2O2 TOWERS AND TANKS FOR WATER-WORKS. 



in sections of 10 to 12 feet. The supply pipe should be secured 

 in every tower panel by a metal collar, from which radial rods 

 should lead to each post. Where there is little likelihood of frost, 

 the case may be entirely omitted and the supply pipe supported 

 .simply by the collar or band and the steel rods. 



Connections. Since nearly all of the large steel companies 

 catalogue and keep ui stock Z-bar columns of various sizes, in 

 their publications they also give designs for standard connec- 

 tions, including capitals, pedestals, panel-point and end con- 

 nections, with bills of material and calculated reactions. The 

 Z-bar column can be so placed that with the four-post tower 

 the connections are square, but when the post is a column built 

 of latticed channels, it is usual to connect the horizontal struts 

 by bent jaw plates riveted to the column. 



The connection at the top of posts consists of a bearing plate, 

 reenforced with angles, and the flange of the circular girder is 

 riveted as may be convenient to the bearing plate. In some 

 designs (Fig. 51) the bearing plate is bent and forms a connection 

 for the diagonal rods. The pedestal or footing is generally a 

 steel plate, reenforced also with angles, but often a cast-iron 

 bearing plate or shoe is designed. The thickness of these base 

 plates depend upon the superimposed load and vary from \ inch 

 to if inches. The other dimensions of the bearing plate at the 

 base must be such as to provide sufficient area for the proper 

 distribution of the weight over the masonry foundations and 

 generally assume at 100 Ibs. per square inch of surface upon 

 brick masonry, but a capstone is usually specified. The load 

 which may be allowed upon monolithic piers varies with the 

 texture of the stone and ranges from 15 to 30 tons per square 

 foot. This matter is further discussed in a subsequent chapter, 

 and in which the question of anchorage is also considered. In 

 the ordinary tower the connections are rigid, but in the design 

 of a recently constructed water-tower having a capacity of 150,000 

 and a vertical height of tower of 200 feet, the bottom of 



