i8 THE COLORADO EXPERIMENT STATION. 



In case time is of little value it would probably prove more 

 economical to build hollow posts. As the amount of reinforcement 

 is not affected by the change from the solid to the hollow post, only 

 the saving in cement, sand and gravel need be considered. It is an 

 easy matter to compute the saving accomplished by the making of 

 hollow posts, and then by knowing the cost of labor, the economy 

 of building them may soon be calculated. With cement at 55 cents 

 per sack and sand at $1.00 per yard, one cubic foot of i to 4 mixture 

 costs 1 8 cents. If a ij4 inch hole were to be left in the center of a 

 post 7 feet long about i J^ cents' worth of material would be saved. 

 With labor at 15 cents per hour, 6 minutes might be given to the 

 extra work of making the post with the hollow core. 



In case of alkali soils the hollow center gives additional ex- ( 

 posed surface upon which the alkali may act. In a 4-inch square 

 post with a i }/2 inch core, the extra surface amounts to about 28 

 per cent, of the original lateral surface. 



Finally there is a serious question as to the relative strength 

 and durability of the hollow post as compared with the solid one. 



CORNER POSTS AND GATE POSTS. 



In the building of a fence with cement or concrete posts, the 

 corner and gate posts must be especially strong, so as to prevent the 

 pull of the wires coming upon the line posts. All the pull of the 

 wires should be borne by the corner or gate posts. With this in 

 mind the designer should aim not only to build a very strong post, 

 but the system of bracing should receive special attention. 



As the cement posts are not as strong as wood posts, we can- 

 not use the same bracing systems, which are so commonly in use 

 in wood post fence construction. It has been found advisable to 

 place the brace so that it supports the post at a point very little, if 

 any, above the middle of the post. For the reason that the posts 

 are strong in compression, but do not stand as much pull as wood 

 posts, it proves advisable to place the brace against the brace post 

 at least one foot below the ground line; thus the post distributes 

 the pressure at the end of the brace against an area of ground equal 

 to the surface covered on the opposite side of the post. 



There should be several wires connecting the brace post and 

 the corner or gate post together. These wires should be placed 

 under the ground at a depth of about one foot. By having these 

 wires tight the corner post cannot move unless the brace post moves, 

 and as this is securely fastened to it, the whole becomes a unit, 

 offering a rigid resistance to the pull of the fence. 



In case of a corner post, the wires may be fastened by wrap- 

 ping them around it, but the most satisfactory way is to cast wire 

 staples in the post. These staples should extend into the post far 



