Structural models

Christine Goulet, Presenter Curt B. Haselton – Assistant Professor, CSU Chico Abbie B. Liel - PhD Candidate, Stanford University Farzin Zareian - Assistant Professor, University of California Irvine

Structural model selection

 Criteria  Represent modern constructions  Building-code compliance, newly designed structures  Provide useful preliminary guidance  Limit the rate of collapse VS older non-ductile structures  The models are also calibrated to allow collapse  Cover different heights/number of stories  4, 12 and 20  Evaluate different structural systems  Special moment resisting frame and shear wall  Use different platforms  OpenSees and Drain

The selected buildings

Building

A

Stories

4 B 12 C D 20 12

Type

Modern special moment frame Modern special moment frame Modern special moment frame Modern (ductile) planar shear wall

Compliance

2003 IBC 2003 IBC, ASCE7 02, ACI 318-02 2003 IBC, ASCE7 02, ACI 318-02 None specifically, but consistent with modern planar wall design

T1 (s)

0.97

2.01

2.63

1.20

Platform

OpenSees OpenSees OpenSees Drain

Building A, B and C: Structural Modeling

Perimeter 2D frame Plastic Hinge Model Joints with panel shear springs Image: Paul Cordova of Stanford University

Building A: 4-story RC SMF

    Based on engineering drawings 4-story perimeter frame, 30’ bay widths, designed to have strength and stiffness expected from a practitioner design Design Code: 2003 IBC Structural Design and Model by: Curt Haselton of CSU Chico

Building A: 4-story RC SMF

 Design base shear 9.2% of weight   T 1 – T 4 (sec) = 0.97, 0.35, 0.18, 0.12

Yielding: Roof drift = 0.5%, interstory drift = 0.7%  Roof drift at 20% strength loss = 5.2% Pushover Curve for Analysis Model (DesA B uffalo v .10noGFrm

g rndDisp) ( AllVar) ( Mean) ( clough), for PO 9991 2000 4 1500 1000

Static Overstrength = 2.3

500 0 0 0.02

0.04

0.06

Roof Drift Ratio 0.08

3 2 1 0 0 0.05

Interstory Drift Ratios 0.10

Building A: 4-story RC SMF

 Nonlinear Dynamic Failure Modes

Marge d’erreur (2% sur 50 ans)

Beam Strength Dead Load and Mass All Element Strengths SCWB Ratio Damping Ratio Slab Capping Rotation Bond Slip Hardening Steel Strain Hardening Tension Softening Slope Foundation Stiffness Slab Strength Joint Shear Strength Variability due to Record-to-Record Variability 0.014

0.016

0.018

0.02

0.022

Structural EDP - Peak Story Drift Ratio of Story Three 0.024

Source: Curt Haselton

Building B: 12-story RC SMF

    Design details reviewed by practicing engineers 12-story special moment resisting (SMF) perimeter frame, 20’ bay widthsDesign Codes: 2003 International Building Code, ASCE7 02, ACI 318-02  Structural design and model by [Design ID #1013]: Curt B. Haselton, PhD, PE, Assistant Professor of Civil Engineering, California State University, Chico.  Brian S. Dean, MS student, Stanford University.

120’x120’ plan

  

Building B: 12-story RC SMF

Design base shear of 4.4% of weight Static overstrength = 1.7

T 1 – T 4 (sec) = 2.01, 0.68, 0.39, 0.27

600 400 200 0

Static Overstrength = 1.7

0 0.01

0.02

Roof Drift Ratio 0.03

12 10 8 6 4 2 0 0.02

0.04

Interstory Drift Ratio 0.06

Building B: 12-story RC SMF

 Nonlinear Dynamic Failure Modes (a) 73% of collapses (b) 25% of collapses (c) 2% of collapses

Building C: 20-story RC SMF

    Design details reviewed by practicing engineers 20-story special moment resisting (SMF) perimeter frame, 20’ bay widths Design Codes: 2003 International Building Code, ASCE7-02, ACI 318-02  Structural design and model by [Design ID #1020]: Curt B. Haselton, PhD, PE, Assistant Professor of Civil Engineering, California State University, Chico.  Brian S. Dean, MS student, Stanford University.

120’x120’ plan

  

Building C: 20-story RC SMF

Design base shear of 4.4% of weight Static overstrength = 1.6

T 1 – T 4 (sec) = 2.63, 0.85, 0.46, 0.32

1000 800 600 400 200 0

Static Overstrength = 1.6

0 10 Roof Drift Ratio 20 x 10 -3 20 15 10 5 0 0.02

0.04

Interstory Drift Ratio 0.06

Building D: 12-story Shear Wall

  12-story planar shear wall, with uniform cross-section over the building height. Design Codes: None specifically, since this is a generic model, but this model is representative with a modern building.

  Structural Design and Model by: Farzin Zareian, PhD, Assistant Professor of Civil Engineering, University of California Irvine.

12 X 12’ = 144’

Building D: 12-story Shear Wall

  Yield base shear of 16.7% of weight T 1 – T 4 (sec) = 1.20, 0.19, 0.068, 0.035

0.2

0.15

0.1

0.05

0 0 No PD With PD 0.01

0.02

0.03

Roof Drift Ratio 0.04

0.05

0.06

The selected buildings

Building

A

Stories

4 B 12 C D 20 12

Type

Modern special moment frame Modern special moment frame Modern special moment frame Modern (ductile) planar shear wall

Compliance

2003 IBC 2003 IBC, ASCE7 02, ACI 318-02 2003 IBC, ASCE7 02, ACI 318-02 None specifically, but consistent with modern planar wall design

T1 (s)

0.97

2.01

2.63

1.20

Platform

OpenSees OpenSees OpenSees Drain