Highway Hollow Slab Widening And Transformation Technology Research And Application

With the development of the economy and society, the number of the cars and the traffic volume grows rapidly. The traffic capacity of highways becomes the bottleneck restriction of development of the economic and society now. A large of the low-level highway need to be broadened and expanded, in which the broadening and extension of bridges are an important part. The most of the small and the middle span bridges are assembly hollow slab bridges. So it is valuable to study the application technology of broadening and extension of this kind of bridges. According to the example of the broadening and extension of Duhe Bridge, and based on the current results, applied technique of the broadening and extension of bridges are studied and analyzed. The main contents are as follows:(1) Static load experiment is carried out to test the structure of the Duhe Bridge, and the usability of the boarded part of hollow slab is calculated and studied. The test shows that there is no large stress and strain in the middle section of the hollow slab under the test loading, and the bending bearing capacity of the old bridge meets the demand.(2) According to the comparative analysis of hollow slab transverse distribution coefficient of old and new bridge, the bearing capacity of the whole bridge is improved with the bearing capacity of the old single hollow slab bridge not changed after the hollow slab bridges are widened.(3) According to the stresses and distortions in the connections of the old and new structures, ANSYS is used to simulate the structure. Under the condition of variety kinds of the traffic loading, the concrete in the connection of the old and new structure will not split because of the tension stress, and the deck will not split too. This way is provided to design and calculate the bridge in the future.(4) Finite element method is used to calculate the displacements and stresses of the piles of the broadening bridge, according to the results, large displacement of the new piles foundation will not happen in the new pileseven under the most adverse load. It provides warrant for designing the bridge piles.(5) A new connection design method of new and old of hollow slab is provided, in which horizontal steels are set in the bottom of the sidewall of the old hollow slab, embedded steels of the new hollow slab are intercrossed and dip into bridge deck pavement, steels are set on the top surface of both old and new hollow slabs and lap horizontally, steel fiber reinforced concrete is poured in the slot between the old and new slab and the connection part of bridge deck.(6) In the condition of pre-pressure on the new broading bridges, the construction technology of concreting in the connection of the new and old structure is provided in the new broadening bridges.