Study On Deformation Capacity Of Continuous Steel-Concrete Composite Beams Pre-stressed With External Tendons

Experimental investigation and theoretical study on load carrying capacity and performance of continuous steel-concrete composite beams are carried out. Two continuous steel-concrete composite beams are tested. One of the specimens is pre-stressed composite beam with external tendons and the other is conventional non-prestressed composite beam.Each beam was tested with monolithically static loading. The recorded phenomena and data are used to make a comparative analysis on the effect of pre-stress for load carrying and deflection capacity of continuous steel-concrete composite beam. The results indicate that the pre-stress can significantly reduce the mid-span deflection and improve the concrete cracking load, but have little use on increase the hogging moment. It could enhance the limit supporting capacity of continuous composite beam mainly by improve the sagging moment. In addition, traditional methods had been carried in the theoretical analysis of the bearing capacity and deformation of continuous steel-concrete composite beams. In the formula, pre-stress is taken as external load and the pre-stress increase has been considered. In order to have a better forecast of the actual value, an adjustment method for the linear calculation results is proposed in the deflection analysis.The comparative analysis results of the theoretical method and actual value shows that the adjustment method for deflection calculation could forecast the mid-span deformation better. Both the ordinary continuous steel-concrete composite beam and the pre-stressed continuous steel-concrete composite beam with external tendons could use the same formula and parameter. Finally, a brief discussion is carried for the direction of future work.