【正文】 ndation elements. The bridge system is physically described with these elements, and the acpanyingparameters are entered for each type. Generally, CWR track is used. If, however, the expanding bridge lengths bee too great, ‘pensation’ welds or pensation constructions, in which the track has overlapping ‘tongues’ and so is free to undergo deformation, must be used due to the rail forces reachingtoo high a level as a result of braking forces and temperature effects. At the location of one of the intermediate supports, bridge section VI is suspended from apylon construction where the bridge is also fixed horizontally. Due to the high stiffness of thisconstruction, this determines the free expansion length to the abutment. This length is greaterthan 60 m, the maximum free expansion length to an abutment for ballasted track. For thisreason two pensation welds are used at the abutment. Prestressing The Ushaped bridges are constructed from prestressed concrete. The following can be distinguished: longitudinal prestressing in the Ushaped beams, through which the beam’s ownweight, the permanent load and the working load are diverted。 508 mm with a wall thickness of 16mm. The piles are filled with concrete and fitted with reinforcement. The use of steel pipepiles for the abutments was made necessary by the settlement of the connecting raised trackbeds as a result of the pressible subsoil which might subject the piles to bending. Prestressedconcrete driven piles turned out not to be able to absorb these bending moments. The columns under the Ushaped bridge ends are coupled crossways with a beam constructiondue to the horizontal forces that are diverted there via the guiding constructions. In order to be able to quantify the interaction of the track with the substructure, a tracklongitudinal forces program has been developed in which the whole system is divided intodiscrete ponents by means of the following elements: rail elements。 fatigue criteria。 第二段到第五段都為 長。在這種情況下，經(jīng)常使用“涼亭式”建筑，沿線路布置一長排支柱，用它來支撐與線路正交的混凝土橋面板。預制混凝土長度在 13m到 18m之間變化，寬在 。 對 167m長的交 叉梁段六，可選擇直徑 152mm，極限張拉應力 1860Mpa 的27 束縱向預應力鋼絞線。纜索經(jīng)由鋼管道，穿過橋體和塔架。 縱橫向固定 U型橋體的水平梁承擔縱向力（制動力、起動力）和橫向力。然而，假如橋面線膨脹變的太大，在軌道相接處，補償焊縫這種能自由變形的補償建筑就必須得到使用。索纜經(jīng)由管道通過橋體到達橋背與斜向塔柱相交處。軌底位于兩寬 邊界凹槽內(nèi)。 ： 這座高架橋必須跨越如下幾部分： 兩條既有線； 兩條新建線； 城市污水排放系統(tǒng)； 一條地下通道。 400 mm through the m wide Ushaped beams. This provided much concernwith respect to acmodating the eight prestressing cables, the shear forces that arise andthe soft steel reinforcement connected with this as a result of the bending of the tensiontrajectories through this deformation. The criterion for the maximum permissible stress (0,45f39。 a polder drainage pool。 the most heavily loaded cable absorbs a maximum reactive force