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TitleBase Isolation Design Guidelines
Tags Mechanical Engineering Friction Stress (Mechanics) Earthquake Engineering
File Size2.8 MB
Total Pages231
Table of Contents
                            INTRODUCTION
	The Concept of Base Isolation
	The Purpose of Base Isolation
	A Brief History of Base Isolation
	The Holmes Isolation Toolbox
	Isolation System Suppliers
	Isolation System Durability
PRINCIPLES OF BASE ISOLATION
	Flexibility – the Period Shift Effect
		The Principle
		Earthquake Characteristics
		Code Earthquake Loads
	Energy Dissipation – Adding Damping
		How Accurate is the B Factor?
		Types of Damping
	Flexibility + Damping
	Design Assuming Rigid Structure on Isolators
		Design to Maximum Base Shear Coefficient
		Design to Maximum Displacement
	What Values of Period and Damping are Reasonable?
	Applicability of Rigid Structure Assumption
	Non-Seismic Loads
	Requirements for a Practical Isolation System
	Types of Isolators
		Sliding Systems
		Elastomeric (Rubber) Bearings
		Springs
		Rollers and Ball Bearings
		Soft Story, Including Sleeved Piles
		Rocking Isolation Systems
	Supplementary Damping
IMPLEMENTATION IN BUILDINGS
	When  to Use Isolation
	Building Codes
	Implementation of  Base Isolation
		Conceptual / Preliminary Design
		Procurement Strategies
		Detailed Design
		Construction
	Costs of Base Isolation
		Engineering, Design and Documentation Costs
		Costs of the Isolators
		Costs of Structural Changes
		Architectural Changes, Services and Non-Structural Items
		Savings in Structural System Costs
		Reduced Damage Costs
		Damage Probability
		Some Rules of Thumb on Cost
	Structural Design Tools
		Preliminary Design
		Structural Analysis
	So, Is It all Too Hard?
IMPLEMENTATION IN BRIDGES
	Seismic Separation of Bridges
	Design Specifications for Bridges
		The 1991 AASHTO Guide Specifications
		The 1999 AASHTO Guide Specifications
	Use of Bridge Specifications for Building Isolator Design
SEISMIC INPUT
	Form of Seismic Input
	Recorded Earthquake Motions
		Pre-1971 Motions
		Post-1971 Motions
	Near Fault Effects
	Variations in Displacements
	Time History Seismic Input
	Recommended Records for Time History Analysis
EFFECT OF ISOLATION ON BUILDINGS
	Prototype Buildings
		Building Configuration
		Design of Isolators
		Evaluation Procedure
			Response Spectrum Analysis
			Time History Analysis
		Comparison with Design Procedure
			Response Spectrum Analysis
			Time History Analysis
		Isolation System Performance
		Building Inertia Loads
			Response Spectrum Analysis
			Time History Analysis
		Floor Accelerations
			Response Spectrum Analysis
			Time History Analysis
		Optimum Isolation Systems
	Problems with the  Response Spectrum Method
		Underestimation of Overturning
		Reason for Underestimation
	Example Assessment of Isolator Properties
ISOLATOR LOCATIONS AND TYPES
	Selection of Isolation Plane
		Buildings
		Architectural Features and Services
		Bridges
		Other Structures
	Selection of device type
		Mixing Isolator Types and Sizes
		Elastomeric Bearings
		High Damping Rubber Bearings
		Lead Rubber Bearings
		Flat Slider Bearings
		Curved Slider (Friction Pendulum) Bearings
		Ball and Roller Bearings
		Supplemental Dampers
		Advantages and Disadvantages of Devices
ENGINEERING PROPERTIES OF ISOLATORS
	Sources of Information
	Engineering Properties Of Lead Rubber Bearings
		Shear Modulus
		Rubber Damping
		Cyclic Change in Properties
		Age Change in Properties
		Design Compressive Stress
		Design Tension Stress
		Maximum Shear Strain
		Bond Strength
		Vertical Deflections
			Long Term Vertical Deflection
			Vertical Deflection under Lateral Load
		Wind Displacement
		Comparison of Test Properties with theory
	Engineering Properties of High Damping Rubber Isolators
		Shear Modulus
		Damping
		Cyclic Change in Properties
		Age Change in Properties
		Design Compressive Stress
		Maximum Shear Strain
		Bond Strength
		Vertical Deflections
			Long Term Vertical Deflections
		Wind Displacements
	Engineering Properties Of Sliding Type Isolators
		Dynamic Friction Coefficient
		Static Friction Coefficient
		Effect of Static Friction on Performance
		Check on Restoring Force
		Age Change in Properties
		Cyclic Change in Properties
		Design Compressive Stress
		Ultimate Compressive Stress
	Design Life Of Isolators
	fire resistance
	Effects of Temperature on Performance
	Temperature Range for Installation
ISOLATION SYSTEM DESIGN
	Design Procedure
	Implementation of the Design Procedure
		Material Definition
		Project Definition
		Isolator Types and Load Data
		Isolator Dimensions
		Isolator Performance
		Properties for Analysis
	Design Equations for Rubber and Lead Rubber Bearings
		Codes
		Empirical Data
		Definitions
		Range of Rubber Properties
		Vertical Stiffness And Load Capacity
		Vertical Stiffness
		Compressive Rated Load Capacity
			AASHTO 1999 Requirements
		Tensile Rated Load Capacity
		Bucking Load Capacity
		Lateral Stiffness and Hysteresis Parameters For Bearing
		Lead Core Confinement
		Design Procedure
	Sliding and Pendulum Systems
	Other Systems
EVALUATING PERFORMANCE
	Structural Analysis
	Single degree-of-freedom Model
	Two Dimensional Nonlinear Model
	Three dimensional Equivalent Linear Model
	Three Dimensional Model - Elastic Superstructure, Yielding Isolators
	Fully Nonlinear Three Dimensional Model
	Device Modeling
	ETABS Analysis For Buildings
		Isolation System Properties
		Procedures for Analysis
		Input Response Spectra
		Damping
	Concurrency Effects
CONNECTION DESIGN
	Elastomeric Based Isolators
		Design Basis
		Design Actions
		Connection Bolt Design
		Load Plate Design
	Sliding Isolators
	Installation Examples
STRUCTURAL DESIGN
	Design Concepts
	UBC Requirements
		Elements Below the Isolation System
		Elements Above the Isolation System
	MCE Level of Earthquake
	Nonstructural Components
	Bridges
SPECIFICATIONS
	General
	Testing
BUILDING EXAMPLE
	Scope Of This Example
	Seismic Input
	Design Of Isolation System
	Analysis Models
	Analysis Results
		Summary of Results
	Test Conditions
	Production Test Results
	Summary
BRIDGE EXAMPLE
	Example Bridge
	Design of Isolators
		Base Isolation Design
		Energy Dissipation Design
	Evaluation of Performance
		Analysis Procedure
		Effect of Isolation on Displacements
		Effect of Isolation on Forces
	Summary
INDUSTRIAL EQUIPMENT EXAMPLE
	Scope of this Example
	Isolator Design
	Seismic Performance
	Alternate Isolation Systems
	Summary
PERFORMANCE IN REAL EARTHQUAKES
BIBLIOGRAPHY
                        
Document Text Contents
Page 1

BASE ISOLATION OF
STRUCTURES

Revision 0: July 2001

DESIGN GUIDELINESDESIGN GUIDELINESDESIGN GUIDELINESDESIGN GUIDELINES
Trevor E Kelly, S.E.Trevor E Kelly, S.E.Trevor E Kelly, S.E.Trevor E Kelly, S.E.

Holmes Consulting Group LtdHolmes Consulting Group Ltd

Page 230

Copyright © 2001. This material must not be copied,
reproduced or otherwise used without the express, written
permission of Holmes Consulting Group.

213

18181818 BIBLIOGRAPHYBIBLIOGRAPHYBIBLIOGRAPHYBIBLIOGRAPHY

[1] An Introduction to Seismic Isolation, Skinner, R. I, Robinson, W. H and McVerry, G. H.
1993, Wiley and Sons.

[2] Design of Seismic Isolated Structures: From Theory to Practice, Farzad Naeim and James M.
Kelly, 1999, John Wiley & Sons, Inc.

[3] Uniform Building Code Appendix Division III Earthquake Regulations for Seismic-Isolated
Structures, UBC, American Association of Building Officials, Whittier, CA, 1994.

[4] Guide Specifications for Seismic Isolation Design, AASHTO, American Association of State
Highway Transportation Officials, Washington D.C, 1991 and 1999.

[5] Design Issues for Base Isolated Bridges: The 1997 Revised AASHTO Code Requirements, R L
Mayes, M R Button and D M Jones, Structural Engineers World Congress, San
Francisco, CA, 1998, Elsevier.

[6] Design of Lead-Rubber Bridge Bearings, New Zealand Ministry of Works and Development,
Civil Engineering Division Publication CDP 818/a : 1983

[7] Rubber Bearings in Base-Isolated Structures - A Summary Paper, Tyler, R. G., Bulletin of the
New Zealand National Society for Earthquake Engineering, Vol 24, No. 3, 1991.

[8] Steel, Concrete and Composite Bridges: Part 9A: Code of Practice for Design of Bearings and Part 9B:
Specification for Materials, Manufacture and Installation of Bearings. British Standards Institution,
British Standard BS5400: 1978.

[9] Design Requirements for Elastomeric Bridge Bearings, Technical Memorandum BE 1/76,
Highways Directorate, Dept. of Environment, Great Britain, Feb. 1976.

[10] AUSTROADS Bridge Design Code Section 4: Bearings and Bridge Joints, AUSTROADS,
Sydney, Australia, 1992.

[11] NEHRP Guidelines for the Seismic Rehabilitation of Buildings, FEMA-273, Federal Emergency
Management Agency, Washington D.C. October, 1997

[12] Engineering Design with Natural Rubber, NR Technical Bulletin, Malaysian Rubber
Producers’ Research Association.

[13] Elastomeric Bearings Design, Construction and Materials, J F Stanton and C W Roeder,
National Cooperative Highway Research Program, Report 248, Augest, 1982.

[14] Concrete Structures Standard : Part 1 - The Design of Concrete Structures, NZS 3101:Part 1:1995,
Standards New Zealand, 1992.

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