Mechanical properties and reinforcement technology of deep joints under static and fatigue loads

Abstract

Fabricated hollow-core slab bridges inevitably contain joints that should be made structurally stable. With the increase in traffic and vehicle loads, the joints are prone to damage. Four new joint reinforcement schemes are proposed to improve the durability of the joint. These reinforcement schemes include pinned rebar reinforcement, prestressing tendon reinforcement, carbon fiber cloth reinforcement after cracking, and carbon fiber cloth reinforcement before cracking. Nine concrete beams with joints were subjected to bending tests under static load and cyclic dynamic load. Results show that under static load, the cracking load and ultimate load of the reinforced joints were higher than those of the control joints. Under cyclic load, the damage process after joint cracking can be divided into three stages: rapid development, slow development, and failure. The fatigue life and integrity of the reinforced joints are higher than those of the control joints. In particular, the fatigue life of the joints reinforced with carbon fiber cloth before cracking is increased by 157.6 times.