Beikou Bridge, ChinaZhejiang ProvinceWenzhou CityDomestic connectionYueqingHuang HuaAndLingkun IslandLocated above the estuary of Oujiang River, it is a double line of Ningbo Taizhou Wenzhou Expressway(National high-speed G15twenty-three）Control project across Oujiang River[3]。
Construction of Beikou Bridge commenced on January 4, 2016[18]；Completion of main bridge closure project on December 30, 2021[12]；Open to traffic on May 27, 2022[1]。
Beikou Bridge starts from Huanghua hub in the north, connects with Lingkun in the middle, and ends at Lecheng in the south;The total length of the bridge is 7913 meters, of which the main bridge across the river is 2090 meters long;The upper layer of the bridge is a two-way six lane expressway with a design speed of 100km/h, and the lower layer is a two-way six lane first-class highway with a design speed of 80km/h[23]。
On February 2, 2012, Beikou Bridge completed the bidding work of pre feasibility study and project feasibility study.
On December 19, 2015, the National Development and Reform Commission of the People's Republic of China approved the Feasibility Report of Wenzhou Oujiang Beikou Bridge and agreed to build the Beikou Bridge[9]；On December 25, the Department of Transport of Zhejiang Province held a preliminary review meeting on the Preliminary Design of Beikou Bridge[11]。
On January 4, 2016, the construction of 40 major projects in Wenzhou started in a centralized manner, and the commencement ceremony was held, including the Beikou Bridge[18]；On January 15, the scientific research planning review meeting of Oujiang Beikou Bridge project was held, which ensured the integrity of the preliminary design of Beikou Bridge in ministerial review[17]；On January 21, Zhejiang Provincial Department of Transport submitted the Request of Zhejiang Provincial Department of Transport for Preliminary Design Approval of Wenzhou Oujiang Beikou Bridge (ZJ [2016] No. 17) to the Ministry of Transport of the People's Republic of China[17]；On March 24, the Ministry of Transport of the People's Republic of China organized a review meeting on the Preliminary Design of Beikou Bridge Project to review the relevant design scheme of Beikou Bridge[11]；On November 30, Beikou Bridge completed contract signing[32]。
On April 24, 2017, the Department of Transport of Zhejiang Province held the first meeting of the technical expert group on the Beikou Bridge in Wenzhou to sort out the technical requirements and management problems related to the bridge[27]；On May 16, Beikou Bridge completed the launching of steel caisson in the middle tower;On May 22, Beikou Bridge completed the installation of the main cable of the steel caisson in the middle tower[29]；On June 21, Beikou Bridge completed the positioning and landing of the steel caisson of the middle tower[30]。
On May 15, 2018, Beikou Bridge completed the first sinking of the south anchor caisson, and on July 6, Beikou Bridge completed the pouring of the bottom sealing concrete of the steel suspension box of the south tower[7]。
On June 10, 2019, Beikou Bridge completed the capping of the north tower[20]；On September 3, Beikou Bridge completed the construction of the north anchorage and the main structure[36]。
On March 16, 2020, Beikou Bridge will complete the erection of the first precast segmental beam[5]；On March 24, Beikou Bridge completed the concrete bottom sealing of the south anchorage caisson;On March 26, Beikou Bridge completed the capping of the south tower[15]；On April 12, Beikou Bridge completed the construction of open caisson at the south anchorage[22]；On September 4, the stiffening beam of Beikou Bridge was hoisted[21]；On November 30, Beikou Bridge completed the capping of the middle tower[14]；On December 29, Beikou Bridge completed cable saddle installation[16]。
On January 3, 2021, Beikou Bridge will carry out pilot cable crossing work[16]；On January 4, Beikou Bridge completed the river crossing of the pilot cable from the south tower to the middle tower[19]；On February 24, Beikou Bridge completed the erection of the first main cable strand[16]；On April 7, Beikou Bridge completed the main cable erection[8]；On October 15, Beikou Bridge completed the lifting of steel truss girder in the cable girder intersection area at the side of the middle tower[13]；On December 30, the main bridge closure project of Beikou Bridge was completed, and the whole bridge was completed[12]。
On April 24, 2022, Beikou Bridge will complete the paving of the upper steel deck median[6]；On May 8, Beikou Bridge completed handover and pre acceptance[28]；On May 9, Beikou Bridge completed the main bridge load test[10]；On May 13, Beikou Bridge passed the handover acceptance review[4]；Completion of handover quality inspection of Beikou Bridge Project[26]；On May 27, Beikou Bridge was opened to traffic and the opening ceremony was held[1]；On June 30, Beikou Bridge carried out light test[2]。
Construction Drawing of Beikou Bridge
Bridge location
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Beikou Bridge is located in Wenzhou, Zhejiang Province, connecting Yueqing City and Longwan District;The bridge is about 2.5 kilometers away from the Oujiang River estuary into Wenzhou Bay in the east and westWenzhou Longwan International AirportAbout 8.5 km;Beikou Bridge starts from Huanghua Hub in Yueqing City in the north, crosses the Oujiang River estuary and connects Lingkun Island and Lingkun Island, and ends at Lecheng Interchange in Longwan District in the south;The bridge route is Ningbo Taizhou Wenzhou Expressway double track(National high-speed G15twenty-three）、Nantang Jinxiang Highway（G228）[24]。
Architectural design
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building structure
Overall layout
Beikou Bridge is composed of main bridge, approach bridge on both sides of the north and south, three towers in the north, middle and south, suspension cables and anchors on both sides;The main body of the bridge is arranged from northeast to southwest[24]。
Design features
Structural characteristics
whole
① Beikou Bridge is a three tower four span double deck steel truss girder suspension bridge.
② Longitudinal viscous dampers are set between stiffening beams and side towers, vertical bearings are set between stiffening beams and bridge towers and side piers, and transverse wind resistant bearings are set between stiffening beams and tower columns.
main beam
① The stiffening beam adopts plate truss composite steel truss, and the double deck highway bridge deck adopts orthotropic steel structure.
② The main truss adopts Warren truss, and the sling is suspended on the corbel outside the beam at the lower chord node of the stiffening beam.
③ Most sections of stiffening beams are made of Q345qD steel, and steel truss beams near the bridge tower are made of Q420qD steel.
④ The steel truss girder is fabricated by the whole segment. The bridge deck and chord top between adjacent segments are connected by welding, and the rest are connected by high-strength bolts.
bridge tower
① The three towers are of reinforced concrete structure.
② The middle tower is A-shaped longitudinally and portal shaped transversely. There are four tower columns in total. The top of the tower is equipped with an upper beam, and the lower beam is set below the stiffening beam;The tower column adopts box section;Open caisson foundation is adopted.
③ H-shaped concrete towers are used for the north and south towers, and bored pile foundations are used for both towers.
Main cable
The main cable is formed by the prefabricated parallel steel wire strand (PPWS) method, and a single cable strand is composed of galvanized high-strength steel wire;Articulated parallel steel wire slings are used for slings, and cast welded composite structures are used for saddles.
Anchorage
Gravity anchors are adopted for the anchors, caisson foundation is adopted for the south anchor, and open cut expanded foundation is adopted for the north anchor.
reference material:[25][31]
Design parameters
Beikou Bridge has a total length of 7913 meters, of which the main bridge is 2090 meters long, with a span of (230+800+800+348) meters.The full width of the stiffening beam is 42.8m (including the width of the beam at the lifting point), the beam height is 14.5m, and the length of the standard section is 20m. The width of the upper subgrade is 33.5m, and the width of the lower subgrade is 33.0m;The main truss is 12.5 meters high, 36.2 meters wide, and 10.0 meters long.The middle tower is 139 meters high, and the chamfer size is (0.6 × 0.6) square meters.The transverse width of the tower column is 7m, the longitudinal width of the tower top junction section gradually changes from 9.0m to 15.245m, and the longitudinal width of each tower column in the bifurcation section is 7.0m;The south tower is 144 meters high and the north tower is 137 meters high.There are 2 main cables with a boom spacing of 10 meters, each of which is 2300 meters long and has 169 cable strands in total. A single cable strand has 127 wires of steel wire with a diameter of 5.4 mm and a tensile ultimate strength of 1860 MPa;The longitudinal standard spacing of slings is 10m;The total width of splay saddle is 5.2m[25][31]。
technical standard
upper strata
lower stratum
Highway grade
expressway
Class I highway
Lane setting
Two way six lane
Design speed
100 km/h
80 km/h
Design wind speed
43.2 m/s
Load standard
Highway - Class I
Flood frequency
Once/100 years
Navigable water level
Clear width: ≥ 474m, clear height: ≥ 53.5m
Navigable tonnage
30000 ton seagoing ship
Environmental category
Class I
Seismic grade
Fortification according to VIII degree
reference material:[25][31]
Equipment and facilities
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Lighting facilities
By June 2022, 5058 sets of lamps and lanterns have been installed on Beikou Bridge to beautify Oujiang River with lights and add a festive atmosphere to the city[2]。
Operation
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Ticket system fare
On May 27, 2022, the Zhejiang Provincial Department of Transport issued the Letter on Matters Related to the Collection of Vehicle Tolls for Wenzhou Oujiang Beikou Bridge, which shows that the charging standard for the Beikou Bridge is:
category
Passenger car
Truck, special operation vehicle
Vehicle classification standard
Fare rate (yuan/vehicle · km)
Train fee (yuan/train)
Vehicle classification standard
Fare rate (yuan/thousand miles)
Class 1
≤ 9 seats (and vehicle length<6m)
zero point four
five
2 axes
(Vehicle length ＜ 6m, maximum allowable total mass ＜ 4500kg)
zero point four five zero
Category 2
10 to 19 seats (and vehicle length<6m)
2 axes
(Vehicle length ≥ 6m or maximum allowable total mass ≥ 4500kg)
zero point eight four one
Passenger train
Category 3
≥ 40 seats (and vehicle length ≥ 6m)
zero point eight
ten
3 axes
one point three two one
Category 4
≥ 40 seats (and vehicle length ≥ 6m)
one point two
fifteen
4-axis
one point six three nine
Category 5
/
5 axes
one point six three nine
Category 6
≥ 6 axes
one point seven four seven
reference material:[34]
Passage
On May 26, 2022, Wenzhou Public Security Bureau and Wenzhou Transportation Bureau issued the Notice on Prohibiting the Passage of Dangerous Chemical Transport Vehicles in Lingkun Huanghua Section of G1523 Ningbo Dongguan Expressway (Oujiang Beikou Bridge), which shows that dangerous chemical transport vehicles are prohibited from passing Beikou Bridge 24 hours a day[39]。
On September 6, 2022, Wenzhou Municipal Public Security Bureau issued the Notice on Prohibiting Vehicles, Pedestrians and Non motorized Vehicles Carrying Dangerous Chemicals from Passing the Lingkun Huanghua Section of National Highway G228 (Oujiang Beikou Bridge), which shows that vehicles, pedestrians and non motorized vehicles carrying dangerous chemicals are prohibited from passing the Beikou Bridge 24 hours a day[38]。
traffic flow
From May 27 to June 27, 2022, the daily average section flow of Beikou Bridge will be 30000 vehicles per time[33]。
Construction achievements
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Technical difficulties
Construction difficulties
The main difficulties in the construction of Beikou Bridge are:
1. The construction of the bridge also faces unfavorable conditions such as strong tide, deep soft soil layer and frequent typhoons at the Oujiang estuary;
2. There is no mature precedent at home and abroad to follow in the construction of large caisson foundation and other difficulties.
3. Large area construction of some main materials for the first time[35]。
construction technique
The main construction technologies of Beikou Bridge include:
1. In view of the difficulties in the construction of the main cable, we explored intelligent tooling technology, developed the first intelligent deep groove saddle entering robot in China, and "pushed" the cable strand into the cable saddle through the hydraulic jack, making the process stable and controllable[2]；
2. After the support system is adopted, the design problems such as large fatigue stress amplitude of the suspender near the bridge tower and large negative reaction force of the support are solved.
3. The stiffening beam adopts the integral double deck steel truss beam combined with the orthotropic steel deck and the main truss, which improves the bending and torsional rigidity of the structure, and has the characteristics of high structural space utilization rate and better comprehensive economic indicators;
4. The middle tower adopts concrete structure, which reduces the construction difficulty and the overall cost of the project;
5. Large caisson foundation is adopted for the middle tower foundation, which has stronger ship collision resistance, greater rigidity and better economy[25]。
6. In the main beam construction link, the first domestic 1000 ton cable crane is developed, which is equipped with human-machine interface, sensor technology, communication technology and other technologies to control the installation accuracy error within 5 mm[35]。
technological innovation
1. The construction method of "cross grooving+full face small pot bottom excavation" is adopted, and the "underwater quick soil borrowing device" is independently developed. The large drilling rig is transformed into underwater soil borrowing. At the same time, the BIM (building information model) technology is used for dynamic monitoring throughout the process to overcome the worldwide problems in the construction of deep sludge layer open caisson.
2. The world's first deep groove cable saddle was designed and manufactured, and the first intelligent deep groove saddle entering robot in China was developed. The hydraulic ejector rod was used as the manipulator to "push" the cable strand into the cable saddle, which increased the efficiency by 30% compared with the traditional manual saddle entering method.
3. A complete set of technologies for construction and control of superstructure of three tower four span suspension bridge in strong typhoon area and a complete set of technologies for open caisson construction in land area of strong tidal estuary have been formed, which have overcome the problems of tight construction period and high safety risks, and provided experience for the subsequent construction of similar bridges.
4. Based on the development and application of the 1000 ton cable crane with the largest lifting capacity in the world, the largest split lifting equipment in China has been developed. The innovative scheme of "1000 ton cable crane and 1400 ton split lifting equipment" relay lifting has been put forward, and the beam section in the intersection area of cable and beam has been installed to effectively improve the efficiency and accuracy of girder lifting, providing new ideas for the construction of similar bridges in China in the future[37]。
Honor recognition
entry name
Honors won
Beikou Bridge
In 2016, the first batch of "green road" projects of the Ministry of Transport of the People's Republic of China
"Quality Engineering" of Zhejiang Provincial Department of Transport in 2016
Key demonstration project of "steel structure bridge promotion and application" of Zhejiang Provincial Department of Transport in 2016
Nomination Award for "2018-2023 Top Ten Most Beautiful Bridges"
reference material:[32][40]
Value significance
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After the Beikou Bridge is opened to traffic, the part of Ningbo Dongguan Expressway in Wenzhou, namely Ningbo Taizhou Wenzhou Expressway double track, will further play its transport role and economic benefits.Through the bridge, the drive from Yueqing citizens across the river to Wenzhou Longwan International Airport has been shortened from more than one hour in the past to 15 minutes[1]。(Evaluated by CCCC Second Harbor Engineering Co., Ltd.)
The opening of the Beikou Bridge marks the completion of the whole line of Ningbo Dongguan Expressway connecting Guangdong, Fujian and Zhejiang provinces, which will help the construction of Ningbo Wenzhou Taiwan Harbor Industrial Belt into the "fast lane" and create better conditions for Wenzhou's deep integration into the integrated development of the Yangtze River Delta and the construction of the Guangdong Hong Kong Macao Greater Bay Area[3]。(Comments by Wenzhou Municipal People's Government)
