200 m/s. The responses obtained for different MSE cases are compared with a uniform seismic excitation of recorded earthquake ground motion of El-Centro 1940, Imperial Valley: 180 deg. Results show that MSE significantly affects the longitudinal and vertical responses of MSB. The girder exhibits 3.3 times higher deflections under soft and medium soil MSE cases. The MSE cases significantly increase the girder axial force by about 6 times that of the uniform excitation case. The side pylons exhibit a 30% – 38% increase in transverse responses and approximately 10–12 times higher longitudinal responses. It is concluded that the local site conditions and corresponding acceleration spectral density of bedrock motion significantly influence the response of MSB. Merely considering the wave-passage effect may underestimate the actual response.

Hybrid columns with partial structural steel-reinforced concrete (SRC) and reinforced concrete (RC) sections in the transfer stories of buildings are prone to premature shear failure due to sudden changes in load bearing and stiffness properties. An experimental program was undertaken in this study to investigate the influence of the length of embedment of structural steel in hybrid SRC-RC columns bending around strong and weak axes. Five large-scale specimens with varying lengths of embedded structural steel were tested under gradually increasing lateral cyclic displacements and constant axial load. The main parameters studied were the failure mechanism, hysteretic response, energy dissipation potential, and lateral stiffness of test specimens. Test results showed that all SRC-RC specimens, irrespective of the direction of lateral loading, had higher lateral strengths than the RC columns. However, specimens with the lower embedment of structural steel performed poorly due to shear-dominated failure. Test results also highlighted the detailing requirements for lateral ties in the zone where structural steel was not present to promote the flexural mode of failure. Numerical analysis based on finite element modeling was carried out to predict the strength and failure mechanism of SRC-RC columns. Based on the findings of this study, recommendations are suggested for the design and detailing of these columns for practical applications.

Abstract Floating solar technology is gaining significant interest among researchers and on a commercial scale. FSPV (Floating Solar Photovoltaic) plants are being installed on water bodies such as thermal power plant reservoirs, balancing reservoirs, lakes, upstream of dams, backwaters, etc, from a small scale to utility scales. While this technology is gaining momentum due to its inherent advantages over the ground mount/rooftop solar system, its design requires further improvements and development to attain maturity. Wind-induced drag loads dominate the FSPV design, which is installed in relatively small reservoirs. On the other hand, wind-induced drag, wave, and current loading becomes critical when it is installed in the dam’s upstream reservoir where the open water area is in the range of 10 square Km. The present study investigates the experimental wind tunnel test results of the real-scale dummy solar panel assembly used for FSPV parks. The testing was carried out at the National Wind Tunnel Facility (NWTF), IIT Kanpur. The test assembly includes five dummy solar panels of 2456 mm × 1134 mm, mounted on HDPE floaters in a 4+1 configuration. One dummy panel was instrumented for wind load measurement. The instrumented dummy panel was relocated from one position to another to get the wind load for each configuration. The tests were carried out for worst-case wind incidence angle, i.e. wind hitting the solar panel from the bottom at wind speed ranging from 0 Km/hr to 200 Km/hr. Drag and lift loads were obtained using load cells mounted underneath the panels. These results are useful for validating the numerical model. The safety of the FSPV lies more in designing the anchoring and mooring system, which relies on wind load calculation. Realistic numerical models are required for the correct estimation of the wind load on the utility-scale FSPV, which can only be ensured after validating the numerical model with the experimental results on real-scale assembly. These well-established computational models can further be used for various changes in the study for which repeated experiments are not viable.

A comparative study has been carried out for tapered chimney considering various wake oscillator models available in the literature. These models are Facchinetti, Farshidian and Dolatabadi and Skop and Griffin. Tip displacement of 210m tall, tapered chimney is evaluated. The structure is analyzed using the stated models in first mode oscillation, and their results are compared with Eurocode method-I response. The nonlinear approach is adopted for analyzing wake oscillator models where the solution of the coupled equation is assumed to be non-harmonic, unlike the analytical models, and is solved using the ODE solver of MATLAB. The nonlinear method is then compared with the analytical solution proposed by the mentioned models, confirming that the nonlinear approach should be chosen for analyzing the lightly damped slender structures. It is observed that except for the models proposed by Farshidian and Dolatabadi, other models predict nearly the same responses. The parameters causing the variation among the models are also discussed.

The literature presents the applicability of reliability principles to wind-sensitive structures like a tall chimney. Many uncertainties involved in the unreliability of any structure subjected to wind-induced vibration are illustrated in the literature. These uncertainties include the randomness of incoming inflow and the precision of models used to predict wind loadings. A 210 m tall, tapered chimney is considered an illustrative example. The reliability analysis is carried out considering the Vickery and Basu spectral analysis for vortex shedding force. Spectral analysis is carried out in the frequency domain considering only the fundamental mode. It is concluded from the study that threshold crossing reliability of the concrete chimney is greatly affected by parameters like randomness or turbulence of the incoming low, structural damping and other critical parameters involved in the spectral analysis. Strouhal number appears to be not imparting any influence on the reliability of the chimney. The study aims to understand the chimney's behavior from a reliability point of view.

Infrastructure projects require billions of dollars, but they are destroyed in seconds due to strong ground motions during earthquakes. The disaster mitigation cell of any nation seeks sustainable and resilient infrastructure schemes to reduce the catastrophic effects of any seismic hazard. This study attempted to carry out detailed seismic microzonation of the Jammu Region (JR), which is located in the northwestern part of the Himalayas. To accomplish this, seismic hazard analysis was carried out with a primary focus on site characterization using geophysical field testing. For the proposed seismic zones, the performance and vulnerability of tunnels were evaluated in various seismic environments. Further, the seismic risk of the 345-km-long Udhampur Srinagar Baramulla Rail Link (USBRL) project was assessed for serviceability in post-seismic conditions. The proposed zonation, risk matrices, and route maps will be useful for auditioning existing and proposed tunneling projects in this area. This will pave the way for earthquake-resistant design of sustainable infrastructure projects in seismically active areas like the Himalayas.

The expanding infrastructural projects together with the prior historical records of significant earthquakes including the deadliest 2005 Kashmir earthquake in the Himalayan region, urge to assess the seismic vulnerability and risk of Jammu and Kashmir. This paper attempts to assess the seismic vulnerability of circular tunnels using the fragility function for various seismic environments. To accomplish this, the seismic performance of tunnels is quantified for each hazard zone with a diverse typology and seismic scenario. Microzonation results aided in defining the four hazard zones based on seismic severity. Zone A, B, C, and D are seismic zones with severe, high, moderate ad low Seismic Hazard Indexing (SHI). Tunnel performance is evaluated for each hazard zone, and empirical correlations for damage indices are defined. For Zone A, the fragility curves presented for minor, moderate, and extensive damage states for both shallow and deep tunnels appear to be extremely catastrophic. For various slippage conditions, the variation of flexibility and racking ratios for tunnels with shallow and deep overburden depths is significant. The proposed fragility curves are used to evaluate the seismic risk of a roadway network that includes A, B, and C routes that pass through Jammu. The risk matrices and probability function revealed that all tunnels on Route A are extremely vulnerable to damage. Extensive portal collapse and tunnel lining failure will render this route inoperable during the post-seismic phase. The developed empirical correlations, fragility curves, and risk matrices will serve as a ready-to-use tool for tunnel design engineers working on any Himalayan infrastructure project.

Jammu and Kashmir in the northwestern part of the Himalayas witnessed many moderate to large magnitude frequent earthquake events. In the last two decades, the progress of infrastructure projects is boomed in this region. Earthquake-resilient design of structural elements of any development project is very challenging, especially in seismic-prone zones. In this paper, an attempt has been done to develop the seismic fragility functions for various tunnels located in three phases of the Udhampur Srinagar Baramulla Rail Link (USBRL) Project. The outcomes of this study reveal that most of the tunnels in Phase 1 of this project are subjected to extensive damage. Near-field active tectonic sources, weathered rock conditions, high seismicity, and landslide vulnerability all contributed to portal damage and significant lining failure at such sites. This study will assist design engineers in advocating for earthquake-resistant tunnels and underground facilities in Jammu and Kashmir. It will pave the way for earthquake-resistant design of infrastructure projects in the Himalayas.

Jammu and Kashmir in the northwestern part of the Himalayan region is frequently triggered with moderate to large magnitude earthquakes due to an active tectonic regime. In this study, a mathematical formulation-based Seismic Tunnel Damage Prediction (STDP) model is proposed using the deep learning (DL) approach. The pertinency of the DL model is validated using tunnel damage data from historical earthquakes such as the 1999 Chi-Chi earthquake, the 2004 Mid-Niigata earthquake, and the 2008 Wenchuan earthquake. Peak ground acceleration (PGA), source to site distance (SSD), overburden depth (OD), lining thickness (t), tunnel diameter (Ф), and geological strength index (GSI) were employed as inputs to train the Feedforward Neural Network (FNN) for damage state prediction. The performance evaluation results provided a clear indication for further use in a variety of risk assessment domains. When compared to models based on historical data, the proposed STDP model produces consistent results, demonstrating the robustness of the methodology used in this work. All models perform well during validation based on fitness metrics. The “STD multiple graphs” is also proposed which provide information on damage indexing, damage pattern, and crack predictive specifications. This can be used as a ready toolbox to check the vulnerability in post-seismic scenarios. The seismic design guidelines for tunnelling projects are also proposed, which discuss the damage pattern and suggest mitigation measures. The proposed STDP model, STD multiple graphs, and seismic design guidance are applicable to any earthquake-prone tunnelling project anywhere in the world.

Management of delays is one of the critical issues in construction contract management. To fix responsibility and avoid disputes in construction projects, delays attributable to the client or contractor and those beyond the control of either party need to be appropriately identified and accounted for in the contract document. The present study critically examined construction contracts for different government organizations in India for various provisions concerning delays, delay damages, and levy of compensation; improvement measures are suggested. In this study, a mathematical framework for calculating the levy of compensation for delays attributable to the contractor, incorporating various relevant factors, was proposed. The findings were based on a detailed study of standard contract documents, manuals, and standard operating procedures for three government organizations-Central Public Works Department (CPWD), Delhi Metro Rail Corporation (DMRC), and National Highway Authority of India (NHAI)-and on subsequent interviews with senior construction professionals working in these organizations. The study found that existing contract provisions for calculating delay compensation are sometimes flawed and biased. Moreover, the prevalent methods for determining the levy of compensation do not consider many relevant factors, such as delays that occurred due to the client and total delay. The proposed framework can help construction practitioners calculate the compensation levy for delay damages in a fair and balanced manner. Practical ApplicationsDelays in construction projects are a chronic issue worldwide. Different contract documents have specific provisions to deal with the delays, delay damages, and the levy of compensation. This study evaluated these provisions in the contract documents used by three large public sector Indian organizations. The fixed percentage-based approach to calculating the levy of compensation in standard contract documents fails to acknowledge many relevant delay factors attributable to different stakeholders and, consequently, often results in an unfair allocation of delay damages to contractors, leading to contractor financial problems, contract disputes with clients, and further project delays. The proposed framework for calculating the levy of compensation offers a rethinking of the scope and coverage of levy of compensation calculation clauses in standard construction contracts, which may protect the financial interests of different stakeholders and reduce conflicts and disputes. Practitioners can use the framework to appropriately account for different categories of delays and other relevant factors while determining the levy of compensation.

Regarding passenger safety and railway network serviceability, the effects of earthquakes on underground transportation systems situated in seismically active regions yield a great challenge. The difficulties are exacerbated by poor weathering and difficult geological conditions. The 345 km long Udhampur Srinagar Baramulla Rail Link (USBRL) project in Jammu and Kashmir is a railway track with underground tunnels and bridges that traverses the tectonically active area of the north-western part of the Himalayas under difficult geological conditions. In this study, outcomes of seismic hazard and microzonation studies are used to evaluate the seismic risk and post-seismic serviceability of this project. The seismic hazard analysis showed that the south-western region, which comprises the districts of Poonch, Rajouri, and portions of Jammu, as well as the north-eastern areas of Kishtwar, is at the highest risk. The tunnel sections situated near zones prone to landslides and large tectonic sources showed significant deformation, squeezing, and cavity formation during the excavation process. The progressive effect of these issues increases the probability that these tunnels may get extensive damage, which would render the track segment inoperable under post-seismic conditions. The risk matrices provided in this study will serve as a valuable tool for increasing public awareness and directing track operations in the future event of major near-field or far-field earthquake events in Jammu and Kashmir.

This paper presents the numerical validation of experiments' transfer columns in hybrid structures with steel-reinforced concrete (SRC) columns in some stories while having reinforced concrete (RC) columns in the others. These hybrid structures may be subjected to localised story failure mechanism in an earthquake if they are not detailed properly. A numerical validation was carried in the ABAQUS software package. The parameters from the experiments were input in the software to get the backbone curve that would match with the experimental results. Once validation is complete, this model can be further used for conducting a parametric study.

In the last few decades, Jammu and Kashmir has faced many moderate to large earthquake events that caused catastrophic damage to the physical infrastructure and significant socioeconomic loss. The growing number of infrastructure projects, as well as previous historical records of severe earthquakes in this area demand the study of the seismic vulnerability of tunnel. In this paper, an attempt has been made to develop the seismic fragility curves for circular tunnels located in four distinct zones classified based on seismic microzonation results of the Jammu Region (JR). The damage probabilities of shallow tunnels in these zones decrease fiercely as lining thickness increases. Furthermore, increasing PGA by 0.2 g increases the exceedance probabilities for minor, moderate, and extensive damage exposed to 82%, 89%, and 93%, respectively for shallow tunnels. The fragility functions proposed for Jammu and Kashmir were employed to assess seismic risk for tunnels under Udhampur Srinagar Baramulla Rail Link (USBRL) project. Most of the tunnels in Phase 3 showed more than 50% of damage probability for the region specific defined seismic environment.

The Jammu region (JR) in the union territory of India is located in the northwestern Himalayas, affected by moderate to large magnitude earthquakes. To assess the possibility of double resonance effects (DRE) during significant earthquake events, this study examines the influence of Reinforced Concrete (RC) building vibrations in the JR in the context of local seismic response investigations. Using microtremor, a single station seismic ambient noise investigation was conducted at 242 locations to assess the predominant frequency (fp) and H/V spectra for subsurface soil. During the field survey, building data is collected, and an empirical relationship between building height and vibration period is developed. The findings show that the fundamental frequency (ff) of 17.35% of structures overlaps with the predominant frequency (fp) of the site locations in the study area where microtremor testing was done. The vulnerability map divides the city into three discrete zones with high, medium, and low resonance levels, allowing for better hazard mitigation and town planning.

In the last ten years, Chile and Japan have experienced several subduction earthquakes that lasted for extended periods of time. These occurrences have emphasized the need for a thorough examination of how the duration of ground motion impacts the performance of the components of the lateral load resisting system. In the present study, three large‐scale experiments were conducted on the wide‐flange brace member to evaluate the seismic vulnerability of the braces under the hazard consistent loading protocol. The loading sequences consider in the study are standard symmetric cyclic loading sequences, collapse‐consistent loading sequences representing subduction zone tension dominated and collapse‐consistent loading sequences representing subduction zone compression dominated. The subassemblage test‐set‐up was taken in the study to consider the effect of the end‐protect zone on the seismic assessments of the brace members. The evolution of strain at the mid‐section of the brace member is observed to be higher in case of the standard loading sequences as compared to the subduction zone loading sequences. The post yielding stiffness and the collapse resistance of the brace member under the subduction zone earthquake are present. The damage state of the open section brace member and evolution of the local bucking at the mid of the brace member were discussed. It is observed that open section delays the accumulation of strain at brace member and delay the fracture initiation. The ductility of the different brace members is compared to highlight the influence of the cross‐section properties of the brace on the ductility of the braced system.

Jammu and Kashmir is one of the most seismically active region on the planet Earth which was affected by several small and large magnitude earthquakes including the devastating 2005 Muzaffarabad earthquake (Mw 7.6). The Jammu city is the winter capital of Jammu and Kashmir and falls under Zone IV of the seismic zoning map of India having severe seismic intensity. This area has witnessed infrastructure work progressing at a faster pace over the past few years including highway construction, dam construction, and tunnelling as part of urban development. The earthquake-induced damages push the framework of development into the dark zone of desolation and lead to affect the overall economic growth. This paper discusses the seismic vulnerability of Jammu City’s residential buildings based on a variety of parameters including population, density under the demographic framework and building height, building age, materials used for construction purposes under structural specifications. According to the finding of the present study, residential buildings constructed in the northern part of the city which lies on the right bank of the Tawi river are extremely vulnerable to earthquakes, and urgent steps should be taken to keep them safe for the people who live in them. To achieve this goal, appropriate urban planning policies should be implemented to handle the seismic damage of residential buildings in Jammu City like urban areas in case of any future earthquake event.

The Khost earthquake in Afghanistan on 22 June 2022 was one of the deadliest, resulting in over 1500 deaths, 3500 injuries, and the collapse of 15,000 houses in the rural areas of Paktika and Khost provinces. This event provided an opportunity to investigate the damage to residential buildings and public infrastructure. A post-earthquake reconnaissance survey was conducted 2 days after the event in Gayan, Barmal, and Spera. Damage data were collected during the survey and field investigation, indicating that more than 50% of the houses and public infrastructures had completely collapsed. For damaged sites, a one-dimensional seismic response analysis is performed, which provides a link to understanding the damage scenario across the province. Further, the rapid damage assessment data were employed to propose vulnerability function for rural houses, which highlighted the probability of damage for various damage grades under varying seismic environments and building material characterisation. The damage probabilities rise to 17.5%, 45.5%, and 11% for slight, moderate, and heavy damage, respectively, indicating that the examined houses retain their basic performance but may sustain some moderate damage at this level of earthquake intensity. The shortest source-to-site distance, poor-quality construction materials, and an irregular town layout were the main issues identified during the surveys and are thought to have had a significant impact on the extent of the destruction. The data set and vulnerability functions provided will aid in assessing earthquake hazards in this region.

Due to the potential seismicity of the region, transportation infrastructure projects in Jammu and Kashmir require resilient design. In the present study, structural integrity and possible seismic hazard are taken into account while modelling seismic loss of tunnelling projects in the Himalayas. For the predicted hazard and vulnerability functions, the impact of seismic exposure, tunnel lining aging, and construction quality are evaluated. The Pir Panjal tunnel is also assessed for seismic risk and structural damage in post-seismic situations while taking source-to-distance effects into account. The proposed vulnerability parameters will be helpful for monitoring, logistical operations, and post-disaster route functionality. For disaster prevention cells in any nation, decision-making and risk assessment are the two key activities that can profit from the findings of this study.

The continuity in the lateral connectivity offered by laced built-up columns enables them to perform better, particularly when the axial demands are large and under lateral loading. The configuration of lacing adopted is one of the important parameters that affects the peak resistance of built-up columns. This paper reports a numerical parametric investigation conducted to study the lacing slenderness influence on the strength variation of short built-up cold-formed steel (CFS) columns. ABAQUS was used to develop the numerical model, where concentric axial loading was applied to the built-up columns constructed from four plain CFS angle sections, fastened by lacing bars configured in N-type latticed pattern, with pin-ended supports. The experimental results of laced CFS built-up columns conducted by the authors earlier and that of on battened CFS built-up column conducted by EI Aghoury et al. were adopted for calibrating the numerical model for performing the numerical parametric study. Lastly, the design axial strengths of the built-up columns were computed by adopting various current standards on steel structures, which were later compared with the numerical results.