Experimental Research on Seismic Performance of Bottom Joints in Prefabricated Steel-Reinforced Concrete Outer Walls of Underground Metro Stations

A prefabricated steel⁃reinforced concrete structure for column⁃free underground metro stations was proposed. The seismic performance of the bottom joints of outer walls was studied by quasi⁃static loading tests on three 1/3⁃scale specimens， including one specimen with concrete solid sidewalls， one specimen with concrete composite sidewalls， and one cast⁃in⁃place specimen. The results showed that the bottom joints of the prefabricated steel⁃reinforced concrete outer walls with solid sidewall and composite sidewall configurations all exhibited excellent structural integrity， with their bearing capacities close to that of the cast⁃in⁃place specimen. The ductility coefficients of the specimens with solid concrete sidewalls and composite concrete sidewalls were 3.1 and 3.0， respectively， which were 7.0% and 3.4% higher than those of the corresponding cast⁃in⁃place specimen.The energy dissipation capacity and stiffness degradation characteristics of the two prefabricated steel⁃reinforced concrete specimens were similar to those of the cast⁃in⁃place specimen.