CHAPTER XII. 

 STRUCTURAL DRAFTING. 



PLANS FOR STRUCTURES. 



Introduction. The plans for a structure must contain all the information necessary for the 

 design of the structure, for ordering the material, for fabricating the structure in the shop, for 

 erecting the structure, and for making a complete estimate of the material used in the structure. 

 Every complete set of plans for a structure must contain the following information, in so far as 

 the different items apply to the particular structure. 



In writing this chapter- the instructions of many bridge companies have been consulted; 

 special credit being due the instructions prepared by the American Bridge Company, the Penn- 

 sylvania Steel Company, and the McClintic-Marshall Construction Company. 



1. General Plan. This will include a profile of the ground; location of the structure; ele- 

 vations of ruling points in the structure; clearances; grades; (for a bridge) direction of flow, high 

 water, and low water; and all other data necessary for designing the substructure and super- 

 structure. 



2. Stress Diagram. This will give the main dimensions of the structure, the loading, stresses 

 in all members for the dead loads, live loads, wind loads, etc., itemized separately; the total 

 maximum stresses and minimum stresses; sizes of members; typical sections of all built members 

 showing arrangement of material, and all information necessary for the detailing of the various 

 parts of the structure. 



3. Shop Drawings. Shop detail drawings should be made for all steel and iron work and 

 detail drawings of all timber, masonry and concrete work. 



4. Foundation or Masonry Plan. The foundation or masonry plan should contain detail 

 drawings of all foundations, walls, piers, etc., that support the structure. The plans should 

 show the loads on the foundations; the depths of footings; the spacing of piles where used; the 

 proportions for the concrete; the quality of masonry and mortar; the allowable bearing on the 

 soil; and all data necessary for accurately locating and constructing the foundations. 



5. Erection Diagram. The erection diagram should show the relative location of every part 

 of the structure; shipping marks for the various members; all main dimensions; number of pieces 

 in a member; packing of pins; size and grip of pins, and any special feature or information that 

 may assist the erector in the field. The approximate weight of heavy pieces will materially assist 

 the erector in designing his falsework and derricks. 



6. Falsework Plans. For ordinary structures it is not common to prepare falsework plans 

 in the office, this important detail being left to the erector in the field. For difficult or important 

 work erection plans should be worked out in the office, and should show in detail all members and 

 connections of the falsework, and also give instructions for the successive steps in carrying out 

 the work. Falsework plans are especially important for concrete and masonry arches and other 

 concrete structures, and for forms for all walls, piers, etc. Detail plans of travelers, derricks, 

 etc., should also be furnished the erector. 



7. Bills of Material. Complete bills of material showing the different parts of the structure 

 with its mark, and the shipping weight should be prepared. This is necessary in checking up 

 the material to see that it has all been shipped or received, and to check the shipping weight. 



8. Rivet List. The rivet list should show the dimensions and number of all field rivets, 

 field bolts, spikes, etc., used in the erection of the structure. 



9. List of Drawings. A list should be made showing the contents of all drawings belonging 

 to the structure. 



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