39 2 



Spacing of Purlins. 

 Form of Trusses. 



Bracing. 



Proposals. 



Detail Plans. 



Approval of Plans. 



Dead Loads. 



SPECIFICATIONS 



6. Purlins shall be spaced not to exceed 4' 9" where cor- 

 rugated steel is used, and shall be placed at panel points of the 

 trusses. 



7. The trusses shall preferably be of the Fink type with 

 panels so subdivided that panel points will come under the 

 purlins. If it is not practicable to place the purlins at panel 

 points, the upper chords of the trusses shall be designed to take 

 both the flexural and direct stresses. Trusses shall preferably 

 be riveted trusses. 



8. Bracing in the plane of the lower chord shall be stiff; 

 bracing in the planes of the top chords, the sides and the ends 

 may be made adjustable. 



9. Contractors in submitting proposals shall furnish com- 

 plete stress sheets, general plans of the proposed structures 

 giving sizes of material, and such detail plans as will clearly 

 show the dimensions of the parts, modes of construction and 

 sectional areas. 



10. The successful contractor shall furnish all work- 

 ing drawings required by the engineer free of cost. Working 

 drawings will, as far as possible, be made on standard size 

 sheets 24" x 36" out to out, 22" x 34" inside the inner border 

 lines. 



11. No work shall be commenced or materials ordered 

 until the working drawings are approved in writing by the en- 

 gineer. The contractor shall be responsible fo r dimensions 

 and details on the working plans, and the approval of the de- 

 tail plans by the engineer will not relieve the contractor "of this 

 responsibility. 



LOADS. 



12. The trusses shall be designed to carry the following 

 loads : 



13. DEAD LOADS. Weight of Trusses --The 

 weight of trusses per square foot of horizontal projection, up 

 to 150 feet span shall be calculated by the formula 



W= P_( l + _^\ 



45 \ 5 V A/ 



where W = weight of trusses per square foot of horizontal 

 projection; 



