Vertical cracks from top to bottom and longitudinal cracks at the top.

Cause analysis: the ground subsidence caused by the uneven vertical settlement or horizontal displacement of the foundation, the shear force and material defects caused by the long-term vehicle load. Due to the vertical uneven settlement or horizontal displacement of the foundation, additional stress is produced in the structure, which exceeds the tensile capacity of the concrete structure and leads to structural cracking.

Disposal method: if the disease is not serious, the surface repair method can be carried out. If the condition is serious and endangers the normal operation of the bridge, it is necessary to carry out the foundation treatment and then block the bridge.

Vertical cracks from bottom to bottom and longitudinal cracks at the bottom

Cause analysis: The tension crack of the lower concrete caused by the upper compression is caused by the insufficient tensile strength of the steel bar.

Disposal method: it should be repaired at once, so as not to endanger the stability of bridge beam. It can be applied to the surface of the crack with cement paste, epoxy paste or paint and asphalt on the surface of concrete. In order to prevent the concrete from cracking under the influence of various functions, the glass fiber cloth can usually be used on the surface of the crack. Grouting or caulking and sealing are adopted for wider cracks or development trend.

Surface cracking caused by thin protective layer

Cause analysis: the protective layer is too thin causing the surface cracks of concrete.

Disposal method: because the disease has no influence on structural stability and structure bearing capacity, surface repair method can be used to apply cement paste, epoxy paste or paint and asphalt on the surface of the crack.

Cracks developed down from the cushion

Cause analysis: because the pier cap is not placed under the support stone, steel bars are subjected to excessive impact force.

Disposal method: if the disease is not serious, the surface repair method can be used. If the width of the crack is large, the closed treatment can be carried out first, and then the carbon fiber fabric is stuck to prevent the continuous expansion of the crack.