Mianyang Yinma Bridge Maintenance and Reinforcement Project
The material manufacturing and installation of the hanger and tie rod system of this project are all undertaken by Liuzhou Guiqiao Cable Co., Ltd.
Yinma Bridge is located on Nanhe Road, Mianyang City,Sichuan Province, crossing the Anchang River.The entire bridge is 260m long and 20m wide.The bridge deck adopts two-way 4-lane,and the horizontal composition of the bridge deck is:3m (railings and sidewalks) + 14m (travel lane) + 3m (railings and sidewalks) = 20m.
The approach bridges on both sides are reinforced concrete simply supported hollow slab bridges, the arches on both sides of the main bridge are hollow slab arch bridges, and the main arch is a half through concrete arch bridge.This bridge is an orthogonal bridge.The bridge was completed in September 1994 and has been in operation for nearly 30 years.
The upper structure of the main arch bridge is made of half through concrete hanger arch,with two transverse arch ribs and 13 hangers for each arch rib. The existing boom structure is made of 30φ15.24 high-strength and low-relaxation steel strand with a thickness of 6mm seamless steel pipe as protection.
Fill the steel pipe with 30# micro-expanded cement mortar, and use C30 concrete to seal the upper and lower anchor heads. Drill holes to take out the concrete core of the beam,and take out the concrete together with the conduits and original steel pipes inside and the steel strands inside.
The technical team carefully studied the anti-corrosion measures,technical process improvements and new technology applications of the system in the manufacture of the new hangers of this bridge,so as to extend the service life of the hangers and provide safety guarantee after the cable replacement of the bridge.The hanger adopts the whole bundle of steel strand extrusion and integral tensioning technology,which has the characteristics of reliable anchoring,compact structure size,easy tensioning and cable adjustment, and good anti-corrosion performance.
The steel strand is coated with special anti-rust grease,a single high density polyethylene pipe protection, the whole bundle is wrapped with high strength polyester tape and then extruded with high density polyethylene outer sheath,multi-layer protection,avoiding the whole bundle of steel wire corrosion due to one corrosion,and the corrosion resistance is superior.
The steel strand is separated by polyethylene pipe, and the structural damping is larger than that of the steel wire cable,and the vibration resistance is good. The steel strand can slide in the polyethylene tube,and the outer polyethylene tube basically does not receive tensile stress,which effectively prevents its tensile stress cracking.