Compound Riveted Girders, As Applied in the Construction of Buildings. with Numerous Practical Illustrations and Tables

PREFACE. IN order to facilitate the calculation attending the construc- tion of Wrought Iron and Steel Riveted Girders, the author has endeavored in this work to supply the linkwhich separates Theory from Practice. Its object may be briefly stated. A riveted girder is to be designed the span, depth, and loads are known, the strains are calculated b the well-known bendingmoment formulae, and largely by the graphic method lastly, the details of construction are fully illustrated. Touching the question of accuracy, it is scarcely necessary to notice the slight difference that may arise between the two methods, i.e., working out the usual formulae, or by measuring from the graphic diagrams. The time consumed in wading through a complicated series of equations to reach a few meas- urements is objectionable when at least such measurements can at once be had by the graphic method. This work does not investigate exceptional or extremely scientific riveted girders, but more especially those of a type now extensively adopted and constructed by well-known architectural iron workers. The diagrams and the various examples explaining the Authors method are submitted to architects and architectural students with the hope that they will become a medium of usefulness to them in the routine of office work. WILLIAM H. BIRKMIRE. NEW YORK, 1893. TABLE OF CONTENTS. PART I. STRAINS IN COMPOUND RIVETED GIRDERS. PAGE Compound riveted girders described I Bending moments 2 Flanges 4 Shearing forces on the webs 5 Buckling of webs 7 Stiffeners 8 Riveting Frict on of plates , . 10 Proportioning rivets n Rivets connecting webs with flanges 12 Spacing rivets according to strain produced in the flanges by the bending moments , 15 Proportioning girders Shearing and bearing resistance of rivets Table 16 Details of construction 17 Extract from the New York Building Law in relation to riveted girders To calculate the approximate weight of girder before its dimensions are fixed IQ Splicing 20 PART II. QUALITY OFMA TERIAL. Wrought-iron 21 Limit of elasticity of wrought-iron 21 Ultimate strength of wrought-iron 21 Rivet iron 21 Mild steel 21 v 8 16 18 VI TABLE OF CONTENTS. Ultimate strength and elongation Rivet steel Painting PART III. EXAMPLE . PACK Girder supporting a concentrated load at centre of span. 23 Construction of flanges in a girder supporting a concentrated load at centre Flanges 25 reduced in area towards the supports in a girder supporting a concentrated load at centre Webs proportioned 26 in a girder supporting a concentrated load at centre of span 28 Stiffeners in a girder supporting a concentrated load at centre of span 2 Rivet spacing in a girder supporting a concentrated load at centre of span. 29, Graphical representation of bending moments and shearing forces in a girder with a concentrated load at centre of span 30 List of material and details of a girder supporting a concentrated load at centre 32 Areas of angles with even legs Table 33 uneven legs Table 33 Sectional area in inches of rivet-holes in plates of various thicknesses Table 34 Gross area of plates of various thicknesses Table 35 Safe buckling value of web plates in wrought-iron Table 35 Shearing value of wrought-iron web plates Table 36 steel web plates Table 37 EXAMPLE II...