产生的背景在我国公路建设事业大发展的条件下 ,高速公路建设发展迅速 ,由于高速公路平纵线形好 ,又是全封闭 ,桥梁设置大多要服从路线 ,因此弯桥、斜桥就必然多 ,立交桥、互通跨线桥等旱桥也大量出现。为了适应这种新情况 ,桥梁结构形式也在不断发展。作为从国外引进的一种新? Produced by the background of the great development of road construction in China under the conditions of the rapid development of highway construction, as the highway flat vertical alignment is closed, most of the bridge set to obey the route, so the curved bridge, the inclined bridge is bound to more, Overpass, interoperability flyover and other dry bridges are also a large number. In order to adapt to this new situation, the bridge structure is also evolving. As a new introduction from abroad?