262 PRACTICAL STRUCTURAL DESIGN 



The loads are tabulated as in the above table and the area of 

 floor served by a column is multiplied by the total load per square 

 foot shown in the last column, in order to determine the column 

 load at each floor. 



The area of floor served by interior columns is equal to the 

 space enclosed between four columns. Side wall columns serve 

 an area equal to one-half this and corner columns serve an area 

 one-fourth that of the space between four columns. In other 

 words loads go to the nearest support. The wall columns carry 

 the additional dead load of the walls, each column carrying a 

 length of wall measured midway between adjacent columns, that 

 is, a panel length. 



For the load permitted on various soils and for the amount 

 of live load to be carried to foundations, with and without pil- 

 ing, consult the various specifications mentioned and the steel 

 handbooks. 



The distribution of load on footings is not treated adequately 

 in many textbooks. The dead load is constant and the live load 

 is variable. If the total load, dead plus reduced live load, is used 

 in proportioning the footings the footings under the interior 

 columns will be entirely too large if the building stands vacant. 

 The footings under the walls, however, will continue to settle 

 and old buildings with humps in the floors over the girders were 

 no doubt so designed that the footings under all columns were 

 proportioned for the total dead and live load, or total dead and 

 reduced live load. 



A common method is to use for interior columns the allowable 

 soil load and for wall columns a soil load about 500 Ibs. per sq. 

 ft. less, and then proportion the footings for the total load brought 

 down as illustrated. Some men make the soil load for the exterior 

 columns one-third less than that for the interior columns and 

 design the footings for the total dead plus the reduced live load. 



Mr. Schneider recommends the following method: Proportion 

 the footing under the column carrying the maximum live load. 

 Divide the total load by the allowable soil pressure and obtain 

 the square feet required to carry the load. Divide the dead load 

 by the area thus found and obtain a reduced soil pressure per 

 square foot. Using this reduced soil pressure design the rest of 

 the footings for the dead load only. This is very conservative 

 but may well be used for reinforced concrete buildings, as all the 



