Anhui Civil Engineering Structures and Materials Laboratory

Anhui, China

Anhui Civil Engineering Structures and Materials Laboratory

Anhui, China
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Wang J.,Hefei University of Technology | Wang J.,Anhui Civil Engineering Structures and Materials Laboratory | Spencer B.F.,University of Illinois at Urbana - Champaign
Journal of Constructional Steel Research | Year: 2013

Experimental tests and numerical analyses were conducted to study the behavior of the blind bolted end plate joint with concrete-filled square hollow section columns to steel beam. A detailed description of the experimental program and the main results of the tests were presented. Four full-scale subassemblages representing interior or exterior beam-to-column joints were tested under monotonic loading. The failure modes, moment-rotation relation curves and connection classification of the joints were evaluated. The test specimens exhibited favorable strength and stiffness, and larger deformation capacities. Then, finite element analysis (FEA) modeling of the tested specimens was developed, and the results obtained from the FEA modeling were verified against those from the test results. Parametric studies were conducted to investigate the influence of axial load level, steel ratio, slenderness ratio of column, and bolt pretension force etc. on the moment capacity and rotational stiffness of composite joints. The feasibility of connecting an end plate to the steel beam using an alternative method to improve the joint behavior has been explored by the FEA studies. The experimental studies and numerical analyses enable improvement to the design of the typed connections to be used in moment-resisting composite frame structures. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved.


Wang J.,Hefei University of Technology | Wang J.,Anhui Civil Engineering Structures and Materials Laboratory | Zhang L.,Hefei University of Technology | Spencer B.F.,University of Illinois at Urbana - Champaign
Engineering Structures | Year: 2013

This paper investigates the seismic behaviour of extended end plate connections to circular or square concrete-filled steel tubular (CFST) columns using blind bolts. Both the end plate type and the column section type are considered. Results of an experimental study involving four bolted moment-resisting connections subjected to cyclic loading are presented. The failure modes, hysteretic performance, strength and stiffness degradation, rigidity classification, and energy dissipation of the blind bolted extended end plate connections to CFST columns were estimated in detail to investigate the seismic behaviour. The anchorage action of reinforcing rebar welded to the bolt with concrete-filled steel tubes was also explored. The experimental results indicated the blind bolted extended end plate connections with circular or square CFST columns exhibited large hysteretic loops, good ductility, and excellent energy dissipation capacity. Failure modes for test specimens under cyclic loading were similar to those under monotonic loading, and their rotation capacities satisfied the ductility design requirements for earthquake-resistance in most seismic regions. These experimental studies enable improvement in the practical design of blind bolted moment connections. © 2013.


Wang J.,Hefei University of Technology | Wang J.,Anhui Civil Engineering Structures and Materials Laboratory | Chen X.,Hefei University of Technology | Shen J.,Illinois Institute of Technology
Thin-Walled Structures | Year: 2012

The objective of this research is to investigate the seismic performance of the composite joint consisting of square concrete filled thin-walled steel tubular (CFTST) column and steel beam with end plate and blind bolts. The cold-formed square tube in each CFTST column connection was fabricated by seam welding together four pieces of lipped angle with nominal wall thickness 1.5 mm or 3 mm. Four exterior joint specimens were tested under axially compressive load on the top of the columns and cyclic loads on the beam tip. The experimental parameters in the study were the thickness of the steel tube and the type of end plate. The seismic response of the blind bolted moment joints to CFTST columns was analyzed and evaluated in terms of the hysteretic behavior, failure modes, stiffness and strength degradation, ductility, and energy dissipation capacities of the joints. To improve the tension behavior of the blind bolted moment connections to the thin tube wall, the anchorage action of reinforcing rebar welded to the bolts with concrete-filled steel tubes was also investigated to consider the effect of cyclic loading. The experimental and analytical results indicated that when the end plate thickness is not less than 3 mm, the flush or extended end plate joints to CFTST columns exhibited large hysteretic loops and excellent seismic performance, such as ductility and energy dissipation capacity. The proposed innovative blind bolted joint was verified as a reliable and effective solution applied in mid- and low-rise buildings through properly design and detailing.


Wang J.,Hefei University of Technology | Wang J.,Anhui Civil Engineering Structures and Materials Laboratory | Gong X.,Hefei University of Technology | Jiang T.,Hefei University of Technology
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2014

To learn about the flexible capacities of end plate connections for concrete-filled steel tubular (CFST) composite frame under negative moments, failure models of the composite joints are given. Mechanical models of composite joints under symmetrical and non-symmetrical loading are proposed respectively. Effects of end plate type, column section type, load type and composite action of slab are considered. Based on failure models, simplified calculation methods for reinforced tensile capacity, bolt tensile capacity and joint compressive capacity are suggested respectively. According to the mechanical equilibrium principle and mechanical model, location of plastic natural axis was determined by the component method. The calculation methods of the flexible capacities of flush and extended end plate composite joints under negative moments are proposed respectively. The proposed simplified methods for the flexible capacities of composite joints are verified by test results. The research results can provide scientific reference for the design of semi-rigid CFST composite frames.


Wang J.,Hefei University of Technology | Wang J.,Anhui Civil Engineering Structures and Materials Laboratory | Guo S.,Hefei University of Technology
Thin-Walled Structures | Year: 2012

This paper presents the results of an experimental study on the structural behavior of blind bolted end plate connections between steel beams and concrete-filled thin-walled steel tubular (CFTST) columns under monotonic loading. The square tube in each CFTST column connection was fabricated by seam welding four pieces of lipped angle with nominal wall thickness 1.5 mm or 3 mm together. In order to enhance the stiffness of the connection, extensions are provided to the blind bolts to link the connection back into the concrete with the tube. The objective of this study is to develop a novel bolted moment connection which is easy to use in the thin-walled structures. The structural performance of the blind bolted connection is evaluated in terms of the failure modes, moment-rotation relationship, connection rigidity and strain response of critical components. Some anchorage strengthening methods were proposed to enhance the strength and stiffness of the connection. The experimental results indicate that the proposed CFTST column connections behave in a semi-rigid and partial strength manner according to the EC3 specification, whilst its rotation capacity satisfies the ductility design requirements for earthquake-resistance in most aseismic region. Adopting reasonable connection measurement, the proposed blind bolted connection to the CFTST columns was a reliable and effective solution for low-layer and multilayer frame structures.


Wang J.,Hefei University of Technology | Wang J.,Anhui Civil Engineering Structures and Materials Laboratory | Chen X.,Hefei University of Technology | Hou H.,Shandong University
Applied Mechanics and Materials | Year: 2012

This paper discusses results of experiments on blind bolted end plate joints to concrete-filled thin-walled steel tubular (CFTST) columns. Four exterior joints to CFTST columns subjected to cyclic loadings. A feature of this novel joint is the use of the blind bolts and extensions to these bolts into the concrete-filled square steel tubular column. Failure modes, moment-rotation hysteretic curves and energy consumption of the connections were analyzed. Further, the connection rigidity and ductility were also elevated by present specifications. The test results showed that the end plate type and the steel tube thickness affect the seismic behaviour of the typed blind bolted end plate joints. The proposed joint has reasonable strength, stiffness and ductility by taking reasonable end plate type, steel tube thickness and blind bolt anchorage; its ultimate connection rotation satisfies the ductility design requirements, and could be reliably and safety used in low-layer or multi-layer composite frames. © (2012) Trans Tech Publications.


Wang J.,Hefei University of Technology | Wang J.,Anhui Civil Engineering Structures and Materials Laboratory | Chen L.,Hefei University of Technology
Journal of Constructional Steel Research | Year: 2012

An experimental programme to obtain the behaviour of blind bolted extended end plate joints to circular or square concrete-filled steel tubular (CFST) columns under monotonic loading has been conducted. In order to enhance the strength and stiffness of the connections, the anchorage extensions are provided to the blind bolts to link the connection back into the concrete with the tubular. This paper investigated the effect of the end plate thickness and the column section type on the static behaviour and failure modes of the tested connections. The structural performance of the blind bolted extended end plate connections was evaluated in terms of the moment-rotation relationship, connection rigidity, the deformation pattern and the strain response. The test results showed that the blind bolted extended end plate connection to CFST columns exhibits high strength and stiffness, while its connection rotation capacity satisfies the ductility requirement for earthquake resistance in aseismic region. The experimental studies also demonstrated that the strength and stiffness of the connections can be improved by providing anchorage extensions to the blind bolts, and utilising moderately thick end plates leads to joints approaching full strength for the extended end plate connections. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved.

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