New Structural Joint by Rebar Looping Applied to Segmental Bridge Construction: Fatigue Strength Tests

Abstract

The objective of this research has been to design, develop, and evaluate experimentally a modified type of construction joint of limited length between concrete slab segments. The design concept is based on an anchorage hook of reduced development length stiffened by transverse reinforcement bars. The purpose of this paper is to investigate the mechanical behavior of the joint in terms of stiffness and strength for an application that requires high durability, which often leads to serviceability problems such as cracking and water leakage at transverse joints. This can regularly appear in bridges. Additionally, bridge decks are structures that are subjected to repeated loading such as traffic loads, making it necessary to evaluate the behavior of joints under fatigue load. Therefore, studies focusing on the strength, stiffness, and serviceability of the joints must be carried out. This paper investigates experimentally the fatigue behavior and strength of loop joints with regard to the loop bar diameter, loop joint width, and applied load ranges. These results were compared with the behavior of RC slabs without joints. A total of eight slabs were fabricated for fatigue loading tests, and the failures of the different specimens (with loop joints and without) were obtained. From the test results, the mechanical behavior of the slabs with loop joints was confirmed to be similar to that of the slabs without joints. The experimental loop joint design was found to perform correctly under fatigue loads.