The construction industry, characterized by unique challenges such as working at heights and using heavy equipment, has turned to unmanned aerial systems (UASs), frequently known as drones, to mitigate workplace hazards, improve safety, and enhance productivity. While numerous benefits claimed, application UASs in construction introduces unique safety challenges. The objectives of the present study are (1) to identify risks associated with the use of UASs for construction operations based on a review of existing literature, and (2) to present the identified risks to industry professionals and practitioners using hypothetical case study examples. The study findings indicate that risks associated with the use of UASs in construction can be classified into four categories: operational errors and safety hazards, privacy intrusions and security risks, mechanical and technical failures, and regulatory and legal considerations. After identifying the risks, three hypothetical examples are carefully developed and presented in collaboration with aviation safety experts to help industry people better comprehend risks associated with the use of UASs in construction. Each case study delineates hazards that could emerge on a construction site and explains the connection between these hazards and the utilization of UASs. The presented case studies also recommend risk mitigation strategies and best practices for using UASs for construction operations. The present study contributes to practice by aiding construction companies in risk awareness, safety training, and risk mitigation for UAS applications in construction.

Earthquakes are one of the most common natural disasters resulting in loss of life and property. A method for reducing damage and fatalities is to evaluate the fragility, i.e., determining the degree of an earthquake susceptibility of a structure using structural analysis. Bridges are categorized as lifeline constructions, as they must be operational in the case of an earthquake. The closure of damaged bridges due to unsatisfactory working conditions might have an adverse impact on everyday traffic. The proposed research would look into the seismic danger that bridges represent located in Surat city of Gujarat. In this work, nonlinear static analysis has been used for investigation. The fragility function has been used to evaluate damage to bridges of varied spans, material quality based on Indian seismic provisions. This investigation can keep track of the possibility of specific damaging circumstances. Using the HAZUS approach, a probability damage assessment has been done. Using ArcGIS software, the likelihood, size, and severity of bridges in Surat have been evaluated. The distinction of present study lies in extending beyond the confines of the HAZUS technical manual, which primarily focuses on generating damage state probabilities for bridges. In this study, author moves a step further by applying this technique to a specific set of bridges, allowing to observe variations in damage state parameters across different bridge types. This approach enables easy comparisons between various bridges, aiding in the identification of specific risk factors and informing subsequent measures for risk mitigation.

Research work of this study focuses on the seismic soil-structure interaction (SSSI) analysis of a base isolated nuclear building (NB) of the Indian pressurized heavy water reactor (IPHWR) under the action of coherent ground motion using the frequency domain approach. The seismic isolation of NB is achieved by installing lead rubber bearings (LRBs) below the raft. The base isolated NB is subjected to SSSI analysis in the frequency domain in order to take the influence of soil-structure interaction into account. LRB base isolators are numerically simulated as spring elements by assigning iterated equivalent linear stiffness. The seismic analysis of base isolated NB is performed using a conventional approach of fixed base analysis and the frequency domain approach of SSSI analysis to evaluate the effect of inclusion of SSSI on NB structures’ performance. This study also evaluates the implication of modeling isolators by assigning constant isolator stiffness as well as assigning equivalent linear stiffness to account for its nonlinear behavior under seismic excitation. Seismic responses in terms of in-structure response spectra and seismic displacements at representative locations of NB substructures are studied. The outcome of the study showed (1) base isolation of NB of IPHWR is achieved successfully by bringing down spectral accelerations and relative structural displacements of NB structure at target frequencies; (2) the conventional approach of fixed base boundary condition and assigning constant isolator parameters derived at isolator design displacement underestimates the structural responses in terms of spectral acceleration, frequencies, and displacements; (3) the conventional fixed base analysis approach fails to capture the spectral amplifications along its height at the fundamental frequencies of the various structure of NB; (4) discounting the SSSI effect along with equivalent iterative isolator parameters underestimates the structural responses marginally under horizontal excitation; and (5) the SSSI effect works like an isolation in the vertical direction and leads to reduced spectral accelerations in the vertical direction.

Steel plate girders are susceptible to web buckling due to slender web. This phenomenon creates an undesirable failure mode and limits their ultimate load capacity. The use of fiber-reinforced polymer (FRP) composite materials offers a good prospect of strengthening the slender web of plate girders to avoid web buckling. This paper presents the details of experimental testing of steel plate girders with nonrigid end posts. These girders were tested in three-point bending. The end shear panels of the girders were strengthened by glass FRP (GFRP) pultruded section stiffeners or glass fiber fabric composite. GFRP stiffeners were applied either vertically or along the compression diagonal in the shear panel. All strengthened panels failed by web shear buckling associated with a breakdown of the employed strengthening scheme. It was found that the shear capacity of the panel remained unchanged by replacing the steel stiffener with GFRP stiffeners in the end panel. The critical buckling load of the strengthened panels increased up to 44% compared to the unstrengthened panel. The shear capacities of the panels strengthened by the glass fabric composite and diagonal GFRP pultruded section were the highest and similar to each other. Both these panels resisted a 50% larger shear compared to the unstrengthened panel. The positions of the plastic hinges in all tested panels were the same due to the same ratio of panel length and depth of the web.

Ensuring the safety of construction sites is a pivotal aspect in the field of construction engineering and management. Frontline supervisors, acting as a central link between upper management, safety personnel, and field workers, play a vital role in this regard. Despite their significance, their role remains largely unexplored and underinvestigated. This study utilized a blend of survey methodology and literature review to assess the mediating impact of frontline supervisors on the behavior of field workers and to identify factors contributing to the enhancement of their overall contribution to site safety. According to the study findings, frontline supervisors play a significant role in mediating workers’ behavior. Consequently, the accountability of frontline supervisors emerges as vital for elevating construction site safety. Moreover, seven factors contributing to the safety performance and overall contribution of frontline supervisors were identified in the reviewed literature. The factors are safety management system, management commitment, safety training, experience, safety knowledge, safety attitude, and leadership skills. As a result, this research enriches the existing body of knowledge and provides practical insights for the industry, enhancing our understanding of the role of frontline supervisors and the necessary resources required to empower them. Industry professionals and practitioners can utilize this study’s findings to make decisions that positively impact safety conditions on their construction sites.

Numerous structural analysis techniques are employed to model the pavement structure, considering factors such as thickness of the pavement layer, mechanical properties, and loads. These techniques include the multilayered elastic theory, finite element method, and finite difference approach. Various computer programs are accessible for estimating pavement responses and conducting analyses using these techniques. The primary focus of this paper is the modeling of pavement structures, utilizing a range of computer programs, including KENLAYER, IITPAVE, and ANSYS. This study compares surface deflections measured at different sensors during a falling weight deflectometer (FWD) test. This study also aims to enhance the finite element model by utilizing static and dynamic analyses within the ANSYS computer program. According to the comparison study, all computer programs are more likely to accurately predict the deflection value, with a small percentage of root mean square error (RMSE) ranging from 0.138% to 3.29% for all models created by the computer programs and field measurement. Additionally, it was determined that dynamic analysis is the superior approach for modeling pavement in FWD testing, as it exhibits an RMSE variation of only 0.13% to 1.0%.

The fineness modulus (FM) denotes the average particle size of fine aggregates. The FM of the sand, and other constituent qualities, have a major effect on the strength and durability of geopolymer mortar. Finer particle size increases the surface area, influencing heat absorption and emission, impacting the mechanical strength of geopolymer concrete. Heat energy notably accelerates reaction kinetics, accelerate geopolymerization processes. The purpose of this study is to ascertain how the compressive strength (CS) of fly ash (FA) and Ground granulated blast-furnace slag (Slag) based geopolymer material (GPM) is affected by the fineness modulus (FM) of sand that has been heated to 100°C±5°C. To make the paste for the geopolymer material, natural river sands with FM of 1.85, 2.41, 2.79, and 3.32 were used. For the investigation, 36 samples of a 50×50×50 mm3 cube were hot cured at 50°C for 3 h to determine the CS of GPM paste after 3 h, 1 day, and 7 days. The study’s conclusions show that sand FM has a large effect on the flow rate (%) of GPM. In particular, a greater flow rate (%) of GPM paste was connected to a higher sand FM. Notably, the most pronounced improvements in CS growth rate (%) were seen in GPM paste made with heated sand that had FM values of 1.85 (fine sand) and 2.79 (medium sand). Furthermore, when heated sand was utilized, the FM had a substantial impact on the CS of GPM matrix. The mineral composition, including unreacted FA and Slag components, underwent assessment using energy dispersive X-Ray analysis (EDX) and scanning electron microscopy (SEM). These analyses revealed that fine aggregates, with increased surface area content, contributed to higher concrete strength compared with those with a higher concentration of coarse aggregates. It follows that when attempting to create geopolymer material with strong early-strength qualities, fine sand, well graded sand ideal match to the ASTM upper and lower bound limits are the best options for fine aggregates.

Bridges are among the most important structures for human civilization. Bridge safety is therefore an ongoing concern of engineers. Scouring of river beds due to blocking of downstream current by the bridge pier is one of the main causes of bridge failure. A bridge pier with a slot facilitates the passage of water downstream and thereby creates less vorticity, which in turn results in the reduction of scour formation. The introduction of a slot in any compression member like a column (or a bridge pier in the present case) is likely to be questioned for its structural safety. Thus, the present work investigated the comprehensive structural behavior of bridge piers with slots in them. Such bridge piers were structurally evolved in the present work based on the basic design philosophy, and were numerically modeled in ABAQUS 2019. Multiple sizes of slots are investigated considering a wider scenario. Different performance measures like natural frequency, Von Mises stress, and strain were evaluated to explore the fundamental structural behavior. The Von Mises stress [considering the pier as a three-dimensional (3D) continuum] was taken into account for the typical design check between capacity and demand at the material level. Although the introduction of slots raises the concern for structural performance of the bridge pier, it was taken into account that there is an insignificant degradation (in terms of Von Mises stress measure as well as Cauchy’s stresses) in the structural performance of the slotted pier in comparison to the pier without slot. Reinforcement was proposed for the slotted pier considering induced stress pattern under reasonable loading scenario. Mode shapes of the slotted pier system were evaluated to understand its dynamic structural behavior. In addition, the overall capacity of the slotted pier system was evaluated on the basis of critical buckling load and axial load-carrying capacity against each of the different slot sizes in the pier, which may help to determine the trade-off between hydraulic requirements versus scouring and structural capacity/safety.

The possibility of detuning resulting from liquid depth fluctuation and low damping characteristics for being deep tanks hinder the utilization of overhead water tanks (OWTs) as tuned sloshing dampers (TSDs). This paper proposes a slender TSD (STSD) that can effectively serve as OWT as well. Unlike conventional TSDs, in an STSD, the liquid depth is allowed to fluctuate within any practically feasible range maintaining the condition h/D≥1, where h is the liquid depth and D is the tank dimension along excitation. For h/D≥1, the frequency and the lumped mass representative of the fundamental sloshing mode become independent of h. To improve damping, STSDs are provided with equally spaced horizontal ring baffles. It is shown that the effective damping ratio of the STSD with equally spaced horizontal ring baffles also becomes practically constant for h/D≥1. Thus, a consistent damper performance is possible despite liquid depth fluctuation. The mathematical model of the damper system is described followed by the design of OWT cum STSD for a real-life apartment building. Significant seismic vibration control of the building by the damper is demonstrated through a numerical study that shows consistent performance by the STSD despite 66.7% liquid depth fluctuation in the tank. The performance of the STSD is found to be comparable with conventional TSD.

In civil structures, a lot of attention is paid to lightweight design, i.e., reduction in self-weight by design without compromising safety, integrity, and performance of a structure. The cost-effectiveness of lightweight design is another important consideration, as it can help to reduce the overall cost of a project. Thanks to the development of steel aluminum foam sandwich panels, a new lightweight design option is now available that offers a number of benefits, including reduced self-weight, improved energy efficiency, and increased durability. In this study, efforts were made to replace the stiffened plate by the sandwich panel with the aim of weight reduction. For this task, three different sandwich panels were selected, a sandwich panel made with face-plates S355, S690, and S1100. In this study, an arbitrary Huisman equipment was chosen which is made of S355 stiffened plate. This structure is redesigned with sandwiches S355, S690, and S1100. Static and buckling analysis was performed on the new design, as well as cost analysis, to evaluate the economic viability of sandwich panels. The findings of the study show that sandwich panels can be used to save significant amounts of weight, while still meeting other design requirements. Weight reduction of up to 30% can be achieved with the use of sandwich panels. The use of sandwich panels can increase the cost of the structure, but this increase can be offset by the savings in weight.