Experimental and Numerical Study on the Mechanical Behavior of Prestressed Continuous Composite I-Girder Bridges with Partial Connection

A partial connection-prestressing (PCP) method is proposed in this paper to decrease the prestress that was transferred to steel girders in the negative moment region of steel-concrete composite bridges. The partial connection is achieved by the application of rubber-sleeved studs (RSS) in the prestressed concrete slab in the negative moment region. Since there is no experimental research on the PCP method in continuous composite girders, to the best of the authors' knowledge, two continuous composite girders were tested under a four-point static load to evaluate their mechanical performance. The test results showed that without decreasing the ultimate strength and overall stiffness of the steel-concrete composite girders, the PCP method enhanced the cracking load (P-cr) 3.1 times. In addition, 12.5% of the prestressing force was transferred into the steel girder at the internal support section with the PCP method, and the girder without the PCP reached 25.9%. Then, to elucidate the partial interaction effect and prestressing effect on continuous girders' mechanical behavior, numerical models were developed and calibrated with the test results. From the numerical analysis, compared with normal composite girders, the application of RSS or prestressing could improve P-cr by 11.8% and 157.0%, respectively, and the value increases to 234.3% when RSS and prestressing are applied at the same time. The results indicate that the application of RSS in the negative moment region could effectively increase the prestressing efficiency in the concrete slab and enhance the bridge's durability.

Automated summary

In this paper, a partial connection-prestressing method is proposed to decrease the prestress transferred to steel girders in the negative moment region of steel-concrete composite bridges. Experimental results show that the PCP method enhances the cracking load (P-cr) by 3.1 times without decreasing the ultimate strength and overall stiffness of the composite girders.