COMPOSITE BRIDGE SPAN STRUCTURE AND METHOD OF ITS PRODUCTION Russian patent published in 2005 - IPC

FIELD: bridge building, particularly preloaded continuous composite bridge structured of steel and reinforced concrete to connect cast-in-place reinforced concrete panel with metal assembly.

SUBSTANCE: span structure includes reinforced concrete panel connected to steel beam by rests embedded in panel body and welded to steel sheet secured to beam. Steel sheet is connected to steel beam belt by high-strength bolts inserted in belt orifices. Orifices have circular shapes in over-pier zone, remainder orifice parts are oval and located so that major oval axis extends along longitudinal span structure axis. Lengths of oval orifices are variable and depend on degree of elastic deformation due to applying squeezing force to reinforced concrete. The greatest length is in preloaded reinforcement anchoring area and length is reduced towards over-pier zone. Ratio between maximal length a of oval orifice to length b of orifice located in over-pier zone and having minimal length a/b = 1.0 - 4.0. High-strength bolts inserted in oval orifices are closed with protective caps to protect bolts against concrete action. Cap contour mates to oval orifice outline. Method of span structure production involves concreting reinforced concrete panel and applying tensioning force to high-strength reinforcement on steel sheet having rests welded thereto and connected to steel beam, wherein steel sheet is connected to steel beam by high-strength bolts inserted in oval orifices and bolts are slackened before reinforcement tensioning. After that reinforced concrete panel resiliently reduces in length on beam belt under the influence of squeezing force and bolts slide along longitudinal orifice. Then protective caps are taken off and blots are tightened with desired force.

EFFECT: prevention of concrete stretching in over-pier area; increased strength and crack-resistance of reinforced concrete panel; increased service life of span structure.

2 cl, 4 dwg