Impact of Vertical Ground Motion on Seismic Response of Steel Frame Structures by Hongyang Wu A thesis submitted to the Graduate Faculty of Auburn University in partial fulfillment of the requirements for the Degree of Master of Science Auburn, Alabama May 7, 2016 Keywords: vertical ground motion, reduced beam section (RBS), buckling-restrained brace (BRB), ductility of steel structures, nonlinear analysis, earthquake engineering Copyright 2015 by Hongyang Wu Approved by Justin D. Marshall, Chair, Associate Professor of Civil Engineering Mary L. Hughes, Lecturer of Civil Engineering James S. Davidson, Professor of Civil Engineering Abstract It is a well-known fact that all earthquakes have three orthogonal components of acceleration including two horizontal and one vertical acceleration. Current design practice for design of structures in United States only focuses on the impact of the horizontal component of earthquakes. However, according to previous research, vertical peak ground acceleration (PGA) can be higher than the horizontal peak acceleration in the same earthquake, which may contribute to structural collapse. Further research is needed to investigate the impact of vertical ground motion on seismic response of structures. In this paper, four three-story and four six-story steel frame structures are chosen to investigate and represent this problem. For each structure height a special moment frame with reduced beam section (RBS) connections and buckling- restrained brace (BRB) frames are designed by the equivalent lateral force (ELF) method based on ASCE 7-10 and analyzed by using nonlinear dynamic analysis. A suite of 40 strong ground motion records are selected including horizontal and vertical ground motions in this study. The range of the ratio of vertical to horizontal acceleration in this study is from 0.5 to 1.2. All the structural models are analyzed under two different loading cases: 1) Horizontal Only and 2) Horizontal plus Vertical. There is a significant impact of vertical ground motion on the column axial force, vertical acceleration and beam midspan vertical deflection. The demand on rotation of reduced beam sections in upper stories also experience a significant influence from the vertical ground motions. ii Acknowledgment I would like to thank my advisor Dr. Marshall for his help in my courses and research throughout my two years at Auburn University. I really appreciate his vast knowledge, guidance and assistance in writing this thesis. I really would like to thank him for giving me a chance to do my further study at Auburn University. His patience and passion has encouraged me greatly. Also, I would like to thank the rest of my committee, Dr. Davidson and Dr. Hughes for all the help they have provided. I also would like to thank my parents for their support and understanding in my entire life. I also appreciate my friends for their friendship and help, especially Todd Deason who helped me check the grammar errors in this paper, encouraged me to communicate with Dr. Marshall and made me enjoy life at Auburn. I would also thank my officemates and all the other fellow graduate students and faculty members. They have offered me a great experience at Auburn University, which I will never forget. iii Table of Contents Abstract ......................................................................................................................................................... ii Acknowledgment ......................................................................................................................................... iii List of Tables .............................................................................................................................................. vii List of Figures .............................................................................................................................................. xi Chapter 1 Introduction .................................................................................................................................. 1 1.1 Motivation for the Research ................................................................................................................ 1 1.2 Scope of work ..................................................................................................................................... 2 1.3 Organization of thesis ......................................................................................................................... 3 Chapter 2 Literature Review ......................................................................................................................... 4 2.1 Introduction of vertical ground motion ............................................................................................... 4 2.2 Near fault influence of vertical ground motion ................................................................................... 6 2.3 Frequency and period influence of vertical ground motion .............................................................. 12 2.4 Field evidence of the damage effect of vertical ground motion ........................................................ 16 2.5 Analytical research on the damage effect of vertical motion based on cantilever model ................. 20 2.6 Analytical research on the damage effect of vertical motion based on frame model ....................... 22 iv 2.7 Research on modeling mass .............................................................................................................. 31 2.6 Summary ........................................................................................................................................... 33 Chapter 3 Modeling of Special Moment Frame (SMF) and BRB Frames.................................................. 34 3.1 Introduction ....................................................................................................................................... 34 3.2 Basic information about the building ................................................................................................ 35 3.2.1 Three-story Moment Frame Structure........................................................................................ 35 3.2.2 Six-story Moment Frame ........................................................................................................... 36 3.2.3 Three-story BRB Brace Frame .................................................................................................. 37 3.2.4 Six-story BRB Brace Frame ...................................................................................................... 37 3.3 Basic Seismic Design ........................................................................................................................ 38 3.3.1 Basic Seismic Information ......................................................................................................... 38 3.3.2 Equivalent Lateral Force (ELF) Procedure for Structure Design .............................................. 38 3.4 Modeling Procedure .......................................................................................................................... 46 3.4.1 Basic Modeling Conception ....................................................................................................... 46 3.4.2 Modeling procedure in Perform 3D ........................................................................................... 48 3.5 Summary ........................................................................................................................................... 77 Chapter 4 Results and Discussion ............................................................................................................... 78 4.1 Introduction ....................................................................................................................................... 78 4.2 Modal Analysis ................................................................................................................................. 78 4.2 Story Drift and Story Residual Drift ................................................................................................. 80 v 4.3 Column Axial Force ........................................................................................................................ 100 4.4 Acceleration .................................................................................................................................... 108 4.4.1 Roof Horizontal Acceleration .................................................................................................. 108 4.4.2 Vertical Acceleration ............................................................................................................... 118 4.5 Vertical Deflection in the Beam ...................................................................................................... 124 4.6 Reduced Beam Section (RBS) Rotation and BRB Deformation .................................................... 133 4.7 Energy ............................................................................................................................................. 158 4.8 Summary ......................................................................................................................................... 162 Chapter 5 Conclusion and Recommendation ............................................................................................ 163 5.1 Summary ......................................................................................................................................... 163 5.2 Conclusion ...................................................................................................................................... 164 5.3 Recommendations ........................................................................................................................... 166 References ................................................................................................................................................. 168 Appendix A ............................................................................................................................................... 177 Appendix B ............................................................................................................................................... 280 vi List of Tables Table 2-1: Basic Ground Motion Information (Collier & Elnashai, 2001) ............................................ 5 Table 2-2: The Properties of Three Different Cantilever Models (IYENGAR & SHINOZUKA, 1972) ................................................................................................................................................... 21 Table 2-3: Relationship between First Mode Horizontal and Vertical Periods for RC Buildings. (Papadopoulou, 1989) ....................................................................................................................... 25 Table 2-4: Relationship between First mode Horizontal and Vertical Periods for Steel Buildings. (Papaleontiou & Roesset, 1993) ....................................................................................................... 26 Table 2-5: Effect of Vertical Motion on Axial Force Response of Steel Frames. (Papaleontiou & Roesset, 1993) .................................................................................................................................... 28 Table 2-6: Effect of Vertical Motion on Tensile Column Forces and Displacements for a RC Frame. No Tension occurs under only Horizontal Loading. (Koukleri, 1992) ........................................ 29 Table 2-7: Effect of Vertical Motion on Compressive Column Forces for a RC Frame. (Koukleri, 1992) ................................................................................................................................................... 29 Table 3-1: Basic Information for Seismic Design (Sabelli, 2001) .......................................................... 39 Table 3-2: Sizes of Beam and Column for Three-Story Moment Frame as Beam Model .................. 40 Table 3-3: Sizes of Beam and Column for Three-Story Moment Frame as Girder Model ................ 41 Table 3-4: Sizes of Beam and Column for Six-Story Moment Frame as Beam Model ....................... 42 Table 3-5: Sizes of Beam and Column for Six-Story Moment Frame as Girder Model ..................... 43 Table 3-6: Column and Beam Sections of Three-Story Braced Frame (Xie, 2015) ............................ 44 Table 3-7: Column and Beam Sections of Six-Story Braced Frame (Xie, 2015) ................................. 44 Table 3-8: BRB Properties of Three-Story Braced Frame (Xie, 2015) ................................................ 44 Table 3-9: BRB Properties of Six-Story Braced Frame (Xie, 2015) ..................................................... 45 Table 3-10: Drift Check Table for Three-Story Moment Frame.......................................................... 45 Table 3-11: Drift check table for six-story moment frame .................................................................... 45 Table 3-12: Summary of the Models' Periods ........................................................................................ 46 Table 3-13: Percentage of Averaged Error by Using Different Kinds of Models (Ju, Liu, & Wu, 2000) ................................................................................................................................................... 49 Table 3-14: Geometrical Characteristics of Reduced Beam Section .................................................... 54 Table 3-15: Strength Properties of Reduced Beam Section .................................................................. 54 Table 3-16: Force-Displacement Capacity Boundary Control Points for Single-Spring System (ATC, 2009a) ...................................................................................................................................... 57 Table 3-17: Force-Displacement Capacity Boundary Control Points for the Model ......................... 58 Table 3-18: Beam Plastic Hinge Location for Three-Story MF as Beam Model ................................. 59 Table 3-19: Beam Plastic Hinge Location for Three-Story MF as Girder Model ............................... 59 Table 3-20: Beam Plastic Hinge Location for Six-Story MF as Beam Model ..................................... 60 Table 3-21: Beam Plastic Hinge Location for Six-Story MF as Girder Model ................................... 60 Table 3-22: Column Plastic Hinge Location for Three-Story MF as Beam Model ............................. 64 vii Table 3-23: Column Plastic Hinge Location for Three-Story MF as Girder Model ........................... 64 Table 3-24: Column Plastic Hinge Location for Six-Story MF as Beam Model ................................. 65 Table 3-25: : Column Plastic Hinge Location for Six-Story MF as Girder Model ............................. 65 Table 3-26: “Strong-Column Weak-Beam” Ratio at each Joint .......................................................... 67 Table 3-27: Thickness of Doubler Plates for Panel Zone at each Joint ................................................ 68 Table 3-28: The Dimensions of W-Shape Composite Beam .................................................................. 71 Table 3-29: Basic Information and Scale Factors of the Selected Earthquake Records .................... 74 Table 4-1: Summary of Story Drift for the Three-Story Moment Frame as Beam Model ................ 81 Table 4-2: Summary of Story Drift for the Three-Story Moment Frame as Girder Model .............. 81 Table 4-3: Summary of Story Drift for the Three-Story Braced Frame with Chevron Configuration ............................................................................................................................................................. 81 Table 4-4: Summary of Story Drift for the Three-Story Braced Frame with Single Diagonal Configuration .................................................................................................................................... 82 Table 4-5: Summary of Story Drift for the Six-Story Moment Frame as Beam Model ..................... 84 Table 4-6: Summary of Story Drift for the Six-Story Moment Frame as Girder Model ................... 85 Table 4-7: Summary of Story Drift for the Six-Story Braced Frame with Chevron Configuration . 85 Table 4-8: Summary of Story Drift for the Six-Story Braced Frame with Single Diagonal Configuration .................................................................................................................................... 85 Table 4-9: Summary of Story Drift by Earthquake Group for the Three-Story Moment Frame as Beam Model ....................................................................................................................................... 91 Table 4-10: Summary of Story Drift by Earthquake Group for the Three-Story Moment Frame as Girder Model ..................................................................................................................................... 92 Table 4-11: Summary of Story Drift by Earthquake Group for the Three-Story Braced Frame with Chevron Configuration ..................................................................................................................... 92 Table 4-12: Summary of Story Drift by Earthquake Group for the Three-Story Braced Frame with Single Diagonal Configuration ......................................................................................................... 93 Table 4-13: Summary of Story Drift by Earthquake Group for the Six-Story Moment Frame as Beam Model ....................................................................................................................................... 95 Table 4-14: Summary of Story Drift by Earthquake Group for the Six-Story Moment Frame as Girder Model ..................................................................................................................................... 96 Table 4-15: Summary of Story Drift by Earthquake Group for the Six-Story Braced Frame with Chevron Configuration ..................................................................................................................... 96 Table 4-16: Summary of Story Drift by Earthquake Group for the Six-Story Braced Frame with Single Diagonal Configuration ......................................................................................................... 97 Table 4-17: Summary of Column Axial Force for the Three-Story Moment Frame as Beam Model ........................................................................................................................................................... 101 Table 4-18: Summary of Column Axial Force for the Three-Story Moment Frame as Girder Model ........................................................................................................................................................... 101 Table 4-19: Summary of Column Axial Force for the Three-Story Braced Frame with Chevron Configuration .................................................................................................................................. 101 Table 4-20: Summary of Column Axial Force for the Three-Story Braced Frame with Single Diagonal Configuration .................................................................................................................. 102 Table 4-21: Summary of Column Axial Force for the Six-Story Moment Frame as Beam Model . 104 Table 4-22: Summary of Column Axial Force for the Six-Story Moment Frame as Girder Model 105 Table 4-23: Summary of Column Axial Force for the Three-Story Braced Frame with Chevron Configuration .................................................................................................................................. 105 Table 4-24: Summary of Column Axial Force for the Three-Story Braced Frame with Single Diagonal Configuration .................................................................................................................. 105 Table 4-25: Summary of Roof Horizontal Acceleration for the Three-Story Models ..................... 109 viii Table 4-26: Summary of Roof Horizontal Acceleration for the Six-Story Models ........................... 109 Table 4-27: Summary of Vertical Acceleration for the Three-Story Moment Frame as Beam Model ........................................................................................................................................................... 119 Table 4-28: Summary of Vertical Acceleration for the Three-Story Moment Frame as Girder Model ................................................................................................................................................ 119 Table 4-29: Summary of Vertical Acceleration for the Three-Story Braced Frame with Chevron Configuration .................................................................................................................................. 119 Table 4-30: Summary of Vertical Acceleration for the Three-Story Braced Frame with Single Diagonal Configuration .................................................................................................................. 119 Table 4-31: Summary of Vertical Acceleration for the Six-Story Moment Frame as Beam Model 120 Table 4-32: Summary of Vertical Acceleration for the Six-Story Moment Frame as Girder Model ........................................................................................................................................................... 120 Table 4-33: Summary of Vertical Acceleration for the Six-Story Braced Frame with Chevron Configuration .................................................................................................................................. 121 Table 4-34: Summary of Vertical Acceleration for the Six-Story Braced Frame with Single Diagonal Configuration .................................................................................................................. 121 Table 4-35: Summary of Vertical Deflection for the Three-Story Moment Frame as Beam Model124 Table 4-36: Summary of Vertical Deflection for the Three-Story Moment Frame as Girder Model ........................................................................................................................................................... 124 Table 4-37: Summary of Vertical Deflection for the Three-Story Braced Frame with Chevron Configuration .................................................................................................................................. 125 Table 4-38: Summary of Vertical Deflection for the Three-Story Braced Frame with Single Diagonal Configuration .................................................................................................................. 125 Table 4-39: Summary of Vertical Deflection for the Six-Story Moment Frame as Beam Model .... 127 Table 4-40: Summary of Vertical Deflection for the Six-Story Moment Frame as Girder Model .. 128 Table 4-41: Summary of Vertical Deflection for the Six-Story Braced Frame with Chevron Configuration .................................................................................................................................. 128 Table 4-42: Summary of Vertical Deflection for the Six-Story Braced Frame with Single Diagonal Configuration .................................................................................................................................. 128 Table 4-43: Yield Deformation of Brace in the Three-Story Braced Frame ..................................... 135 Table 4-44: Yield Deformation of Brace in the Six-Story Braced Frame .......................................... 135 Table 4-45: Summary of RBS Deformation for the Three-Story Moment Frame as Beam Model 136 Table 4-46: Summary of RBS Deformation for the Three-Story Moment Frame as Girder Model ........................................................................................................................................................... 136 Table 4-47: Summary of BRB Deformation for the Three-Story Braced Frame with Chevron Configuration Model ....................................................................................................................... 136 Table 4-48: Summary of BRB Deformation for the Three-Story Braced Frame with Single Diagonal Configuration Model ....................................................................................................................... 137 Table 4-49: Summary of RBS Deformation for the Six-Story Moment Frame as Beam Model ..... 139 Table 4-50: Summary of RBS Deformation for the Six-Story Moment Frame as Girder Model ... 140 Table 4-51: Summary of BRB Deformation for the Six-Story Braced Frame with Chevron Configuration Model ....................................................................................................................... 140 Table 4-52: Summary of BRB Deformation for the Six-Story Braced Frame with Single Diagonal Configuration Model ....................................................................................................................... 140 Table 4-53: Summary of RBS Rotation by Earthquake Group for the Three-Story Moment Frame as Beam Model ................................................................................................................................ 148 Table 4-54: Summary of RBS Rotation by Earthquake Group for the Three-Story Moment Frame as Girder Model .............................................................................................................................. 149 ix Table 4-55: Summary of BRB Deformation by Earthquake Group for the Three-Story Braced Frame with Chevron Configuration .............................................................................................. 149 Table 4-56: Summary of BRB Deformation by Earthquake Group for the Three-Story Braced Frame with Single Diagonal Configuration .................................................................................. 150 Table 4-57: Summary of RBS Rotation by Earthquake Group for the Six-Story Moment Frame as Beam Model ..................................................................................................................................... 153 Table 4-58: Summary of RBS Rotation by Earthquake Group for the Six-Story Moment Frame as Girder Model ................................................................................................................................... 154 Table 4-59: Summary of BRB Deformation by Earthquake Group for the Six-Story Braced Frame with Chevron Configuration .......................................................................................................... 154 Table 4-60: Summary of BRB Deformation by Earthquake Group for the Six-Story Braced Frame with Single Diagonal Configuration .............................................................................................. 155 Table 4-61: Energy Dissipation for Each Earthquake in the Six-Story Moment Frame as Beam Model ................................................................................................................................................ 160 Table 4-62: Energy Dissipation for Each Earthquake in the Six-Story Braced Frame with Chevron Configuration Model ....................................................................................................................... 161 Table B-1: Collected Result for 3 story MF as Beam--Horizontal Only ............................................ 281 Table B-2: Collected Result for 3 story MF as beam--Horizontal+ Vertical ..................................... 284 Table B-3: Collected Result for 3 story MF as Girder--Horizontal Only .......................................... 287 Table B-4: Collected Result for 3 story MF as Girder--Horizontal+ Vertical .................................. 290 Table B-5: Collected Result for 3 Story Braced Frame-- Chevron--Horizontal Only ...................... 293 Table B-6: Collected Result for 3 Story Braced Frame-- Chevron --Horizontal+ Vertical ............. 296 Table B-7: Collected Result for 3 Story Braced Frame-- Single Diagonal--Horizontal Only .......... 299 Table B-8: Collected Result for 3 Story Braced Frame-- Single Diagonal --Horizontal+ Vertical . 302 Table B-9: Collected Result for 6 story MF as Beam for Each Earthquake--Horizontal Only ....... 305 Table B-10: Collected Result for 6 story MF as Beam for Each Earthquake--Horizontal + Vertical ........................................................................................................................................................... 311 Table B-11: Collected Result for 6 story MF as Girder for Each Earthquake--Horizontal Only ... 317 Table B-12: Collected Result for 6 story MF as Girder for Each Earthquake--Horizontal + Vertical ........................................................................................................................................................... 323 Table B-13: Collected Result for 6 story Braced Frame for Each Earthquake-- Chevron -- Horizontal Only ............................................................................................................................... 329 Table B-14: Collected Result for 6 story Braced Frame for Each Earthquake-- Chevron -- Horizontal + Vertical ...................................................................................................................... 335 Table B-15: Collected Result for 6 story Braced Frame for Each Earthquake-- Single Diagonal -- Horizontal Only ............................................................................................................................... 341 Table B-16: Collected Result for 6 story Braced Frame for Each Earthquake-- Single Diagonal -- Horizontal + Vertical ...................................................................................................................... 347 Table B-17: Energy Dissipation – Three-Story MF as Beam -- .......................................................... 353 Table B-18: Energy Dissipation-- Three-Story MF as Girder -- ........................................................ 354 Table B-19: Energy Dissipation -- Three-Story Chevron -- ................................................................ 355 Table B-20: Energy Dissipation -- Three-Story Single Diagonal – ..................................................... 356 Table B-21: Energy Dissipation – Six-Story MF as Beam – ................................................................ 357 Table B-22: Energy Dissipation-- Six-Story MF as Girder -- ............................................................. 358 Table B-23: Energy Dissipation -- Six-Story Chevron –...................................................................... 359 Table B-24: Energy Dissipation -- Six-Story Single Diagonal – .......................................................... 360 x