Temperature Induced Stresses in Highway Bridges by Finite Element Analysis and Field Tests

摘要

This research focused on the application of finite element computer programs to the transient heat conduction and static stress analysis of bridge-type structures. The temperature distribution is assumed to be constant along the center-line of the bridge but can vary arbitrarily over its cross section. A computer program, TSAP, was developed for the prediction of the transient temperature distribution due to either daily variations of the environment such as solar radiation, ambient air temperature, and wind speed, or measured surface temperatures. This program, which also included thermal stress analysis based on elastic beam theory, was used extensively in this work to establish quantitatively typical magnitudes of temperature induced stresses for selected bridge types located in the state of Texas. Specific attention was given to the extreme summer and winter climatic conditions representative of the city of Austin, Texas. A static analysis program, SHELL8, which utilizes two-dimensional finite elements in a three-dimensional global assemblage with six degrees of freedom at each node point, was also developed to determine the thermally induced stresses and bridge movements. A concrete slab bridge was analyzed using this program to investigate skew and transverse behavior. Also, correlations between the field measured slope changes on two prestressed concrete bridges, and results that were obtained using the finite element programs, have been included.