Ultimate Shear Strength of Component Model of Composite Beam with Perfobond Shear Connector

In general, a steel beam is assembled with a concrete slab by shear connectors. The connection requires high stiffness and strength to secure the composite effect even in the ultimate state. Facing this need, perfobond shear connectors are attracting a great attention by virtue of its outstanding mechanical performance. However, the connector is subjected to the fully reversed cyclic stress between the compression and tension during an earthquake. Therefore, as presented in the earlier research addressing stud shear connectors, the concrete may originate cracks under the tensile stress; and eventually, the expected composite effect is not possibly performed. To address this concern, this research carried out a total of three fully reversed cyclic loading tests using the component model of perfobond shear connection. The parameters are the presence of reinforcing bars and concrete strength. In conclusion, it was found that perfobond shear connectors exhibit more stable mechanical behavior and capacity than stud shear connectors regardless of stress orientation due to a localized stress transfer mechanism that results in smaller cracks in the slab under a fully reversed cyclic loading.

Behavior of Structural Concrete Frames with Hybrid Reinforcement under Cyclic Loading

A substantial amount of work was carried out on the use of fiber-reinforced polymer (FRP) in reinforcing concrete structural elements, which demonstrated considerable inelasticity or deformity through monotonous and fatigue loads. Even so, the action of FRP bars in FRP-RC columns and frame structures has not yet been studied during reversed cyclic loading. In this research, reversed cyclic loading was conducted on three beam-column joint models using the finite element method with ANSYS software. The first model was for a joint designed with steel rebar for both the longitudinal reinforcement and stirrups. Glass fiber reinforced polymer (GFRP) rebar was used to reinforced the second joint model for both longitudinal reinforcement and steel stirrups, and the third joint model was designed with hybrid steel/GFRP reinforcement for the longitudinal reinforcement and steel stirrups. The performance of the three models under reversed cyclic loading, such as load vs. story drift and energy dissipation capacity, were compared. The GFRP-reinforced model displayed a predominantly elastic activity up to failure. Although its energy dissipation was weak, its performance in terms of total storey drift demand was satisfactory.