Miscellaneous Uses of Reinforced Concrete

The tie consists of two "foundation blocks," one placed under each rail, and a third or "filling piece" in the middle, connecting the two. The three pieces are held together by a tie rod with a nut and washer at each end.

For the rail fastening, hollow, malleable-iron castings are embedded in the concrete. These castings are rec tangular in shape, inches wide and 3 inches long, and are plugged with wood, into which the spikes are driven in the ordinary manner. The rectangular shape of the casting allows of the adjustment of the spike lining. To act as a cushion and protect the tie from any crumbling, oak blocks are used. These oak-cushion blocks are placed immediately on top of the tie ; and between the block and the rail, a ribbed tie plate is placed The plate is perforated in the usual manner so that spikes can be driven through it into the wood plugs in the malleable castings. A lip extends down from the tie plate engaging the inside spike close to the surface of the concrete, thus reducing the leverage on the spike. This lip is the same width as the spike, so that when the cushion block wears, the lip will be pushed down into the wood plug. The bearing area of the tic plate is 60 square inches, and the plate is designed to be stiff enough to distribute the weight from the rail uniformly.

Telegraph and Telephone Poles. Telephone, telegraph, and electric railway managers and in vestors will be interested in a new concrete pole known as the Bailey.

In a general way the poles are built on the plan of all armored concrete work, says the "Scientific American," though the construction is quite distinctive in character. In the body of the pole and near its circumference, equally spaced, are continuous rods of twisted carbon steel especially prepared for this purpose. These rods are tied together and held in position by continuous spiral binding wires. These form the skeleton work of the pole, or the reinforce meat, which is then enclosed in a form into which the cement is poured.

Extreme climatic conditions of summer and winter, or the heavy demands upon strength and elasticity of a heavy pole line, leave the poles made by this process absolutely unimpaired. One of the features of the poles is their remark able elasticity. A thirty-foot pole will deflect thirty-one inches at the top without seriously cracking the concrete. The breaking strain of the pole is figured at 5,000 pounds—three times the strength of the common wooden pole.

Carefully calculated accounts of all expendi tures for labor and material in the construction show that under average conditions the first cost is slightly more than that of cedar poles. While

the average life of a cedar pole is about twelve years, that of a concrete pole is practically un limited. When a cedar pole decays, the labor cost of removing it and attaching the wires to a new pole is far greater than the cost of the pole itself. Such cost is by far the greatest item of depreciation in both telephone and telegraph properties. Indeed, this very item is perhaps the only one that has made telephone securities less desirable than railroad stocks. With cement poles, this renewal cost is eliminated.

Our forests are disappearing rapidly, and good cedar poles are almost unobtainable, and the price of those of even moderate quality is fast advancing. It is estimated that there are 40,000,000 poles in the ground in the United States, worth $200,000,000. These poles have an average life of twelve years. More than 3,200,000 poles are required every year to re place those decayed, at a cost of from $15,000,000 to $17,000,000 a year. When it is considered that much of this may be saved by the use of concrete poles, their enormous value to the public service corporations of the country may be appreciated.

Concrete poles 150 feet high have been erected at St. Catherines, Ontario; and though they have been subjected to hard stress, not a crack or sign of one has appeared.

An electric company has completed a huge reinforced concrete tower 115 feet high. It will carry sixteen transmission cables across the Monongahela river at Brownsville, Pa. The United States Government regulations are such that the tower must support the wires across a span 1,014 feet long, and at least 79 feet above low-water mark. The tower is built in the form of a square. It is 8 feet 2 inches on a side at the base, and tapers to 1 foot at the top. It is hollow for a height of 84 feet from the ground, the walls being 1 foot in thickness, and reinforced with old steel rails and scrap iron. The tower is solid for the remaining 31 feet. Bedrock was found at so great a depth that its use as a foundation was impracticable. Therefore it was decided to build a concrete base, to carry the enormous weight of the structure. Concrete was reinforced with old rails, laid criss-cross, and made into a block, 30 feet square and 4 feet 6 inches deep, at the center, with the top tapering away to 1 foot 6 inches at the edges. The false work which sup ported the forms and extended to the top of the tower was 12 feet square.