Bridge in Mist
Pulixiang, Yunnan, China/Puli Bridge surprised and shocked the bridge community when it become the world’s second highest suspension bridge in 2015 with a deck 485 meters over the surface of Puli creek. The inaccessible terrain on the east and west slopes along Puli Creek made it difficult for the bridge engineers to create an exact topographic model of the bottom of the Puli Creek canyon and once rock stability was ensured near the towers there was little need for them to find out how far down the elevation of the creek was. In 2014 I was able to measure the height from the construction catwalk of the main cables confirming a vertical drop of 500 meters. With the center of the span at around 1,828 meters, the bottom of the nearby Gexiang River Gorge is approximately 600 meters lower at around 1,228 meters elevation.The main span of 628 meters will be unique among China’s highest suspension bridges in that it will have a thin, steel box deck girder instead of the usual truss. The Longjiang Bridge – also under construction in Yunnan Province – will also utilize an aerodynamic box deck girder. The entire main span of Puli is composed of 52 segments of 12 meters in length. Puli Bridge will remain the highest bridge in Yunnan Province until the Jinshajiang Bridge Taku surpasses it in 2020. The first pilot line for the main cable was shot across the canyon tethered to the back end of a rocket in early 2013. This is only the 3rd time this has ever been done after the Siduhe and Lishuihe Bridges. The span is part of the new G56 expressway that will connect the city of Xuanwei, Yunnan with Liupanshui, Guizhou as well as the G76 expressway in Bijie, Guizhou. This entire Yunnan/Guizhou border region is becoming a new hot spot of high Chinese bridges. In addition to Puli they include the nearby Beipanjiang Bridge Duge which will become the World’s Highest Bridge in 2016 as well as the Beipanjiang Railway, Beipanjiang Shuipan and Dimuhe Bridges.
普立特大桥是桥梁界意外的震撼，当它2015年建成时，将不仅是世界最高的悬索桥，而且是各种桥梁中桥面最高的。大约超出普立峡谷500米的高度。 普立峡谷两侧陡峭的悬崖使谷底无法接近。以至桥梁工程师难以做出此桥精确三维模型。当然只要发现两端桥塔的地面牢固，桥底究竟多深对建设工程来说并不十分重要。在2014年我决定从这座桥的建设猫道上亲自测量其高度，发现此桥竟深达500米。桥面中部海拔在1828米左右，邻近的革香河河底海拔只有1228米，约比桥面低600米。普立沟在注入革香河的最后几百米中下降了大约100米。 这座主跨628米的大桥在中国很独特，因为它使用钢箱梁而非钢桁梁。 云南省的另一座在建大型悬索桥——龙江特大桥，将也使用钢箱梁。全桥52节段，每节12米。普立特大桥在约2020年塔库金沙江大桥建成前将始终保持云南最高桥的地位。 第一根先导索于2013年初用火箭发射越过峡谷。这是火箭发射牵引法第三次应用，前两次是四渡河和澧水大桥。 这座桥是G56杭瑞高速公路一部分，这段高速公路从云南宣威通到贵州六盘水，直到毕节联结G76厦蓉高速公路。这一云南/贵州边界地区将成为中国山地高桥的新热点。除普立特大桥外，附近还有都格北盘江大桥（2016年建成后会取代普立成为世界最高桥），北盘江铁路桥，水盘高速北盘江大桥，抵母河大桥等。www.highestbridges.com