The increase in the speed of the automobile and the increase in the volume of traffic has presented many problems to the highway designer, one of the most important being the elimination of grade crossings.
The rigid frame bridge, introduced in this country in the early 1920's, offered a very satisfactory solution to the problem of grade separation. This type of structure was used quite extensively by the Westchester County Park Commission in the expansion of the highway system of lower New York State. The rigid frame is more economical, has greater simplicity, and is more adaptable to architectural treatment than the more conventional deck or through girder bridge.
The problem of grade separation was simplified to a still greater degree by the use of the skewed rigid frame, but due to the complexity of analyzing this type of structure its use was limited in early installations.
Early theories for the analysis of the skewed type of structure were based on the theories of the right rigid frame and arch, but when these theories proved inadequate it was necessary to develop a more rigorous analysis. Although the new theories were accurate, they were also much too involved for practical use and certain assumptions were made to reduce their complexity.
Although the newly developed theories did solve the problem of analyzing the skewed rigid frame, another problem arose, namely that or the validity of the assumptions. Although structural failures were few, the use of high, and in some respects indeterminate, factors of safety may well have compensated for any errors in the assumptions.
Committee 314 of the A.C.I . is now making a study of the rigid frame bridge. It is hoped that at some time in the near future a theory, more in keeping with the true behavior of the skewed rigid frame, will be developed.
The Committee has decided that model tests offer a convenient solution to many of the problems arising in the development of a new theory.
It is the purpose of this thesis to find the stress distribution at the knee of a skewed rigid frame bridge model for various loading conditions. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/52183 |
| Date | January 1953 |
| Creators | Cusano, Michael Charles |
| Contributors | Civil Engineering |
| Publisher | Virginia Polytechnic Institute |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 79 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 18186073 |
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