Development of improved loop joint applied for precast PC deck slab

Abstract

Ordinary “loop joint” applied to precast prestressed concrete (PC) deck slab tends to increase its thickness. By decreasing this thickness, the dead load of the deck slab can be reduced. Hence, we have developed an “improved (inclined) loop joint” that reduces the deck slab thickness. This study presents the results of static bending test of slab specimens to confirm the load-carrying behavior and wheel moving load test to examine the fatigue durability of precast PC deck slabs with improved loop joints. The bending load-carrying behavior satisfied the requirements for highways in Japan. In addition, in the wheel moving load test, no sudden increase in vertical deflection and joint opening was confirmed at a load step of 250 kN × 100 000 times equivalent to 100 years on an actual bridge. Moreover, there was no water leakage at the bottom surface of the deck slab during the water-filling test. Based on the test results, it was inferred that the required load-carrying behavior and fatigue durability could be retained for 100 years in the improved loop joint.