. Journal of electricity. / _$-«-_ _ ^««.„ *» .w/W. -*l UPPER ARCH TRUSSES WITH FILLERS—FIG. 3 the line of pressure in the arch ring. Take, for in-stance, an arch slice 1 foot wide with the middle of thecrown at elevation 5, and with the middle of this sliceat the springing line at elevation 5 + = eleva-tion With reservoir full to the crest, the water-load at the middle point of the crown would correspond May 1, 1918] JOURNAL OF ELECTRICITY 449 to 5. X = pounds per sq. ft., whereas thewater pressure at the corresponding point at thespringing line would correspond to 12
. Journal of electricity. / _$-«-_ _ ^««.„ *» .w/W. -*l UPPER ARCH TRUSSES WITH FILLERS—FIG. 3 the line of pressure in the arch ring. Take, for in-stance, an arch slice 1 foot wide with the middle of thecrown at elevation 5, and with the middle of this sliceat the springing line at elevation 5 + = eleva-tion With reservoir full to the crest, the water-load at the middle point of the crown would correspond May 1, 1918] JOURNAL OF ELECTRICITY 449 to 5. X = pounds per sq. ft., whereas thewater pressure at the corresponding point at thespringing line would correspond to X =. pounds, or nearly times more than at thecrown. At lower elevations this large difference () is fast disappearing and becomes unimportantwith crown elevations below elevation 15. In the up-per portion of the dam the radial component of thearch weight borne directly by the arch itself tends to-wards neutralizing the large difference in water pres-sure between the crown and the corresponding abut-ment points, as this weight component has its largestvalue at the crown and its smallest value at the abut-ments. This can most clearly be shown graphically,and in Fig. 1 and Fig. 2, two arch slices are drawn, as-sumed to be one foot wide. One (Fig. 1) with thecrown at elevation-5 (the middle of the crown at ele-vation 5, and then six inches on either side), and theother (Fig. 2) with its crown at elevation 10. Thearch is divided up into 20 voussoirs and the forces act-ing on these voussoirs are calculated. These forces,Avhile not uniformly distributed, are of course symmet-ric
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Keywords: ., bookcentury1900, bookdecade1910, bookidjo, booksubjectelectricity
