The boiler room should be so located that coal and ashes can be handled direct from or to cars without manual labor. This can be accomplished by so placing the boiler room that either or both the coal and ashes can be handled by gravity. Where this is impossible, conveyors should be used.

The lighting of car houses is usually accomplished by means of electric lamps suspended on drop cords and connected with the trolley circuit through conduits run on the roof or ceiling. All lights should be controlled by local switches near the lights and by main switches in the foreman's office, and also at some point outside the building.

The trolley and other power circuits inside the building should also be controlled by a main switch outside the building.

All wiring should be done strictly in accordance with the fire underwriters' rules and with all local ordinances and requirements.

I come to urge you to study men. Why? Because much of your learning is done through other men, because you will do your work through men, and because men are so difficult to understand that careful study is required. Men are the most important objects of interest that will come within your sphere of knowledge. I urge you, graduates, to study men because I am safe in saying that there are some among you who will fail to be useful in the world simply because you will fail to understand men until it is too late.

Please note that you are urged to study men for perfectly unmoral reasons. You are not urged to study men to learn how to improve their morals, not for any effect it may have upon your own morals. You are urged to study men in order to make yourself more efficient as an engineer— the purpose for which you study steel or concrete.

-Hayford.

Notes on the Tests of Some Large Reinforced

Concrete Pipe

W. J. SCHLICK*

One of the later developments of the reinforced concrete industries has been the manufacture of factory moulded pipe of large sizes. Such pipes have been used quite extensively for railway culverts and more recently in highway work.

During the summer the Good Roads Section of the Engineering Experiment Station, in co-operation with the C. F. Massey Company of Chicago, made strength tests of some of these pipes in sizes of from 18 inches to 48 inches in diameter. The purpose of these tests was to secure data on the supporting strength which would be comparable with similar data for other types of pipes and with data from future tests. The only previously published data on the strength of such pipe is that in Bulletin 22 of the Illinois Engineering Experiment Station and is the results of tests conducted by Professor A. N. Talbot. In Professor Talbot's investigation the pipes were given the benefit of lateral support by being tested in a rigidly constructed box with the space (about 12 inches) between the pipe and the side of the box rammed full of sand. In order to obtain data which would be comparable with that from tests of other kinds of pipe, the Iowa method of distributed sand bearing was used in these tests.

All of the thirteen pipes tested were made by the Massey Company at their Chicago and Minneapolis plants and furnished free of charge to the Experiment Station. The pipes were eliptical in shape, with one ring of circular reinforcing, thus bringing the reinforcing nearer the tension faces when the pipe is loaded with the long diameter vertical. The pipes were all of the type commonly known as "bell and spigot," and were in 8 foot lengths. The design was the same for all sizes, the only dif

*B. C. E. '09 Drainage Engineer, Engineering Experiment Station, Iowa State College, Ames, Iowa.

ference being in the dimensions of the pipes and in the amount and kind of reinforcing.

The reinforcing in 36 inch and 48 inch pipe was of %inch bars, spaced 3 inches and 334 inches, respectively, with 3/8-inch longitudinal bars to which the circular rings were

Fig. 1. Standard 23x20 inch Concrete Culvert Pipe, Showing Wire Mesh Reinforcing.

securely wired. By measurement after the pipes were tested the distances between the circular rings in some pipes were found to vary as much as 4 inches. The pipes were designed to have the reinforcing at 1 inch from the tension face at top, bottom and sides. By measurements after the test, the greatest variation was found in pipe No. 703, where this distance varied from 5% of an inch to 114 inches.

In the other three sizes American Steel and Wire Co. triangular mesh reinforcing was used, No. 4 mesh being used for the 18 inch pipe and No. 23 mesh for the 24 inch and 30 inch sizes. Measurements taken after the test did not check very closely with the standards for this mesh either in size of longitudinal wires or in the spacing between these wires. The per cents of reinforcing were calculated as the area of reinforcing in a unit section divided by the area of that section of the pipe wall between the center line of the reinforcing and the compression face of the tile wall.

In order to make strength tests of these large pipes a

special machine had to be constructed. The general features of the machine are shown in Fig. 3. The wooden frame shown in this picture was used simply to support the upper I beams and the hydraulic jacks while preparing the pipe and upper sand bearing for the test. The pressure was applied by 2 (later 1) 100 ton, 12 inch runout, independent pump hydraulic jacks through sand bearings over onefourth the circufrenence of the center line of the pipe wall, using the short diameter and a circular section in calculating this distance. After the first test it was found necessary to reinforce the sides of the sand boxes by running a 1-inch bolt through each sand box. After the first three tests it was found that one jack was sufficient. The machine was accordingly altered so as to bring one set of I beams over the center of the pipe.

Deflection measurements were taken on all pipe when placed in the machine and during the application of the load. The measurements were taken betwen brass plates,

Fig. 2. Reinforcing.

Standard 40x36 inch Concrete Culvert Pipe, Showing Steel Bar

cemented to the pipe wall by means of an Ames dial attached to a micrometer. The changes in both the vertical and horizontal diameters were obtained, measurements being taken after each increment of the load until the cracking of the pipe displaced the brass plates. The large dial shown on

Fig. 3. The Testing Machine and Pipe No. 701 as It Appeared after the Maximum Load had been Applied. Note the Location of the Principal Side Failure and the Comparatively Small Number of Cracks in the Side Exposed.

the end of the pipe in Fig. 5 was used as a check on the change in the horizontal diameter and for measuring the deflections when the pipe was near failure.

The relation of the center of the application of the load to the center of the pipe is shown in Fig. 2. The load was applied in 8 ton increments when two jacks were used and in 4 ton and 2 ton increments when only one jack was used. After each increment of load the deflection measurements were taken and the number and extent of the cracks noted. The loading was continued until no greater load could be ob