Imágenes de páginas
PDF
EPUB

V.5040

66.94 Eno, 718,94.5 DEVARU I

'AN 15 1897

LIBRARY Hayes fund.

[ocr errors]

HARV

PREFACE

The primary object which the author had in view in writing this book was to prepare a text-book for students attending the first portion of his lectures on Materials and Structures; but he considers that the work may be found useful not only to engineering students in Technical Colleges and Universities, but also to those engaged in the design of constructional iron and steel work.

The modern methods of determining the safe intensity of working stresses in structures have been considered in the first chapter, and have been employed more or less throughout the work.

The subjects treated in the various chapters have been considered as briefly as possible, and the numerous examples given are relied upon for more complete explanation.

The special feature of the work lies in the various examples which illustrate the design of the most important classes of structures in iron, steel, and timber; these have all been selected from existing works.

The author's experience in teaching has convinced him of the necessity of thoroughly illustrating the various principles underlying the theory and practice of construction, as a student is never certain whether

he understands these principles or not until he has attempted to apply them.

The author has freely availed himself of the works of others, which he has endeavoured to acknowledge as far as possible throughout the work : but he is especially indebted to the Proceedings of the Institution of Civil Engineers, the American Society of Civil Engineers, the Specifications of Mr. Theodore Cooper, M.Amer.Soc.C.E. ; the works of Professors Dubois, Burr, and Waddell; also to Mr. Hickson, M.Inst.C.E., Commissioner and Engineer-in-chief for Roads and Bridges, New South Wales, for drawings of the continuous-girder road bridge, the swing bridge, and the hinged-arch bridge.

Although the subject of foundations is at least as important as that of superstructures, it has only been treated briefly for pile trestle viaducts and cylinder piers.

The author considers that the subject of foundations could be more conveniently dealt with in connection with a book on Engineering Construction in Brickwork, Masonry, and Concrete, which he hopes to write as soon as time will permit.

In spite of the care which has been exercised in preparing this work, it is possible that in a first edition errors may have escaped detection; the author will therefore be thankful for any information as to errors in diagrams or calculations.

UNIVERSITY OF SYDNEY,

New South Walzs.

CONTENTS

[blocks in formation]

CHAPTER II.

STRENGTH AND ELASTICITY OF TIMBER.

General remarks on the testing of timber

The tensile and compressive strengths and elasticity of timber

Tables of strengths of Anierican, European, and Australian timber columns

Shearing strength of timber.

Tables of shearing strengths of American, European, and Australian timber .

Transverse strength and elasticity of timber

Tables of strength and elasticity of American, European, and Australian timbers

Safe values of the modulus of rupture

Increase in deflection of beams due to long-continued application of load

Factor of safety in timber structures

General remarks on the growth, felling, and preservation of timber

23

24

25

26

27

27

28

30

30

31

31

« AnteriorContinuar »