Mechanical properties and seismic isolation behavior of scrap tire pads subjected to thermal-cold cycles in rural construction

This paper presented systemic research evaluating the mechanical properties and seismic isolation behavior of scrap tire pads (STP) subjected to thermal-cold (TC) cycles. The mechanism of the TC-damaged tire rubber was linked to the mechanical characteristics and seismic isolation behavior of the TC-damaged STP. Thus, the deterioration mechanism of the TC-damaged tire rubber was investigated first. Then, vertical compression tests were conducted with 15 groups of STP to study the vertical mechanical properties. The vertical stiffness, vertical deformation performance, and vertical ultimate bearing capacity were analyzed. Results showed that with an increasing number of TC cycles, the vertical deformation performance and vertical ultimate bearing capacity of STP decreased, whereas the vertical stiffness increased. In addition, to promote the use of STP in village frame structures, a novel seismic isolation device under the column (SIDC) was proposed. In SIDC, the hysteresis behavior, destructive properties, horizontal equivalent stiffness, and equivalent damping coefficient of STP were investigated. The results showed that the horizontal equivalent stiffness was lowered by 45.20 %, the equivalent damping coefficient dropped by 8.04 %, and the cumulative energy degradation was up to 35.0 % when the number of TC cycles increased to 520 compared to that of STP without TC cycles. Finally, an optimized nonlinear two-spring restoring force model was proposed to describe the hysteresis hardening characteristics of TCdamaged STP in SIDC. Furthermore, the theoretical model and experimental findings were compared, with the theoretical model describing the hysteresis hardening behavior the best.