ABSTRACT
Shear Metallic Damper (abbr. SMD) has been widely used in building structures to reduce the seismic response due to the excellent performance of dissipating energy during earthquake. The yield displacement of SMD is very small as the allowed displacements between adjacent floors of buildings are small, and the stiffness of SMD is relative large in the deformed plane. The initial stiffness can be strengthened by extending the steel plate of the damper in its own plane, the energy dissipating ability can be increased by changing the geometry of the steel plate of the damper, which was proposed by Li (2006), and quasi-static tests of five types of SMD were carried out. A novel steel shear panel damper called a buckling restrained shear panel damper (abbr. BRSPD) was proposed by Deng (2014, 2015), in which two restraining plates were used to limit the out-plane displacement of energy dissipation plate, quasi-static tests of five specimens were carried out to investigate the performance of the BRSPDs, and the dampers were used to reduce the seismic response of the bridge. However, the expansion caused by temperature was not considered. The hysteric model for SMD and Buckling-Restrained Brace (abbr. BRB) can be sim-
SMD can be driven by relative displacements between girder and towers or piers for long-span cable-stayed bridge with floating or half-floating supporting systems. There is a significant difference between the building structures and bridges, and expansion movements are required by bridges between girder and towers or piers, which may be caused by temperature or moving vehicles. For example, temperatures may cause a significant internal force in the girder. A simply supported steel bridge is taken as an example to demonstrate the effect of temperature on the expansion, and the diagram is shown in Fig. 1. The length of the bridge (L) is 500 m, the section area (A) is 0.9 m2, and the temperature change (ΔT) is 20°C; the gravity of the bridge is ignored. The elastic module (E) and temperature coefficient (α) of steel are 2.06 × 108 kPa and 1.2 × 10−5 respectively. SMD was installed directly between girder and supports, with the lateral stiffness of SMD khorizontal of 2e5 kN/m and the free expansion of each end of 0.06 m (calculated by αΔTL/2), and the axial force is 7795.4 kN (calculated by F = 0.5αΔT/[1/EA+1/(Lkhorizontal)]). It is obvious that the internal force caused by temperature is very high.
