API REPORT 80-26A Acceleration Time Histories for Earthquake Analysis Studies of Offshore Structures
 |
| Purchase Information |
| Use this form to request purchase information on API online subscriptions. |
|
|
Document API REPORT 80-26A is offered by IHS as part of an online subscription. This subscription contains many documents on the same topic.
You may also purchase this document alone from the IHS Standards Store.
API REPORT 80-26A Document Information:
Title
Acceleration Time Histories for Earthquake Analysis Studies of Offshore Structures
American Petroleum Institute
Publication Date:
Oct 1, 1980
Scope:
INTRODUCTION
The American Petroleum Institute (API) has initiated a research
project for the analysis of the response of offshore structures under
earthquake loading conditions (API PRAC project 80-26A). The scope of
the investigation entails three dimensional time history dynamic
analyses of a typical offshore platform under design conditions
comparable to American Petroleum Institute recommended practice (API
RP 2A) earthquake design provisions for Southern California offshore
environment.
The API RP 2A earthquake design provision provides for strength and
ductility requirements. The strength requirements are intended to
provide a platform, which is adequately sized for strength and
stiffness to insure no significant structural damage for the level of
earthquake shaking that has a reasonable likelihood of not being
exceeded during the life of the structure. The ductility requirements
are intended to insure that the platform has sufficient energy
absorption capacity to prevent its collapse during rare intense
earthquake motion, although structural damage may occur.
In the absence of a detailed site-specific seismic exposure study, the
strength level earthquake is described through a normalized major
horizontal component response spectra (soil dependent), an effective
ground acceleration design coefficient (G-scaling factor) as a
function of zone relative seismicity, and provisions for the
orthogonal weaker horizontal and vertical components as a fraction of
the specified major component. The major horizontal component (applied
along a major axis of the platform) consists of the response spectrum
(appropriate to the specific soil condition) shown in Figure 1 and
scaled by a design coefficient appropriate to the various seismic
zones presented in Figure 2. The minor horizontal component (acting in
an orthogonal direction to the major axis of the structure) is taken
as two-thirds of that assigned to the major horizontal component. A
response spectrum of one-half the major component is assigned to the
vertical component.
The ductility requirements are defined in terms of performance goals
to insure that the platform has adequate energy absorption capacity to
prevent collapse under a rare intense earthquake. However, for the
present study, the ductility requirements will be defined in terms of
response spectra having ordinates twice those defined for the strength
requirement.
This report summarizes Woodward-Clyde Consultants' effort conducted
for the API on this project to evaluate earthquake time histories
appropriate to characterize design earthquake provisions of the API RP
2A strength and ductility requirements for offshore Southern
California environment.
About IHS
IHS (NYSE: IHS) is a leading global provider of critical technical information, decision-support tools and related services in a number of industries including aerospace and defense, automotive, construction, electronics, and energy. IHS serves customers ranging from large governments and multinational corporations to smaller companies and technical professionals in more than 100 countries. IHS been in business for more than 45 years and employ more than 2,300 people around the world.
