Experimental study on seismic behavior of plane frame structures of RC stilted buildings

In order to investigate the seismic performance of the stilted frame structure built on sloping field, a typical 7-story reinforced concrete (RC) stilted frame structure was designed. According to the ratio of 1/3, the lower three-story two-span substructure along the slope was extracted as the test object, a quasi-static test of plane frame stilted structure was carried out, the process of crack development and failure mode was observed, and the seismic performance was analyzed in terms of hysteretic behavior, ultimate capacity, ductility and damage path. The failure mode of the stilted floor was discussed. The results show that: the failure mode of the sub-structure is the plastic hinges of beams and columns. First, the plastic hinge is formed at the beam end of the second floor, then the hinge is formed at the lower end of the short column, the beam end adjacent to the column, and the top of the middle column of the third floor. The final failure is marked by the concrete collapse of the short column, the concrete spalling at the beam end and concrete spalling on both sides of the top of the 3-story central column. The failure path of the stilted layer is that the short column develops downward along the slope, and that of the second layer develops from the middle column to both sides. Bending failure is still the main failure mode of the short column where the failure mode of strong shear and weak bending can be realized by reasonable design. The non-uniform stiffness of columns of stilted floor leads to the difference of the damage state of columns at the stilted floor, and the failures are mainly focused on the short column and the adjacent beam end of the stilted floor. In order to prevent serious local damage, it is beneficial to resolve non-uniform distribution of the stiffness between the columns of the stilted floor. © 2022, Editorial Office of Journal of Building Structures. All right reserved.