2 STRUCTURAL ENGINEERS' HANDBOOK. 



saving in shop cost, it often results in a material increase in the weight of the details of the struc- 

 ture, and in the number of field rivets, so thac the efficiency of the structure is not increased, 

 and the final cost of the structure is not reduced. The author has in mind a case where to change 

 the details of a plate girder so that multiple punches might be used required the addition of details 

 equal to 5 per cent of the weight of the span and the addition of 25 per cent to the number of field 

 rivets, with no increase in efficiency. 



The best results are obtained when the structural engineer prepares carefully worked out 

 detail drawings (not shop drawings) in which the efficiency of the structure, ease of fabrication 

 and ease of erection are given due consideration. The shop drawings may then be prepared by 

 the bridge company to take the greatest possible advantage of improved shop methods without 

 decreasing the efficiency of the structure, or increasing the total weight, or increasing the cost of 

 erection. 



Part I is divided into seventeen chapters, of which the first eleven chapters cover different 

 types of structures, and the last six chapters cover subjects which apply to all types of steel con- 

 struction. While the aim has been to present the largest possible amount of information in the 

 limited space, each subject presented is discussed briefly in a logical order. 



While the author has drawn on his other books in the various chapters, the reader will find 

 much new material on the subjects covered in the other books, especially in Chapter I, Steel Roof 

 Trusses and Mill Buildings, and Chapter III, Steel Highway Bridges, so that this book supple- 

 ments the author's other books on structures. Each chapter is self-contained, the illustrations 

 and tables being numbered independently of the other chapters. As far as possible the different 

 subjects are discussed fully in each chapter, thus reducing cross-references. The most of the 

 cross-referencing is made through the index, which together with the table of contents will be 

 found invaluable to the reader. 





