Author Bert, Stephen M
Author's Email Address sbert@vt.edu
URN etd-05162005-073043
Title Using Maturity to Predict Girder Camber
Degree Master of Science
Department Civil Engineering
Advisory Committee
Advisor Name Title
Dr. Carin Roberts-Wollmann Committee Chair
Dr Richard Weyers Committee Member
Dr Thomas Cousins Committee Member
Keywords
* Modulus of Elasticity
* Maturity
* Camber
Date of Defense 2005-05-04
Availability unrestricted
Abstract
The objective of this research was to determine if differential camber of prestressed concrete girders could be reduced by accurate prediction of initial camber at release of prestress. Maturity at prestress transfer was used to calculate modulus of elasticity for predicting camber at release. The research consists of a literature review of maturity methods, testing of a standard concrete mix to determine strength and modulus functions and measurement of girder camber and maturity.
Both the Nurse-Saul and the Arrhenius maturity models were evaluated. Maturity relationships were developed for concrete mixes containing Type II and Type III cements. A relationship of modulus as a function of maturity was developed. Seven girders were tested. Camber predictions within 0 to ¼ in. of actual camber were obtained using modulus of elasticity calculated from a maturity based function. Comparison was made between maturity based modulus and standard strength based modulus models. Camber predictions based on modulus calculated based on field cured cylinder strengths were within 0 to ½ in.
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