Paper presented to Joint Technical Sessions Between

Jamaica Institution of Engineers (JIE) and the

Caribbean Division of the Institution of Structural Engineers (UK)

 

Recent Code Developments for Earthquake Resistance

 

By Alfrico D. Adams F.I.Struct.E, FJIE

May 27, 2004

 

TABLES

(Reference IBC)

 

 

TABLE 4.3.1.2A        -           VALUES OF  Fa AS A FUNCTION OF SITE

(Class and Mapped Short Period Maximum Considered Spectral Acceleration)

 

SITE CLASS

SOIL TYPE

Mapped Maximum Considered Earthquake

Spectral Accelerations at Short Periods

 

 

 

SS = 0.75

SS = 1.0

 

A

 

B

 

C

 

 

D

 

E

 

F

 

Hard Rock

 

Med Rock

 

Dense Soil

Or soft Rock

 

Stiff Soil

 

Soil N<15

 

Vulnerable

Soils

 

0.8

 

1.0

 

1.1

 

 

1.2

 

1.2

 

Site Specific in investigation & dynamic analysis needed

 

0.8

 

1.0

 

1.0

 

 

1.1

 

0.9

 

 

 

 

 

 

 

 

TABLE 4.3.1.2B

VALUES OF FV AS A FUNCTION OF SITE CLASS AND MAPPED 1 SECOND ACCELERATION

 

SITE CLASS

SOIL TYPE

Mapped Maximum Considered
Spectral Accelerations for 1 Second Period

 

 

S1 = 0.3

S1 = 0.4

 

A

 

B

 

C

 

 

D

 

E

 

F

 

Hard Rock

 

Med. Rock

 

Dense Soil or Soft Rock

 

Stiff Soil

 

Soil N < 15

 

Vulnerable Soil

 

 

0.8

 

1.0

 

1.5

 

 

1.8

 

2.8

 

Site specific investigation and dynamic response analysis

 

 

0.8

 

1.0

 

1.4

 

 

1.6

 

2.4

 

 

 

 

TABLE 4.3.3.1           – SEISMIC USE GROUPS & IMPORTANCE FACTORS

 

USE GROUPS

NATURE OF OCCUPANCY

SEISMIC IMPORTANCE FACTORS IS

 

I

 

II

 

 

 

 

 

 

III

 

 

 

 

 

IV

 

Buildings Other than Groups II – IV

 

Building and other structures that represent a substantial hazard to human life in the event of failure:-

e.g. Building’s where more than 300 persons congregate; schools, health care facilities, power stations.  (See IBC for full list)

 

Buildings and other structures designated as essential facilities including:-

 

Hospitals, fire stations, emergency shelters, etc police stations, etc (See IBC for full list)

 

Buildings and other structures representing a low hazard to human life e.g. agricultural facilities etc.

 

1.0

 

 

 

 

 

1.25

 

 

 

 

 

1.5

 

 

110

 

 

 

 

 

 

TABLE 4.3.3.2           -           SEISMIC DESIGN CATEGORY

 

All structures are assigned to a Seismic Design Category based on their Seismic Use Group and the design spectral response coefficient SDS or SD1.  Each structure shall be assigned to the more severe of the two categories.

 

A    -     SEISMIC DESIGN CATEGORY BASED ON SDS – (SHORT PERIOD)

 

VALUE OF SDS

SEISMIC USE GROUPS

 

I

II

III

 

SDS <0.167g

 

0.167g ≤ SDS < 0.33g

 

0.33g ≤ SDS < 0.5g

 

0.5g ≤ SDS

 

A

 

B

 

C

 

Da

 

A

 

B

 

C

 

Da

 

A

 

C

 

D

 

Da

 

a    -    Other conditions apply

 

 

B    -    SEISMIC DESIGN CATEGORY

BASED ON 1 SECOND PERIOD RESPONSE ACCELERATION

 

 

SEISMIC USE GROUPS

 

I

II

III

 

SD1 < 0.067g

 

0.067g ≤ SD1 < 0.133g

 

0.133g ≤ SD1 < 0.2g

 

0.2g ≤ SD1

 

A

 

B

 

C

 

Da

 

A

 

B

 

C

 

Da

 

A

 

C

 

D

 

Da

 

                               a    -    Other conditions apply