Weian Liu 3. Research Interest • Soil Structure Interaction • Seismic Analysis and Design of Bridge Structures • Earthquake Engineering and Structural Dynamics 2. Research Activities • Design of soil and structure compatible yielding to improve system performance (NEES) • Seismic response analysis and design of long-span bridges (State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji Univ., Shanghai CHN) • Seismic response analysis of High-Rise pile foundation (SLDRCE, Tongji Univ., Shanghai, CHN) 1. Educational Background • UC San Diego (CA), PhD Student, 2009- • Syracuse University (NY), PhD Student, 2007-2009 • Tongji University (CHN), Master of Engineering (Bridge Engineering), 2004-2007 • Wuhan Univ. of Tech. (CHN), Bachelor of Engineering (Civil Engineering), 2000-2004
Transcript
Weian Liu
3. Research Interest• Soil Structure Interaction• Seismic Analysis and Design of Bridge Structures• Earthquake Engineering and Structural Dynamics
2. Research Activities• Design of soil and structure compatible yielding to improve system performance (NEES)• Seismic response analysis and design of long-span bridges (State Key Laboratory for
Disaster Reduction in Civil Engineering, Tongji Univ., Shanghai CHN)• Seismic response analysis of High-Rise pile foundation (SLDRCE, Tongji Univ.,
Shanghai, CHN)
1. Educational Background
• UC San Diego (CA), PhD Student, 2009-• Syracuse University (NY), PhD Student, 2007-2009• Tongji University (CHN), Master of Engineering (Bridge Engineering), 2004-2007 • Wuhan Univ. of Tech. (CHN), Bachelor of Engineering (Civil Engineering), 2000-2004
Concepts for designing small scale realistic buildings & Task 2 NEESR-CoSSY
October 14, 2009
Project Kick-off Meeting @ UC Davis
3-Story Model
1-Story Model
NEESR-City Blocks (Bray et al.)
PEER-Shallow Foundations(Chang et al.)
Complementary systems?Chang et al. tests
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Test H SC 16: Fuse 8
Structural fuses
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Foundations
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O ne BayTw o Bay
Complementary? (more research questions – sorry Sashi)
• What measures are most important to control (and predict) such that complementary yielding between foundation & structural elements is achieved (e.g. structure: Mcap, limit, global parameters; foundation: Smax, max, Mcap)?
• What are key (desirable) characteristics of structural fuses? Bilinear M- behavior, elastic shear & axial, simplicity – same question applies to footings…
• Do we have a preference re: complementary nature of system performance eg (i) series vs parallel, (ii) can we achieve (in reality) series behavior, what defines/controls yielding in the next element, which one yields first?
Question for TTT
• Has practice embraced rocking concept – or do we need to do more work in this area convincing practitioners?
• How much our effort should be concentrated here?
2 key papers1) Gajan et al. (2009, Earthquake Spectra, in press) –
summarizes modeling efforts of PEER-supported study
2) Alavi & Krawinkler (2004); strength & story drift distributions in wall-frame systems (including hinged wall)
3) Foundation modeling review paper (e.g. Dutta & Roy, 2002)
5) Building performance limit states (e.g. latest code literature) – TTT?
Subject Bruce asked me to talk about
Building design concepts• Start simple
• Links with prototypical buildings, via basic parameters?– System: Period, yield strength, yield drift ratio– Foundation: Type, degree of precompression, bearing stress– Do we want rocking systems to have the same range of
prototypical (fixed-base) structures?
• Incorporate compatible mechanisms of yielding at strategic locations in superstructure– Goal: protect superstructure from damage & foundation from
excessive deformation
Prototypical Building Characteristics• ATC-63: ArchType structures• Ganuza & Gupta/Krawinkler studies
– Three base lateral load systems: (i) steel eccentrically braced frame (EBF), (ii) steel special moment resisting frame (SRMF), (iii) reinforced concrete shear walls.
– 3-story (39’ plan dimensions 120’ x 180’), 5-story (65’ plan dimensions 150’ x 150’), and 9-story (122’ plan dimensions 150’ x 150’).
– T1FB spans 0.18 → 2.64 seconds
– Yield drift ratio spans 0.06 → 1.37%– Yield strength Vy spans 0.14 → 0.55 x seismic weight
2 4 6 8 10# Stories
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System with same yield drift ratio can have different yield strength
Model & testing considerations• 2D versus 3D buildings?
• N? (all tests same?)
• Replaceable structural fuses? Locking fuses?
• What are the performance objectives of the building-foundation system?
• When should the structural fuses yield (what is acceptable at the foundation level)?
• Identify most important variables in Test-1 model – [simulation can help guide this]
• Motion protocol – selection, sequencing, etc.?
Task 2: Implementation & Validation of Analysis Tools
• OpenSees
• FE models for soil-footing interface– Continued development & validation of Gajan
& Raychowdhury models
• Soil-foundation-building systems– Integration of soil-footing models w/ structural
system
• Ground motions for parametric studies
References
• Ganuza, E. (2006). Seismic behavior of hybrid lateral force resisting systems. MS Thesis, SUNY-Buffalo.
• Gupta, A. and Krawinkler, H. (1999) “Seismic Demands for Performance Evaluation of Steel Moment Resisting Frame Structures”. John A. Blume Earthquake Engineering Center, Report No. 132, Dept. of Civil Engineering, Stanford University, Stanford, CA
