Wallace-LA-Tall-Buildings-May-2008-Distribution.pdf

J. Wallace UCLA Civil Engineering LA Tall Buildings Meeting – May 2008 1 ATC-72 Report – Chapter 4 Modeling of Core Walls Systems and Components John Wallace Marisol Salas David Naish University of California, Los Angeles Department of Civil Engineering May 9, 2008 Los Angeles Chapter 4 – Overview Wall models – Elastic – Effective Stiffness Wall models – Nonlinear – Hinge/Fiber models – Shear behavior – Strain limits/sensitivity Coupling beams – Preliminary results May 2007 Meeting Wall modeling – Summary Coupling beams – New test results – Modeling studies Slab-column frames – Modeling System Studies – Case studies Today Tall and Special Buildings – Special Issue December 2007 J. Wallace UCLA Civil Engineering LA Tall Buildings Meeting – May 2008 2 Wall Modeling - Recommendations RW2 TW2 RW3-O Effective Stiffness FEMA 356: Ieffective = 0.5Igross 2007 Meeting: Ieffective = 2.0Igross Ieffective = 0.2Igross Canadian Code – Upper bound (Service) – Lower bound (Design) 0 0.05 0.1 0.15 0.2 P/fc Ag 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 I e / I g Upper Bound Lower Bound J. Wallace UCLA Civil Engineering LA Tall Buildings Meeting – May 2008 3 Effective Stiffness: M-Φ RW3-O φ u RW3-O 0.0000 0.0002 0.0004 0.0006 0.0008 0.0010 Curvature (/in) 0 1000 2000 3000 4000 5000 6000 M om en t ( in -k ip s) Analytical - BIAX Measured - LVDTs 0 100 200 300 400 500 600 M om en t ( kN -m ) 0.000 0.004 0.008 0.012 0.016 0.020 0.024 Curvature (/mm) P=0.1Agf’c Effective Stiffness: M-Φ 0 0.0004 0.0008 0.0012 Curvature, φ (1/in) 0 40000 80000 120000 160000 200000 M om en t ( k- in ) IN, at g.l. FOS, 2 ft above g.l. FOS, 2 ft below g.l. EX, 1 ft below g.l. Section analysis: average rebar σ?ε P=0.03Agf’c J. Wallace UCLA Civil Engineering LA Tall Buildings Meeting – May 2008 4 Effective Stiffness: M-Φ 0 0.0002 0.0004 0.0006 Curvature (/in.) 0 2000 4000 6000 8000 M om en t ( in -k ip s) P=0.20Agfc, Asb P=0.10Agfc, Asb P=0.10Agfc, (1/2)Asb TEST φy 0.5EIg 0.2EIgEIg Nonlinear Modeling – Commerci