52 CAMBKIA STEEL. 



BEAM TABLES. 



Tables of safe loads for beams and channels and spacings of 

 I -Beams for floors are given with explanatory notes on pages 

 100 to 135. 



BEAMS AS GIRDERS. 



In some cases two or more beams may be bolted together side by 

 side to form a girder, in which case cast iron separators with bolts 

 should be used to hold the various members together. Separators 

 should be placed at each end of the girder, at points of concen- 

 trated loading, and for uniform loading should be located at dis- 

 tances apart not greater than twenty times the width of the small- 

 est beam flange, in order to laterally support the upper flanges 

 which are in compression and prevent their failure by buckling. 

 The separators should preferably fit closely between the beam 

 flanges so as to unite the beams forming the girder and thereby 

 cause them to act together in resisting the load. Tables of Stand- 

 ard and Special Separators are given on pages 66 and 67. 



CONNECTION ANGLES. 



When beams are coped or fitted together at right angles, con- 

 nection angles are generally used, standards for which, covering 

 usual cases, are shown on pages 53, 54 and 55. Explanations and 

 tables of limiting spans for which these standards may be used are 

 given on pages 56 to 59. Beams may be fitted together thus with 

 flush tops or bottoms or in intermediate positions, as required in 

 cases where the girder or trimmer beam is the larger. In cases 

 where the girder or trimmer beam is the smaller, special stirrups 

 or other connections are required. 



LIVE LOADS FOR FLOORS. 



The following loads per square foot, exclusive of weight of floor 

 materials, show the range assumed in usual practice: 



Dwellings 70 Ibs. per sq. ft. 



Offices 70 to 100 Ibs. per sq. ft. 



Buildings for public assembly. 120 to 150 Ibs. per sq. ft. 



Stores, warehouses, etc 150 to 250 Ibs. and upwards per sq.ft. 



On page 328 are given in detail the safe loads for which floors 

 should be designed in accordance with the building laws of 

 various cities. 



