Up: Luxfer Prism
6 of 9
|| These are arranged at required
distances, and provide for such movement as may take place on account
of expansion or contraction of the slab.
FIG. 11. SIDEWALK VAULT LIGHTS, PERSPECTIVE
| Concrete being a poor conductor of
heat, the condensation with other systems is wholly avoided.|
|NO EXPOSED IRON.
|| Iron plates, ordinarily used, are entirely
omitted in this system, thus doing away with the joints which cause such
endless difficulty, and eliminating the danger from slipping on exposed
FIG. 12. FINISHED SLAB OF GLASS AND CONCRETE
| The top surface is rubbed down smooth, presents
a fine appearance, and makes an excellent wearing pavement.
The under-surface may be pointed and painted, or it may be plastered
flush with the bottom of the lenses with cement or white mortar. This
is the only system to which such a finish can be applied.
|| This system is particularly desirable
for quick setting-- the materials are always ready and can be assembled and
set without the usual delay necessitated in making patterns and castings.
FIG. 13. TEST BY CONCENTRATED LOAD
Of 11,882 lbs. applied on disc 8½ inches in diameter
|TESTS OF STEEL
| Cuts 12, 13 and 14 illustrate the
method and results of strength test of steel-concrete sidewalk vault light
slab recently made by Tucker & Vinton, and under the direction of Mr. Wm.
Barclay Parsons, Chief Engineer of the New York Rapid Transit Railway.
For this test two twelve-inch I-beams thirteen and one-half feet long
were spaced five feet apart, center to center, and supported by blocking
at their extremities. Between these two beams were set three five inch
I-beams, with their tops two inches below the flange of the twelve-inch
beams. The vault light slab rested on this framework, but was not in
any way connected to it. This slab was two inches thick, except over the
five-inch beams, where fillers were provided to give it bearing upon
them. The constriction of the slab is shown by Fig. 12.