Structural form and architectural design characteristics
Panyu Bridge, as a key highway project in Guangdong Province, is a key project undertaken by Guangdong Highway Survey, Planning and Design Institute. The main designers are Liang Linong and Ma Chunsheng. The design is divided into three stages: August 1993 to May 1994, which is the stage of engineering feasibility study; June 1994 to June 1994 is the preliminary design stage; 1995 65438+ 10 to 1996 65438+ 10 is the construction drawing design stage.
Design conditions of Panyu Bridge: the main bridge spans the Pearl River, with a river width of about 460m, a flow velocity of 0.9m/s- 1.0m/s, an average tidal range of about 2.32m, an average navigable water level of 9. 1m, and a bridge site area of11000 20m. Minimum temperature-0.4℃; The annual average temperature is 265438 0.8℃, and the annual average relative humidity is 78% ~ 83%.
Main technical standards: mainline standard: first-class highway in plain and hilly areas; The design speed is100 km/h; Design load: automobile-super class 20, trailer-120; Bridge deck width: the main bridge is 37.7m, the approach bridge is 2× 18.5 m, and there are 8 lanes in both directions; Navigation standard: clear width 180m, clear height 34m；; Anti-collision standard: 7000-ton ships are considered in the main channel; Basic seismic resolution: 7 degrees.
Overall design: The main line starts from Yingbin Road in Panyu, passes through three perfume lanes and the Pearl River in turn, goes straight north to South China Expressway, and builds an interchange at the starting point and Shaxi Yingbin Avenue. The main bridge161m+380m+1m is an ultra-wide cable-stayed bridge with continuous twin towers and double cable plane floating system. Each side span is provided with an auxiliary pier, and the side span is divided into 702m+9 1m, so as to improve the rigidity of the whole bridge and the mechanical properties of the structure.
The approach bridge is a continuous box girder bridge with variable height, a partially prestressed continuous box girder bridge with contour curve, a partially prestressed continuous plate girder bridge, a partially prestressed simply supported T girder bridge and a continuous rigid frame-continuous beam composite bridge. The total length of the route is 4.875 kilometers, of which the bridge is 3458.2 meters long. ..
Structural design of main bridge:
Main pier foundation: each main pier adopts 183.0m bored pile foundation, which is designed as rock-socketed pile. The cap is 5.5m thick and poured in three layers, each layer is 1.5m-2.0m thick. The main pier in the middle of the river is provided with a hanging anti-collision tray with a width of 3m at the top of the pile cap.
Main tower: The main tower adopts rhombic reinforced concrete frame structure, with tower height 140.3m, lower tower column inclination 1: 3.84, middle tower column inclination 1: 3, hollow thin-walled section, lower tower column transverse dimension 4m-5m, longitudinal dimension 7m-9m and arm thickness/kloc-0. ; The middle tower column has the same cross section, the transverse dimension is 4 m, the longitudinal dimension is 7m, the arm thickness is 0.8- 1m, the beam height is 7m, the width is 6.5m, the arm thickness is 0.8m, the prestress is set in the beam, the outer dimension of the tower crown is 7×7m, and the arm thickness is 0.7m-1.5m. It is a single-box and double-chamber cross section, and the horizontal circumferential prestress is set.
Main girder: The main girder is a partially prestressed concrete structure with an open section of the side beam, with a height of 2.2m and a width of 37.7m. The bottom of the side rib changes from 2m in the middle of the span to 2.6m in the center of the tower, with a deck of 28cm and a cross beam of 6m. The 34cm-thick main girder is cast-in-situ with brackets, and the rest is suspended by hanging baskets.
Stay cables: Stay cables are arranged in double cable planes. There are 244 stay cables in the whole bridge. The standard cable spacing on the tower is 1.3m, and the standard cable spacing on the beam is 6m. Stay cables are made of φ 7 galvanized high-strength steel wires, and the number of steel wires varies from 1, 2 1 to 367. Two layers of PE protective materials are hot extruded outside, black inside and white outside, and the main girder is anchored by stay cables.
Auxiliary pier and side pier: The auxiliary pier and side pier adopt hollow thin-walled cross section, and the overall dimension is 3m×3.5m Vertical cables are arranged between the auxiliary pier and the main girder to form a tension and compression bearing.
Structural analysis and construction control of main bridge: structural analysis includes plane and space static analysis, construction analysis, stability analysis, local stress analysis and dynamic analysis. The construction control adopts the principle of three controls of cable force, elevation and internal force. Each stay cable is tensioned once during construction (the adjustment in the same construction stage is regarded as a tensioning), and a few stay cables are fine-tuned once after being closed according to the test results.
The design features of Panyu Bridge: In addition to its deck width of 37.7 meters, it ranks first among similar bridges in China, second among similar bridges in the world and first among similar bridges with a span of more than 200 meters, Panyu Bridge has also solved a series of theoretical problems in the design and calculation of cable-stayed bridges with ultra-wide side beams, such as the torsion of side ribs in construction and use, the compression, bending, torsion and shear stability of thin diaphragm beams, and Liang Chao.
At present, the tower column with large inclination angle of 1: 3.84 and the tower column with large inclination angle of 1: 3 are the largest in the cable-stayed bridge, which is beneficial to reducing the foundation width and the number of tower projects, making the tower and spatial curved cable more layered and stereoscopic, but also increasing the design difficulty. They determined the reasonable design internal force and construction scheme of the tower column, analyzed and calculated the position, pre-tension and pre-jacking force of the tie rod and strut, and made the finite element analysis of the relevant nodes, and carried out the construction stress tracking test on the four sections of the main tower, thus solving the design and construction control problems of the tower column with large inclination angle.
For the first time in China, the spatial double cable plane suspension system is adopted on the long-span ultra-wide side beam, which greatly improves the torsional stiffness of its section and the wind resistance of the side beam section in windy areas.
Using the cross section of the side beam on the ultra-wide cable-stayed bridge, the main compression area and mass are concentrated on the ribs on both sides of the elastic support of the stay cable, which not only helps to bear the horizontal component of the stay cable, but also greatly reduces the dead load of the beam and saves the cost. At the same time, the cable hanging basket is very beneficial to the construction of the side beam section.
For the first time, the large-tonnage special-shaped prestressed anchor group system was adopted in the anchorage section of stay cables at the top of the tower, which was beneficial to the arrangement of prestress and simplified construction.
The extensive use of partial prestress technology not only saves materials, but also improves the ductility of the structure, which is beneficial to earthquake resistance and cost saving.
Plane and space programs are used to analyze structures. In the construction process, it is successful to control the cable-stayed bridge to reduce the influence of temperature by using one-time tensioning technology, adjusting cable elongation and high differential mode. The cable-stayed bridge that has been completed at present is stable and has no control problems.
Using computer-aided design technology, a large number of automatic design programs have been compiled, which has improved the design accuracy and efficiency of cable-stayed bridge with double cable planes in complex space, optimized the structural design, and achieved good economic benefits for the main girder.
On the premise of advanced technology and reasonable economy, we will strive to explore the harmonious and unified design of bridge art and environment, and strive to make Panyu Bridge simple and smooth in line shape, reasonable in layout, balanced in mass ratio, novel and diverse in shape and vivid in image.
For more exclusive information about the construction industry, please pay attention to the micro-signal of the construction network in real time.
For more information about bid writing and improving the winning rate, click on the bottom customer service for free consultation.