Design thermal gradients for concrete bridges

The influence of various parameters, including section shape, wind speed, ambient temperature on black-top thickness, on the thermal response of concrete bridges is investigated. On the basis of conservative thermal conditions, a new design gradient is proposed as a replacement to the sixth power 30 degrees C gradient widely used in New Zealand. The proposed gradient will generally result in a substantial reduction in the magnitude of the critical soffit tension stresses for continuous prestressed concrete bridges, thus reducing the required level of prestress with consequential economic advantages.