carries four lanes for motor vehicles and two pedestrian walkways. The bridges are structurally a combination of a girder design and a cable-stayed design. The bridges use a box-girder cross section where the box girder is trussed in the elevation (or side) view). The box girder is tall and . The pedestrian walkways cantilever from the top of the box girder, making the top deck wide. Stay cables are in a single plane. Cables connect in the center of the top deck of the box girder. The towers are reminiscent of an ancient Chinese weaving shuttle and can also be described as needle shaped. The deck passes through the tower at its widest part, what might be considered the eye of the needle. The towers are constructed of cast-in-place concrete. The towers are 18 meters wide at the bottom, spread to a maximum width of 35 meters at the level of the upper deck, and narrow to 7 meters at the top. The water level of the rivers varies 39 meters between wet and dry seasons, controlled mainly by discharges from the Three Gorges Dam which is 570 kilometers away. At low water levels, the deck is approximately 60 meters above the water and the tower top is 100 meters above the deck. Dongshuimen Bridge The Dongshuimen Bridge crosses the Yangtze River with a cable-stayed main span that is long, connecting the Yuzhong and Nan'an Districts. The bridge is long, with asymmetric cable-stayed back span lengths of on the Yuzhong end and on the Nan'an end. There are nine pairs of cables connecting each tower to the deck. At the time of its opening, the length of the main span ranks the Donshuimen Bridge among the longest one hundred in the world. The substructure was built by China Railway Construction Bridge Engineering Bureau Group Co. Ltd. The superstructure was built by China Railway Eighth Civil Engineering Group Corporation (Beijing). The bridge opened to both road and rail traffic in April 2014. Qiansimen Bridge The Qiansimen Bridge (sometimes Qianximen Bridge) crosses the Jialing River with a cable-stayed main span that is , connecting the Jiangbei and the Yuzhong Districts. The placement of the single tower means that the cable-stayed back span of provides a secondary channel for shipping. The bridge has a total length of as it includes girder spans of and . The bridge has nine pairs of cables. The