Date of Award

2014

Degree Type

Thesis

Department

Civil and Environmental Engineering

First Advisor

Delatte, Norbert

Subject Headings

Bridge railings, Concrete bridges -- Maintenance and repair, Concrete bridges -- Cracking, Bridge railings -- Cracking -- Ohio -- Prevention, Bridge railings -- Design and construction, Bridge parapets, concrete, cracking, improved parapet designs, joint details, deeper saw cuts, fibers, GFRP

Abstract

Premature cracking of concrete bridge parapets is a potentially complex problem, with a number of possible causes. Identifying the cause of premature cracking, and avoiding this problem in the future has several benefits, including: a potential cost savings for the district, improving the safety of these structures in future construction, and increasing the overall understanding of parapets. The objective of this study was to analyze the reasons for uncontrolled cracking in order to establish an improved parapet design, and provide recommendations to the Ohio Transportation (ODOT) to prevent such cracking in the future. Previous research carried out a forensic investigation of four bridges in Northeast Ohio that exhibited extensive parapet cracking. In many cases, vertical cracks appeared between control joints. The study evaluated a number of hypotheses as to the causes of cracking, which were utilized in developing modifications to implement on test parapets for continued research. Potential factors examined in this study to continue research included: properties of the concrete mixtures used, construction methods, joint details, composite structural action, and durability of the concrete and reinforcement. A total of 22 test parapets were constructed as part of this project to evaluate different approaches to address premature cracking. In this study, 15 of the 22 parapets were constructed and examined. Not enough information was gathered thus far on the use of deeper saw cuts through glass fiber reinforced polymer (GFRP) reinforcement or field cut steel reinforcement to determine if this modification is a cost-effective choice. The parapets that included polypropylene fibers in the mixture did not perform any differently than the parapets without fiber in regards to early age cracking. Fibers may not have been needed with the concrete mixture that was used to prevent shrinkage or thermal cracking, but it may prove to be an efficient modification in the future by improving the durabili

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