Experimental study on slotted rectangular and square hollow structural section (HSS) tension connections

2008 ◽  
Vol 35 (11) ◽  
pp. 1318-1330 ◽  
Author(s):  
R. G. Zhao ◽  
R. F. Huang ◽  
H. A. Khoo ◽  
J. J.R. Cheng
Keyword(s):  
Experimental Study ◽  
Plate Thickness ◽  
Length Ratio ◽  
Shear Lag ◽  
Design Standards ◽  
Gusset Plate ◽  
Design Standard ◽  
Slot Opening ◽  
Hollow Structural Section ◽  
Longitudinal Welds

An experimental study has been carried out on slotted hollow structural section (HSS) connections with and without welding at the end of the gusset plate. A total of 30 slotted square and rectangular HSS specimens, with 16 different connection configurations, were investigated for effects of weld length ratio, slot orientation, gusset plate thickness, slot opening length, and end welding. Experimental results show that the net section efficiency of the specimen with no end welding was greater than unity for a weld length ratio (L/w), where L is weld length and w is the circumferenctial distance between the longitudinal welds, as low as 0.8, and full net section efficiency was achieved with L/w ratio as low as 0.76 for a square HSS specimen with end welding. These results support findings from other research that show provisions to account for the effect of shear lag in slotted HSS connections are overly conservative in both Canadian and American design standards. Recommendations are provided to improve on provisions to account for shear lag in the Canadian design standard.

Behaviour of gusset plate connections to ends of round and elliptical hollow structural section members

2006 ◽  
Vol 33 (4) ◽  
pp. 373-383 ◽  
Author(s):  
S Willibald ◽  
J A Packer ◽  
G Martinez-Saucedo
Keyword(s):  
Experimental Study ◽  
Base Material ◽  
Tensile Failure ◽  
Shear Lag ◽  
Gusset Plate ◽  
Short Side ◽  
Current Design ◽  
Connection Type ◽  
Plate Connections ◽  
Hollow Structural Section

Gusset plate connections to the ends of hollow structural section (HSS) members are regularly used in steel-framed buildings and roof trusses. Recent research on this connection type has indicated that current design recommendations for preventing tensile failure induced by shear lag may be overly conservative. This paper presents an experimental study on 13 gusset plate end connections to circular and elliptical HSS members under quasi-static tension and compression loadings. Current design proposals found in research studies and in design guides and specifications are compared with the experimental work. Various fabrication details for this connection type have been considered, and the influence of connection length, gusset plate orientation (in the tube long side versus short side), and distance between welds has been studied. In the experimental study, failure of all specimens under tensile loading was caused by circumferential fracture of the HSS or by tear-out of the HSS base material along the weld. The compression specimens failed by local buckling of the HSS at the connection end. A preferred static design approach for such connections is thus recommended.Key words: gusset plate, hollow section, tube, connection, round, elliptical, shear lag, tear-out failure.

scholarly journals Net Section Fracture Assessment of Welded Rectangular Hollow Structural Sections

2020 ◽  
Vol 6 (7) ◽  
pp. 1243-1254
Author(s):  
Mohammad Abedin ◽  
Nafiseh Kiani ◽  
Esmail Shahrokhinasab ◽  
Sohrab Mokhtari
Keyword(s):  
Plate Thickness ◽  
Tensile Load ◽  
Steel Structures ◽  
Shear Lag ◽  
Effective Parameters ◽  
Gusset Plate ◽  
Hollow Section ◽  
Symmetric Connection ◽  
Plate Connections ◽  
Connection Length

Rectangular Hollow Sections (RHS) because of their high resistance to tension, as well as compression, are commonly used as a bracing member with slotted gusset plate connections in steel structures. Since in this type of connection only part of the section contributes in transferring the tensile load to the gusset plate, shear lag failure may occur in the connection. The AISC specification decreases the effective section net area by a factor to consider the effect of shear lag for a limited connection configuration. This study investigates the effective parameters on the shear lag phenomenon for rectangular hollow section members connected at corners using a single concentric gusset plate. The results of the numerical analysis show that the connection length and connection eccentricity are the only effective parameters in the shear lag, and the effect of gusset plate thickness is negligible because of the symmetric connection. The ultimate tensile capacity of the suggested connection in this study were compared to the typical RHS connection presented in the AISC and the similar double angle sections connected at both legs. The comparison indicates that tensile performance of the suggested connection in this study because of its lower connection eccentricity is much higher than the typical slotted connection and double angle connections. Therefore, a new equation is suggested based on the finite element analyses to modify the AISC equation for these connections.

scholarly journals Shear Lag Effects in Angles Welded at Both Legs

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Mohammad Abedin ◽  
Shervin Maleki ◽  
Nafiseh Kiani ◽  
Esmail Shahrokhinasab
Keyword(s):  
Numerical Methods ◽  
Plate Thickness ◽  
Numerical Analyses ◽  
Shear Lag ◽  
Gusset Plate ◽  
Lag Effects ◽  
Free Length ◽  
Steel Sections ◽  
Connection Length ◽  
Tension Members

The shear lag phenomenon is known to reduce the tensile capacity of tension members. There are various parameters affecting shear lag that have not been considered before. In addition, previous studies have been conducted mainly on single steel sections. Using numerical methods, the present study investigates the effects of relevant parameters on shear lag in single- and double-angle sections welded at both legs. The studied parameters are connection eccentricity, connection length, gusset plate thickness, member-free length, and connection-free length. The results of the numerical analyses show that, in single-angle connections, the effects of connection length, connection eccentricity, and gusset plate thickness are more pronounced, while in double-angle connections the last parameter is not very critical. Comparing the results with the AISC-LRFD predictions, it is concluded that the specification relations are conservative in most cases. In order to reduce the overconservatism, some new equations for shear lag estimate are introduced.

Strength of slotted tubular tension members

1998 ◽  
Vol 25 (6) ◽  
pp. 982-991 ◽  
Author(s):  
J J. Roger Cheng ◽  
G L Kulak ◽  
Heng-Aik Khoo
Keyword(s):  
Equivalent Plastic Strain ◽  
Experimental Program ◽  
Shear Lag ◽  
Element Analysis ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Lag Effect ◽  
Load Carrying ◽  
Tension Members ◽  
Hollow Structural Section

An experimental program and associated numerical analysis were undertaken to study the shear-lag effect in round hollow structural section (HSS) tension members that are welded to gusset plates at their ends. The connection is made by slotting the tube longitudinally, inserting the gusset plate, and then placing longitudinal fillet welds at the tube-gusset interface. A total of nine specimens with three different tube sizes (HSS 102 × 6.4, HSS 102 × 4.8, and HSS 219 × 8.0) and various weld lengths were tested in the program. Most of the specimens failed by fracture of the tube somewhere between the two gusset plates, and there was considerable ductility prior to fracture. Most importantly, there was no reduction in the effective net area for the tested specimens, even with a weld length as little as 80% of the distance between the welds. Numerical analyses of the connections were carried out using an elastoplastic model and measured material properties. The studies showed that the restraint provided by the gusset plate at the slotted end effectively increases the load-carrying capacity of the tube as compared with that of the unrestrained portion of the member. In the analysis, fracture is assumed to have occurred when the equivalent plastic strain reaches a critical value. The test results are discussed in light of the requirements in the Canadian standard for design of steel structures.Key words: connections, steel, shear lag, finite element analysis, gusset plates, hollow structural section, tension, welds.

Experimental Study on Seismic Performance of Ridge Joint of Double C Steel under Cyclic Loading

2011 ◽  
Vol 243-249 ◽  
pp. 1435-1438 ◽  
Author(s):  
Ming Chen ◽  
Yang Sun ◽  
Bing Qian Pi
Keyword(s):  
Experimental Study ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Engineering Application ◽  
Steel Structure ◽  
Energy Performance ◽  
Gusset Plate ◽  
Cold Formed Steel ◽  
Bolt Spacing ◽  
Steel Section

The double C steel section is made of two C steels with gusset plate through bolts. A ridge joint of double C steel is studied through experiment under cyclic loading in this paper. Through the four specimens with different gusset-plate’s thickness and bolt spacing, we analyze the effect of the gusset-plate’s thickness and bolt spacing on stiffness, ductility and energy performance. At last we recommend the suitable gusset-plate’s thickness. The results can give a reference to the engineering application of cold-formed steel structure.

Experimental cyclic loading of concentric HSS braces

2011 ◽  
Vol 38 (1) ◽  
pp. 110-123 ◽  
Author(s):  
Madhar Haddad ◽  
Tom Brown ◽  
Nigel Shrive
Keyword(s):  
Energy Dissipation ◽  
Material Properties ◽  
Slenderness Ratio ◽  
Plate Thickness ◽  
Earthquake Ground Motion ◽  
Braced Frames ◽  
Gusset Plate ◽  
Plate Size ◽  
Tension And Compression ◽  
Hysteresis Behaviour

During earthquake ground motion, diagonal braces in braced frames are subject to a series of cyclic loadings, alternately tension and compression. The brace can buckle and deform plastically, dissipating energy with damage accumulating in the steel. Eventually a crack may form and the brace fractures. To optimize energy dissipation, the effects of brace and gusset plate dimensions (thickness and length of the gusset plate, size of the brace, length of the brace), and material properties, on brace behaviour, need to be understood. Ten concentric bracing members, designed according to the weak brace – strong gusset concept, were tested. The objective was to investigate the effects of displacement history, brace effective slenderness ratio, and brace width/thickness ratio, on the hysteresis behaviour of bracing members. Displacement history was found to affect energy dissipation and fracture life. The effects of increasing the gusset plate thickness on the energy dissipation and the fracture life is not the same as reducing the effective slenderness ratio of the bracing member resulted from reducing the length of the HSS. New fracture life and energy life equations are proposed.

Recommended Stress Formulae for Tubular Conical Transition Designs

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Albert Ku ◽  
Jieyan Chen
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Shell Theory ◽  
Plate Thickness ◽  
Design Standards ◽  
Shell Equations ◽  
Offshore Industry ◽  
Hoop Stresses ◽  
Code Provisions

Abstract For the design of tubular conical transitions, the axial, bending, and hoop stresses at the junctions are required. Among the offshore design standards, API RP-2A, ISO 19902, and NORSOK N-004, various equations exist for the same stress quantity which may cause confusions. The quality of these existing stress formulae will be examined in this paper. The tubular conical stress equations used in the offshore industry started from Boardman’s studies in the 1940s. Recently, Lotsberg re-formulated this problem and applied the results to stress concentration factor (SCF) applications. This paper solves the same set of shell equations but the formulations are cast in a different form. This new format allows for an in-depth examination of existing code equations. In addition, the formulation as presented can be used for modifications to gain higher accuracy. Several recommended new stress formulae are provided. It is observed that the existing code provisions’ accuracy quickly deteriorates for cases where plate thickness in tubular and cone differ. The recommended approach is based on theoretical framework of shell mechanics, which better facilitate tubular/cone force balances when compared with existing equations. The sectional relationships among moment, shear, and hoop loads are also treated consistently using shell theory. The resulted improvements make the recommended formulae more accurate than the existing provisions.

A Discussion on the Differences between Arch Dam Design Standards of the United States, China and Vietnam

2012 ◽  
Vol 212-213 ◽  
pp. 841-845
Author(s):  
Hoang Hung Vu ◽  
Tong Chun Li ◽  
Quang Hung Nguyen
Keyword(s):  
United States ◽  
The United States ◽  
Arch Dam ◽  
Strength Analysis ◽  
Research Focus ◽  
Design Standards ◽  
Technical Design ◽  
Design Standard ◽  
Technical Specifications

In arch dam design, every country has it own technical design standard. In Vietnam, the standard is far lessconprehensive compared with those of the United States and China. This research focus on analysis of the differences between three above standard systems, in order to give some suggestions to improve the Vietnamese standard for arch dam. Differnces in stability and strength analysis under static and seismic conditions is discussed in depth. A case study of Namchien arch dam in Vietnam, which has being constructed in Vietnam, is presented. The results show that if arch dam design based on the Vietnamese standard, stability and strength analysis should be paid more attention on the discussed differences. The research aims atcontributing constructive suggestions concerning to existing Vietnamese standard and providing some technical specifications for designer in arch dam design.

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