Testing of Extended Shear Tab Connections Subjected to Shear Jacob Hertz Civil Engineering and Applied Mechanics McGill University, Montreal August 2014 A thesis submitted to McGill University in partial fulfillments of the requirements of the degree of Master of Engineering (M.Eng.) Thesis Option © Jacob Hertz 2014 Abstract 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 ii supporting girder web and flange for partial-height connections. Design equations are proposed for both of these limit states. iii Résumé Les plaques de cisaillement sont largement utilisées en tant que connexions de cisaillement simple dans la construction de structures en acier. Ces connexions prennent la forme d'une unique plaque soudée à une colonne ou une poutre. Pendant le montage, la poutre est mise en place et reliée à la plaque de cisaillement en utilisant des boulons. Dans certains cas, l'excentricité du groupe de boulons sur la face de l'élément de support (soit la colonne soit la poutre) doit être augmentée à cause de l'encombrement à proximité de la face d'appui ou à des fins de constructibilité. Dans ce cas, la plaque de cisaillement est considérée comme «étendue» (l'alternative étant classique). Le manuel de la construction en acier par l'Institut canadien de la construction en acier (ICCA) et celui par l'Institut américain pour la construction en acier (IACA) incluent tous les deux des plaques de cisaillement conventionnelles déjà préconçues. Les résistances en cisaillement ont été établies à l'aide de la méthode de L'IACA [confirmée par les tests de Astaneh et al. (1989)]. Contrairement au Manuel de l'ICCA, le Manuel IACA comprend une méthode de conception pour les configurations étendues, qui est principalement basée sur la recherche ci-dessus. Cette recherche vise à vérifier l'exactitude dans la prédiction de la résistance au cisaillement de connexions étendues en utilisant une méthode modifiée, combinant celle des Manuels de l'ICCA et de l'IACA. La résistance au cisaillement de 12 connexions étendues représentatives a été prédite à l'aide de cette méthode modifiée et comparée à celle mesurée par des tests à grande échelle. Quatre plaques de cisaillements étendues utilisées comme connexions poutre-colonne et huit pour des connexions poutre-poutre ont été conçues et testées dans le laboratoire de structures de génie civil Macdonald. Deux tests poutre-colonne furent régis par flexion suivi par le déchirement de la soudure. Les soudures ont été réalisées, comme spécifié dans la méthode de conception IACA, à 5/8èmes de l'épaisseur de la plaque (ce qui suppose un acier soudable de 345MPa avec des électrodes E49). L'auteur recommande de dimensionner les soudures en utilisant une équation de conception qui prend en compte la contrainte de rendement probable de l'acier. Deux tests ont abouti à un voilement plastique sur le bord inférieur de la plaque de cisaillement. La méthode de conception de l'IACA indique que la résistance de voilement doit être calculé en utilisant deux iv modèles : i ) flambement par torsion latérale ou ii ) un flambement classique conservateur. Les résistances au voilement local mesurées pour les deux tests ont été mieux prédites par ce dernier, et ce, de manière significative. Les tests sur les connexions poutre-poutre ont révélés que deux états limites doivent être pris en compte dans la méthode de conception : i) un flambement biaxial sur toute la hauteur de la plaque de cisaillement étendue, et ii) une déformation localisée de l'âme et de la semelle de la poutre de support. Des équations sont proposées pour la conception dans ces deux états limites. v Acknowledgements I would like to thank my supervisors: Professor Colin Rogers and Professor Dimitrios Lignos. Their patience, guidance, and feedback along every stage of this research program was invaluable. I would like to thank ADF Group Inc., DPHV Structural Consultants, and NSERC, for their financial contributions. The real-world knowledge of Martin Frappier and Denis D’Aronco, of DPHV, was crucial in the design and analysis stages. I would also like to thank Augustin Silva, of ADF Group, for coordinating fabrication and delivery of the test specimens. Rigorous lab testing would not have been possible without day-to-day help from the lab team: Harrison Moir, Farbod Pakpour, Milad Moradi, and Mohammad Motallebi. I also owe a big thank you to the lab coordinator, Dr. William Cook, and the lab staff: Marek Przykorski, John Bartczak, and Gerard Bechard. Marco D’Aronco, of DPHV, was of great assistance in teaching me the ins and outs of lab testing. I would like to thank Heng Khoo of Carleton University for permitting the use of Carleton University’s lab facilities as well as Stanley Conley for assistance in coupon testing. This has been no trivial task and I owe many thanks to my friends and family, especially to my parents, Debra and Blaine, for shaping me into the man I am today. Thank you Gloria Ivanković for your unwavering support and love. This has been a journey not just for me, but for the both of us. I will always be grateful to you for standing by me. vi Table of Contents Abstract _____________________________________________________________________________________ ii Résumé _____________________________________________________________________________________ iv Acknowledgements ___________________________________________________________________________ vi Table of Contents ____________________________________________________________________________ vii List of Figures ________________________________________________________________________________ ix List of Tables _______________________________________________________________________________ xii Chapter 1 – Introduction ________________________________________________________________________ 1 1.1. Overview __________________________________________________________________________ 1 1.2. Objectives _________________________________________________________________________ 6 1.3. Scope _____________________________________________________________________________ 7 1.4. Outline ____________________________________________________________________________ 7 Chapter 2 – Literature Review ___________________________________________________________________ 8 2.1. Overview __________________________________________________________________________ 8 2.2. Research __________________________________________________________________________ 8 2.2.1. Full-Scale Testing _________________________________________________________________ 8 2.2.2. Numerical Finite Element Studies ___________________________________________________ 34 2.2.3. Design Aids ____________________________________________________________________ 40 2.3. Design Handbooks _________________________________________________________________ 42 2.3.1. Canada ________________________________________________________________________ 42 2.3.2. USA __________________________________________________________________________ 43 2.4. Summary _________________________________________________________________________ 45 Chapter 3 – Testing Program ___________________________________________________________________ 47 3.1 Overview ___________________________________________________________________________ 47 3.2 Test Specimens _______________________________________________________________________ 47 3.3 Design Method _______________________________________________________________________ 51 3.3.1. Definition of Extended Shear Tab Connections _________________________________________ 51 3.3.2. Design Check 1: Bolt Shear and Bolt Bearing __________________________________________ 52 3.3.3. Design Check 2: Plate Ductility _____________________________________________________ 54 3.3.4. Design Check 3: Shear Yielding, Rupture, Block Rupture ________________________________ 54 3.3.5. Design Check 4: Combined Shear and Flexural Yielding _________________________________ 55 3.3.6. Design Check 5: Buckling _________________________________________________________ 58 3.3.7. Design of Beams _________________________________________________________________ 59 3.3.8. Design of Girders ________________________________________________________________ 61 3.4. Testing Setup ______________________________________________________________________ 63 3.4.1. Test Beams _____________________________________________________________________ 67 vii 3.4.2. Reaction Frames, Stub Columns, and Girder Segments ___________________________________ 67 3.4.3. Compression and Tension Actuators _________________________________________________ 70 3.4.4. Lateral Bracing System ___________________________________________________________ 72 3.4.5. Installation of Test Configurations ___________________________________________________ 72 3.5. Test Procedure _____________________________________________________________________ 73 3.5.1. Instrumentation __________________________________________________________________ 73 3.5.2. Test Procedure __________________________________________________________________ 77 3.6. Summary _________________________________________________________________________ 79 Chapter 4 – Discussion of Experimental Results ____________________________________________________ 81 4.1. Overview _________________________________________________________________________ 81 4.2. Coupon Testing ____________________________________________________________________ 81 4.2.1. Test Methodology ________________________________________________________________ 81 4.2.2. Test Results_____________________________________________________________________ 84 4.2.3. Remarks _______________________________________________________________________ 85 4.3. Experimental Results and Discussion ___________________________________________________ 87 4.3.1. Predicted Resistances _____________________________________________________________ 87 4.3.2. Summary of Experimental Results and Comparisons ____________________________________ 88 4.3.4. Beam-to-Girder Extended Shear Tab Connections ______________________________________ 97 4.4. Recommendations _________________________________________________________________ 111 4.4.1. Weld Proportioning _____________________________________________________________ 111 4.4.2. Buckling at Unsupported Edges of Shear Tab Connections_______________________________ 112 4.4.3. Buckling of Full Height Beam-to-Girder Connections __________________________________ 113 4.4.4. Girder Rigidity _________________________________________________________________ 117 4.5. Summary ________________________________________________________________________ 119 Chapter 5 – Conclusions and Recommendations ___________________________________________________ 121 5.1. Summary ________________________________________________________________________ 121 5.2. Recommendations _________________________________________________________________ 123 5.3. Future Work _____________________________________________________________________ 124 References ________________________________________________________________________________ 125 Appendix A – Design Calculations ____________________________________________________ A-1 Appendix B – Fabrication Drawings ___________________________________________________ B-1 Appendix C – Test Setup and Instrumentation ____________________________________________ C-1 Appendix D – Specimen Test Summaries________________________________________________ D-1 viii List of Figures Figure 1.1: Shear Tab Connection Examples __________________________________________________ 1 Figure 1.2: Rigid vs. Flexible Support Conditions for Shear Tab Connections ________________________ 2 Figure 1.3: Conventional vs. Extended Shear Tab Configurations __________________________________ 3 Figure 1.4: Comparison of Installation Method for Beam-to-Girder Shear Connections _________________ 5 Figure 1.5: Plan View of Installation Method for Shear Tab Connection with Beam Coped at Both Ends ____ 5 Figure 1.6: Beam-to-Column Extended Shear Tab Example (Courtesy of DPHV Structural Consultants) ____ 6 Figure 2.1: Shear-Deflection Curves for Welded-Bolted Single Plate Connections, Lipson (1968) _________ 9 Figure 2.2: Load-Deformation for 19mm Bolts Connecting 9.5mm Plates, Richard et al. (1980) _________ 10 Figure 2.3: Proposed Block Shear Failure Model, Ricles (1980) __________________________________ 12 Figure 2.4: Test 5A, W460x39 Beam with 402mm Deep Girder (45°), Stiemer et al. (1986) _____________ 13 Figure 2.5: Test 2B, W460x61 Beam with 452mm Deep Girder (0°), Stiemer et al. (1986) ______________ 13 Figure 2.6: Tri-Linear Shear-Rotation Curve for Shear Tab Connections, Astaneh et al. (1989) __________ 14 Figure 2.7: Yielding of Girder Web (Flecks Indicate Yielding), Shaw and Astaneh (1992) ______________ 16 Figure 2.8: Girder Web Deformation, Shaw and Astaneh (1992) __________________________________ 16 Figure 2.9: Typical Test Setup, Liu and Astaneh (2000) ________________________________________ 17 Figure 2.10: Deformation of Bolt Hole and Fracture, Bare-Steel Test, Liu and Astaneh (2000)___________ 18 Figure 2.11: Load-Drift Response for Specimens with and without a Slab, Liu and Astaneh (2000) _______ 19 Figure 2.12: Load-Drift Response for Specimens with and without Angle, Liu and Astaneh (2000) _______ 20 Figure 2.13: Specimen with Supplemental Seat Angle, End of Test, Liu and Astaneh (2000) ____________ 20 Figure 2.14: Conventional Shear Tab Connection, Sherman and Ghorbanpoor (2002) _________________ 21 Figure 2.15: Unstiffened vs. Stiffened Extended Shear Tabs, Sherman and Ghorbanpoor (2002) _________ 22 Figure 2.16: Inflection Point Eccentricity, e, Sherman and Ghorbanpoor (2002) ______________________ 24 Figure 2.17: Conventional vs. Extended Unstiffened Beam-to-Column Shear Tab Connections __________ 27 Figure 2.18: Shear Tab Before Testing, Test 1, Goodrich (2005) __________________________________ 27 Figure 2.19: Buckled Shear Tab, Test 1, Goodrich (2005) _______________________________________ 28 Figure 2.20: Weld Rupture, Test 5b, Baldwin Metzger (2006)____________________________________ 30 Figure 2.21: Flexible Support Beam-to-Column Test Setup, D'Aronco (2014) _______________________ 33 Figure 2.22: Shear Tab Deformation, Rigid vs. Flexible Support, D'Aronco (2014) ___________________ 34 Figure 2.23: Stress Distribution within Shear Tab, Ashakul (2004) ________________________________ 35 Figure 2.24: Twist Failure Mode in Shear Tab for Five Bolt Connection, Rahman et al. (2007) __________ 37 Figure 2.25: Web Mechanism for Three Bolt Connection, Rahman et al. (2007) ______________________ 37 Figure 2.26: Modelled Web Failure for 10 Bolt Beam-to-Girder Connection, Mahamid et al. (2007) ______ 38 Figure 2.27: Component-Based Model of Shear Tab Connection, Koduru and Driver (2013) ____________ 39 ix Figure 3.1: Beam-to-Column Extended Shear Tab Configurations ________________________________ 48 Figure 3.2: Full Height vs. Partial Height Shear Tabs __________________________________________ 49 Figure 3.3: Installation Method for Side Plate Connections (Configuration 8) ________________________ 50 Figure 3.4: Renderings of Typical Test Setup (Arrows Indicate Actuator Locations) __________________ 64 Figure 3.5: Plan View of the Beam-to-Column Test Setup (Configuration 1 pictured); dimensions in mm __ 65 Figure 3.6: Plan View of the Beam-to-Girder Test Setup (Configuration 5 pictured); Dimensions in mm ___ 66 Figure 3.7: Reaction Frame Details, Elevation and Section Views; Dimensions in mm _________________ 68 Figure 3.8: Beam-to-Column Reaction Frame with Stub Column Installed __________________________ 69 Figure 3.9: Beam-to-Girder Reaction Frame _________________________________________________ 70 Figure 3.10: Compression Actuator ________________________________________________________ 71 Figure 3.11: Tension Actuator ____________________________________________________________ 71 Figure 3.12: Lateral Bracing System _______________________________________________________ 72 Figure 3.13: Welding Procedure, Shear Tab with Partial "C" Weld ________________________________ 73 Figure 3.14: Instrumentation Plan, Configuration 3, Dimensions in mm ____________________________ 74 Figure 3.15: Out-of-Plane LVDT Placement (Configuration 4 Pictured) ____________________________ 76 Figure 3.16: Modified Shear-Rotation Response for Shear Tab Connections, Marosi (2011) ____________ 77 Figure 3.17: Rotational and Shear Response for Beam _________________________________________ 78 Figure 3.18: Half Cylinder and Rollers _____________________________________________________ 79 Figure 4.1: Beam Coupon Locations (Image Courtesy of DPHV Structural Consultants) _______________ 82 Figure 4.2: Coupon Test Setup ___________________________________________________________ 83 Figure 4.3: Coupon Specimens Before (W24x94 Flange) and After (W27x84 Flange) Uniaxial Tensile Test 85 Figure 4.4: Engineering Stress vs. Strain, Coupon PL3/8 5A-3 (horizontal direction in shear tab) _________ 86 Figure 4.5: Engineering Stress vs. Strain, Coupon PL3/8 5B-3 (vertical direction in shear tab) ___________ 86 Figure 4.6: Connection Shear vs. Rotation, Configurations 1 & 3 _________________________________ 90 Figure 4.7: Weld Tearing and Deformed Shear Tab, Configuration 1 ______________________________ 91 Figure 4.8: Weld Tearing and Deformed Shear Tab, Configuration 3 ______________________________ 91 Figure 4.9: Sheared Bolt, Configuration 1 ___________________________________________________ 92 Figure 4.10: Eccentric Loads on Bolt Groups, Reproduction of CISC Handbook (2010) ________________ 93 Figure 4.11: Connection Shear vs. Rotation, Configuration 2 ____________________________________ 94 Figure 4.12: Bottom Edge of Shear Tab, Configuration 2 _______________________________________ 94 Figure 4.13: Connection Shear vs. Rotation, Configuration 4 ____________________________________ 96 Figure 4.14: Shear Tab Deformation at End of Test, Configuration 4 ______________________________ 96 Figure 4.15: Buckling Failure Mode Shape (Configuration 5 Pictured) _____________________________ 97 Figure 4.16: Strain Gauge Layout, Full Height Beam-to-Girder Shear Tab Connections ________________ 98 Figure 4.17: Connection Shear vs. Rotation, Full Height Beam-to-Girder Shear Tab Connections ________ 98 Figure 4.18: Buckled Shear Tab at Test End, Full Height Beam-to-Girder Shear Tab Connections ________ 99 x