34 The Colorado Experiment Station. 
HOLLOW POSTS. 
It has been suggested that the cement and concrete posts should 
be made hollow. The hollow post would require less mixture and 
it would also be lighter. As the material in the center of the post 
does not have a good opportunity to act to the best advantage in 
compression, it is argued that the strength of the hollow post would 
be nearly as great as that of the solid post. 
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 1 to 4 mixture 
costs 18 cents. If a 1^ inch hole were to be left in the center of a 
post 7 feet long about 1cents’ 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 iy 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 
