Cracking of continuous composite beams with precast decks

Analytical and experimental studies were performed to suggest the design basis for longitudinal prestress of continuous composite bridges with full-depth precast decks. In case of continuous bridges with precast decks, combination of two kinds of prestress should be used to introduce the compression at the joints in negative moment regions, especially the joint area behind shear pockets. Two continuous composite beams with precast decks were tested and their results are presented. Static tests are performed to estimate the behaviour in the elastic range before cracking, to evaluate the reduction of flexural stiffness after cracking and to investigate the inelastic behaviour. Nonlinear finite element (FE) analysis is carried out to compare and to analyze test results. Judging from the test results, the prevention of tensile stress under service loads makes it possible to control cracks at transverse joints. FE analysis shows that additional prestressing after shear connection should be introduced in order to prevent cracking of the deck, and details of precast decks should be carefully designed considering the stress distribution caused by longitudinal prestress. (C) 2002 Published by Elsevier Science Ltd