Date of Award

1-1-2013

Document Type

Open Access Thesis

Department

Civil and Environmental Engineering

Sub-Department

Civil Engineering

First Advisor

Paul H Ziehl

Abstract

This study investigates the behavior and performance of latex modified concrete (LMC) as a closure pour material with a U-bar connection detail in longitudinal joints between precast deck bulb tee bridge girders with integral concrete decks. The objective was to determine if the joint detail was capable of resisting service shear and moment stresses as well as eliminate the formation of cracks in the joint during fatigue loading. This study tested two large scale reinforced concrete slab specimens measuring 6 ft x 6 ft x 8 in joined together by the longitudinal joint detail in fatigue flexure shear loading. The fatigue loading consisted of 2,000,000 cycles at 1.5 Hz and varied between 4.4 and 25 kips. At 500,000 cycle intervals, a service level overload was performed where the specimen was loaded to 46.9 kips. During the fatigue and service level testing, the joint area was inspected visually to determine whether cracks had formed, and a ponding test was initiated after the conclusion of testing to determine whether the joint was water tight. Vertical through cracking of the longitudinal joint was not detected throughout the study. During the ponding test, water was not seen leaking vertically through the joint, however a slight discharge could be seen at one joint end. Since the leak was in the compressive zone of the joint, it is assumed that this crack developed from drying shrinkage, and not from external loading. Based on the performance of the joint, the U-bar detail with an LMC closure pour is recommended for longitudinal joints in precast deck bulb tee bridge systems.

Rights

© 2013, Clark Baer

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