Study on Fire Resistance Limit of Bolted Prefabricated Beam-Beam Joints

In this paper, the fire resistance limit state of a new bolted prefabricated beam-to-beam joint exposed to fire, and the influencing factors of its fire resistance limit were studied. Based on the ABAQUS finite element software, a numerical simulation of bolted prefabricated beam-beam joints under temperature load and static load is carried out, and the mid-span deflection curve is drawn according to the fire exposure time for different components. The mid-span deflection of the bolted prefabricated beam-beam joints gradually increases with the increase of fire exposure time, and breaks away from the linear growth when approaching the fire resistance limit. With the increase of fire exposure time, the growth rate of the mid-span deflection of the components is constantly increasing, and the growth rate of the mid-span deflection of specimens with different fire resistance is also different, the greater the load ratio of the components, the shorter their fire resistance limit; the higher the concrete strength grade, the thicker the concrete protective layer, and the longer the fire resistance limit. The size of the bolt pretightening force and the bolt strength grade have no effect on the fire resistance rating in the present model design.