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 constructionsBuilding-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 stories4, 12 and 20

Evaluate different structural systemsSpecial moment resisting frame and shear wall

Use different platformsOpenSees and Drain

The selected buildings

Building Stories Type Compliance T1 (s) Platform

A 4 Modern special moment frame

2003 IBC 0.97 OpenSees

B 12 Modern special moment frame

2003 IBC, ASCE7-02, ACI 318-02

2.01 OpenSees

C 20 Modern special moment frame

2003 IBC, ASCE7-02, ACI 318-02

2.63 OpenSees

D 12 Modern (ductile) planar shear wall

None specifically, but consistent with modern planar wall

design

1.20 Drain

Building A, B and C: Structural Modeling

Joints with panel shear springs

Plastic Hinge Model

Image: Paul Cordova of Stanford University

Perimeter 2D frame

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

T1 – T4 (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%

0 0.02 0.04 0.06 0.080

500

1000

1500

2000Pushover Curve for Analysis Model (DesA

Buffalo

v.10noGFrm

grndDisp)

(AllVar)

(Mean)

(clough), for PO 9991

Bas

e S

hear

(ki

ps)

Roof Drift Ratio

Static Overstrengt

h = 2.3

0 0.05 0.100

1

2

3

4

Flo

or

Num

ber

Interstory Drift Ratios

Building A: 4-story RC SMF

Nonlinear Dynamic Failure Modes

0.014 0.016 0.018 0.02 0.022 0.024

Joint Shear Strength

Slab Strength

Foundation Stiffness

Tension Softening Slope

Steel Strain Hardening

Bond Slip Hardening

Slab Capping Rotation

Damping Ratio

SCWB Ratio

All Element Strengths

Dead Load and Mass

Beam Strength

Structural EDP - Peak Story Drift Ratio of Story Three

Variability due to Record-to-Record Variability

Marge d’erreur (2% sur 50 ans)

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

0 0.01 0.02 0.030

200

400

600

Bas

e S

hear

(ki

ps)

Roof Drift Ratio

Building B: 12-story RC SMF Design base shear of 4.4% of weight

Static overstrength = 1.7

T1 – T4 (sec) = 2.01, 0.68, 0.39, 0.27

Static Overstrength

= 1.7

0 0.02 0.04 0.06

2

4

6

8

10

12

Flo

or N

umbe

r

Interstory Drift Ratio

(a) 73% of collapses

(b) 25% of collapses (c) 2% of collapses

Nonlinear Dynamic Failure Modes

Building B: 12-story RC SMF

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

0 10 20

x 10-3

0

200

400

600

800

1000

Bas

e S

hear

(ki

ps)

Roof Drift Ratio

Building C: 20-story RC SMF Design base shear of 4.4% of weight

Static overstrength = 1.6

T1 – T4 (sec) = 2.63, 0.85, 0.46, 0.32

Static Overstrength

= 1.6

0 0.02 0.04 0.06

5

10

15

20

Flo

or N

umbe

r

Interstory Drift Ratio

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

T1 – T4 (sec) = 1.20, 0.19, 0.068, 0.035

0

0.05

0.1

0.15

0.2

0 0.01 0.02 0.03 0.04 0.05 0.06

Roof Drift Ratio

Bas

e S

hea

r C

oef

fici

ent

No PD

With PD

The selected buildings

Building Stories Type Compliance T1 (s) Platform

A 4 Modern special moment frame

2003 IBC 0.97 OpenSees

B 12 Modern special moment frame

2003 IBC, ASCE7-02, ACI 318-02

2.01 OpenSees

C 20 Modern special moment frame

2003 IBC, ASCE7-02, ACI 318-02

2.63 OpenSees

D 12 Modern (ductile) planar shear wall

None specifically, but consistent with modern planar wall

design

1.20 Drain