Experimental study on the seismic behavior of steel-reinforced ultra-high-strength concrete frame joints with cyclic loads

Abstract

A research program on the seismic behavior of steel-reinforced ultra-high-strength concrete exterior joints is conducted herein by testing 11 specimens under a reversed cyclic loading profile. This study analyzes the testing results in terms of the load-displacement relationship, ductility, energy dissipation capacity, strength and stiffness degradations, steel panel strain, and confinement in the specimen joints. The axial compression and stirrup volumetric ratios are two significant parameters dominating the shear behavior of the steel-reinforced ultra-high-strength concrete frame exterior joints. The effect of the axial compression ratio on the shear capacity of the steel-reinforced ultra-high-strength concrete frame exterior joints characterized by a dividing point is also proposed. Furthermore, a design formula for the shear strength of the joint core area is derived using the strain analysis method with the shear model that considers the inner concrete compression strut, outer concrete compression strut, steel web panel shear mechanisms, and stirrup confinement mechanisms. The formula is verified by the experiment results.

Seismic behaviour of steel-reinforced ultra-high-strength concrete composite frame: Experimental study

“…It is a critical region in high-rise buildings that were often subjected to inelastic response under severe seismic loading. As reported (Jia et al, 2013; Liu and Jia, 2017; Zhu et al, 2013), the research results indicated that encasing structural steel and high-strength stirrups into the ultra-high-strength concrete columns can significantly increase the curvature ductility of sections and axial compression capacity.…”

“…It can be used extensively in high-rise, super high-rise buildings within the earthquake zone. However, previous researches were carried out on the mechanical properties and seismic behaviour of SRUHSC beams (Yao et al, 2014), columns (Zhu, 2014), exterior and interior composite beam-to-column joints consisting of SRC beams and SRUHSC columns (Liu and Jia, 2017; Yan and Jia, 2010) as well as one-bay, one-story composite frame consisting of SRC beams and SRUHSC columns (Ma et al, 2017). All the studies were focused more on the seismic performance of the separated SRUHSC components.…”

Plastic hinge relocation in exterior reinforced beam–column joint and compliance issues to seismic design guidelines—A review

“…Steel-reinforced ultra-high-strength concrete corner BCJ tested under cyclic loadings also failed by joint shear as reported by Liu and Jia. 46 The specimens were F I G U R E 3 Joint reinforcement detail: (joint detail 1) cross hair; (joint detail 2) conventional transverse type 26 designed for various joint core stirrup ratio of 0.8-1.6, average 28th day concrete compressive strength of 112 MPa, and joint aspect ratio of 1.5 which were tested under different axial load ratio (ALR) ranging from 0.25 to 0.45. At lower ALR, shear cracks were observed at the joint core with more damage occurring in the plastic hinge regions of adjacent beams.…”

Experimental analysis of hysteretic behavior and strain field of external diaphragm joints between steel beams and CFDST columns

“…It is verified that the inner circle steel tube in the CFDST column can improve the shear stiffness. However, the axial load level is the main influential parameter on shear stiffness (Liu and Jia, 2017), so SRJ1-3 with the minimum axial load level in the test has the smallest shear stiffness and specimen SRJ1-1 has the largest initial shear stiffness. Specimens SRJ2-1 and SRJ5-1 with wider external diaphragm also have larger initial shear stiffness because the wide external diaphragm can improve the ability to limit the tendency of mutual dislocation in the panel zone as shown in Figure 5(b).…”