THE PERFORMANCE OF LAPPED SPLICES UNDER RAPID LOADING

The impact or dynamic response and resistance of structures or structural components has been of increasing interest in recent years. The failures of lapped splices at the bases of some concrete highway support structures during the San Fernando earthquake led to questions as to the suitability and adequacy of a lapped splice subjected to fast loading rates. In addition, the damage produced by hurricane and toronadoes supresses earthquake damage and gives added impetus to the study of structural behavior under dynamic loads. In this investigation the behavior of lapped splices subjected to impact loading was studied. The objective was to compare the strength and behavior of splices under static and dynamic loads and to determine whether the design provisions based primarily on static tests could be relied on under dynamic loading conditions. Two series of tests were conducted. In the first series (eight beams), the specimens was subjected to impact loading producing failure in either one cycle or in three to five cycles of incrementally increasing magnitude. In the second series (twelve beams), the specimens were subjected to either unidirectional or reversed cycles of impact loading. This investigation concentrates on explaining differences between dynamic (impact) and static behavior of splices. Analytical studies were carried out to help evaluate the experimental data. In general, the dynamic moment capacity of a splices is at least a large as large and usually larger than the static moment capacity. A splice length based on design specifications developed using static test results would appear to provide adequate capacity under dynamic loading conditions.