Design Verification of a New Socket Partially Embedded Connection between Precast Rectangular Columns and Stepped Pile Caps

Socket connections are suggested to connect a precast column with adjacent members in accelerated bridge construction owing to their large construction tolerance. However, a typical socket-embedded connection always causes a heavy footing or pile cap due to the required embedment length, which is not preferable in the seismic design of a bridge system. In this paper, a new type of socket connection, namely, the partially embedded connection between a precast rectangular column and a stepped pile cap, is proposed to overcome this defect. Three half-scale specimens, that is, a cast-in-place specimen and two such designed socketed specimens with different step heights, were fabricated and tested to verify the new socket connection design concept. Experimental results showed that all specimens formed the approximate plastic hinges at the column bases and only minor damage occurred in the pile caps and the connecting regions; the hysteretic curves of the socketed specimens were approximately the same as that of the cast-in-place specimen, which proves that this new socket partially embedded connection is reliable to transfer the horizontal bending moment from columns to pile caps in a column–pile cap system and, meanwhile, can not only reduce the pile cap volume but also achieve the expected seismic performance.