Concrete bridge rails are rated according to three performance levels. For classification at a given performance level, the rail must meet specific strength and geometric requirements. To meet the strength requirement, the rail must be able to satisfactorily withstand a transverse concentrated load applied at the top of the rail. This load is called F<sub>t</sub> (kips) and is listed for each performance level in the Draft NCHRP Project 12-33 document entitled Development of a Comprehensive Bridge Specification and Commentary.
Researchers at the Texas Transportation Institute have developed equations to determine R<sub>w</sub> (kips), the total transverse resistance of a rail (which must be greater than or equal to F<sub>t</sub>), and L<sub>c</sub> (ft), the critical length of wall failure (Hirsch 1978). These equations (referred to as Hirsch equations is this study) were developed by yield line analysis for a constant thickness concrete parapet wall.
The purpose of this study is to develop similar equations for R<sub>w</sub> and L<sub>c</sub> based on yield line analysis of a variable thickness New Jersey concrete parapet wall instead of a constant thickness wall.
The results from this study indicate that the Hirsch equations significantly over estimate R<sub>w</sub> for variable thickness concrete walls where M<sub>c</sub>, the flexural resistance of the wall about the horizontal axis, varies substantially over the height of the wall. This study recommends that an average value for M<sub>c</sub>, taken over the height of the wall, be used in the Hirsch equations when this situation arises. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/34936 |
| Date | 05 September 2009 |
| Creators | Calloway, Benita R. |
| Contributors | Civil Engineering, Barker, Richard M., Holzer, Siegfried M., Garst, Donald A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | x, 71 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 29040201, LD5655.V855_1993.C344.pdf |
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