Behaviour and strength of bolted connections failing in shear (original) (raw)
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Ultimate Shear-Out Capacities of Structural-Steel Bolted Connections
Journal of Structural Engineering, 2015
Based on the previous research results of the authors, this paper presents an accurate and consistent equation for determining the ultimate shear-out capacity of a structural steel bolted connection. The equation is verified against independent laboratory test results obtained by other researchers around the world. Comparisons against alternative equations found in the design specifications and literature are also included. The paper explains why certain equations appear to be accurate for particular configurations, but are grossly inaccurate for others. This paper describes the various assumptions embedded in the existing equations, some optimistic and others pessimistic. It shows that the current code equations lead to very significant errors on either side of conservatism, while the proposed equation is consistently accurate for all test specimens known to fail in shear-out. A resistance factor of 0.85 is recommended for the proposed equation in order to achieve a reliability index of 4.0. The use of the proposed equation instead of the current AISC specification's equation will facilitate structural designs that are more economical yet reliable.
Block shear failure planes of bolted connections — Direct experimental verifications
Journal of Constructional Steel Research
This paper presents direct experimental verifications of the active shear planes in bolted connections, previously identified by the first author for determining the block shear capacity. The laboratory test results were obtained by independent researchers for specimens where the applied loads were resisted by the "block" in shear only. The first set consists of five bolted connection specimens in the webs of wide flange sections where the tensile resistance planes had been sawn off. The second set consists of ten bolted connection specimens each in one leg of an angle section that had fractured completely along the net tensile plane through a block shear failure. Comparisons among the gross, net, and active shear planes against the independent laboratory test results showed that the critical shear planes of bolted connections were best represented by the active shear planes rather than either the gross or the net shear planes. It is also pointed out that full or almost full shear strain hardening was generally achieved at the ultimate limit state of block shear failure of bolted connections in hot-rolled steel plates or sections, irrespective of the connection length. Verification against independent laboratory test results of tee sections bolted at the web reinforces this point.
Combined Bearing and Shear-Out Capacity of Structural Steel Bolted Connections
Journal of Structural Engineering, 2016
This study is concerned with the strength limit state of serial bolted connections in structural steel plates. It points out that the ultimate load capacity of a serial bolted connection failing in combined bearing and shearout cannot be computed as the simple sum of the respective ultimate bearing and ultimate shear-out capacities, which is implicitly permitted in design specifications worldwide. Based on the laboratory test results of 10 hot-rolled steel plate specimens composed of three different grades with nominal thicknesses ranging from 5 to 8 mm, the paper first establishes the ultimate bearing coefficient of a 20-mm bolted connection in a structural steel plate to be 3.5. Coupled with the shear-out equation previously derived, a design equation where the shear-out capacity of the downstream bolt varying quadratically with the end distance is then proposed to determine the combined bearing and shear-out capacity. The proposed equation is demonstrated through verification against independent laboratory test results involving 5-mm plates of three different grades to be significantly more accurate than the simple sum. Explanation for the unexplained results obtained by another researcher using his own equation is provided in this paper.
Analysis on Shear Behavior of High-Strength Bolts Connection
Because of high cost of tests and numerical calculation using solid element of high-strength bolts connection in steel frameworks, it is important to find an accurate and simplified approach to describe the shear behavior of high-strength bolts connection. The paper aims to find a spring element to simulate the shear behavior instead of solid element in structure. Firstly, solid element model of high-strength bolt connection is established, which is proved correct and applicable comparing with existing typical shear tests. Then, base on the reliability of finite element model, the shear behavior of bolts connection is further discussed through a large number of parameter analyses. The three feature points and four stages of the simplified shear model are calibrated according to tests and calculation results. A simplified shear behavior model and hysteretic criterion of high-strength bolts connection are proposed. According to cases study, feasibility of the proposed model is validated. The proposed model gives a simple process to provide quite accurate results, which provides a great tool for engineering applications.
A Review of the Fatigue Strength of Shear Bolted Connections
International Journal of Steel Structures, 2018
Steel bolted connections are the typical joints used in civil engineering but also in the field of mechanical engineering. In particular, slip-resistant bolted connections are those most used in bridge construction. In these applications, bolted joints are subjected to a cyclic load that arises from traffic flow. It is well known that joints are the critical components of constructions subjected to cyclic loads, due to stress concentration that causes fatigue crack initiation. The purpose of this paper is to provide a summary of considerations, from principal scientific studies of fatigue strength and the behaviour of bolted joints, as well as an up-to-date comprehensive assessment for future development. In particular, a discussion is proposed regarding the parameters that influence the fatigue of bolted joints. The paper concludes with a summary of the major results reported in terms of S-N curves.
COMPRESSIVE STRENGTH ANALYSIS OF A STEEL BOLTED CONNECTION UNDER BOLT LOSS CONDITIONS
Communications - Scientific letters of the University of Zilina, 2022
The aim of the study is the numerical analysis of a bolted connection under the conditions of loss of bearing capacity of some fasteners in this connection. The joined plates in the connection were made of the 3D finite elements, while the fasteners were treated as hybrid models consisting of rigid heads and nuts and flexible beams between them. A model of unilateral contact with friction was used between the joined plates. The bolted connection was first preloaded according to three different tensioning sequences and with a normalised force. After all the bolts were tensioned, the selected bolts were removed, simulating bolt damage under connection loading conditions. The connection was tested for external compressive loads up to 210 kN. The effect of the loosening of the connection on the load in the remaining bolts at the stage of the connection operation was investigated.
This paper presents a research about the monotonic and failure behaviours of bolted joints made of thin plates of S350GD and S355MC steels grades applied for rack structures. A full factorial matrix of static monotonic tests was performed considering two joints configurations, two material thicknesses, three surface coatings and two preload levels. Slip tests were also performed according to the EN 1090-2 standard to evaluate joint slip factors for the three material surface conditions. Numerical simulations of static tests were also performed using J2 plasticity and compared with experimental data. From experimental results, it is verified that increasing thickness and preload results an increasing of failure loads and sliding loads, respectively. Slip tests revealed the lowest slip factors for the painted specimens, followed by uncoated specimens and the higher slip factor was verified for zinc-coated specimens. Regarding failure modes, it verified that the S355MC specimens with single connection fractured by shear, while the S350GD specimens fractured from splitting and shear. In addition, for specimens with multiple connections for both materials, the failure occurred in net cross-section. The FE results reproduced conveniently the ultimate loads as well as the failure modes, including the clamping and friction effects.
Net section fracture assessment of steel bolted joints with shear lag effect
MATEC Web of Conferences
Bolted connections are willingly used in steel structures because of their easiness of fabrication and assembly, but often they are the weakest component in the construction. In case of tensile lap connections, fracture of net cross section usually determines a joint capacity. Additionally, possible eccentricities can affect the distribution of stresses in the cross section and hence its load capacity. Analysis of fracture is a completely different issue compared to well-known and established problems of stability or plastic resistance. Paper relates to steel angle tension members connected by one bolt. It starts from the description of experimental investigations which results were used for hierarchical validation of computational models. Choice between two types of material models (elastic-plastic and Gurson–Tvergaard–Needleman) and building of FE models, representing different degrees of complexity, were described. Paper ends with parametric study taking into account influence of...
Finite element investigation on the structural behaviour of cold-formed steel bolted connections
Engineering Structures, 2001
A finite element model with three-dimensional solid elements was established to investigate the bearing failure of cold-formed steel bolted connections under shear. It was demonstrated (Chung and Ip. Engineering Structures 2000;22:1271-1284) that the predicted load-extension curves of bolted connections in lap shear tests followed closely to the measured load-extension curves provided that measured steel strengths and geometrical dimensions were used in the analysis. Furthermore, it was shown (Chung and Ip.