Seismic Performance of Full-Scale Joints Composed by Concrete-Filled Steel Tube Column and Reinforced Concrete Beam with Steel Plate-Stud Connections

Yashuang Liu,Zhenbao Li,Zhenyun Tang,Qianqian Wang,Hua Ma

doi:10.1155/2019/5476909

Abstract

A concrete-filled steel tube (CFST) column has the advantages of high bearing capacity, high stiffness, and good ductility, while reinforced concrete (RC) structure systems are familiar to engineers. The combinational usage of CFST and RC components is playing an important role in contemporary projects. However, existing CFST column-RC beam joints are either too complex or have insufficient stiffness at the interface, so their practical engineering application has been limited. In this study, the results of a practical engineering project were used to develop two kinds of CFST column-RC beam joints that are connected by vertical or U-shaped steel plates and studs. The seismic performance of full-scale column-beam joints with a shear span ratio of 4 was examined when they were subjected to a low-cyclic reversed loading test. The results showed a plump load-displacement curve for the CFST column-RC beam joint connected by steel plates and studs, and the connection performance satisfied the building code. The beam showed a bending failure mode similar to that of traditional RC joints. The failure area was mainly concentrated outside the steel plate, and the plastic hinge moved outward from the ends of the beam. When the calculated cross section was set at the ends of the beam, the bending capacity of joints with the vertical or U-shaped steel plates and studs increased compared to the RC joint. However, when the calculated cross section was set to the failure area, the capacity was similar to that of the RC joint. The proposed joints showed increases in the energy dissipation, average energy dissipation coefficient, and ductility coefficient compared to the RC joint.

Highlights

Concrete-filled steel tube (CFST) columns are widely used in practical engineering because of their excellent constructability, such as reduced labor and materials, lack of formwork, and quick construction
Fang et al [14] proposed adding a ring beam outside the CFST column with longitudinal reinforcements of the slab beam anchored to the ring beam: the ring beam resists the bending moment of the reinforced concrete (RC) beam by bearing the torsion, and the surface of the connection between the beam and steel tube is bonded with a welded steel ring. ey performed experiments on 14 CFST column-ring beam specimens subjected to a cyclic lateral load and studied the seismic performance of the ring beam joint. e joints exhibited good energy dissipation capacity, and the failure of the joint did not influence the load carrying capacity of the column
Shi et al [16] suggested two types of connections for an outer-plated steel-concrete composite beam and CFST column. ey carried out a low-cyclic reversed loading test and finite element simulation for the two types of joints and analyzed the performance in terms of the failure mode, hysteretic curve, strength, ductility, and strain of the steel bars, plates, and tubes. e results showed that both connections provided a high carrying capacity, ductility, and energy dissipation capacity

Summary

Introduction

Concrete-filled steel tube (CFST) columns are widely used in practical engineering because of their excellent constructability, such as reduced labor and materials, lack of formwork, and quick construction. Ey carried out a low-cyclic reversed loading test and finite element simulation for the two types of joints and analyzed the performance in terms of the failure mode, hysteretic curve, strength, ductility, and strain of the steel bars, plates, and tubes. Zha et al [24] carried out a lowcyclic reversed loading test and finite element simulation analysis on nonwelded CFST column-RC beam joints and showed that such joints demonstrated good ductility and energy dissipation capacity. These joints have been applied to some engineering projects, each type has some disadvantages, such as difficulties in welding and pouring concrete into tubes because of corbels. Low-cyclic reversed loading tests were performed to study the failure mode, failure mechanism, hysteretic curve, and skeleton curve. e results showed that the proposed joints have good mechanical properties and ductility, so they have a wide range of engineering applicability

Types of Proposed Joints and Experimental Plan

Test Results and Discussion

Figure 4

Conclusions