Steel Design Guide Series Floor Vibrations Due to Human Activity
Steel Design Guide Series存款利息表
Floor Vibrations
Due to Human Activity
Thomas M. Murray, PhD, P.E.
Montague-Betts Professor of Structural Steel Design
The Charles E. Via, Jr. Department of Civil Engineering
Virginia Polytechnic Institute and State University
Blacksburg, Virginia, USA
David E. Allen, PhD
Senior Rearch Officer
Institute for Rearch in Construction
National Rearch Council Canada
Ottawa, Ontario, Canada
Eric E. Ungar, ScD, P.E.
Chief Engineering Scientist
Acentech Incorporated
Cambridge, Massachutts, USA
A M E R I C A N I N S T I T U T E O F S T E E L C O N S T R U C T I O N C A N A D I A N I N S T I T U T E O F S T E E L C O N S T R U C T I O N
Copyright 1997
by
American Institute of Steel Construction, Inc.
All rights rerved. This book or any part thereof
must not be reproduced in any form without the
written permission of the publisher.
The information prented in this publication has been prepared in accordance with rec-ognized engineering principles and is for general information only. While it is believed to be accurate, this information should not be ud or relied upon for any specific appli-cation without competent professional examination and verification of its accuracy, suitablility, and applicability by a licend professional engineer, designer, or architect. The publication of the material contained herein is not intended as a reprentation or warranty on the part of the American Institute of Steel Construction or of any other person named herein, that this information is suitable for any general or particular u or of freedom from infringement of any patent or patents. Anyone making u of this information assumes all liability arising from such u.
Caution must be exercid when relying upon other specifications and codes developed by other bodies and incorporated by reference herein since such material may be mod-ified or amended from time to time subquent to the printing of this edition. The Institute bears no responsibility for such material other than to refer to it and incorporate it by reference at the time of the initial publication of this edition.
Printed in the United States of America
Second Printing: October 2003
The co-sponsorship of this publication by the Canadian Institute
of Steel Construction is gratefully acknowledged.
TABLE OF CONTENTS
1. Introduction (1)
轻蔑怎么读1.1 Objectives of the Design G u i d e (1)
乌龟放多少水合适
1.2 Road M a p (1)
1.3 B a c k g r o u n d (1)
1.4 Basic Vibration Terminology (1)
1.5 Floor Vibration Principles (3)
2. Acceptance Criteria For Human Comfort (7)
2.1 Human Respon to Floor M o t i o n (7)
2.2 Recommended Criteria for Structural Design (7)
2.2.1 Walking Excitation (7)
2.2.2 Rhythmic Excitation (9)
3. Natural Frequency of Steel Framed
Floor S y s t e m s (11)
3.1 Fundamental Relationships (11)
3.2 Composite A c t i o n (12)
淋巴水肿的治疗3.3 Distributed W e i g h t (12)
3.4 Deflection Due to Flexure: Continuity (12)
3.5 Deflection Due to Shear in Beams and Truss.. 14
3.6 Special Consideration for Open Web Joists
and Joist G i r d e r s (14)
4. Design For Walking Excitation (17)
4.1 Recommended Criterion (17)
工会年终工作总结
4.2 Estimation of Required Parameters (17)
4.3 Application of C r i t e r i o n (19)
4.4 Example C a l c u l a t i o n s (20)
4.4.1 Footbridge E x a m p l e s (20)
4.4.2 Typical Interior Bay of an Office
Building Examples (23)
4.4.3 Mezzanines E x a m p l 325. Design For Rhythmic Excitation (37)
5.1 Recommended C r i t e r i o n (37)
5.2 Estimation of Required Parameters (37)
5.3 Application of the Criterion (39)
5.4 Example C a l c u l a t i o n s (40)
6. Design For Sensitive Equipment (45)
6.1 Recommended C r i t e r i o n (45)寒食帖原文及解释
6.2 Estimation of Peak Vibration of Floor due
to W a l k i n g (47)
6.3 Application of Criterion (49)
6.4 Additional Considerations (50)
6.5 Example C a l c u l a t i o n s (51)
7. Evaluation of Vibration Problems and
Remedial M e a s u r e s (55)
7.1 E v a l u a t i o n (55)
7.2 Remedial M e a s u r e s (55)
7.3 Remedial Techniques in Development (59)
7.4 Protection of Sensitive E q u i p m e n t (60)
References (63)
Notation (65)
Appendix: Historical Development of Acceptance
C r i t e r i a (67)
Chapter 1 INTRODUCTION
1.1 Objectives of the Design Guide
The primary objective of this Design Guide is to provide basic principles and simple analytical tools to evaluate steel framed floor systems and footbridges for vibration rviceability due to human activities. Both human comfort and the need to control movement for nsitive equipment are considered. The condary objective is to provide guidance on developing remedial measures for problem floors.
1.2 Road Map
This Design Guide is organized for the reader to move from basic principles of floor vibration and the associated termi-nology in Chapter 1, to rviceability criteria for evaluation and design in Chapter 2, to estimation of natural floor fre-quency (the most important floor vibration property) in Chap-ter 3, to applications of the criteria in Chapters 4,5 and 6, and finally to possible remedial measures in Chapter 7. Chapter 4 covers walking-induced vibration, a topic of widespread im-portance in structural design practice. Chapter 5 concerns vibrations due to rhythmic activities such as aerobics and Chapter 6 provides guidance on the design of floor systems which support nsitive equipment,
忌廉汤
英语的重要性topics requiring in-cread specialization. Becau many floor vibrations prob-lems occur in practice, Chapter 7 provides guidance on their evaluation and the choice of remedial measures. The Appen-dix contains a short historical development of the various floor vibration criteria ud in North America.
1.3 Background
For floor rviceability, stiffness and resonance are dominant considerations in the design of steel floor structures and footbridges. The first known stiffness criterion appeared nearly 170 years ago. Tredgold (1828) wrote that girders over long spans should be "made deep to avoid the inconvenience of not being able to move on the floor without shaking everything in the room". Traditionally, soldiers "break step" when marching across bridges to avoid large, potentially dangerous, resonant vibration.
A traditional stiffness criterion for steel floors limits the live load deflection of beams or girders supporting "plastered ceilings" to span/360. This limitation, along with restricting member span-to-depth rations to 24 or less, have been widely applied to steel framed floor systems in an attempt to control vibrations, but with limited success.
Resonance has been ignored in the design of floors and footbridges until recently. Approximately 30 years ago, prob-
lems aro with vibrations induced by walking on steel-joist supported floors that satisfied traditional stiffness criteria.
Since that time much has been learned about the loading function due to walking and the potential for resonance.
More recently, rhythmic activities, such as aerobics and high-impact dancing, have caud rious floor vibration problems due to resonance.
A number of analytical procedures have been developed
which allow a structural designer to asss the floor structure for occupant comfort for a specific activity and for suitability for nsitive equipment. Generally, the analytical tools require the calculation of the first natural frequency of the floor system and the maximum amplitude of acceleration, velocity or displacement for a reference excitation. An esti-mate of damping in the floor is also required in some in-stances. A human comfort scale or nsitive equipment crite-rion is then
ud to determine whether the floor system meets rviceability requirements. Some of the analytical tools in-corporate limits on acceleration into a single design formula who parameters are estimated by the designer.
1.4 Basic Vibration Terminology
The purpo of this ction is to introduce the reader to terminology and basic concepts ud in this Design Guide.
Dynamic Loadings. Dynamic loadings can be classified as harmonic, periodic, transient, and impulsive as shown in Figure 1.1. Harmonic or sinusoidal loads are usually associ-ated with rotating machinery. Periodic loads are caud by rhythmic human activities such as dancing and aerobics and by impactive machinery. Transient loads occur from the movement of p eople and include walking and running. Single jumps and heel-drop impacts are examples of impulsive loads.
Period and Frequency. Period is the time, usually in c-onds, between successive peak excursions in repeating events. Period is associated with harmonic (or sinusoidal) and repetitive time functions as shown in Figure 1.1. Frequency is the reciprocal of period and is usually expresd in Hertz (cycles per cond, Hz).
Steady State and Transient Motion.If a structural system is subjected to a continuous harmonic driving force (e Figure l.la), the resulting motion will have a constant fre-quency and constant maximum amplitude and is referred to as steady state motion. If a real structural system is subjected to a single impul, damping in the system will cau the 1
