The Application Of Grillage Method In The Calculation Of Skew Bridge Detection

Since the 1980s, a peak period has appeared in the skew bridge construction. Urban construction of the highway departments have fully changed the view that the road line type must submit to the bridge's tendency. For this, the skew bridge's proportion of the bridge is increasing, especially high-grade highway bridges. Due to frequent loads, the worse overloading, the invasion of nature, nature disasters, the impact of traffic accidents and man-made disturbances etc., a large number of skew bridges have been damaged or partially damaged after they have been used. Hence many skew bridges need a loading test to determine their existing bearing capacity. Currently detection and checking theoretic of straight bridge are studied far more, but the study of skew bridge is less.The paper is based on Hongwei Bridge which crosses the Cheng-Yu highway. By the test-sited data from the loading test of the bridge,using the method from the handbook"Design Handbook of Highway Bridge"and the grillage method to analyze bridge, the author has analyzed theoretically the bridge.①With the test-sited data of Hongwei Bridge loading test, the paper has analyzed the difference between the loading test efficiency and loading test coefficient from the grillage simulation and the computed results from the computing method of"handbook", and comes out the conclusion that the grillage simulation is much safer and more precocious for the checkup of skew bridge loading test.②Compared the computing method of"handbook"and the grillage simulation on the computed results, the author has applied the shear-flexibility grillage simulation which is widely used in the box beam superstructures to the shear hinged deck, and figured out the grillage simulation of shear hinged deck.③Make the analysis and comparison the internal forces of the skew bridge by the method of"Handbook"and the grillage simulation. The analysis are focused on the moment and the shear at the mid-span, one fourth-span, three fourth-span and at the supported sections. The conclusion that the method of"Handbook"is much safer has been arrived.④Make the analysis and comparison the internal forces of the skew bridge by the skew-crossing grillage simulation and orthogonal grillage simulation. The analysis are focused on the moment and the shear at the mid-span, one fourth-span, three fourth-span and at the supported sections. The conclusion that the skew-crossing grillage simulation is much safer has been arrived.⑤Using the grillage method to analyze the methods that a skew bridge is appraised as a straight bridge or calculated as a straight bridge. Then numerical analysis the loading test efficiency and loading test coefficient which come from the the grillage method. At last the modified formulation is obtained for loading test efficiency and loading test coefficient from the comparison of the results when a skew bridge is appraised as a straight bridge or calculated as a straight bridge. The span of the bridge is 19.3m and the width of the bridge is 8m.