In this study, both fire tests and low-frequency cyclic loading tests after fire were conducted on three conventional high strength concrete (HSC) shear walls and a superimposed HSC shear wall with precast recycled aggregate concrete (RAC) panels. The RAC in this paper was made with recycled concrete aggregate. When specimens suffered the fire exposure on one side for 45 min, 90 min, and 135 min separately, spalling of concrete, temperature distribution and deformation of specimens were investigated as indicators of fire response. When specimens were subjected to cyclic load after fire, hysteresis curves were obtained, based on which the secant stiffness degradation and energy dissipation capacity of walls were analyzed. The results indicated that HSC would suffer severe spalling during the fire and that fire response of the superimposed wall including spalling was smaller than that of conventional walls. Using RAC panel as a thermal barrier was found to be effective to alleviate spalling, as it reduced more than 60% of spalling of HSC compared with bare walls. Based on the seismic tests results, the fire exposure deteriorated the load bearing capacity, lateral stiffness and energy dissipation capacity of walls, whereas the application of RAC panels improved the load bearing capacity by about 10% even when the superimposed wall was exposed to the fire for a long time.
An experimental program concerning 48 specimens of grouted sleeve splices, first heated up to 600°C and then subjected to cyclic loading was presented and discussed in this study. Similar rebar splices were often used in the precast concrete structures designed for seismic regions. The temperature of the splice and the compressive strength of the grout were the main variables considered in this study. It is found that the temperature mainly affected the peak bearing capacity of the grout and the failure pattern of the connection. In fact, the typical failure pattern at room temperature (rebar fracture outside the sleeve) turned to rebar pullout of the sleeve above 400°C, which indicated that below this temperature grout‐to‐rebar bond kept most of its original efficacy. On the contrary, bond failure occurred for all specimens at 600°C because of rebar slip. A calculation method was proposed as well to evaluate the peak bearing capacity of grouted sleeve splice, based on the load transferring mechanisms of the bond between grout‐to‐rebar and sleeve‐to‐grout. The conducted experimental study and analysis provide a better understanding on the bond mechanism of thermally damaged grouted sleeve splices subjected to cyclic loading.
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