Measurement and Simplified Modeling Method of the Non-composite Deflections of Steel Plate Girder Bridges

Abstract

Many of today's bridge construction projects are erected in stages to limit traffic interruptions or to minimize environmental impacts. Typically, one half of the bridge superstructure is constructed in the first stage and the other half constructed in the second stage. The final stage is to cast a closure strip to join the deck slabs of the two structures together. Due to the inability of current analysis methods to accurately predict the non-composite dead load deflection for steel plate girder bridge during construction, three-dimensional finite element bridge models have been developed to more accurately predict the bridge behavior. However, the bridge engineer must first consider the complexity of and the time spent modeling bridges in this way.

The objective of this research is to develop a simplified modeling method to predict the non-composite dead load deflections of the steel plate bridge girder. The study is focused on creating a modeling method for both single span and two-span continuous bridges. Parameters such as bridge skew, cross-frame stiffness, and stay-in-place metal deck forms were considered in the development of the simplified models. By measuring the deflections in the field during the construction, the true non-composite deflection behavior of the bridge was captured and compared to the results from modeling.

As a result, the predicted deflection of the simplified models agreed well with the measured results for the single span bridges. Additionally, predicted deflections from the simplified models correlated well with the deflection results from finite element models for the single span bridges. However, the predicted deflections from the simplified models had a poor agreement with the measured results for the two-span continuous bridge. It was also concluded from both field measurements and modeling results that stay-in-place metal deck forms have a significant effect to the non-composite dead load deflection behavior for skewed steel plate girder bridges.