Testing of Extended Shear Tab Connections Subjected to Shear PDF Download

Author: Jacob Hertz
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
"Shear tab, or single-plate, connections are widely used as simple shear connections in the construction of steel structures. These connections take the form of a single plate shop welded to a supporting column or girder. During erection, the supported beam is moved into place and connected to the shear tab using bolts. In some cases, the eccentricity of the bolt group to the face of the supporting member must be increased due to congestion near the support face or for constructability. In this case, the shear tab connection is considered "extended" (the alternative being conventional). The Canadian Institute of Steel Construction (CISC) Handbook of Steel Construction and the American Institute for Steel Construction (AISC) Steel Construction Manual both include pre-designed conventional shear tab connections, the shear resistances of which were computed using the AISC design method [confirmed through testing by Astaneh et al. (1989)]. In addition, the AISC Manual includes a design method for extended configurations.This research aims to verify the accuracy in predicting the shear resistance of extended shear tab connections using a modified method, combining that of CSA S16-09 (2009), the CISC Handbook (2010), and the AISC Manual (2010). The shear resistances of 12 representative shear tab connections were predicted using said method and compared with the measured resistances found through full-scale testing. Four beam-to-column and eight beam-to-girder extended shear tab connections were tested in the Macdonald Engineering Jamieson Structures Laboratory at McGill University. Two of the four beam-to-column tests were governed by flexural tearing of the weld. The welds were sized, as specified in the AISC design method, at 5/8ths of the plate thickness (which assumes 345MPa steel welded with E49 electrodes). This author recommends the welds be sized using a design equation that takes into account the probable yield stress of the steel. The other two beam-to-column tests resulted in plastic local buckling of the bottom edge of the shear tab. The AISC design method allows for the buckling resistance to be calculated using two models: i) lateral torsional buckling or ii) a conservative classical plate buckling. The measured buckling resistances for both tests were significantly better predicted by the latter model. The beam-to-girder tests revealed that two limit states should be accounted for in the design method: i) biaxial buckling of full-height connections, and ii) localized deformation of the supporting girder web and flange for partial-height connections. Design equations are proposed for both of these limit states." --

Author: Nathan Goldstein Apt
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
"Beam-to-girder steel connections are commonly constructed using either extended shear tabs or coped beams. The American Institute of Steel Construction has outlined a design procedure for coped beams, and as of 2011 also included guidelines for the design of extended shear tabs. On the other hand, Canadian standards do not provide professional engineers with guidelines for the design of coped beams and only address conventional shear tab connections. Therefore, a total of thirteen full-scale tests were performed in order to provide structural engineers with relevant experimental results from which to predict the behaviour of extended shear tabs of different depths and coped beams with varying reinforcements, cope details, and connectors subject to shear loading. Four of the tests were used to investigate two specific limit states: buckling of extended full depth shear tabs and localized deformations in the supporting girder web of partial depth extended shear tabs. It was found that by reducing the slenderness of the shear tab plate, out-of-plane deformations in the plate were reduced but not avoided. In order to more accurately represent the restraints in a building, a pseudo-concrete slab was installed to prevent girder rotation; however, this did not prevent girder web deformation. As a result, a retrofit steel plate was welded, connecting the shear tab and the girder web in order to engage a larger area of the supporting member. Even though the local girder web punching was decreased with this retrofit, the web deformation was not eliminated.In order to gain a better understanding of the behaviour of coped beams, nine full-scale tests were conducted. These specimens were divided into four categories: bolted single coped (coped compression flange), bolted double coped (coped compression and tension flanges), single and double coped welded in-shop, and single coped haunched beams. The bolted configurations were connected to the supporting girder with the use of a stiffener plate welded to the girder flanges and web. Two reinforcement schemes were also investigated; horizontal stiffeners and doubler plates were considered to assess their effectiveness in improving the strength of coped beams. The interaction between shear and flexural forces based on the Von Mises criterion, which is not part of any current design standard, consistently governed the design and could be used to accurately predict the behaviour of coped beam configurations, and as such, is proposed for inclusion in a standard design procedure. " --

Author: Mohammad Motallebi Nasrabadi
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
"The configuration of a shear tab connection depends greatly on the location and geometry of the supported and supporting structural members. In comparison to the short (conventional) shear tab, the long (extended) shear tab is considered as a more economical solution to join a simply supported beam to the web of a supporting girder or column. Despite a long history of use of the extended shear tab in the USA and Canada, both the American and Canadian steel design codes provide no design recommendation for extended shear tabs under combined axial and shear forces. The Steel Construction Manual of the American Institute of Steel Construction (AISC) provides a procedure for the design of extended shear tabs under gravity induced shear force, while the Handbook of Steel Construction of the Canadian Institute of Steel Construction (CISC) is silent. To address this shortcoming, a series of full-scale tests was performed in the Jamieson Structures Laboratory at the McGill University. The tested specimens consisted of two stiffened and four unstiffened extended shear tabs. These specimens varied in the number of vertical bolt lines and bolt rows, the bolt size, the depth and thickness of the shear plate, the offset of the bolt group from the face of the support, and the applied axial force. The test results shaped a baseline for validation of the finite element models and a subsequent parametric study. In addition to the various geometric parameters of the shear tab, the impact of the axial force with varied magnitude and direction was investigated for both unstiffened and stiffened configurations of the extended shear tab connection. Based on the experimental-numerical results, modifications to the current AISC procedure for the design of the extended shear tabs are introduced, and applied in the case of coupled axial and shear demands"--

Author: Alireza Mirzaei
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
"A common approach to connect steel beams to columns is to use single plate shear tabs. Numerous laboratory test programs of these connections subjected to vertical loading alone have been completed over the past 30 years. However, the effect of axial forces on the shear tab's performance has only recently been the subject of study. The presence of an axial force in the shear tab connection will typically result in the need for multiple vertical rows of bolts, which is not addressed in any Canadian design guide. The main objective of the research program described herein was to develop a design approach that could be used by the engineering community to address the effect of combined axial and shear force on a shear tab connection.A series of four full-scale tests were performed on shear tab connections between a W610x140 beam and a W360 x 196 column, as well as a W310 x 60 beam and a W360 x 196 column. The shear tab, which was configured as a double bolt row connection, was subjected to a combined vertical (shear) force and axial tension along with the anticipated rotation of a typical beam-to-column joint. A matching specimen was then tested under shear and axial compression. The results from these tests and previous shear tabs tested under gravity load alone were used in the development of a finite element model that is capable of simulating the response of the connection under shear load; predict the ultimate resistance and the progression of failure. Previous finite element modelling of shear tabs lacked damage simulation capability, did not include the effect of weld tearing, and as such often overestimated the connection resistance. The models presented in this thesis featured special modelling techniques and were able to predict all types of failure modes such as bearing, net area fracture, shear yielding, flexural yielding, and weld tearing of the connections.The FE models were then used to investigate the performance of shear tabs subjected to combined shear and axial force. Shear force-axial force interaction curves were generated for various levels of axial tension and compression force for twelve connections. A design approach was proposed which allows practicing engineers to include the effect of any axial force level in the design of a shear tab connection." --

Author: Steven C. Rech
Publisher:
ISBN:
Category : Bolted joints
Languages : en
Pages : 246

View

Book Description

Author: Andrea Iachetta
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
"Single plate shear tab connections are commonly used due to their relatively simple design, ease of fabrication and safe erection on-site. They are fillet welded to a supporting column or girder, and then bolted to a supported beam. Extended shear tabs can either frame into the web, a flexible support, or the flange, a rigid support, of a column. The shear tab connection is assumed to function as a pin in the analysis of the overall structure. However, testing has shown that it must withstand shear and moment associated with the eccentricity applied to the shear tab, relative to the support. Current design procedures have little guidance on how to account for this added moment to the column, which may not be a concern for shear tab connections framing into a rigid support (column bending about major axis), but may be more critical when framing into a column’s minor axis (which is considered as a flexible support condition).The existing design procedures for shear tab connections were formulated from past research studies. The 2015 CISC Handbook of Steel Construction lacks a design approach for extended shear tabs. The 2017 AISC Steel Construction Manual has a conservative design approach only based on unstiffened connections, despite the frequent use of stiffened extended shear tab connections. Further research and testing is required to provide recommendations for a more efficient and complete design procedure.Finite element models were used to analyse the behaviour and capacity of beam-to-column web extended shear tab connections. Five validation models were first created to simulate laboratory tests by D’Aronco (2013) to verify the modelling assumptions. The obtained shear forces, rotations and displacements proved to be accurate, confirming that the modelling approach could be used in a subsequent parametric study. The parametric study included the influence of the supporting column, single- vs. double-sided connections, the effect of the type and connection pattern of stabilizer plates, the addition of vertical rows of bolts, the shape of the shear plate, and the effect of the loading protocol.The results demonstrate that the column size, the addition of a vertical row of bolts and the shape of the shear tab did not alter the connection capacity. Also, the welds connecting the stabilizer plates to the column web are not necessary, if the plates are welded to the column flanges. Introducing a gap between the stabilizer plates and the column flanges can benefit the column by reducing the moments applied to it. Finally, the loading protocol greatly influences the connection behaviour; more studies are required to further investigate this aspect"--

Author: Mohamed Fawzi Suleiman
Publisher:
ISBN:
Category :
Languages : en
Pages : 149

View

Book Description
The Manual of Steel Construction AISC 14th edition refers to an extended shear tab as a single plate shear connection. This method of providing simple connections has become quite popular with both fabricators and erectors. Extended shear tab connections were formally introduced in the 13th edition of AISC Steel Construction Manual. Using experimental data from extended shear tab connections, Sherman and Ghorbanpoor introduced a design methodology in 2002 for extended shear connections. Twisting of the shear tab controlled the capacity of the specimens tested by Sherman and Ghorbanpoor, which were not laterally braced. In the latest edition of AISC Steel Manual, design equations are provided to assess the need for stabilizer plates in the connection region of extended shear tabs. In an effort to understand whether twisting of the shear tab can be a controlling design limit state, three-dimensional nonlinear finite element analyses in conjunction with design case studies were conducted. The analyses included 364 connections with different configurations were studided with an "a" distance of (9, 11, and 16 inches). The finite element models were comprehensive in terms of simulating nonlinear material properties, boundary conditions, pretensioning in the bolts, geometric nonlinearity, etc. It was possible to accurately replicate the responses (shear force-connection vertical deflection and shear force-connection angle of twist) measured in a number of previous tests, and to fairly well predict the observed failure modes. Using a 3D nonlinear finite element analysis technique, the response of 16 selected connections, which had been designed to meet all the applicable limit states in AISC Steel Manual, were evaluated. The presence of floor slab, which braces the top flange of the beam, was simulated in the analyses. For a number of cases, the connection behavior at the ultimate limit state was dominated by twisting, i.e., the relationship between torsional moment and angle twist indicated a noticeable level of loss of stiffness in comparison to that from the shear-vertical displacement relationship. However, the level of lateral displacement of the shear tab was small, particularly for unfactored loads when control of deformations is an important design objective. According to AISC provisions (Eq.10-6), stabilizer plates would not be required for any of these 16 connections, which were evaluated by 3D nonlinear FEA. Therefore, current AISC provisions are a good predictor of the expected level of out-of-plane displacement of the shear tab due to twisting. It should be noted that large lateral displacements occurred at the ultimate state when the connection ductility is the main design consideration but not the magnitudes of deformations and distortions. Therfore, this equation can be used to determine whether stabilizer plates are needed or not; however, it does not predict whether the response at the ultimate limit state will be dominated by excessive loss of torsional stiffness of the shear tab. Instead of using stabilizer plates, a thicker plate can be used for the shear tab. This solution is considered to be more economical and easier than welding stabilizer plates in the connection region.

Author: Kristin S. Thomas
Publisher:
ISBN:
Category : Building, Iron and steel
Languages : en
Pages : 146

View

Book Description
Current design procedures for extended shear tab connections tend to be conservative and often do not include considerations for axial load. To address these problems, an investigation into the behaviour of extended shear tabs was completed by testing 23 full-scale specimens. Both unstiffened and stiffened extended shear tab specimens were tested that varied in plate thickness, plate depth, and the number of horizontal bolt lines. The specimens were tested by rotating the beam to 0.03 radians, applying a horizontal load, and then applying vertical load until failure. The horizontal loads varied from 500 kN in compression to 200 kN in tension. Based on the test results, design recommendations were made for both unstiffened and stiffened extended shear tabs. The recommendations include strength equations for bolt group design and plate design, while connection ductility is addressed by ensuring the plate will fail prior to bolt or weld rupture.

Author: Jacob Donnellan
Publisher:
ISBN:
Category : Bolted joints
Languages : en
Pages : 346

View

Book Description

Author: Marian A. Giżejowski
Publisher: Routledge
ISBN: 1000459527
Category : Technology & Engineering
Languages : en
Pages : 689

View

Book Description
Modern Trends in Research on Steel, Aluminium and Composite Structures includes papers presented at the 14th International Conference on Metal Structures 2021 (ICMS 2021, Poznań, Poland, 16-18 June 2021). The 14th ICMS summarised a few years’ theoretical, numerical and experimental research on steel, aluminium and composite structures, and presented new concepts. This book contains six plenary lectures and all the individual papers presented during the Conference. Seven plenary lectures were presented at the Conference, including "Research developments on glass structures under extreme loads", Parhp3D – The parallel MPI/openMPI implementation of the 3D hp-adaptive FE code", "Design of beam-to-column steel-concrete composite joints: from Eurocodes and beyond", "Stainless steel structures – research, codification and practice", "Testing, modelling and design of bolted joints – effect of size, structural properties, integrity and robustness", "Design of hybrid beam-to-column joints between RHS tubular columns and I-section beams" and "Selected aspects of designing the cold-formed steel structures". The individual contributions delivered by authors covered a wide variety of topics: – Advanced analysis and direct methods of design, – Cold-formed elements and structures, – Composite structures, – Engineering structures, – Joints and connections, – Structural stability and integrity, – Structural steel, metallurgy, durability and behaviour in fire. Modern Trends in Research on Steel, Aluminium and Composite Structures is a useful reference source for academic researchers, graduate students as well as designers and fabricators.