Winter temperature measurements in a composite girder segment

This article presents experimental results from a concrete-steel composite girder. The girder is composed of an I-shape steel beam that is topped by a reinforced concrete slab. The girder was constructed in an open environment so that it is freely subjected to the variation of the atmospheric thermal loads. These loads include the solar radiation, temperature of the surrounding air and speed of the wind. Therefore, a weather station that includes sensors to measure the three aforementioned thermal loads was installed beside the girder. The girder was instrumented with thermocouples that were either embedded in the concrete slab or attached to the steel beam. The thermocouples were distributed across the slab thickness, along its width and along the vertical centerline of the composite girder. The aim of this research is to provide experimental measurements that facilitate better understanding of temperature gradient distributions in composite bridge girders in winter. The test records were continued for approximately two months during the cold season. The test results showed that the negative vertical temperature gradient was higher than the corresponding positive one due to the low intensity of solar radiation. Similarly, the lateral positive temperature gradient along the width of the concrete slab was higher than the vertical positive temperature gradient due to the low altitude of solar radiations.