Experimental Investigation of Post-cracked Flexural Behavior for PC Girder Bridges

Extended studies are more and more needed for evaluating the post-cracked flexural behavior of PC (prestressed concrete) bridges where the design concept of eliminating cracks cannot be satisfied. In this paper, an experimental program is provided with six scaled specimens to analyze post-cracked flexural behavior of prestressed concrete girders. Mechanical properties, such as ductility, flexural rigidity and load-bearing capacity, are examined according to grouting, loading types and deflections at midspan. The results reveal that grouting provides better behavior by increasing ductility and crack resistance for PC structures. Load cycles have insignificant influence on cracking, ultimate loads and flexural rigidity of the prestressed concrete beams. However, load cycles may decrease non-prestress reinforcement (NPR) yielding loads by 5-12% and will reduce ductility by decreasing ultimate deflection. Furthermore, empirical equations have been presented and validated for evaluating flexural rigidity and load-bearing capacity for PC beams with cracks.