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 F_a 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 F_V 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 S_DS or S_D1. Each structure shall be assigned to the more severe of the two categories.

A - SEISMIC DESIGN CATEGORY BASED ON S_DS – (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 D^a	A B C D^a		A C D D^a

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 D^a	A B C D^a	A C D D^a

a - Other conditions apply