Structural strengthening, these are the key points! Foundation treatment, bond steel plate reinforcement, rebar anchorage, carbon fiber fabric reinforcement​, crack repair

Foundation reinforcement

(1) Controlling settlement and differential settlement, controlling settlement rate, measuring the degree and condition of foundation development, judging the settlement rate of foundation according to soil type, and getting the maximum settlement rate at the end of loading.

(2) Soil factors such as soft soil with weak permeability should be considered before construction. Pore water is not easy to remove and the settlement stability of buildings takes a long time.

Bond steel plate reinforcement

(1) when the steel plate is pasted, the installation bolts should be tightened immediately to make the glue just squeeze out from the edge of the steel plate.

(2) Structural adhesives need to be used for 2-5 days when they are solidified at about 20 C. The bonding area of anchorage zone should not be less than 90% and that of non-anchorage zone should not be less than 70%.

(3) After the inspection of the sticky steel is qualified, the next step is to carry out rust removal and fire-proof coating, control the ambient temperature and relative humidity to meet the requirements of the coating products, and clean the surface before the construction.

(4) The rust-proof part should be cleaned up to reveal the true color of the steel. When preparing the rust-proof paint, it is necessary to ensure uniform color and viscosity. The primer surface can be coated after drying, and attention should be paid to stirring evenly.

Rebar anchorage

(1) The length of rust removal of steel bar for anchorage is 5 and the glue is injected into 3/4 of the hole when the steel bar is planted. The cleaning end of the steel bar is covered with structural glue and rotated into the bottom of the hole, so that the glue overflow is qualified.

(2) during the curing of planting bar adhesive, special personnel should be inspected to avoid disturbance and displacement test.

(3) when the section is strengthened, the foundation should be chipped and polished, and the interface agent should be painted.

Carbon fiber fabric reinforcement

(1) Before CFRP strengthening, the concave part of the result surface should be flattened and filled, and the corner part should be repaired as a smooth arc.

(2) attention should be paid to the uniform coating when brushing the underlying resin.

(3) When pasting CFRP, it is necessary to roll and extrude the bubbles several times, and ensure the integrity of CFRP during construction. The multi-layer pasting should be carried out on the next layer when the surface of each layer of CFRP is touched and dried.

(4) Carbon fiber sheets are all pasted for surface protection, mainly for spraying fire retardant coatings, fire resistance limit to meet the design requirements.

Crack repair

(1) Continuous pressure and pressure should be controlled when using continuous low-pressure injection repair. It is injected into the components, which are often used in various main structures and have safety considerations.

(2) When high-pressure injection repairing method is adopted, the repairing material is injected into the component under pressure within a certain period of time, which is often used in the continuous wall structure of underground part, and the filling material can be selected according to the actual use situation.

(3) When the groove method is used, the V-shaped groove is chiseled on the surface of the structure or cut out by a diamond cutter, filled with epoxy resin or elastic filling material, and then covered with glass fiber on the working face. It is often used for drying shrinkage cracks between brick walls or partitions and concrete.