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Tham khảo tài liệu 'structural steel designers handbook part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 12.68 SECTION TWELVE TABLE 12.39 Composite Section for G1 for Maximum Moment Material A d Ad Ad2 Io I ứ For dead loads n 30 Steel section 93.5 -534 74 550 Concrete 84 X 7 30 19.6 37.0 725 26 830 80 26 900 113.1 191 101 450 ds0 191 113.1 1.669 in -1.69 X 191 -320 Ina 101 130 Distance from neutral axis of composite section to Top of steel 31.50 - 1.69 29.81 in Bottom of steel 32.00 1.69 33.69 in Top of concrete 29.81 2 7 38.81 in Section moduli Top of steel Bottom of steel Top of concrete Sst 101 130 29.81 Ssb 101 130 33.69 Sc 101 130 38.81 3 400 in3 3 010 in3 2 615 in3 b For live loads n 10 Materials A d Ad Ad2 Io I Steel section 93.5 -534 74 500 Concrete 84 X 7 1 0 58.8 37.0 2 175 80 510 240 80 750 152.3 1 641 155 300 d10 1 641 152.3 10.76 -10.76 X 1 641 -17 700 Ina 137 600 Distance from neutral axis of composite section to Top of steel 31.50 - 10.76 20.74 in Bottom of steel 32.00 10.76 42.76 in Top of concrete 20.74 2 7 29.74 in Section moduli Top of steel Bottom of steel Top of concrete Sst 137 600 20.74 Ssb 137 600 42.76 Sc 137 600 29.74 6 630 in3 3 210 in3 4 630 in3 BEAM AND GIRDER BRIDGES 12.69 TABLE 12.40 Maximum Lateral Bending Moments ft-kips DL Ml -0.1 X 12 X 1 767 15 2 300 X 61.75 -26 SDL Ml -0.1 X 12 X 838 15 2 3000 X 64.38 -12 LL I Ml -0.1 X 12 X 1 297 15 2 300 X 66.03 -18 mil. -56 Total Therefore the composite section for G1 is satisfactory. Use for G1 in the region of maximum moment the section shown in Fig. 12.27. The procedure is the same for design of other sections and for the other stringers. For design of other elements see Arts. 12.2 and 12.4. Fatigue design is similar to that for straight girders. 12.8 DECK PLATE-GIRDER BRIDGES WITH FLOORBEAMS For long spans use of fewer but deeper girders to span the long distance between supports becomes more efficient. With appropriately spaced stringers between the main girders of highway bridges depth of concrete roadway slab can be kept to the minimum permitted thus avoiding increase in dead load from .
