. Engineering and Contracting . cally, to derrick No. 1, already de-scribed. These wall forms are divided horizontally into twoparts, permitting their adaptation to two slightly different pro-portions of the wall used in different localities; and permit-ting also an easier taking down and setting up of the sections, {77) hiK/ilir cniKi I iiul Contracting fur March .4, 19W. the latter 16 ft. by about 20 ft. in size, being rather bulkywithout division into pieces. Derrick No. 2, besides handling the forms, does such back-filling behind the finished wall footing as is necessary to se-cure the ear
. Engineering and Contracting . cally, to derrick No. 1, already de-scribed. These wall forms are divided horizontally into twoparts, permitting their adaptation to two slightly different pro-portions of the wall used in different localities; and permit-ting also an easier taking down and setting up of the sections, {77) hiK/ilir cniKi I iiul Contracting fur March .4, 19W. the latter 16 ft. by about 20 ft. in size, being rather bulkywithout division into pieces. Derrick No. 2, besides handling the forms, does such back-filling behind the finished wall footing as is necessary to se-cure the earth under the narrow gage concreting track, thesteep slope of the excavation, under thaw, sloughing off some-what in places. Most of the back fill will be done morecheaply by a big dragline in the course of the regular riverchannel improvement. Derrick No. 2 also hoists and dumpsconcrete cars, which in case of the upper forms cannot chutethe material directly into place. The sand and gravel for the concrete are obtained from the. MIAMI RIVER • Fig. 2—Construction Plant Layout. bed of the river and are washed, screened and sorted in aplant situated on the river bank. From this plant the pre-pared materials are hauled in 5-tou motor-dump truck to themixing plant at the work, where they are dumped into hop-pers at the top of an incline, leading to bins for the sand andthe aggregates. The sand runs from % in- down; the finegravel from 14 to 1% in.; and the coarse gravel from 1% 3 in. The bins hold about cu. yd. each. From the bins the materials are drawn through chutes intothe bottom dump cars running on a track built at 15° incline,which leads to p platform over the mixer. Between thechutes and the car. measuring boxes are interposed, whichpermit the proper proportioning of the material. These pro-portions are 4 sacks cement to cu. ft. of sand, to 10 cu. of the fine and the gravel. This gives a 1:2:4:5concrete. The car is hauled up the incline by
Size: 1849px × 1351px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicago, bookyear19
