"Building the Capital of Bridges" to Build the Hongqiao - Documentary of the Construction of Wuhan Gutian Bridge
Release Time： 2022-08-18 11:22
The two "Arc de Triomphe"-style main towers are like a pair of lovers watching across the river, and the "Magpie Bridge" connecting them, with its European-style shape and pale Prussian blue appearance, has become the "City of Bridge Construction" against the blue sky and white clouds. ——The new business card of Wuhan City, Hubei Province. This is the investment and construction of China Construction Third Bureau, known as the most beautiful bridge on the Han River - Wuhan Gutian Bridge.
Wuhan Gutian Bridge main line viaduct has a total length of 3050 meters, setting 4 construction records: the anchorage for "pulling" the main cable is not built on the ground, but on its own approach bridge, which is the first self-anchored suspension bridge in Wuhan; the bridge deck 41 meters wide, with 8 two-way lanes and non-motorized vehicle lanes, it is the widest bridge that has been built on the Han River; the two 80-meter-high light Prussian blue steel main towers are elegant and beautiful in shape, especially when the lights are on at night, the whole bridge Showing a dreamy blue color, it is the most beautiful bridge on the Han River; in order not to affect the navigation of the river, the steel box girder of the main bridge deck with a total weight of about 8,000 tons was pushed across the river at one time during construction, and the 90-meter push span was created. It has the largest jacking span of similar bridges in China.
"Grab" the pile foundation
The main bridge of Wuhan Gutian Bridge has 36 pile foundations, ranging from 96 meters to 100 meters in length and 2.5 meters in diameter. The sand layer in the pile foundation construction area is 35-60 meters thick, the bedrock lithology changes greatly, the hardness is uneven, and the geological conditions are complex.
The first pile of the project tried to use the gas lift reverse circulation rotary drilling machine to form a hole, which took more than 20 days and seriously exceeded the construction period. What should I do? The Bridge Project Department (hereinafter referred to as the Gutian Bridge Project Department) decided to try to use the combined construction process of the rotary drilling rig and the rotary drilling rig. Second, the rotary drilling rig is used to "relay" the rock drilling, thereby shortening the pile formation time to half of the original, and greatly improving the construction efficiency.
In the construction of bridges on the Han River, it is necessary to find out the nature of the river water: May to October is the violent flood season, November to April is the dry season, and it is also the best time for the construction of the substructure of the project. In order to seize the golden period of construction, the Gutian Bridge Project Department has broken down the progress plan into months, weeks, days and hours. In May 2012, in the management log of the project site, it was clearly recorded that the water level of the Han River rose rapidly for several days. The water level is gradually approaching the warning line, but the bottom cap of the No. 4 downstream cap of the main tower on the Hanyang side has not yet been sealed, and the concrete pouring of the two upstream and downstream caps of No. 3 has not yet been completed. If the water of the Han River floods the bearing platform during construction, the cost loss will be huge and the subsequent construction will fall into a situation of passive beating. Faced with the difficult situation, the Gutianqiao project department forged its will and divided the construction workers in an orderly manner: one was responsible for stepping up the construction of the cap, one was responsible for building sandbags and dams according to the water level of the Han River, and one was responsible for cleaning up the river water that had penetrated into the construction site with a pump... In the end, all the capping construction was completed before the river overflowed the dam.
The 90-meter push-up span is the longest in China
In the construction of Gutian Bridge in Wuhan, in order not to affect the normal navigation and flood control work of the Han River, the Gutian Bridge Project Department abandoned the simplest and easiest construction technology of hoisting the bridge on the river surface, and adopted the complete jacking method, that is, the bridge was assembled by the Hankou bank. Afterwards, 18 walking jacks were used to apply force horizontally to push the beam with a total weight of about 8,000 tons from Hankou to Hanyang. During the whole construction, the top of each section of the bridge is pushed to the opposite bank, and the construction process hardly needs to occupy the river surface.
In order to realize this idea, the technicians of Gutianqiao Project Department have reconsidered every small link and formulated the optimal response plan. For example, anti-collision piers are set up to protect the safety of temporary piers in the water, the front end of the guide beam of the main tower is designed in a duckbill shape to facilitate the push of the steel beam, and back braces are designed on the main beam and guide beam to reduce the deflection of the front end of the main beam. The closing sections are arranged on both sides of the main girder to ensure the accurate pushing position of the main girder.
On March 12, 2013, the engineering steel box girder jacking construction was officially launched. It takes 1 hour for the steel beam to push 1 meter, and about 20 hours for one round of pushing. The monitoring personnel of the Gutianqiao Project Department stayed at the scene for 24 hours. They held the walkie-talkie, kept an eye on the progress of the push, and corrected the deviation in time.
Just 1 meter a day, the beam of Gutian Bridge slowly "walked" for 277 days before crossing the Han River. On October 28, 2013, the steel box girder of the main bridge successfully completed the 10th round of jacking construction, and the steel girder of the main bridge arrived at the designated position in Hanyang. So far, the most difficult jacking operation of the bridge construction has been completed, and the jacking span of 90 meters has hit a record high. Domestic first. After appraisal, the project "Key Technology of Flexible Steel Beam Large Span Jacking" has reached the international advanced level as a whole.
Building the first self-anchored suspension bridge in Wuhan
The cable system of Wuhan Gutian Bridge is mainly composed of main cable, cable saddle, cable clamp and sling. Each main cable consists of 37 strands, and each strand is composed of 127 galvanized aluminum high-strength steel wires with a diameter of 5.3 mm. There are a total of 9,398 high-strength steel wires in the two main cables of the whole bridge. Both ends of each main cable are anchored on the concrete beam. In order to ensure the safety of the structure, the concrete anchoring end beam is 6.6 meters high and 45 meters wide, which is extremely difficult to construct. Bridge loads are transferred to the two main cables through 244 suspension cables and 122 cable clamps throughout the bridge. Due to the special structural form of the self-anchored suspension bridge, the vertical load on the main cable is transmitted from the main tower to the foundation, and the longitudinal horizontal force of the bridge is borne by the main beam itself.
The construction of the cable system must go through multiple steps such as anchor channel construction, main cable erection, cable tightening, cable clips, sling installation, and system conversion. In order to ensure that the entire construction process meets the requirements of safety, quality, construction period and other aspects, the Gutian Bridge Project Department pays close attention to each construction step. Especially during the cable tightening construction, in order to meet the requirement of 20% of the cable tightening void ratio, the project needs to be constructed at night. The management personnel of the Gutian Bridge Project Department will stick to the construction site in 24-hour shifts to ensure the cable tightening quality and construction safety.
On November 20, 2014, after 333 days, the cable system conversion construction was completed, and the void ratio of more than 500 points in the project all reached the standard at one time. On February 16, 2015, Gutian Bridge was officially opened to traffic, and the first self-anchored suspension bridge in Wuhan stunned Jiangcheng.