Due to the stress characteristics of rigid-flexible combination, the middle tower adopts longitudinal herringbone and transverse portal rigid frame steel tower structure, which has large geometric size and weight and high manufacturing accuracy. The total weight of the middle tower is 13000 tons, and a large number of high-strength thick steel plates are used, of which 69.5% are Q420qD, and the thickness of more than 57.8% is 50 to 60 mm, and the thickness of the thickest steel plate is150 mm. It is very difficult to ensure the welding quality and control the welding deformation. The steel tower column is a rectangular structure with variable cross-section and variable tangent angle, with the maximum cross-section of 5.0× 12.69m and the maximum length of15 m. According to the requirements of stress and alignment, the dimension tolerance of cross-section in transverse and longitudinal bridge directions is 2mm, the allowable error of diagonal difference and distortion is not more than 3mm, the flatness of the whole section is less than or equal to 0.25mm, the verticality of the end faces in transverse and longitudinal bridge directions of tower sections is less than or equal to110000, the metal contact rate between wall plates and webs between tower sections is more than or equal to 50%, and the longitudinal ribs are in metal contact.
The middle tower adopts longitudinal herringbone and transverse portal frame steel tower, and its large-section manufacturing and installation technology is the first time in China.
Bridge hoisting design
The lower tower section is installed by floating crane, and the upper tower section is hoisted by MD3600 tower crane. The hoisting weight of each hoisting segment of the upper tower column shall be controlled within 140 tons, and the height of the corresponding segment shall be controlled within 7.5 ~12m. The correct positioning and installation of D0 segment is the basis of the whole tower installation and linear control, and its installation accuracy will determine the installation accuracy of tower column. There are ***4 D0 segments, which are inclined in both directions. There are 34 holes with diameters of 200mm and 180mm on the bearing plate and top plate at the bottom of each segment. During installation, the same number of bolts with the diameter of 130mm (the diameter of threaded parts at both ends is 140mm) should be inserted into the corresponding circular holes of the bottom plate and top plate of the steel tower. In the process of "perforation" of steel tower column, the gradient should be adjusted to 1:4 in the longitudinal direction and 3.9: 192 in the transverse direction, and the deviation should not exceed 20 mm, so the installation and positioning accuracy is very high.
Bridge cable system
Compared with the traditional two-tower suspension bridge, the cable system of the three-tower suspension bridge is more complicated. First, it is difficult to design and construct the catwalk, and the influence of the structural behavior of the middle tower on the catwalk structure should be considered. The reserved embedding of the catwalk crossing the top of the tower is limited by the steel tower structure. Second, the cable erection conditions are complicated, and the main cable strand needs to cross the top of the tower three times during the erection process, so the cable strand is more likely to produce bad phenomena such as broken belt, drum wire, torsion and hula hoop, which puts forward higher requirements for traction equipment and cable release system.
North-South Anchorage Foundation
Rectangular caisson foundation with strong bearing capacity is adopted, with caisson length of 67.9 meters and width of 52 meters, caisson height of north anchorage of 57 meters, basement elevation of -55.0 meters, caisson height of south anchorage of 465,438+0 meters and basement elevation of -39 meters.
Bridge steel deck structure
Taizhou Yangtze River Highway Bridge is a three-tower multi-span suspension bridge. Because the two sides of the middle tower are long-span flexible cable systems, the overall stiffness is lower than that of the traditional suspension bridge. Therefore, the design of super-long and super-flexible steel bridge deck structure is flexible, which intensifies the flexibility of the bridge deck system and leads to complex structural behavior characteristics of the bridge system.
Paving materials and technology
Due to the flexibility of the super-long and super-flexible steel bridge deck structure, the large deformation characteristics of the super-long and super-flexible bridge deck system require the pavement system to have good deformation flexibility, which puts forward higher requirements for the modulus optimization of the pavement structure and new requirements for the material properties and construction technology of the bridge deck pavement.