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Dream it, Design it, Build it. www.ccee.engineering.iastate.edu I OWA S TATE U NIVERSITY Civil, Construction & Environmental Engineering Bradley Fleming, Sri Sritharan, & JinWei Huang Iowa State University Kanthasamy Muraleetharan & Gerald Miller Oklahoma University

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1.Finite Element (OpenSees) Detailed 3D analysis Used to understand complex interactions between pile and improved soil improved soil and unimproved soil 2.p-y Analysis Method (LPILE) Simple 2D analysis Attractive for engineers in industry Account for improved soil of limited width by applying modification factors to p-y relationships

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Pile (forceBeamColumn) 7.23 m total length 34 beam elements 5.3 m embedded length Non-linear fiber section (half of pile) Soil Island (OpenSeesPL soil mesh generation) 10.3 m long, 5.15 m wide, and 7.62 m high 3,450 nodes 2,492 soil elements Soil Contact Elements (BeamContact3D) Pile r m1 m2 slave P Soil Elements (SSPbrick) ClaySand PressureIndependMultiYieldPressureDependMultiYield G max = 3250 kN/m 2G max = 1.0E+5 kN/m 2 c = 30.5 kN/m 2 = 37 deg. sat =1.8 ton/m 3 sat =2.0 ton/m 3 Clay Sand

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Unimproved PileImproved Pile

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Guo and Lee (2001) Attenuation of stresses in soil layer

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R Equivalent rigidity (analogous to AE for axially loaded member) L eff - Length of uniform soil layer k i Equivalent stiffness of the p-y curve S - Stiffness of spring Improved SoilUnimproved Soil

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JinWei Huang (2011)

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Both LPILE and OpenSees closely resembles centrifuge and field behavior OpenSees is an effective analysis tool but requires specialized knowledge and involves high computation costs LPILE is an attractive tool for engineers and has flexibility to modify p-y curves The proposed method for modifying p-y curves does well in characterizing the behavior of piles in improved soil of limited width