Design Acceleration Response Spectra forDesign Acceleration Response Spectra for Port-au-Prince

Brady R. Cox, Ph.D., P.E.Brady R. Cox, Ph.D., P.E.The University of Arkansas

Department of Civil Engineering

Geotechnical Earthquake Engineering for Seismic Design Workshop,

Department of Civil Engineering

Port-au-Prince, Haiti, November 18-19, 2010

Design Acceleration Response SpectraRequired by Seismic Provisions in Building CodesRequired by Seismic Provisions in Building Codes

IBC (2009) ASCE 7-05

Step 1: Locate Site

Presidential Palace

Hotel Karibe

ASCE 7-05

Step 2: Determine Ss and S1 for “Rock” ConditionsSpectral Accelerations with a 2% Probability of Exceedance in 50 years

Ss = Short Period Spectral Acceleration (T = 0.2 sec, f = 5 Hz)Ss Short Period Spectral Acceleration (T 0.2 sec, f 5 Hz)

S1 = 1-sec Period Spectral Acceleration (T = 1.0 sec, f = 1 Hz)

Determined from PSHA by USGS (Frankel et al. 2010)

Maps Provided in the GIS Database

ASCE 7-05Site Ss (g) S1 (g)

Presidential Palace 1.75 0.6

Hotel Karibe 2.0 0.7

Step 3: Determine Site ClassificationUse the Seismic Site Classification Map Provided in the GIS Database

Site Ss (g) S1 (g) Site Class

Presidential Palace 1.75 0.6 DPresidential Palace 1.75 0.6 D

Hotel Karibe 2.0 0.7 C

Step 4: Determine Site Amplification CoefficientsF Si A lifi i C ffi i f SFa = Site Amplification Coefficient for Ss

pg. 115 ASCE 7-05

Fv = Site Amplification Coefficient for S1

ASCE 7-05

Step 4: Presidential PalaceF Si A lifi i C ffi i f SFa = Site Amplification Coefficient for Ss

Ss = 1.75 g Fa = 1.0

Fv = Site Amplification Coefficient for S1

ASCE 7-05S1 = 0.6 gFv = 1.5

Step 4: Hotel KaribeF Si A lifi i C ffi i f SFa = Site Amplification Coefficient for Ss

Ss = 2.0 g Fa = 1.0

Fv = Site Amplification Coefficient for S1

ASCE 7-05S1 = 0.7 gFv = 1.3

Step 5: Determine SMs and SM1

Spectral Accelerations with a 2% Probability of Exceedance in 50 years Adjusted for Local Soil Conditions (Site Classification)

Often Termed the Maximum Considered Earthquake (MCE) Spectral Accelerations

pg 115 ASCE 7-05pg. 115 ASCE 7-05

Site Ss (g) S1 (g) Site Class Fa Fv SMs (g) SM1 (g)

Presidential Palace 1.75 0.6 D 1.0 1.5 1.75 0.90

Hotel Karibe 2.0 0.7 C 1.0 1.3 2.00 0.91

Step 6: Determine SDs and SD1

Design Spectral Acceleration Values

Maximum Considered Earthquake (MCE) Spectral AccelerationsMaximum Considered Earthquake (MCE) Spectral Accelerations Reduced by 1/3

pg 115 ASCE 7-05pg. 115 ASCE 7-05

Site Ss (g) S1 (g) Site Class Fa Fv SMs (g) SM1 (g) SDs (g) SD1 (g)

Presidential Palace 1.75 0.6 D 1.0 1.5 1.75 0.90 1.17 0.60

Hotel Karibe 2.0 0.7 C 1.0 1.3 2.00 0.91 1.33 0.61

Step 7: Calculate Design Response Spectrum

pg. 115 ASCE 7-05

C l fCan neglect for most structures (only for very tall buildings; > 30+buildings; > 30+ stories)

Step 7: Design Response Spectrum Equationspg. 115 ASCE 7-05

SDs

SD1D1PGA

T=1 0 T=3 0T 0 2*SD1 T=1.0 T=3.0T0=0.2*SD1SDs

T = SD1TS= D1SDs

Step 7: Design Response Spectrum Presidential Palace

SD = 1 17gSDs 1.17g

SDs = 0.6gPGA 0 47PGA = 0.47gSa = 0.2g

T = 0 1 secT0= 0.1 secTS= 0.51 sec T=1.0 T=3.0

Step 7: Design Response Spectrum Presidential Palace

T= 0 2 sec T= 1 secT 0.2 sec~ 2 stories

T 1 sec~ 10 stories

Remember, fso = Vb ~ W*Sa Refer to Code for More Details

Step 7: Design Response Spectrum Hotel Karibe

SD = 1 33gSDs 1.33g

SDs = 0.61gPGA 0 53PGA = 0.53gSa = 0.2g

T = 0 09 secT0= 0.09 secTS= 0.46 sec T=1.0 T=3.0

Step 7: Design Response Spectrum Hotel Karibe

T= 0 2 sec T= 1 secT 0.2 sec~ 2 stories

T 1 sec~ 10 stories

Remember, fso = Vb ~ W*Sa Refer to Code for More Details

Comparison

You Should Now Be Able to CalculateYou Should Now Be Able to Calculate Acceleration Design Response Spectra

A h i P t P i !Anywhere in Port-au-Prince!

You Will Need to Study the Building C d t D t i th D t il f thCodes to Determine the Details of the

Structural Designg

Questions?Questions?