Development of Temporary Joint Structure for Width-Dividing Construction of Slab Replacement Work

Abstract

A precast prestressed concrete slab has been commonly used for the replacement work of a deteriorated reinforced concrete slab in terms of shortening its period and longevity in Japan. Although most replacement work at an expressway causes its roads to be closed completely, width-dividing construction of slabs can make one lane open in the case of a two-lane expressway. One of the methods is that a no-shrinkage mortar is filled in the longitudinal joint between divided slabs, and pre-stress is introduced so that these slabs are connected in the transverse direction.

One problem of this method is that the relative displacement between the primary slab and the secondary slab, which were set firstly and secondly, respectively, occurs by traffic repetitive loading on the primary slabs. This displacement may cause cracks or openings at the longitudinal joint while the no-shrinkage mortar has been hardened. Thus, a temporary joint called plate-type joint, which comprised of a steel plate strengthened by a vertical stiffener, and a prestressing tendon, was developed to temporarily connect divided slabs and restrain relative displacement. In this research, experiments to identify the friction coefficient of the boundary between the temporary joint and the concrete were conducted by using beam specimens. In addition, wheel running fatigue tests were carried out to determine the structural performance, the results of which confirm sufficient fatigue resistance against opening at the longitudinal joint.