Wind Wizard: Alan G. Davenport and the Art of Wind Engineering

293 Pages·2012·7.94 MB·English

by  Siobhan Roberts

WIND WIZARD
WIND WIZARD
Alan G. Davenport and the Art of Wind Engineering
SIOBHAN ROBERTS
PRINCETON UNIVERSITY PRESS
PRINCETON AND OXFORD
Copyright © 2013 by Siobhan Roberts Requests for permission to reproduce material from this
work should be sent to Permissions, Princeton University Press Published by Princeton University
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In the United Kingdom: Princeton University Press, 6 Oxford Street, Woodstock, Oxfordshire
OX20 1TW
press.princeton.edu
Jacket photograph by Ron Nelson. Courtesy of the estate of Ron Nelson.
All Rights Reserved
Library of Congress Cataloging-in-Publication Data Roberts, Siobhan.
Wind wizard : Alan G. Davenport and the art of wind engineering / Siobhan Roberts.
p. cm.
Includes bibliographical references and index.
ISBN 978-0-691-15153-3 (hardcover : alk. paper) 1. Wind-pressure. 2. Davenport, Alan G. 3.
Buildings—Aerodynamics. 4. Bridges—Aerodynamics. I. Title.
TA654.5.R636 2012
624.1′75—dc23 2012015170
British Library Cataloging-in-Publication Data is available This book has been composed in
Minion Pro Printed on acid-free paper. ∞
Printed in the United States of America 1 3 5 7 9 10 8 6 4 2
In memoriam
Alan Davenport
1932–2009
CONTENTS
I
Sowing Wind Science 1
II
Tall and Taller Towers 32
III
Long and Longer Bridges 129
IV
Project Storm Shelter 183
Acknowledgments 227
Notes 229
Interview Sources 243
Glossary 245
Bibliography 251
Index 267
WIND WIZARD
I
Sowing Wind Science
N
o sooner did the Tacoma Narrows Bridge—the world’s third longest
suspension bridge, and the pride of Washington State—open in July
1940 than it earned its epitaphic nickname, “Galloping Gertie.” The
4,000-foot structure, its main span reaching 2,800 feet, twisted and
bucked in the wind. The pronounced heave, or more technically
speaking the longitudinal undulation, caused some automobile
passengers to complain of seasickness during crossings. Others observed
oncoming cars disappearing from sight as if traveling a hilly country
road. By November 7, amid 39-mile-an-hour winds, the $6,400,000
bridge wobbled and flailed, then rippled and rolled, then twisted like a
roller coaster, until in its final throes it plunged, with a beastly roar, 190
feet into the waters of Puget Sound.
See Glossary for definitions
Speaking to a New York Times reporter the day after the collapse, Leon
S. Moisseff, the bridge’s designer and engineer, was at a loss to explain
the cause, placing blame on “a peculiar wind condition.”
Wind engineer Alan G. Davenport, founder of the Boundary Layer
Wind Tunnel Laboratory at the University of Western Ontario, often
summoned the memory of the Tacoma Narrows Bridge disaster as a
cautionary tale. “Most features of this disaster are too familiar to bear
repeating,” he told his audiences, whether assembled at technical
lectures or at popular talks. Both occasions always included screenings of
grainy film footage capturing the bridge misbehaving as though