[PERSON] and [PERSON] [14] focus on repairing and rehabilitation of existing shear-damaged precast bridge girders by implementing fiber reinforced polymer (FRP), one of the sustainable materials that has high corrosion resistance. The current study carries out three-point bending tests for the full-scale precast bridge girders, and presents a strut-and-tie model to predict the shear capacity of the FRP-repaired precast girders. For the better safety of our built environment under probable manmade and natural disasters, this Special Issue addresses various extreme loading conditions, including earthquakes, impact threats, and fire, etc. To examine the effects of strong earthquakes on buildings with rectangular hollow section (RHS) trusses, [PERSON] et al. [15] conduct lateral cyclic loading tests on three plate-to-RHS K-truss specimens. It is found that the specimens show increased initial stiffness and ultimate strength when it is provided with chord face stiffeners. The structural responses of the specimens with different connection details are analyzed and compared with those predicted by the current design codes. On the other hand, [PERSON] and [PERSON] [16] assess the effects of accidental torsion and increased responses of buildings subjected to seismic loads. Various parameters, including the ratio of torsional frequency between uncoupled and uncoupled systems and the floor plan aspect ratio, are included in static and dynamic analyses of a set of 72 multistory buildings. For estimation of damage status and limits of concrete structures subjected to impact loading, [PERSON] and [PERSON] [17; 18] carry out experimental and analytical studies and present their findings in two series of papers. A total of 402 impact test results are collected and comparedwith their proposed method for verifications. An energy-based impact model developed based on the experimental data is found to be more effective in predicting the penetration depth, scabbing depth, scabbing limit, and perforation limit of concrete panels, compared to existing formulae. [PERSON] and [PERSON] (2019) focus on the effect of boundary conditions on thermal expansion of steel structures exposed to high temperature, and investigate the fire performance evaluation of the steel truss system depending on the support conditions. For this research, kinematically admissible failure mechanisms of selected steel truss systems are first identified, and then behaviors of the trusses under fire conditions, such as axial force and load-carrying capacity of individual elements, are estimated through a reliability analysis. It is concluded that additional supports can prohibit thermal expansion of the truss system, deteriorating its fire resistance. Finally, structural performance evaluation of underground infrastructure is one of the remaining areas that require substantial research. [PERSON] et al. (2020) conduct 3-D FE analysis for concrete pipes buried in soil. The numerical simulations adopt a nonlinear elastoplastic model for backfill materials, and include various effects such as groundwater table and voids around pipes to obtain more accurate and realistic soil pressure distributions. Propagation of concrete cracking is also studied through the numerical simulations. [PERSON] et al. (2011) conduct a comparative study on design solutions of Kazakhstan (SP RK 5.01-102-2013) and European (Eurocode 7) codes for shallow foundations. The design outcomes from the two different approaches are compared in terms of various aspects such as bearing capacity and elastic settlement of the soil, and over-design factors. It is found that the European code tends to yield a more conservative design outcome for the design of shallow foundations. In closing, the guest editors are really pleased to take this opportunity to manage and share the state-of-art research results with the potential readers of _Applied Sciences_ in the world.