Self-centering bracing systems, by which residual deformations of structures after earthquakes can be minimized, are considered effective solutions to achieve seismic resilience. In this paper, a parametric study on the seismic response of intermediate and highrise steel-framed buildings with novel self-centering tension-only braces (SC-TOBs) is numerically conducted. ree key parameters, the stiffness degradation factor, the activation strain, and the initial axial stiffness of the SC-TOBs, are investigated to explore the design space for the SC-TOB frames (SC-TOBFs) because of their unique tunability compared with traditional bracing systems. Identical steel frames equipped with buckling restrained braces (BRBs) are also designed and examined for comparison purposes. e results indicate that increasing the stiffness degradation factor can improve the second stiffness of SC-TOBFs and successfully make the distribution of interstory drifts more uniform; an increase in the activation strain leads to a larger activation deformation of SC-TOBFs, but it has a very limited effect on the interstory drifts; increasing the initial axial stiffness appropriately is beneficial to reduce the interstory drifts of the low stories. e lateral behavior of SC-TOBFs is comparable to that of BRB frames when a lower activation strain and a higher initial axial stiffness are selected. Furthermore, when a higher stiffness degradation factor and a lower initial axial stiffness are selected simultaneously, the seismic action on SC-TOBFs can be effectively reduced, and a relatively uniform distribution over the building height can be obtained. e SC-TOBFs are considered to be a type of performance-tunable structure, and tuning can be achieved by varying a frame's adjustable parameters.

The self-centering tension-only brace (SC-TOB) is a new and innovative bracing system that provides both a flag-shaped recentering hysteresis and load mitigation to structures. This paper presents an extensive investigation of the nonlinear seismic response of multistory steel frames built with SC-TOBs to internal force, drift, and energy dissipation. Pushover analysis subjected to two lateral load distributions and nonlinear dynamic analysis under ground motion ensembles corresponding to four hazard levels were conducted. The SC-TOBs can be designed to serve as conventional tension-only braces (TOBs) only providing lateral stiffness during minor earthquakes, to function with energy dissipation as intensity increases, and to fully recenter a structure even after severe earthquakes. The findings show that with an increase in the earthquake intensity, both the force response and drift response of the SC-TOB frames (SC-TOBFs) increased; however, the force distribution and drift distribution shapes of the SC-TOBFs remained almost constant. The SC-TOBFs generally experienced more energy dissipation in the lower parts of the building, while the upper stories dissipated almost no energy under certain load conditions, suggesting that the bracings on those stories could be replaced by conventional TOBs for economy. It is demonstrated that the SC-TOBs have immense potential to effectively improve seismic resilience to structures such that rehabilitation costs and operational disruptions after earthquakes are minimized.

The finite element analysis method was adopted to simulate the masonry wall strengthened with steel strips and was verified by comparing with test results. The influence rules of two factors including the cross sectional area of steel strips and vertical compression were investigated. The results show that, as for unreinforced masonry wall, the relationship of the shear capacity of unreinforced masonry wall and the vertical compressive strain is linear under lateral load; the speed of stiffness degeneration is accelerated after the peak point of the curves, but decrease with the increasing of lateral displacement. As for masonry wall strengthened with steel strips, the shear capacity increases significantly, and shows nonlinear relationship with the cross section area of the steel strips and vertical compression; ductility is improved. Finally, a computational formula of shear capacity based on a lot of parametric analysis is proposed to calculate the sectional dimension of steel strips, and it provides theoretical foundation for establishing thorough design method of masonry wall strengthened with steel strips.

The self-centering tension-only brace (SC-TOB) is a new type of flexible bracing system that provides both energy dissipation and re-centering capacities to the structure. In this paper, a computational investigation on the seismic performance of steel frames with SC-TOBs is conducted. Two main parameters, including the stiffness degradation factor and the activation strain of the SC-TOB, are investigated through pushover analysis. The results indicate that increasing the stiffness degradation factor leads to a larger second stiffness of the SC-TOB frames (SC-TOBFs), which is beneficial to make the distribution of drifts more uniform over the building height; the activation strain has a significant impact on the activation deformation of SC-TOBFs, but a slight effect on the distribution of drifts. The SC-TOBFs is deemed as a type of performance-tunable structure, which can be achieved by varying a frame’s adjustable design parameters.

Because of the seismic vulnerability of these masonry structures, many strengthened technologies for improving their its seismic performance of masonry panels have been improved in old days. In this paper, a rapid strengthening approach of masonry structures which is diagonal steel strips attached to the masonry panels is proposed. To investigate crack pattern, shear strength, lateral stiffness and ultimate displacement, four Specimens constructed at with 1:2 scale are designed. One specimen was not strengthened by steel strips, and the others strengthen by steel strips with different width and thickness. They are tested under combined constant vertical compression and cyclic lateral loading. The experimental results prove that reinforcement approach could a changed crack pattern. Also, it could significantly increase in the shear strength and lateral stiffness of masonry panels. The width of steel strips is more significant than the thickness of steel strips in strengthening shear strength and lateral stiffness of masonry wall.

Accelerated bridge construction is desired in urban areas or after natural disasters, thus, it has drawn the attention of the bridge community and transportation agencies worldwide. It has lead to the advancement of accelerated construction techniques using prefabricated bridge elements. In this paper, an innovative self-balanced bridge structure consisting of assembly truss units, flexible cables, and struts is proposed. All components of this truss string structure are fabricated in the precast plant before being shipped to the construction site, therefore reducing the amount of labor and time on-site significantly. The mechanical performance of this structure is studied with three-dimensional finite-element method under the influence of key parameters such as the number of struts, the distance between struts, sag-span ratio, and initial pretension. Parametric analysis of 6 pedestrian bridge models with typical span shows that the optimized structure form reduces steel consumption by up to 59.4% compared to regular truss structures.

Recent research has developed the self-centering tension-only brace (SC-TOB) that provides both seismic resilience and load mitigation to the structure. This study examined the seismic behavior of the SC-TOB frames (SC-TOBFs) through pushover and nonlinear dynamic analysis. The results indicate that the SC-TOBs can be designed to perform as conventional tension-only braces just offering required lateral stiffness to the structure under minor earthquakes and to function with excellent energy dissipation and recentering capabilities during significant earthquakes. The SC-TOBFs are capable of recentering both within 2% roof drift angle in pushover analysis and under the most severe hazard level in the dynamic analysis. The SC-TOBs are thereby deemed to be promising bracing members that have the potential to minimize the repair costs and operation disruption after earthquakes.