The box-plate steel structure residence is a box structure with stiffened steel plates directly used as load-bearing walls and floors. In practical engineering, due to the functional requirements of the building, it is necessary to open door or window openings on the box-plate steel structure walls. To study the seismic performance of the box-plate steel structure with openings system, two three-story single-compartment box-plate steel structures with openings modular units were designed and fabricated according to the 1:3 reduced scale. Through the quasi-static loading test, numerical simulation, and theoretical analysis, the failure process, failure mode, lateral force resistant capacity, and hysteresis performance of the specimens were studied. The impact of the different opening areas and opening position on the seismic performance of the box-plate steel structure was emphatically analyzed. The results of the test indicated that the openings on the steel wall plate would reduce the initial stiffness and the lateral force resistant capacity of the specimen; the destruction of the box-plate steel structure with openings modular unit under the low cyclic loading effect started with the tear in the corner of the openings and ended with the tear in the corner steel wall plate. Then, the finite element analysis (FEA) models were developed to supplement the experimental study, and the comparisons were made between measured and simulated results on load versus displacement relationships and failure modes. On the basis of the stressing mechanism of the box-plate structure modular unit, the calculation equation of the lateral force resistant capacity of the box-plate structure with openings modular unit was put forward. Then, the proved finite element analysis (FEA) models were used for parameter analysis of different influence parameters to verify the proposed calculation equation. The results showed that the proposed calculation equation had high accuracy and could be used as a design basis for practical engineering.

Compared with the traditional frame structures, the novel composite frame with replaceable steel links can realize the rapid recovery of building occupancy after seismic actions to provide the capacity of reducing structural damage and ensure the reuse of a structure. In this system, plastic deformation and damage mainly concentrated in the steel links serving as the structural fuses and other structural members still remained elastic or minor plastic, and then the damaged steel links can be easy for replace. In order to study the seismic performance of the replaceable steel links, a total of four test specimens with different short length ratios were designed. A low-cycle reversed loading test was carried out in terms of failure characteristic, hysteretic response and shear strength. The results indicated that all tested specimens presented a stable and full hysteretic response while the steel links especially exhibited a large inelastic deformation capacity and fully developed shear strength as the structural fuses. Besides, failure modes of steel links included two types of shear failure and bending-shear failure, followed by two types of damage features, including web-to-stiffener weld tear, web buckling, flange-to-end plate weld tear and flange buckling, respectively. Finally, nonlinear finite element models (FEMs) of test specimens were implemented by the Abaqus software. The numerical results were in good agreement with the experimental results in terms of load-deformation curves, initial stiffness, the development of Von Mises stress and cumulative plastic equivalent strain (PEEQ) indexes to facilitate design practice.

Reinforced concrete and steel (RCS) composite moment frame structures consist of reinforced concrete (RC) columns and steel (S) beams. Such systems combined with several advantages of the two structural members have larger structural stiffness, lower cost, and faster construction speed than the traditional concrete or steel frame system to be a particularly well viable alternative for use in seismic risk regions. The calculation of joint shear capacity is an essential step in seismic design. This study introduces the typical configuration characteristics of the RCS connection and reviews the state of the art of the shear bearing capacity in terms of failure models, shear distribution mechanisms, calculation mechanisms, and requirements given in the experimental and theoretical study to provide reference and foundation for the subsequent study. Finally, the development of recommendations and further research studies on seismic performance of RCS composite frames are provided.

Sustainable structures or structural components as one of the frontiers in civil engineering can solve the problem of construction and demolition waste and also enhance the reuse of structural components at the end of their service life or after damage. In terms of sustainable assessment, steel-concrete composite beams with or without novel demountable shear connectors were performed in this work. Structural configuration and mechanical properties of proposed sustainable steel-concrete composite beams were firstly presented and then the nonlinear analysis of this composite beams using the Abaqus software was validated. Three specimens with different types of shear connectors were designed and tested under two-point loading to investigate the flexural behavior and deconstructability. Results from this research showed that these composite beams exhibited a flexure-shear or flexural behavior, presenting the typical failure modes of yielding of steel beam, slab concrete split or concrete crushing of plug. Compared to that of traditional composite beam with embedded welded bolts, specimens with demountable shear bolts and demountable shear connections experienced reduced initial flexural stiffness (about 29.8% and 37.2%), yield strength (by about 18.3% and 32.1%) and ultimate strength (about 12.9% and 24.9%) due to the relative slip between the steel beam and precast concrete slab, respectively. Whereas these of composite beams developed a better deformation capacity and ductility coefficient. Additionally, sustainable steel-concrete composite beam with demountable shear connections could easily allow for easy installment and disassemble to achieve the recycle of these structural members and also replacement with new plugs to permit a quick seismic rehabilitation after earthquake damage. Finally, some suggestions of this sustainable composite beam and demountable shear connections were proposed to provide references for the design in practice.