Cause analysis and preventive measures for longitudinal cracks in bottom slab of trough girder bridges

Large transverse moment and reduction of concrete strength under complex stress state are pointed out as two main reasons for longitudinal cracking along the bottom slab of trough girder bridges while the effect of Poisson on transverse stress is not significant through the analysis of a finite element program based on a prestressed concrete trough girder bridge. A concept of transversal prestressing design, U-type transversal prestressing, is introduced in order to prevent the bottom slab cracking of trough girder bridges. Advantages of this concept are explained in detail and some design recommendations are mentioned.