Revision of the Niagara Railway Arch Bridge . — 42 — 42 1950 REVISION OF NIAGARA RAILWAY ARCH BRIDGE trains as indicated on Fig. 8, the details of each train being recordedin a record of Test Loads. The date of the readings is given inthe second column, and the exact hour in the third column. Thisenabled exact co-ordination of temperatures taken from sheets similarto Fig. 12. The first of the three columns headed Temperaturegives the reading of the thermometers in the standard bars. Twostandard bars were needed, one for each observation crew, and thesewere standardized one with the other, so t
Revision of the Niagara Railway Arch Bridge . — 42 — 42 1950 REVISION OF NIAGARA RAILWAY ARCH BRIDGE trains as indicated on Fig. 8, the details of each train being recordedin a record of Test Loads. The date of the readings is given inthe second column, and the exact hour in the third column. Thisenabled exact co-ordination of temperatures taken from sheets similarto Fig. 12. The first of the three columns headed Temperaturegives the reading of the thermometers in the standard bars. Twostandard bars were needed, one for each observation crew, and thesewere standardized one with the other, so that readings could be com-pared, and with duplicate bars kept in the fireproof vault, so that incase of loss they could be replaced. The second temperature columnheaded Arch contains the temperature as reduced from a largenumber of thermometers at various places on the structure, and rep-resents the values used in making corrections for temperature third temperature column gives that of the member read, and was Time p ^ Fig. from thermometers fastened directly to the member or toone adjacent. The results in the numbered columns are the strain-gauge dialunits for the corresponding numbered point on the cross-section of themember in Table 4. The figures given are the averages of all thereadings for that point, which were always two or more independentreadings. Two temperature corrections were made for some of them,one, where there was a difference between the temperature of themember and the standard bar, and the other due to the temperaturestresses in the arch. The large figures are the corrected ones, and thesmall ones the originals, thus making it possible to check the tempera-ture corrections at any time. The tables of live load stress measurements, Table 4 being typical,give the deformations in dial units which are direct deductions from . REVISION OF NIAGARA RAILWAY ARCH BRIDGE 1951 the dead and live load averages, and the stresses in po
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Keywords: ., bookcentury1900, bookdecade1920, bookidrevisionofni, bookyear1920
