Investigation on structural performance of perfobond strip connector group in steel-concrete joints

Abstract

The use of an innovative type of perfobond rib (PBL) shear connector in steel–concrete joints of hybrid girder bridges has gained wide popularity among bridge engineers. For a PBL group with multi-row PBLs in tandem arrays, comprehensive interactions exist among the connectors. However, the current design approaches assume that the force transferred by each row of PBL is uniform, resulting in an overestimated shear resistance of the connector group. The main objective of this paper is to introduce a mathematical approach, which accounts for the bonding-friction effects (BF) at the perforated steel plate/concrete slab interfaces and the reinforced concrete dowel (RD) effects by the perfobond hole, to assess the ultimate resistance of PBL group under the RD fracture failure mode. In this study, six push-out specimens for different PBL groups, with varying connectors’ quantity, were evaluated experimentally to determine the key parameters for the proposed analytical model. The experimental results revealed the significant reduction in average resistance of single PBL in a connector group as connector number increased. The proposed approach is validated by an experimental database that includes push-out test results obtained from the previously published studies and afterwards converted to the design load level, which can be extensively applied to the PBL group using normal concrete and ultra-high performance concrete (UHPC). The proposed analytical approach provides an efficient tool for analyzing and designing of PBL group in steel–concrete joints of hybrid girder bridges.