Combined Bearing and Shear-Out Capacity of Structural Steel Bolted Connections (original) (raw)

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.

Effect of Bolt Direction on the Bearing Capacity of Double Shear Connections

2017

The direction of bolts and its effect on the bearing capacity of double shear bolted connections has been examined in this paper. Sixteen specimens with up to four bolts have been tested under tensile load. These specimens have been sorted into two series (L, T) according to the bolt direction with applied loads. The experimental results have clearly indicated that the bearing capacity of connections had been considerably affected by changing the direction of bolts. With tear-out failure, All specimens of L series showed high bearing capacity and good ductility while block shear failure was the distinguishing feature of specimens of T series.

An Investigation on the Ultimate Strength of Cold-Formed Steel Bolted Connections

Engineering, Technology & Applied Science Research, 2017

This paper presents experimental results and finite element analysis of the cold-formed steel bolted connection under shear loading. Experiments are conducted to study the ultimate behaviors, such as ultimate strength and failure mode of connections. The samples were fabricated into three different groups, single bolted, double bolted and quadruple bolted connection. Material properties were determined by tensile coupon testing. Bearing failure modes were detected in the bolted connection tests. The ultimate capacities were compared with the nominal strengths calculated using the AISI (2012). The comparisons show that the nominal strength parameters predicted by this specification is conservative. The finite element analysis shell elements were used to model the cold-formed steel plate while solid elements were used to model the bolted fastenings for the purpose of studying the structural behavior of bolted connections. Material nonlinearities, contact problem and geometry nonlinear...

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.

Ultimate Tilt-Bearing Capacity of Bolted Connections in Cold-Reduced Steel Sheets

Journal of Structural Engineering, 2017

This paper examines the accuracy of design equations specified in the North American, European, and Australasian codes for cold-formed steel structures in determining the ultimate tilt-bearing capacity of single-shear bolted connections without washers in flat steel sheets. It points out that all the code equations do not properly distinguish the tilt-bearing failure mode from the conventional bearing failure mode. While the latter takes place downstream of the bolt, the former takes place upstream. Unlike the conventional bearing capacity, the tilt-bearing capacity is affected by the width of the connected sheet and does not vary linearly with either the sheet thickness or the bolt diameter. Furthermore, it is not affected by material ductility. Based on the test results of 156 specimens composed of G2 and G450 sheet steels having various dimensional configurations, this paper proposes a design equation that is dimensionally consistent and that is considerably more accurate than all the code equations. The proposed equation was also verified against single-shear single-row bolted connections tested by independent researchers which failed in the tilt-bearing mode. The verified thicknesses ranged from 0.92 to 3.0 mm, and the bolt diameters ranged from 6.4 to 16 mm. An additional finding is that the tilt-bearing capacity is not significantly affected by the orientation of the bolt head or nut. A resistance factor of 0.75 is recommended for use with the proposed equation for determining the tilt-bearing capacity of single shear single-row bolted connections in cold-reduced steel sheets.

Behaviour and strength of bolted connections failing in shear

Journal of Constructional Steel Research, 2019

This paper investigates the behaviour and strength of structural steel bolted connections whose failure modes involve shear yielding and/or fracture. Such failure modes include the shear-out (or tearout) and the block shear failure modes. The use of shear failure planes corresponding to the bolt diameter is shown to result in significant overestimations of the ultimate capacities for bolted connections with reduced or no hole clearance. In contrast, the use of the effective (or active) shear planes are consistently accurate for the specimens with standard, oversize or no clearance bolt holes. The paper points out that the location of fracture initiation can be easily misidentified by a superficial inspection of the deformed and fractured state of the bolt hole. The paper also explains that the ultimate shear-out capacity of a steel bolted connection can be reached without fracture due to geometric changes downstream of the bolt, provided the reduction in resistance is not offset by strain hardening. The explanation is demonstrated through a finite element analysis that does not simulate fracture, but is able to accurately determine the ultimate shear-out capacity of a high-strength steel specimen tested by independent researchers.

A General Design Rule for Bearing Failure of Bolted Connections Between Cold-formed Steel Strips

2000

This paper presents the results of a finite element investigation 1,2,3 on the structural performance of cold-formed steel bolted connections. A parametric study on various connection configurations was performed to relate the bearing resistances of cold-formed steel bolted connections with steel strengths and thicknesses, and bolt diameters. A semi-empirical design rule for bearing resistances of bolted connections based on finite element results is proposed in which the bearing resistances are directly related with the design yield strength, and the design tensile strength of steel strips, steel thickness, and also with bolt diameters. Design expressions for resistance contributions due to both bearing and friction actions are given after calibration against fmite element results.

Experimental Tests and Analytical Studies of Bearing-Type Axial Steel Connection

The capacity of the bolted connection on steel tensile rods can be determined through capacity analysis and connection failure. In term of capacity analysis and failure of steel tensile connection, the specified tensile connection capacity is generated based on several parameters such as cross-section of rod, grade of steel, thickness and grade of the steel plate, and grade and diameter of bolts. The capacity of steel tensile connections as a result of capacity analysis and connection failure often has a lower value than the connection capacity in real conditions. In this research, the comparison of 30x30x3mm angle cross-section connections with BJ37 grade quality was connected with 2 mm steel plate (also BJ37 grade) using 8 mm bolt connectors (A307 grade), through capacity analysis, failure study, and experimental study with type of failure is bolt bearing failure. In the capacity analysis study and the failure of steel tensile connections obtained a nominal capacity is 14.21 kN with the type of failure is shear failure. In the experimental study was tested 3 specimens, the average value of ultimate capacity was 18.67 kN and the failure for all of the three specimens are shear failures. The conclusion that can be drawn from this research is both the result of analytical calculations and experimental testing in the laboratory showed a good agreement and have the same trend. The test specimens were designed on the basis of analytical calculations for bolt bearing failure, experimental test results for all of three specimens all showed a failure pattern of bolt shear. The nominal strength from the results of the analytical study with the ultimate load of the experimental study results has a difference of 31.4% with higher experimental results. Through this research is expected to be a learning-media to know one type of failure on the steel connections that is bolt shear failure, obtain a comparison between analytical calculation results referring to applicable design standards, and the results of experimental testing in the laboratory.