The re -breakthrough of the Santa Cold Bridge -Ma'anshan Gongtie Dual -use Yangtze River Bridge Program Research

Author:Bridge magazine Time:2022.09.08

The Chaoma Intercity Railway Ma'anshan Gong Railway Bridge is located in Ma'anshan City, Anhui Province. It is a multi -functional bridge that integrates high -speed railways, intercity railways and urban expressways. The project where the project is located is located in the eastern part of Anhui Province. It is located in the two urban areas of Nanjing and Hefei. It is an important industrial city. The construction is of great significance for the integration of Maanshan into the Yangtze River Delta urban group and promoting the economic development of both sides of the Yangtze River.

Public rail co -construction is more advantageous

The project is located in the lower reaches of the Yangtze River. The area of the area has the characteristics of rivers wide, high navigation requirements, large construction investment in the river crossing, and tight shoreline resources. Combined with the requirements of the river channel and road network planning, it is recommended to use public railway construction methods to jointly build a combination of public railway construction. Cross the Yangtze River. The use of a variety of transportation functions can be used to cross the river simultaneously, which can effectively use river channel resources. At the same time, in the case of increasing investment in high -speed railway, it can increase short -distance traffic functions and better promote the integration of cross -strait economic development.

After the analysis of railway transportation and road traffic volume, it is determined that the construction standard of the 4 -line railway+6 -lane highway is finally determined. Among them, the two -tier railway is the planned Chaoma Intercity Railway. The determined speed target value is 250km/h; the two -line intercity railway is reserved, and the speed target value is 200km/h. The two -way six -lane, the design speed is 80km/h.

Bridge choice

The proposed project is located in the Ma'anshan River section of the lower reaches of the Yangtze River. The Yangtze River flows through Ma'anshan from south to north, and the city is divided into two sides of the east and west sides. By analyzing factors such as terrain geological conditions, urban and coastline planning, road network layout, Yangtze River hydrology, river potential, navigation and other factors, a total of 4 large channels were selected. Seven lines are selected.

Figure 1 Ma'anshan Public Railway Cross Jiang Channel Plane Plane layout

Through comparison, it is recommended to adopt aunt line. This line is the country's approval channel and planned control. The rivers at the line are relatively stable, the cross -strait public railway transportation organizations are smooth, the demolition volume is small, the investment scale is moderate, and the public railway co -construction bridge plan can be implemented.

The aunt line is located in the upper reaches of the two -purpose Yangtze River Bridge of Maanshan Gong Railway, and the public railway is about 9.8km in length. The beach, crossing the left of the Yangtze River, passing through the middle of Jiangxinzhou, crossing the Yangtze River on the Yangtze River on the head of the Yangtze River, and reaching the bank of Dangtu County. The Yangtze River is divided into Zuoyu Channel and Right Channel from the Jiang Xinzhou with a width of about 5km at the bridge.

Construction condition

The project is located in the lower reaches of the Yangtze River and is located in the hilly plain area. The near -shore area of the Yangtze River belongs to the Yangtze River, with flat terrain and wide terrain.

The area where the project is in the North Asian tropical monsoon climate. The average annual temperature is 15-16 ° C, the extreme maximum temperature is 43 ° C, and the extreme minimum temperature is -14.0 ° C. The average wind speed of the Ma'anshan area is 2.3m/s for many years. The maximum wind speed over the years is 24.0m/s. According to the current highway bridges, combined with the information of the nearby Nanjing, Luzhou and Wuhu Meteorological Station, and combined with the project characteristics, the basic wind speed across the river bridge is 28.9m/s.

Combined with the current status and planning of the river channels, channels, ports, and plans in the basin where the bridge is located, the research on the evaluation of the channels of the channel of the channel is obtained. The two-way navigation and width of the hole should not be less than 700m; the grade of the deputy roads I- (3), the design of the highest navigation water level above the navigation level is not less than 18m, and the single-hole two-way navigation net width should not be less than 285m.

The coverage layer on both sides of the bridge site is relatively thin, and Jiang Xinzhou is thicker; the base rock surface along the line is slightly undulating. The coverage layer is mainly the fourth sectors. The fourth sectors are mainly the new Founded River sedimentary stratum powder fine sand layer, flowing plastic-soft plastic powder clay, round gravel, and drifting stones. Clane, sand layer and round gravel layer; base rocks include powder sandy clay, mud powder sandstone, sandstone, arges, lithite, and gray grave.

The main and deputy channel bridges set up the first level of the first level according to the 10%seismic parameters of 100 years. 0.15g; the characteristics of the reaction spectrum are 0.55s.

Main Channel Bridge Design

Bridge span layout

The Yangtze River is divided into the main channel and right auxiliary channel from Jiang Xinzhou at the bridge.

For the main channel of Zuo Yan, the left and right sides in history are more frequent in river beds, which have the characteristics of "30 years in Hedong, 30 years of Hexi". In recent years, through the implementation of river governance and waterway rectification projects, the Shenhong line and deep grooves have swinged to the right, and gradually stabilized.

Figure 2 The topographical facade (unit: M)

The layout of the bridge pier mainly follows the following principles: arranged on the 10.5m and other deep lines and channel rectification lines, the valid channel width is not less than the existing highway bridge; the left side of the beach is less. The beach protection shore project; when crossing the embankment, it needs to meet the safety distance requirements. According to the above principles, the inter -crossing of the bridge is initially determined to be (124+2 × 248+300+510+1260+330+2 × 150) m, with a total length of 3320m.

Fig

The cross -layout plan of the bridge has covered the scope of the Shenzhen -Hong Hong line, deep grooves and habitual routes in recent years. The adaptability of the channel changes and the habitual routes of the bridge area of the bridge area can meet the navigation requirements.

With the deepening of the research, the distance between the bridge distance has been built at only 2.3km. The bridge span is arranged at 2 × 1080m. The hole -crossing layout of the river beach area cannot meet the navigation requirements of the main channel ship, and there are certain hidden dangers to the safety of shipping. More, the stability of the beach and the accumulation of the downstream Zhengpu Port area will have adverse effects. As a result, the two major cross -bridge and span layout schemes corresponding to the navigation hole corresponding to the Changjiang Highway Bridge of Maanshan, with a main span of 2 × 1120m. The safety hazards of the bridge construction to the Yangtze River shipping to ensure the smooth flow of the Golden Waterway in the Yangtze River.

Figure 4 The two major spans of the main channel bridge

(Recommended scheme) Facial diagram (unit: M)

Design

① Comparison of lane layout

The project is implemented in accordance with the scale of the 4 -line railway+6 lane roads. In order to choose a reasonable lane layout method, it is based on flat vertical and horizontal layout, wiring scheme, area, traffic organization, structural force, construction difficulty, landscape and economic pairing pairs The public railway dual -layer scheme (the lower level of the railway, the upper highway), the double -layer scheme of the railway (the upper 2 -line railway, the lower -level 2 -line railway+highway), and the public railway level plan are comprehensive comparison. The vertical line is good, the traffic organization is simple, the area is small, the economy is good, the construction process is mature, and the landscape effect is good. It is a recommended lane layout method.

② Bridge scheme comparison

The main channel bridge is arranged with a 2 × 1120m span. For the public iron dual -use bridge of the span, the multi -tower cable load -bearing bridge can be considered. It is currently divided into two categories: cable -stayed bridge and suspension bridge. Pull bridge and three tower two main cross -suspension bridges. In response to the two schemes, comprehensive comparisons were made from all aspects of structure, force, construction, and economy. Through comparison, the two mains cross the cable bridge plan, the overall stiffness of the structure is relatively large, the base of the medium tower is relatively small, the impact on flood control is small, the economy is better, the construction risk is low, and the technology is mature. Therefore 1120M Three Tower Coverer Bridge Plan.

③ Structure design

The Main Channel Bridge is a three -tower trapped bridge solution for public railways that dominate more than kilometers. In order to achieve the design goals with reasonable rigidity, good economy, and beautiful shapes, from a overall support system, the proportion of the medium -sized tower, the middle side, the middle side The structure selection, side length selection, auxiliary pier layout, etc. of the tower conducted in -depth research, and conducted detailed comparison of the selection of components such as the specific main tower, main beam, main tower foundation, and cable cable. Through the study comparison, the following main structural design solutions are formed.

The support system adopts the vertical and horizontal wind resistance support of the middle tower. The two side towers are set up with vertical damping device and horizontal wind resistance support. The auxiliary pier and the edge pier are set up with vertical support and horizontal wind resistance.

The main tower of the Three Tower adopts the form of no high arrangement. The height of the middle tower is 24.5m higher than the edge tower.

The middle tower adopts the structure of the triangle, which improves the longitudinal stiffness of the middle tower and reduces the section size of the single tower column to facilitate construction control. The two towers are relatively small, and the triangle structure consistent with the medium tower is used in the horizontal direction, and the vertical is i -shaped. The total height of the middle tower is 345m, and the two towers are 306m and 308m. The three towers use steel mixed structures.

The base of the main tower is 50-70m deep, and the basic scheme of drilling piles is used. At the same time, in order to give full play to the base rock carrying capacity and optimize the roots of the pile foundation, it is recommended to use a large diameter diameter drilling pile with a diameter of 4m. Among them, the middle tower adopts 60 roots, and the plane of Chengtai is rectangular on the four sides; 36 sides of the two side towers are used with dumbbell -shaped inheritance.

The main beam of the steel adopts double layer, the upper floor is 6 lane roads, and the lower floor is a 4 -line railway. The main beam uses the N -shaped truffle vertically, the standard spacing is 14m, and 3 trustees are arranged horizontally, with a spacing of 2 × 15.5m; The upper and lower string rods are box -shaped cross section, and the abdominal rod uses an H -shaped or box -shaped section. The railway bridge surface adopts the overall steel box structure; the highway bridge surface adopts the overall steel bridge surface of the orthogonal heterosexual board.

The cable cable uses a parallel steel wire pulling cable with a strength of 2100MPa and a maximum length of about 650m.

Deputy Channel Bridge Design

Bridge span layout

The deputy channel bridge corresponds to the right of the Yangtze River, which is a deputy channel. Since 2006, the Shenhong line and deep tanks have stabilized, and there have been no change in the middle of the river. The section is "V". Combined with factors such as the embankment and the net width of the navigation, the span of the main span 392m span the auxiliary channel, and the 168m span spans the embankment on both sides. The navigation holes have completely covered the scope of the Shenhong line, deep grooves and habitual routes for many years, and basically cross the navigation waters to meet the requirements of navigation.

Figure 5 Significance of cross -arrangement of the auxiliary channel bridge (unit: M)

Design

① Position comparison

According to the cross -layout of the bridge, combined with the characteristics of the public railway bridge and the construction of the bridge, the auxiliary channel bridge is compared to the two schemes of the steel truffle beam cable bridge and the rigid beam flexible arch bridge. Through comparison, the structure of the two schemes and stiffness meets the requirements, and the landscape also has its own characteristics. The comparison of the stretch bridge solution is simple, the construction difficulty is small, and the economy is better. Therefore, it is a recommended scheme.

Figure 6 Positive Channel Bridge Chart (Unit: M)

② Structure design

The deputy 汊 uses the Double Tower Covenant Bridge with a main 392m, and has a lot of mature experience. Through the selection of structural constraint system, main beam, main tower, foundation, cable cable, etc., and combined with relevant boundary conditions and landscape requirements, the reasonable structure of the auxiliary channel bridge is determined.

The support system adopts the main tower to set up vertical damping device and horizontal wind resistance support, and the side pier is set up with vertical support and horizontal wind resistance. The auxiliary pier is set up with vertical support and the middle trusher.

The main tower shape corresponds to the main channel bridge, the horizontal direction is triangular, and the tower column adopts steel concrete structure. The tower height is 170m, and the single tower anchor 12 cable cables. The foundation of the main tower is used in drilling piles, and a single main tower adopts 30 diameter of 2.8m pile, and the inheritance is dumbbell -shaped.

The steel main beam is the same as the channel bridge, using double layers. N -shaped truffles are used vertically, the standard pitch is 14m, 3 trustees are arranged horizontally, and the spacing is 2 × 15.5m; the height of the border truss is 15.3m. The upper and lower string rods are box -shaped cross section, and the abdominal rod uses an H -shaped or box -shaped section. The railway bridge surface adopts the orthogonal heterosexual board structure welded with the string rod to participate in the overall force of the structure;

Candido is recommended to use 2100MPA steel twisted cable, which can optimize the structure size of the main tower and facilitate construction and installation. The cable cable uses the steel anchor beam anchor and anchor plate anchor on the beam.

Bridge

The length of the bridge public railway construction section is about 9.8km, of which the 5.7km public railway co -construction bridge. In response to bridge programs, it was selected from the aspects of flood control, engineering cost, and construction plan. Considering Jiang Xinzhou and Dangtu side as flood discharge areas, in order to reduce the impact of bridge construction on the flood, the 40.7m bridge is arranged; the water side of the county side is located on the back of the embankment. , Easy to standardize construction. The bridge is arranged with a double layer, and the lower layer is a railway beam with a simple branch structure. The upper highway bridge uses multiple cross -continuous beams; the main beams use box -shaped cross -section, and the upstream and downstream scales are arranged. The pier structure corresponds to the layout of the main beam, and the double -layer frame pier is adopted.

Ma'anshan Gongtie Dual -use Yangtze River Bridge adopts a planned aunt line to cross the Yangtze River. The total length of the public railway construction section is about 9.8 kilometers. The main channel bridge adopts the three -tower cable -stayed bridge solution of the main span 2 × 1120m. The auxiliary hoe uses two tower cable -stayed bridges with main span 392M. Requirements in all aspects. The bridge and bridge scheme selection has been selected by scientific comparison as the best solution.