CFRP Strengthening Wan Chuan River Bridge

Project overview

Wan Chuan River Bridge is located on the WAN Chuan River, built in 2002. The WAN Chuan River Bridge has been repaired several times in recent years. In September 2008, maintenance was carried out because it was identified as a dangerous bridge. However, due to the lack of original design grade, with the increase of traffic volume and overloading heavy duty vehicles, the bridge damage has been accelerated, and it is quickly listed as a dangerous disease bridge in Lanzhou. In August 2012, the bridge was reinforced again. In September 2013, the WAN Chuan River Bridge was restricted by high disease. The construction personnel of the middle section of the Lanzhou highway were repaired and reinforced successively. However, less than a year after the maintenance, the line was restricted in July 2014. In 2016, the bridge was repaired again. Now the bridge is in good condition and can withstand the action of general vehicles.

Bridge disease

(1) bridge deck system

Crack crack of bridge surface: because the bridge deck pavement directly bears the function of driving load, deformation of beam body and environmental factors, there are some phenomena of partial wear, deformation and pit in the bridge surface under the long-term effect.

There is a slight settlement at the bridge head: slight settlement, that is, the visible height difference between the bridge head and the road surface. The settlement of bridge head will cause the vehicle to jump in the passing of the road, which causes the impact load on the bridge. The greater the bridge head settlement, the greater the impact load, the greater the harm to the bridge.

The expansion joints are seriously obstructed: filling garbage and impurities in expansion joints to make the joints of the expansion joints abnormal, and the expansion joints are limited.

Impact: due to the disease of the bridge deck, it will cause unnecessary trouble to the driving, if not timely maintenance will accelerate the destruction of the bridge, greatly reduce the life of the bridge.

(2) superstructure

There are cracks on the surface of the main girder: the upper surface is subjected to load and the environment is affected, and the concrete surface is cracked.

The main beam is exposed to corrosion: internal rebar and water react to expand, resulting in concrete spalling and reinforcement corrosion.

Diaphragms stripped exposed bars: concrete spalling and reinforcement exposed by collision of diaphragms.

Influence: the superstructure is mainly used to bear the load, so the upper structure should be dealt with in time when there is disease, otherwise the bearing capacity of the bridge will be greatly reduced.

(3) substructure

Longitudinal cracks in pier body may be caused by inadequate or unreasonable reinforcement of reinforced concrete pier piers.

The foundation has a slight erosion: due to the erosion of water flow and the unreasonable artificial sand mining, the top of the pile foundation is higher than the ground and is partly eroding to a certain extent.

Abutment concrete peeling: concrete is peeled off by external forces.

The taper slope of abutment and abutment is separated from the abutment. The width of the gap is about 10-25mm. The reason is the settlement of the foundation, the downward slide of the abutment slope, and the cause of the erosion of the ground by the surrounding water.

The bearing has slight deformation: under the action of external force, the main girder is relatively rubbed, causing the bearing to deform.

Influence: the lower structure is to bear the upper load and transfer the force to the pile foundation. Because there are many diseases here, it may reduce the bearing capacity of the bridge and indirectly shorten the life of the bridge.

Solution

CFRP strengthening