100 



STEEL OFFICE BUILDINGS. 



CHAP. II. 



SPANDREL SECTIONS. The design of the curtain walls that are supported by the spandrel 

 beams will depend upon the material of which the wall is built, the amount and character of the 

 ornamentation, and the details of the windows. The details of the wall construction in the 

 United Fire Company's Building, New York, are given in Fig. 18. The spandrel masonry is carried 

 by the wall girders and by horizontal angles bracketed from their outer faces. The angles in the 

 outer flanges of the wall girders are often wider than those in the inner flanges to give additional 

 support to the masonry, and both they and the detached spandrel angles have holes through their 

 horizontal flanges to receive vertical expansion and wedge bolts to hold the stone or terra- 

 cotta. The mullions over the windows are made of 3 in. by 4 in. tees. 



mm mm 



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no 4* *i 



V54 



fwifropu r lT.l._.SJ J Jj 1 



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FIG. 23. FOUNDATION PLAN OF SINGER BUILDING. 



The details of the spandrel walls should be worked out by the architect and the engineer 

 working together if the best results are to be obtained. 



WIND BRACING. The arrangement of the wind bracing in a steel frame building will 

 depend upon the size and height of the building, upon the arrangement of the columns and the 

 space that may be occupied by the wind bracing. Several types of wind bracing are shown in 

 Fig. 19. Where space permits the diagonal bracing is the most effective. Diagonal bracing can 

 only be used in solid walls or partitions. Knee braces (b) and portal bracing (c), can be used 

 in outside walls where there is sufficient space above and below windows. Brackets (d) are 

 used where the vertical clearance is limited and in wind bracing transversely through the building. 

 Details of wind bracing of the United Fire Company's Building, New York, are given in Fig. 20 

 and Fig. 21. The building is 130 ft. 6 in. by 173 ft. 6 in. in plan and 25 stories in height. The 

 columns are of Bethlehem H sections two stories in height. The floor panels are chiefly 15 ft. 

 6 in. by 24 ft. 3 in. The columns rest on grillages which rest on pneumatic piers. 



Details of the wind bracing in the Singer Building are given in Fig. 24, Fig. 25, and Fig. 26. 



