Simulation of 3-D Global Bridge Response to Shaking and Lateral Spreading Scott J. Brandenberg, Jian Zhang, Yili Huo, and Minxing Zhao, UCLA PEER Transportation Systems Research Program May 2, 2011 Project Description PEER Transportation Systems Research Program 2/14 1-D site response analyses • Ground Motion Records from 2007 Niigata Earthquake • Records from Centrifuge Test PEER Transportation Systems Research Program 3/14 1-D site response analyses • Records from Numerical Simulation 10 with dilatancy ) 2 5 0 -5 Acceleration (m/s Acceleration Ground surface motion -10 0 10 20 30 Time (second) 1 0.5 0 -0.5 in loose sand -1 Excess Pore Pressure Ratio Pressure Pore Excess 0 10 20 30 Time (second) 10 ) 2 5 0 -5 Acceleration (m/s Acceleration Base input motion No.35 -10 0 10 20 30 Time (second) A liquefied sand layer is not a “base isolator”. PEER Transportation Systems Research Program 4/14 1-D site response analyses • Site Amplification Factor – Baseline Soil Profile liq.liq. noliq.noliq. 10 10 ) ) 2 2 s / s / m m ( ( liq noliq a 1 a 1 S S 0.1 0.1 0.01 0.1 1 10 0.01 0.1 1 10 Period (second) Period (second) = Fa Sa liq/ Sa noliq a 1 1 a F Median of F of Median median curve 0.1 0.01 0.1 1 10 0.01 0.1 1 10 Period (second) Period (second) PEER Transportation Systems Research Program 5/14 1-D site response analyses • Site Amplification Factor – Monte Carlo Simulations a F 1 f o n a i d e M 0.01 0.1 1 10 Period (second) PEER Transportation Systems Research Program 6/14 Modeling of the studied case 6 6 3 3 Disp (m) Disp (m) Disp(m) Disp (m) 0 1 2 0 1 2 -2 -1 0 -2 -1 0 0 0 0 0 7s Bridge and soil layer sketch Depth(m) 14s (m) Depth -3 -3 -3 21s -3 28s 35s -6 -6 (m) Depth -6 Depth(m) 42s -6 49s 56s -9 -9 -9 63s -9 70s Soil layer simplification (a) Left abut (b) Left pier (c) Right pier (d) Right abut Longitudinal displacement profiles with motion No. 10 Bridge modeling PEER Transportation Systems Research Program 7/14 Response plot Longitudinal Transverse PEER Transportation Systems Research Program 8/14 Response animation PEER Transportation Systems Research Program 9/14 Optimal IM search Data point 0.00674 Data point 0.04979 Transverse Transverse Longitudinal Longitudinal Square root Square root 0.01832 Regression Regression Square root 0.00248 Square root 0.00674 0.00248 9.11882E-4 9.11882E-4 Maximum pierratio drift column Maximum Maximum pier column drift ratio columndrift Maximum pier 3.35463E-4 3.35463E-4 0.04979 0.13534 0.36788 1 2.71828 0.13534 0.36788 Longitudinal residual displacement (m) Longitudinal peak acceleration (g) Liquefaction case Non-liquefaction case PEER Transportation Systems Research Program 10/14 CEDP =EDPLiq /EDPNon-Liq • Goal: Provide an estimate of CEDP as function of non-liquefied ground surface motion, structural properties, and soil properties. Data Regression Cov=0.71 20.08554 7.38906 EDP C 2.71828 (EDP='Type 1' square-root column drift ratio) drift columnsquare-root 1' (EDP='Type ∆ C 1 0.13534 0.36788 1 2.71828 7.38906 IM=Square-root CAD of IMnon-liquefaction motions (m) PEER Transportation Systems Research Program 11/14 Local static analyses • Numerical Model • Structural response ∆∆∆ top continuous superstructure 0 -2 -4 -6 ) m ( -8 h t p -10 e ∆∆∆soil Icap D -12 Clay -14 Pile -16 Soil -18 Loose Sand 0 0.25 0.5 -8000 0 8000 -2000 0 2000 Lateral Displacement (m) Bending Moment (kN-m) Subgrade Reaction (kN/m) Dense Sand PEER Transportation Systems Research Program 12/14 Local static analyses • Continuous Superstructure – Boundary conditions – Comparison of pile cap displacements 10 Prd 10 1 1 (m) ,top,1 ∆ cap,s C C 0.1 ∆ 0.1 0.01 0.001 0.01 0 5 10 15 20 0.01 0.1 1 10 ∆ Case No. cap,d (m) PEER Transportation Systems Research Program 13/14 Questions? Thank you ! PEER Transportation Systems Research Program 14/14.