Bridge works Safety construction organization design
1. Design overview (1). Road grade: urban trunk road; (2) Design load: urban level A, crowd load 3KN/m2; (3) . Design speed: 50Km/h (XX bridge); 60Km/h (XX bridge) (4), bridge width: 3.75m (pedestrian and push ramp)+2.25m (arch rib area)+0.5m (guardrail)+10.75m (motorway)+0.5m (median separator)+10.75m (motorway)+0.5m (guardrail)+2.25m (arch rib area)+3.75m (pedestrian and push ramp)=35m; XX bridge approach: 3.5~6m (pedestrian and ramp)+0.5m (guardrail)+10.75m (motorway)+0.5m (median)+10.75m (motorway)+0.5m (guardrail)+3.5~6m (pedestrian and ramp)=30~35m; Main bridge of XX bridge: 4.1m (pedestrian and push ramp+handrail)+1.4m (arch rib area)+0.5m (collision barrier)+15.0m (traffic lane)+0.5m (collision barrier)+1.4m (arch rib area)+4.1m (pedestrian and push ramp+handrail)=27m; (5) Channel class: Class III; (6) Channel clearance: 60 × 7m, design maximum navigable water level: 3.01m, design minimum navigable water level: 0.81m, design flood frequency: 1/100; 2. Overview of bridge structure The whole bridge span group is (11 × 25)+82+(20+3 × 25) m, and the bridge length is 458.28m. The main bridge is a through steel box basket arch bridge, and the approach bridge is a 20m and 25m span composite box girder. The bridge is located on a convex vertical curve with a radius of 1800m and a longitudinal slope of 3.0% on the east and west sides. The whole bridge plane is located on a circular curve with a radius of 5000m. The arch rib is a fully welded steel box structure with 2 arch ribs. The calculated span is 80m, the projection height in the vertical plane is 20m (20.447m in the inclined plane), the rise span ratio is 1/4, the arch axis line is a quadratic parabola, the arch rib is a basket arch, and the arch rib inclines inward 12 degrees. The transverse distance of the arch rib center is 17.798m at the arch crown and 26.3m at the arch foot. The arch rib is of rectangular section, 1.8m high and 1.565m wide. There are three manufacturing types from vault to arch foot. The tie bar adopts full welded parallelogram section, with a height of 2.0m and a width of 1.7m. One middle cross beam is set at the suspender of the main bridge. There are 15 middle cross beams in the whole bridge. The longitudinal spacing of the middle cross beams is 4.9m. The middle cross beams are I-shaped steel beams with a length of 23m and a height of 1.745~1.96m. Seven longitudinal beams are set between the two cross beams, which are I-shaped steel beams. The bridge deck is a precast concrete bridge deck with a thickness of 25cm. A composite beam is formed with the steel beam through the shear studs on the top of the beam. The arch springing at both ends of the main bridge is provided with an end beam, which is a box section with a beam length of 23m and a beam height of 1.745~1.96m. The beam is a steel-concrete composite beam, which is composed of shear studs on the top surface of the beam and a reinforced concrete bridge deck. The substructure of the main bridge adopts separated reinforced concrete column piers with rectangular section, 2.6m wide along the bridge and 1.6m wide across the bridge. The main pier cushion cap is 2.0m thick, the plane size of the side cushion cap is 6.4 × 6.4m, and the pile foundation is four φ 1.5m bored piles; The plane size of the middle cushion cap is 2.6 × 6.4 m, and the pile foundation is two φ 1.5 m bored cast-in-place piles. The side and middle cushion caps are connected by tie beams with a section size of 2.0 × 2.0 m. The upper structure of the approach bridge adopts a structural system of 20 and 25 m span fabricated partially prestressed concrete simple supported continuous box girders, 9 pieces (bridge width 30 m) and 10 pieces (bridge width 35 m) horizontally, box girders are prefabricated separately, simply supported and installed, and cast-in-place continuous joints are simply supported continuous. The piers of the substructure of the approach bridge are of 5-column type, with column spacing of 5.95m (bridge width 30m) and 6.95m (bridge width 35m), column diameter of 1.3m, and φ 1.5m bored piles for the foundation; U-shaped abutment is used for 0 # abutment, 14 φ 1.2m bored piles are used for foundation, ribbed slab abutment is used for 16 # abutment, and 10 φ 1.2m bored piles are used for foundation.