No abstract

Push-out tests were carried out to examine the shear strength of corrugated perfobond rib shear connections. The corrugated perfobond rib shear connection, formed by folding the straight perfobond rib steel panel, can be expected to increase the shear capacity and ductility of a shear connector due to the shear resistance and deformation of the inclined rib panel. To examine the shear behaviour of the corrugated perfobond rib connection and compare it with that of the perfobond rib, the push-out specimens were fabricated to suit the shear corrugated rib resistance parameters of depth of rib, height of rib, holes in the corrugated rib and whether transverse rebar is placed in the corrugated rib holes. Results of the push-outs show that the failure of corrugated perfobond rib shear connection is determined by concrete bearing and small deformations of inclined perfobond rib panel. Specifically, the corrugated rib specimens showed different relative slips at each side of the composite interface owing to the stress flow along the inclined rib developed by inclined direction of the welded corrugated perfobond rib. The transverse rebar in the rib hole reduced the difference in relative slips. The shear strength of the corrugated connection is increased by about 198∼512% compared with the standard perfobond rib specimen connection with transverse rebars and without transverse rebars respectively. However, the contribution of other shear resistance parameters is found to be relatively small compared with the contribution provided by transverse rebars in the rib holes. In terms of the ductility of the shear connector, the relative slip of the corrugated rib connections increased after ultimate load, so it is evaluated to have a sufficient ductility.

The strengthening of a plate girder bridge with external prestressing tendons is a commonly used method of upgrading existing bridges. Indeed, it has been known to offer advantages such behaviors as increased elastic behaviors under higher loading, increased ultimate resistance, and reduced deflection under service loads. However, this method has notable disadvantages such as stress concentration at anchorages and inefficient live load-carrying capacity. The thermal prestressing method (TPSM) for steel bridges proposed in this study uses thermal expansion and contraction of a cover-plate to provide a combination with the prestress effects of an external prestressing tendon and the section enlargement benefits of the external bonding method. In this study, the basic concepts of the proposed strengthening protocol using multi-stepwise TPSM are presented. The existence of the strengthening effect is well substantiated and the proposed analytical approach is also rigorously verified. The significant strengthening effects on a simply supported plate girder bridge are analyzed.

No abstract