by saeed fathali, ph.d. and bret lizundia, s.e. rutherford

1Fathali and Lizundia,

© Rutherford & Chekene2011 EERI Annual Meeting Presentation

February 11, 2011

Saeed Fathali, Ph.D. and Bret Lizundia, S.E.

Rutherford & Chekene

by

2011 EERI Annual Meeting Presentation

February 11, 2011

Component Period (sec.)



February 11, 2011

Outline

• Background

• Study Goals

• Peak Floor Acceleration

(PFA) vs. PGA Studies

• Component Amplification

Factor (ap) Studies

• Findings and

Recommendations

(1994 Northridge Earthquake, Mason Industries)

(1999 Izmit Earthquake, NISEE Izmit Collection,

Halil Sezen, published in FEMA E74 )



February 11, 2011

Background

ASCE/SEI 7-05 (and 7-10)

– Equation 13.3-1: Fp = (0.4 ap SDS Ip [1 + 2 (z / h)] / Rp )Wp

– Equation 13.3-2: Fp ≤ 1.6 SDS Ip Wp

– Equation 13.3-3: Fp ≥ 0.3 SDS Ip Wp

– Equation 13.3-4: Fp = ((ai ap ) / (Rp / Ip )) Ax Wp

• Covers architectural and MEP components.

• Uses NEHRP Map values for seismic demand.

• Variables include height up the building and

component amplification, importance and ductility.



February 11, 2011

Study Goals

• Goal: Collect, analyze, and study the response data

recorded from instrumented buildings to improve code

provisions for seismic demand on nonstructural

components in buildings.

• Focus: ASCE/SEI 7-05 Equation 13.3-1.

Fp / Wp = 0.4 ap SDS Ip [1 + 2 (z / h)] / Rp

PFA/PGA Studies

ap StudiesAnchored

Component House of Anchored

Components

R

z

h

5

4

3

2



February 11, 2011

Database Fields

• City and building description

• CSMIP station number

• Number of earthquake records

• Number of stories

• Roof elevation

• Lateral force-resisting system along two orthogonal, principal axes

• Vertical load-carrying system

• Original design date

• Approximate fundamental period, calculated per ASCE/SEI 7-05

• Orientation of principal axes

• Number of accelerometers

• Direction, location, elevation, and elevation relative to the roof height (z/h)

for each accelerometer



February 11, 2011

Database Characteristics

• Buildings: 151 fixed base and 18 seismically isolated

• Earthquakes: 73 for the fixed base bldgs, from 1978 to 2010

• Building-earthquake combinations: 541 for fixed base bldgs

0

20

40

60

80

100

120

140

≥ 0.01 ≥ 0.02 ≥ 0.05 ≥ 0.10 ≥ 0.20 ≥ 0.30 ≥ 0.40 ≥ 0.50 ≥ 0.60 ≥ 0.70 ≥ 0.8

139129

104

71

34

15

53

2 21

No.

Experienced PGA (g)

PGA Experienced for

Fixed Base Stations



February 11, 2011

“The Cloud” of Current Acceleration Data

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4 5 6 7 8 9

z/h

PFA/PGA

Data Points from Fixed-base CSMIP Building Stations (N=3241)

CSMIP Data

No. = 2224

No. = 920

No. = 97

• 151 Fixed-base Building Stations• 73 Earthquakes• 541 “Building-Earthquake” Cases

IncreasingAmplification

Inc.Height



February 11, 2011

PFA/PGA Studies: Trend Line through Data Points



February 11, 2011

Finding Meaning in the Cloud – Relevant Issues

• How should the recorded data be processed?– Separate the orthogonal directions or combine?

– Use sensors at edges of floor plate or simulated at center of rotation?

– Use mean, maximum, vector maximum, or geomean?

• What variables are important?– Elevation in building, PGA, building period, lateral system, etc.

• Is the recorded data sufficiently robust?

• Equations that find the central trends in the data vs. those

that are used for design. The focus today is on design.

• Striking a balance between accuracy and ease of use.

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by saeed fathali, ph.d. and bret lizundia, s.e. rutherford

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