Performance of non-contact lap splices in geometrically dissimilar bridge column to drilled shaft connections

Abstract

It is often required to provide a reinforcing steel splicing arrangement with non-contact lap splices due to the limitation of internal space or geometric irregularity for the connection of non-circular bridge columns interfacing directly with circular drilled shafts. But there are concerns regarding the safety and cost-effectiveness of such non-contact lap splices at bridge column to drilled shaft connections because the guidelines in AASHTO LRFD Bridge Design Specifications (2017) and studies on this type of connection are limited. This paper presents an experimental investigation of non-contact lap splices in non-circular bridge column to circular drilled shaft connections. A total of seven large-scale column-drilled shaft specimens were tested to investigate the effects of the critical parameters affecting the performance of such non-contact lap splices. The investigated parameters were the non-contact splice distance between the spliced bars, the lap splice length and the amount of transverse reinforcement in the non-contact lap splice zone. The specimens were subjected to flexure action with both monotonic and cyclic loading. The results of this study provide a basic understanding of the behavior of non-contact lap splices in non-circular columns to circular drilled shaft connections. Based on the findings from the experimental investigation, a set of design recommendations is provided for the design of non-contact lap splices in geometrically dissimilar bridge column to drilled shaft connections. All in all, with the consideration of the current AASHTO LRFD code and the design recommendations from this study, a safe non-circular column to circular drilled shaft connection can be constructed.