Optimized performance of ultra-high performance concrete bridge connections

Abstract

In this study, research is presented on the structural performance and evaluation of two separate UHPC mixes (one proprietary mix and one non-proprietary mix) using methods to quantify their performance especially as it pertains to UHPC non-contact lap splice bridge connections. Four defining tests (fresh, compressive, tensile, and UHPC-rebar bond) are outlined and results from the tests are analyzed in context with industry standards and past research on UHPC. Additionally, a finite element model was developed in ABAQUS to simulate the structural performance of a commonly employed UHPC bridge connection. Modeling techniques and comparison between the model and the physical structural test are explained and evaluated to assess the performance of UHPC non-contact lap splice connections. Ultimately, the rebar pull-out test results for both the proprietary and non-proprietary mixes support the UHPC connection guidelines by FHWA in terms of minimum requirements for development length, lap splice length, minimum rebar cover, and maximum clear space between adjacent lap spliced rebar. Also, unique insight is provided on detailing a UHPC connection for adequate connection performance based on the test results obtained between the two mixes’ failure mode, peak bar axial stress, and bond strength.