The behaviour of ultra-high-performance concrete in precast concrete bridge deck connections

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Date
2020-03
Authors
Stefaniuk, Heather
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Abstract
This thesis studies the behaviour of ultra-high-performance concrete (UHPC) in the precast concrete bridge deck connections. The experimental program consisted of shear pocket push-out testing and full-scale bridge deck testing. The main objective was to study the UHPC performance in the shear pocket and joint connections. All specimens were statically loaded until failure. The push-out test specimens consisted of two small 45 MPa concrete slabs on either side of a built-up steel section, joined together by shear studs and UHPC shear pockets. There were three 6-stud specimens, two 3-stud specimens and two 0-stud specimens. The 6-stud specimens reached ultimate loads of 2642 kN, 2892 kN, and 3045 kN. The 3-stud specimens reached ultimate loads of 1445 kN and 1674 kN. The 0-stud specimens reached ultimate loads of 4.91 kN and 3.44 kN. The failure modes for the 6-stud and 3-stud specimens were stud failure or concrete crushing, while the 0-stud specimens failed when the UHPC and steel section surface debonded. The push-out specimens were instrumented with LVDTs, pi-gauges and strain gauges to collect data on the displacements, debonding, and shear stud strains throughout testing. The bridge deck testing included a full panel deck (FPD) and jointed panel deck (JPD). The FPD was cast monolithically with regular strength concrete and had UHPC shear pocket connections to the steel support girders. The JPD was cast as two half-size regular strength panels connected together with a UHPC joint, and connected to the steel support girders with UHPC shear pockets. The FPD and JPD reached ultimate loads of 1926 kN and 1878 kN, respectively. Both decks failed by concrete punching under the load point. The bridge decks were instrumented with LVDTs, pi-gauges, and strain gauges to collect data on the deflections, crack widths, steel strains, concrete strains, and shear stud strains throughout testing. The experimental results implied the number and length of the studs in the shear pockets may be reduced. The better performance of the FPD also indicated the circular pockets were superior and the use of UHPC in precast deck connections does not significantly improve the overall performance.
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Precast concrete, Ultra-High Performance Concrete, UHPC, Bridge decks, Shear pocket, Joint, Shear stud, Push-out test
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