| 摘要 |
PROBLEM TO BE SOLVED: To provide a grating crib construction method which dispenses with mortar coating work in a round even if the gradient of a slope is large, reduces the number of steps in constructing grating crib works, suppresses the consumption of cement, and ensures the unity/uniformity of transverse girders. SOLUTION: According to the method, a sectional area of the transverse girder 6 is the same as that of a longitudinal girder 5, and a cross section of the transverse girder 6 is bilaterally asymmetric such that one of lateral sides connecting between upper and lower sides 6a, 6b which are in parallel with each other, is inclined and the other one is perpendicular to the upper and lower sides. By arranging the inclined lateral side 6c so as to form a ridge surface and the perpendicular side 6d of a valley surface, respectively, a dent 7 with an inverted gradient formed on the back face of the transverse girder 6 can be eliminated or minimized. As a result, the formation of rainwater puddles is avoided, and the root rod of vegetation and the erosion of the surface of the natural ground are suppressed, which leads to the expectation of avoidance of secondary works such as the construction of a draining concrete structure. COPYRIGHT: (C)2004,JPO
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