Early crack mechanism and ultimate bearing capacity of RC hollow slabs

In the light of the formation mechanism of early cracks of a batch of precast reinforced concrete hollow slab members of four certain bridges in construction whose midspan appears transverse cracks, investigation ranging from method of construction to distribution of cracks are conducted in situ. The possibility of the occurrence of cracks is discussed in detail. Theoretical value is excellently in agreement with numerical analysis result. It is shown that theoretical calculation as well as numerical analysis reveals that the main reason of formation early cracks in members is self-weight loading. In order to estimate the performance of the bridge deck system which appears cracks and evaluate the effect of these early cracks on structural behavior, numerical analysis is performed to conclude that the bridge deck is favorable to fulfill serviceability and adequate for ultimate bearing capacity. In view of the fact that this kind of slab is widely used in bridge projects for its convenience in construction and advantage in cost, effective and economical crack control measurement and technical proposal are recommended with regard to the design, construction and amendment of design specifications. This paper can be referred for bridge engineers in design and construction.