Aizhai Bridge

Aizhai Bridge

Ai'zhai bridge is a high-speed passage in Xiangxi Tujia and Miao Autonomous Prefecture of Hunan Province, China. It is located on the Dehang Grand Canyon. It is a part of the northwest highway of Jishou City and a key control project of Baotou Maoming expressway.

The construction of Aizhai bridge started on October 28, 2007;

The closure project of the main bridge was completed on August 20, 2011, and the whole bridge was connected;

It was put into operation on March 31, 2012, and the opening ceremony was held.

Aizhai bridge starts from Potou tunnel in the west, crosses Dehang Grand Canyon and ends at Aizhai No.3 tunnel in the East. The total length of the line is 1779 meters, and the total length of the main bridge is 1414 meters. The bridge deck is a two-way four lane Expressway with a design speed of 80 km / h.

Construction process

In 2004, Aizhai bridge was surveyed and designed.

On June 25, 2006, Hunan Provincial Department of transportation organized the pre evaluation of the technical design of Aizhai bridge.

On October 24, 2007, Hunan Provincial Committee of the Communist Party of China held an expert seminar on the technical scheme of Aizhai bridge in Changsha;

On October 28, construction of Aizhai bridge started.

On November 8, 2008, the technical seminar on the superstructure installation scheme of Aizhai bridge was held in Changsha. Experts discussed the superstructure installation scheme.

On March 1, 2009, Aizhai bridge carried out the construction of cable tower at Chadong bank; on December 9, Aizhai bridge completed the full-scale model test of main truss erection segment with track cable moving beam method.

On March 10, 2010, Aizhai bridge completed the construction of gravity anchor; on March 28, Aizhai bridge completed the work of pilot cable traction;

On July 18, the main cable of Aizhai bridge was erected;

On October 20, Aizhai bridge completed the main cable erection.

On February 23, 2011, the lifting saddle of Aizhai bridge was completed; on April 10, the erection of steel truss girder of Aizhai bridge was carried out;

On August 20, Aizhai bridge completed the main bridge closure project, and the whole bridge was connected;

On September 17, Aizhai bridge completed the deck installation work; on October 29, Aizhai bridge completed the main bridge asphalt laying work; on November 10, Aizhai bridge completed the sling coating work; on December 29, Aizhai bridge completed the bridge load test work.

On March 18, 2012, Aizhai bridge carried out lighting test;

On March 31, Aizhai bridge was opened to traffic and a opening ceremony was held.

On May 1, 2013, Aizhai bridge was put into trial operation for sightseeing elevator;

On October 1, lightning protection test of sightseeing elevator was carried out on Aizhai bridge.

Bridge location

Aizhai bridge is located in the northwest of Xiangxi Tujia and Miao Autonomous Prefecture, Hunan Province, China. It is located on the Dehang Grand Canyon, about 20 kilometers away from Jishou City. It starts from Potou tunnel in the west, crosses Dehang Grand Canyon and Aizhai bridge scenic area in the East, and ends at Aizhai No.3 tunnel in the East; Baotou Maoming Expressway < I (National Expressway G65) < / I.

Architectural design

building structure

Overall layout

Aizhai bridge is composed of main bridge, two pylons, cables, anchorages, suspenders and connecting tunnels; the main bridge section is arranged from northwest to Southeast.

 

Design concept

Aizhai bridge adopts a unique main structure art form. The cable tower and stiffening steel truss beam built on both sides of the mountain top are directly connected with the tunnel on the cliff. The tunnel anchor and gravity anchor cleverly designed according to the geological and topographical conditions are very harmonious with the beautiful natural landscape around. At the same time, the top of the bridge tower adopts the ox head pattern, which is the worship and mascot of the local people Symbolizing the people's modesty and kindness, strength and progress, the horn shaped bridge tower facing each other on the two mountains is integrated with the arc-shaped suspension cable, thus forming a local landmark building.

 

Design features

Design parameters

Aizhai bridge has a total length of 1779 meters and a main bridge of 1414 meters, with a span of (113 + 1228 + 73) meters, a width of 24.5 meters and a deck height of 355 meters. The main girder is 1000.5m wide and 7.5m high, the steel truss stiffening girder is 27m wide, the truss height is 7.5m, the truss width is 27m, the length between small sections is 7.25m, and the length between large sections is 14.5m. Jishou bank tower is 123 meters high, Chadong bank tower is 66 meters high, and the distance between its bottom and the top of the tunnel is about 44 meters. The transverse bridge spacing of the main cable is 27 meters, the rise span ratio is 1 / 9.6, the span arrangement is (242 + 1176 + 116), the length of a single main cable is 1637.807 meters, the single strand is composed of 91 wires with a diameter of 5.1 mm, and the number of strands is 234. The length of Jishou bank anchorage is 25m, the horizontal angle is 42.5 degrees, the horizontal angle of Chadong bank anchorage is 38degrees, the length of anchorage is 45m.

 

Equipment and facilities

lighting

As of March 2013, Aizhai bridge has nearly 2000 colored lights, including more than 200 for main cable, 1668 for steel beam and 80 for cable tower, with a total investment of more than 6 million yuan.

 

Sightseeing facilities

As of August 2019, Aizhai bridge is equipped with a sightseeing channel and platform, providing a perfect place for tourists to not only enjoy the majestic appearance of Lingyue bridge, but also overlook the wonders of Aizhai highway.

 

Operation

Fare system

On March 31, 2012, Aizhai bridge was put into operation. The bridge is an integral part of Jishou Chadong Expressway (National Expressway G65), and charges are charged according to its requirements.

 

Construction achievements

Technical problems

Construction problems

The main problems of Aizhai bridge are as follows:

1. The terrain is dangerous, the height difference between the bridge deck and the bottom of the canyon is 355 meters, and the location of the cable towers on both sides is only 70 to 100 meters away from the edge of the cliff;

2. Because of the complex geology, there are some unfavorable geological phenomena such as rock pile, karst, fissure and dangerous rock mass at the bridge site;

3. The weather is changeable, the canyon is foggy, and the instantaneous maximum wind speed is extremely high, which seriously affects the construction survey and main cable erection;

4. The main cable and steel truss girder are erected 355 to 400 meters above the valley bottom, and the total amount of single hoisting is nearly 20000 tons;

5. Transportation is difficult, civil engineering transportation volume is large, only steel, cement, sand and other materials and construction.

 

technological innovation

The main innovative technologies of Aizhai bridge are as follows:

1. A new structure of tower girder separated suspension bridge is proposed for the first time, which realizes the perfect integration of structure and environment;

2. The method of adding vertical rock anchor sling in the non sling area of the main cable solves the structural problem caused by the long non sling area;

3. High performance composite CFRP and ultra-high performance concrete RPC are used as the bonding medium at both ends of the bolt to form a new rock anchor system with high efficiency and durability;

4. Through the three-dimensional numerical simulation analysis, the stability of the structure system in the mountain during the construction and operation is analyzed, and a new technology for the stability of the structure and mountain system is formed.

 

Scientific research achievements

Honorary recognition

Cultural characteristics

International low altitude skydiving Festival

On September 14, 2012, "the first international low altitude skydiving festival of Aizhai bridge in Xiangxi in 2012" was held at Aizhai bridge, which was attended by 40 athletes from 13 countries.

 

sightseeing lift

As of March 2013, Aizhai bridge has been equipped with a sightseeing elevator, which is built with a steel structure derrick. Four R-type sightseeing elevators are set up to operate in parallel and separate parts. The curved glass type is adopted, which has the characteristics of wide field of vision, and provides convenient for tourists to enjoy the scenery of Aizhai bridge.

 

The terrain of China

In 2013, in the approved textbook geography for Grade 8 of Hunan Education Press, the first section of China's terrain (page 28) in Chapter 2 natural environment of China included pictures of Aizhai bridge, with the introduction of the geographical location and basic information of the bridge, so that students can understand the feat of Aizhai Bridge.

 

Jishou Drum Culture Festival 2016

October 1, 2016

Chinese PinYin : Ai Zhai Da Qiao