台湾中山高速公路五股—杨梅段拓宽工程设计与施工

台湾中山高速公路于1978年完工通车后，成为台湾经济快速发展之重要交通动脉。近十余年来，由于都市人口的快速集中，来往台北都会区与邻近的桃园、新竹地区的交通量大增，使得中山高速公路北部路段饱和拥塞。鉴于此，对中山高速公路五股-杨梅段进行拓宽，以疏解台湾政经中心（台北）与科技中心（新竹）之间的交通，串连沿线科技产业聚落，畅通往返桃园国际机场的车流。五股-杨梅段拓宽工程系利用现有高速公路两侧兴建高架桥，途中行经林口路段属地质敏感坡地，仅能在高速公路单侧兴建高架桥，故需两度跨越高速公路，并在高速公路单侧兴建双层高架桥。由于跨越桥不得在现有高速公路上设置桥墩，故跨越桥主跨径达216cm，为目前台湾最大跨径之钢梁桥。而介于两座跨越桥间之单侧双层桥，采F形单柱式共构桥墩，造型特殊且工法创新。本工程系在狭窄的环境条件下施工，又必须维持现有高速公路的畅通，故大跨径跨越桥采用台湾首见的旋转工法，双层共构桥采用钢梁逐跨架设工法，此均为台湾难得一见的创新施工法。对五股-杨梅段拓宽工程作简要介绍外，拟对林口跨越桥及双层共构桥的设计与施工做出说明，供工程界同行参考。

Design and Construction of Sun Yat-Sen Freeway Widening Works from Wugu to Yangmei

After its completion and open to traffic in 1978, the Sun Yat-Sen Freeway has become a major transportation artery to service the fast economical development of Taiwan. Over the last decade, the rapid concentration of urban population and the dramatic growth of traffic between Taipei metropolitan anc its neighboring areas, namely Taoyuan and Hsinchu, have caused considerable congestions. To solve this problem, the government took to widen the Wugu-Yangmei section of Sun Yat-Sen Freeway as a means to ease the traffic condition between the eco-political center of Taiwan （Taipei） and the technology center of the island （Hsinchu）, to connect the technology industry clusters along the line and to maintain a smooth traffic flow to and from the Taoyuan International Airport. The widening project from Wugu to Yangmei was implemented by constructing elevated bridges along two sides of the freeway; however, the geologically sensitive slopes in the middle of the alignment at Linkou require the construction of bridges to be on one side of the freeway within this area. As a result, one direction of the traffic has to cross the freeway and join the traffic on the other side in the form of double deck bridge then divert to cross the freeway again to resume the original two-side configuration at the end of the geologically sensitive area. Because no piers are allowed to be constructed on the freeway below, the structure is designed to cross bridges withdouble deck bridge in this section is supported by F-shaped eccentric single pier which is unique in design anti innovative in construction method. This widening project was constructed with limited space and required not to cause interruption to the traffic of the freeway. For this purpose, the long-span crossing bridge was built with the adoption of rotation method, and the double deck bridge was realized with span-by-span steel girder erection method. Both these two methods are first time to be found in Taiwan. Beside brief introduction to the widening works from Wugu t