Civil Engineering

 

First Advisor

Dr. Chungwook Sim

Second Advisor

Dr. Joshua Steelman

Third Advisor

Dr. Jiong Hu

Date of this Version

Fall 11-30-2018

Citation

Bleyhl, A. T. (2018), "Experimental Study on a New Type of Transverse Connection for Nebraska County Bridge System," Master's Thesis, School of Civil Engineering, University of Nebraska, Lincoln, NE.

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Civil Engineering, Under the Supervision of Professor Chungwook Sim. Lincoln, Nebraska: December, 2018

Copyright (c) 2018 Alexander T. Bleyhl

Abstract

Many county-owned bridges in Nebraska need replacement due to their structural deficiency. Most of the bridges needing replacement are in the 40 to 60 ft range. This span range lacks a standard design that fits Nebraska county practices in terms of speed and simplicity of construction. The current systems being used are (a) Precast 1 by 2 ft planks which can span up to 30 ft, (b) Cast-in-place slab bridges which can span up to 50 ft but require extensive field formwork, concrete placing, and curing, and are best when constructed in three-span units, and (c) Inverted tees which can span 40 to 80 ft, but require cast-in-place decks. The objective of this research project is to develop and evaluate a cross section that can be easily configured for optimal structural efficiency across a range of spans from 40 to 60 feet, while reducing the number of longitudinal shear keys, and retaining the ease of construction presented by the plank design. To achieve this objective, three phases of research were conducted. The first phase included evaluating various sections for spans up to 60 ft. This phase was completed through an extensive literature review and a, new type of cross-section was proposed in this study. The second phase of the research evaluated a new type of transverse connection to connect adjacent units of the proposed cross section for the proposed state county bridge system through small-scale testing on ten slab specimens. Finally, two sets of full-scale bridge specimens were tested to evaluate the system behavior, including the performance of the proposed transverse connection that included the new type of mechanical connection, and staggered rebar splice joints with a commercial high-performance concrete used for the shear key. Test results indicated that the new type of mechanical joint system (transverse connection of adjacent precast beam bridges) can resist an experimental joint moment of 38 ft-kip on average, provided that the maximum spacing between mechanical joints along the bridge span does not exceed 4 ft. It was also noted that the high-performance concrete can carry a joint moment of 17.5 kip-ft per foot length which is 2.5 times larger than the equivalent moment carried by the mechanical joint system with self-consolidating concrete grout.

Advisor: Chungwook Sim

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