The effect of temperature change in the pre-stressing of IAB's deck

The key factor for understanding integral bridges service behavior is the studying effects of thermal loads and the way it can be accommodate in the design of integral abutment bridges. Temperature is major factor of time dependent affects, it also influences creep and shrinkage in two ways. Firstly, increases time ratio as evaporate water from concrete in low humidity and In the second one it increases the concrete age by affecting concrete properties due to influence of cement hydration. The consequences are related to the thermal changes in bridges and pre-stress losses have several form. Steam curing affect pre-stress forces as a result of high fluctuation of the temperature in a short curing time and leads to losses in precast pre-tensioned members. During first three year after pre-stressing, temperature changes cause the expansion and contraction of the concrete member. In addition it affects creep and shrinkage due to ambient relative humidity which in opposite trends with the temperature.