SIDE SHEAR STRENGTH OF MEMBER SOCKET CONNECTIONS FOR PRECAST BRIDGE CONCRETE SUBSTRUCTURE ELEMENTS

The design of connections for precast bridge concrete elements, particularly those connecting columns to their foundation/cap beam, poses a major challenge in the widespread practical implementation of Accelerated Bridge Construction (ABC). Member sockets, among various connections used that resemble cast-in-place concrete, offer unique advantage of facilitating easy construction with large installation tolerance. Ensuring sufficient side shear capacity in member sockets of precast concrete substructure, is crucial due to high axial load transfer from the superstructure. However, the shear-friction behaviour at the interface between the precast concrete column and the spread footing is not well understood to date. This lack of understanding extends also to the shear stress limits required to design the connection effectively. To address the aforementioned gaps, the main objective of the current paper is to quantify the side shear capacity of the precast column-to-spread footing socket connection using ultrahigh-performance concrete (UHPC) grout. To achieve this objective, two scaled specimens with varying grout thickness are subjected to uniaxial, displacement-controlled load. The visual observation also reveals that with the use of UHPC grout, significant damage on the precast components can be avoided. The test results show that the test connection specimens exhibited side shear failure mechanism. The force-displacement response illustrates that increased grout thickness leads to higher side shear strength and stiffness before slipping occurs.