An investigation of hooped concrete columns . at the pro-per distance apart. These plugs were made of l/2-in. roundbars cut to 1-in. lengths. The holes for these were drilledwith l/3-in. star drills, the top half of the hole being chippedto a larger size to allow room for enough plaster of pari8 tohold the plug steady. In setting, the holes were filled withplaster of paris and the plugs were then driven in to a solidbearing. No trouble was experienced with loose plugs, exceptin a few cases where these were cut from 7/l6-in. rods. Thesewere readily tightened by driving two or three short brads
An investigation of hooped concrete columns . at the pro-per distance apart. These plugs were made of l/2-in. roundbars cut to 1-in. lengths. The holes for these were drilledwith l/3-in. star drills, the top half of the hole being chippedto a larger size to allow room for enough plaster of pari8 tohold the plug steady. In setting, the holes were filled withplaster of paris and the plugs were then driven in to a solidbearing. No trouble was experienced with loose plugs, exceptin a few cases where these were cut from 7/l6-in. rods. Thesewere readily tightened by driving two or three short brads in theplaster by the side of the plugs. in general, the longitudinalgage lines were nine inches long where the pitch of the spiralwas 1 l/2-in., and lOin. for the 1-in. pitch, but there weresome exceptions. Except the first two columns, all the getting readyand drilling the holes was done by one of the workmen in thelaboratory, and to hi3 careful end rapid work is due, to a largeextent, the possibility of making the large number of tests in. 16 a comparatively short time. 8. The columns were placed in the testingmachine and the upper end carefully centered between the taking off the rods the head of the machine war run downuntil the spherical bearing block rested on the upper block was then shifted so as to give as near an axial load-i rg as possible. It is believed that the center of the blockwas set to within an eighth of an inch of the center of allcolumns tested. Zero readings were taken with only the weight cf thebearing block on the column. After the first increment ofload (usually 350 lb. per sq. in.) had been applied, the bear-ing block was fixed by means of angle blocks and wedges to pre-vent rotation, - that is, - to make a fixed ended column. Theseblocks and wedges can be seen in position in the photographpage 204. In all tests the load was applied with the speed ofthe head of l/lO-in. per minute.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttheses, bookyear1914
