On the crack detection and identification of cracks in houses - Huaqiang Electronic Network

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Questions about the detection and identification of cracks in houses and cracks in houses:
Regarding the problem of crack detection and identification of houses, the company has a professional consulting team that can undertake the inspection and appraisal of engineering structures and provide various social structural security questions for the society. There are more than 20 technicians in the company, including national registered structural engineers, senior engineers, engineers, experimental engineers, assistant engineers, and professional technicians. All major inspectors hold the employment certificates that have passed the training of the Ministry of Labor and Social Security of the People's Republic of China or the Guangdong Provincial Construction Engineering Quality and Safety Supervision and Inspection Station. Specializing in the safety inspection and identification of construction engineering structures, reinforcement design and construction of building structures, the company has strong technical strength and is based in Shenzhen. It has close relations with various administrative departments, rental management departments, public security systems and education authorities. Lease-type housing safety testing, hotel and hotel, school kindergarten, building plus layer, foreign enterprise inspection, floor bearing, dangerous house identification, post-fire damage detection, decoration and renovation safety impact assessment, etc. The report is true and effective, scientific and accurate. After the company's painstaking efforts, the company's business has spread throughout the South China region, in Shenzhen, Huizhou, Dongguan, Jiangmen, Shantou, Fujian, Hunan and other regions have a safe home inspection and identification business.

Regarding the problem of crack detection and identification of houses, we will look for Shenzhen Zhongzheng Engineering Technology Co., Ltd. to undertake the national business scope, provide free technical consulting services, contact telephone number, 15999691719 Manager Li

Questions about the cracks in houses and the identification of cracks in houses - what are structural cracks:

First, structural cracks

Structural cracks are caused by insufficient bearing capacity. The cracks formed by different types of forces are different. This difference is not only meaningful during reinforcement, but also should be paid attention to when testing and pre-reinforcing measures.

1. Cracks that may cause brittle fracture of components

1 Punching and cutting cracks: the surrounding annular cracks on the plate with concentrated loads or the eight-slot joints (vertical seams) on both sides of the concentrated load on the beam.

2 Shear failure crack: The oblique crack at the maximum shearing force of the bending shear member or the cross section of the joint and the loose portion penetrates the crack. Do concrete strength testing, if the location of the design is set to shear additional steel bars to check the actual layout of the steel bars.

3 Longitudinal cracks on the pressed side of the beam: If it occurs at the largest part of the bending moment, it may be a sign that the concrete in the compression zone reaches the ultimate deformation. This situation generally occurs in the super-strength beam. In the case of super-gluten formation, the design may be improperly designed, the concrete strength is too small, the geometrical size is too small (especially the height) or the concrete quality is too poor, and the unreasonable pouring causes the grading of the beam concrete along the height. The content of the test should include the influence of various factors mentioned above.

4 Longitudinal cracks in the axial direction of the compression member: The deformation of the concrete under compression is close to the sign of ultimate deformation. Such a situation is a serious state in engineering accidents. The necessary support measures should be taken before the reinforcement is detected. Such measures should be formulated in conjunction with the axial force check calculation. If the strength reference value is required in the early stage, the core cannot be taken in situ. Even after taking the support measures, the core should be calculated and calculated at the designated position. It is best to take the core in the same batch and other components of the same grade. The detection and treatment of such cracks shall be carried out in cooperation with the original design unit. If the commissioning indicates that the tester is to do so alone, the actual load and completed conditions of the structure shall be recorded in detail, and the model shall be checked and verified according to the actual situation.

5 Cracks caused by the loss of steel bond: In the structural design, the density of the longitudinal ribs is often too high, and the reinforced concrete forms two pieces that are almost detached from the upper and lower sides. In this case, longitudinal cracks along the steel bars may occur, which generally occur in the beams. On the side, the difference between such cracks and rust cracks is that the steel bars are free of rust. Such cracks are rare but difficult to reinforce.

6 Prestressed girders Prestressed anchoring effect caused by cracks: Simultaneously with the loss of prestress, once the beam occurs, multiple curved cracks deep into the compression zone will occur at the same time. In this case, the support should be restored immediately. The support should exert the anti-top stress as much as possible, and the anchorage crack should be re-tensioned and closed naturally.

7 Crack caused by torsion: The spiral-shaped oblique crack along the surface of the member subjected to torque, and the member that is obviously subjected to the torque generally has a torsion check calculation, and this possibility is unlikely.

2, cracks that will not cause brittle fracture of components

1 Bending cracks on the beam: appearing at the maximum bending moment of the beam, generally due to insufficient configuration of the bending reinforcement, such cracks appear on both sides at the same time, the bottom is large and small, and the crack does not extend to the compression zone without brittle failure. .

2 Bending cracks on the plate: Cracks appearing along the long direction of the plate in the lower part of the plate may occur simultaneously in two mutually perpendicular directions for the nearly square plate. The bottom of the plate is insufficient, and the bottom is large and small, and generally does not pass through. If it is penetrated, the plate thickness may be too small (the thicker surface of the plate has the same effect as the plate thickness is too small). Cracks generally do not develop to the edge of the board. If it develops to the edge of the board, other factors should be considered.

3 Early stress cracks on the board: cracks caused by premature demoulding or (and) early overloading, the cracks vary greatly depending on the demoulding (disassembly) and loading conditions. The most common crack caused by the simple demoulding is the splayed eight-character joint, which is similar to the crack of the negative rib of the slab. (There may be a negative sag at the same time.) It is more serious and generally penetrates. . If such a crack has a half-annular joint (and a lower intermediate joint), the concrete strength during demoulding is very low. The cracks in the early overload are similar to the general stress cracks of the plate, and are generally heavy.

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Problems concerning the detection and identification of cracks in houses and cracks in houses -

Crack treatment is a problem that is often encountered in the field of building repair and reinforcement. Crack treatment is a process of grouting, filling, repairing and repairing cracks and cracks generated in buildings.

Various cracking phenomena and crack damage caused by reinforced concrete structures are repaired and repaired with epoxy resin low-pressure grouting pulp, which can achieve the expected strength and prolong the service life of the structure without affecting the production operation. The construction is quick and convenient, does not require large-scale mechanical operations, and the reinforcement effect is safe and reliable.

Crack repair method:

1 Surface sealing method: For the micro-independent cracks (ω≤0.2mm) and reticular cracks on the concrete surface, the crack channel can be closed by the repairing glue with low viscosity and good permeability.

2 Injection method: repair the glue with low viscosity and high strength crack under a certain pressure. Inject into the crack cavity. Practical and independent cracks, penetrating cracks and honeycomb local defects of 0.1 ≤ ω ≤ 1.5 mm.

3 Pressure grouting method: for large-scale structural penetrating cracks, large-scale honeycomb defects of large-volume concrete and deep and flawed cracks.

4 Filling and sealing method: a V-shaped groove with a groove depth of not less than 20 mm and a groove width of not less than 15 mm is formed on the surface of the member along the crack, and then filled with a modified epoxy mortar or an elastic caulking material. It is used to treat active cracks and static cracks with ω ≥ 0.5mm.

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