Investigation of temperature gradients in composite girders in the southern region of the black sea

Based on an experimental composite concrete slab-steel beam girder and using a verified finite element thermal model, a case study analysis was performed to evaluate the temperature gradients in composite girders in the Black Sea’s Turkish city Samsun. The case study was conducted based on extreme data records of approximately 50 years. The extreme daily solar radiation and air temperature difference were utilized in finite element thermal analysis for six months that represent the different seasons of the year. The investigated months were the hot months (April, June, and July) and cold months (October, November, and December). The study focused on the vertical temperature gradients (along the vertical centerline of the girder) and the lateral temperature gradients (along the horizontal centerline of the topping concrete slab). The finite element results showed that the maximum vertical temperature gradient occurred in June and was 13.55 °C, while the maximum lateral temperature gradient occurred in December and was 10.11 °C. The results also showed that different behaviors of the positive vertical gradient were recorded for the cold months than those for the hot months. Similarly, the distributions of the positive lateral gradients were different for the two groups of months. These differences were attributed to the different sun movements and solar radiation striking angles in summer and winter.