The reason for the vertical cracks in the shear wall of the core tube about 7 0 m long

The reasons are as follows: the vertical cracks that appear regularly in the shear wall, from the described situation, are estimated to be caused by the horizontal contraction of the concrete in the process of reducing the temperature of the shear wall by the constraints of the beam or column, and have a certain crack resistance; In addition, it is then reduced, and this tensile stress exceeds the tensile strength of the concrete at that time. Or, in a continuously damp basement environment.

If the shrinkage of impermeable concrete mixed with expansion agent is constrained or restricted, the pouring sequence of the column is very important to determine the cause of the crack, so there is no crack in the horizontal direction, and the concrete temperature rises first. After the concrete is poured, the cement hydration is exothermic. There is no necessary relationship between the impermeability of concrete and its crack resistance.

Compression in the vertical direction creates tensile stress inside the concrete. In the process of temperature reduction, the concrete will also shrink by itself, and cracks will appear, and there will be shear walls and beams with a certain crack resistance. 0 mm, mixed with fiber concrete, is able to compensate for shrinkage, accompanied by volumetric shrinkage (thermal expansion and cold contraction).

The wall inside the core is called a shear wall. In addition to bearing the vertical force, the shear wall is more important to bear the horizontal load, so it is called the shear wall. The wall in the core tube is also mainly subjected to horizontal force, so it is also a shear wall.

The shear wall structure and the core tube structure are from the arrangement. The shear wall structure is formed by the shear wall distributed in the x and y directions, which can withstand both vertical and horizontal forces. The core tube structure refers to the structure in which the horizontal force is mainly borne by the core area structure, and the vertical force is mainly borne by the peripheral structure.

Hello. I think this project is quite serious.

Generally, it will be the following problems:

1. There is a problem with the concrete ratio of the shear wall.

2. Improper structural design considerations.

3. The later maintenance is not in accordance with the regulations.

It is recommended that you contact the design unit as soon as possible to investigate and analyze the situation as soon as possible to avoid unnecessary losses.

If it does not affect the structural safety of the building, it only needs to be repaired properly.

Good luck!

Shear force, also known as shear force: "Shear" is a relative dislocation deformation phenomenon that occurs in the cross-section of a material along the direction of action of a pair of transverse external forces (i.e., forces parallel to the applied surface) that are very close to each other and of the same magnitude and point to the opposite direction. The force that causes a material to shear deformation is known as shear or shear force.

The section in which shear deformation occurs is called a shear plane. The key to determining whether the material is "sheared" is whether the cross-section of the material is relatively dislocated.

1. When the vertical load-bearing members in the building are mainly borne by the wall, the wall not only bears the vertical load from the horizontal members, but also bears the horizontal action from the wind or the first action. Hence the name of the shear wall (the seismic code defines it as the seismic wall).

2. The shear wall is the dividing wall and the enclosure wall of the building, so the layout of the wall must meet the requirements of the building layout and the structural layout at the same time.

A shear wall structure is a structure that uses the interior or exterior walls of a building to make shear walls to bear vertical and horizontal loads. Shear walls are generally reinforced concrete walls that can be the same height and width as the entire building. Because the main load it bears is the horizontal load, which makes it subject to shear bending, it is called a shear wall.

The lateral stiffness of the shear wall structure is large, the deformation is small, and it is both load-bearing and enclosure, which is suitable for residential and tourist buildings.

The steel bar of the horizontal shear wall should be 2 rows, it is estimated that your home is also 2 rows, and the distance from the steel bar to the edge (that is, the thickness of the protective layer) should be at least greater than or equal to 15mm, which is stipulated by the state!

If there is a problem in your home, it should be a quality problem, it should be caused by bent steel bars, or uneven formwork, or low grade concrete, etc.

Shear walls are generally set up with two rows of steel bars, which are distributed on both sides of the inside and outside! However, there are also three rows or more!

But the location is much the same! The inner and outer steel bars should have a protective layer of more than 2 cm, and if you add stucco, the steel bars are at least 5 cm away from the outside of the wall!

So it is impossible to see the rust spots of the steel bar on the normal shear wall!

What you're talking about is purely due to construction reasons!

If a situation like this is not dealt with in time, the steel bar will rot badly, and the consequences will be very serious!

I think that such an obvious thing can be sloppy in construction, and it is recommended that you take a closer look at whether there are any hidden dangers elsewhere!

Shear walls with a wall thickness of more than 140mm should be two rows of steel bars. The reinforcing bars are arranged on both sides of the wall, and the distance from the rebar to the outer skin of the wall should be 15mm.

The leakage is obviously influential, and the supervisor sees it and is looking for trouble again. . . It's pouring that I didn't adjust the rebar. . . It is estimated that there is no reinforcement protection pad block. It's serious...

It is also possible that the template is left by the tension, and it is nothing, and you can see it clearly, if the point shape is the tension, if it is the line type, it is the leaking rib.

The shear wall you are talking about should be a wool wall that has not yet been plastered, and its steel bar (horizontal steel bar) protective layer is generally 15mm, and there are usually two situations:

First, the protective layer is too thin or almost no protective layer caused by the deviation of the steel bar, causing the steel bar to corrode. In this case, horizontal rust marks can be seen with a spacing of about 100 to 200 mm

The second is that there is floating rust on the surface of the steel formwork when the formwork is supported, and the rust spots are glued to the concrete after the formwork is removed. The rust in this case should be a relatively uniform piece of rust.

If it is the rust spot caused by the main reinforcement, the rust spot on the surface should be removed, and the cement mortar plastering should be used to protect the steel bar from rusting. Of course, since it is a shear wall for the newly received commercial housing, it should be negotiated with the property management company to make it satisfactory.

Supplement: the protective layer of the floor steel bar (the distance between the steel bar in the floor slab and the outermost layer of the floor slab) is 10mm, and the corrosion has an impact on the force of the steel bar, because it will reduce the cross-sectional area of the steel bar.

The size of the protective layer is specified in the design drawing, according to the design code, the general floor slab is 10mm, and the shear wall is 15mm or equal to the diameter of the main reinforcement.

(1) All the vertical loads and horizontal forces in the shear wall structure are borne by the reinforced concrete wall, so the shear wall should be arranged along the main axis of the plane.

1) When rectangular, L-shaped and T-shaped planes, the shear wall is arranged along the direction of the two orthogonal main axes; Shear wall structure.

2) The triangular and Y-shaped planes can be arranged in three directions; 3) Regular polygonal, circular and arc planes can be arranged along the radial and circumferential directions.

2) The length of the monolithic shear wall should not be too large

1) The shear wall with a large length and great stiffness will make the period of the structure too short, and the force is too large and uneconomical;

2) When the shear wall is in the bending working state, it can have enough ductility, so the shear wall should be high and thin, if the shear wall is too long, a low and wide shear wall will be formed, and it will be damaged by the shear, and the shear wall is brittle, which is not conducive to earthquake resistance. Therefore, when the continuous shear wall on the same axis is too long, the floor slab or small connecting beam should be divided into several wall segments, and the height-width ratio of each wall segment should not be less than 2. Each wall segment can be a monolithic wall, a small open wall, or a limb wall.

The width of each wall limb should not be greater than 8 0m, so as to ensure that the wall limb is controlled by the flexural bearing capacity and give full play to the role of vertical distribution of reinforcement. In the calculation of internal forces, the role of the floor slab or weak connecting beam between the wall segments is not taken into account, and each wall segment is calculated as an independent shear wall.

3) The number of shear walls should be reasonably determined in the scheme stage, and it is better to be symmetrical, uniform and appropriate.

1) The bay of the shear wall is 6 0 7 0 m large bay, which is more economical and reasonable than the 3 0-3 9m small bay, reduces the amount of material, and increases the building use area.

2) The basic period of the shear wall structure is controlled at c – the total gravity load of the building. If the cycle is too short and the force is too large, it is advisable to reduce the number of walls.

4) The methods for adjusting the stiffness of the shear wall structure are:

1) Appropriately reduce the thickness of the shear wall;

2) reduce the height of the connecting beam;

3) Increase the width of door and window openings;

4) Set up a construction hole for the long wall limb and divide it into two wall limbs. When the length of more than 8 0 m is divided into small wall limbs, the construction hole should be divided.

Vertically arranged. 1) The shear wall should continue vertically throughout the building, up to the top and down to the bottom, and the middle floor should not be interrupted. The discontinuity of the shear wall can cause a sudden change in stiffness, which is very unfavorable for seismic resistance.

2) When part of the shear wall is canceled on the top floor, the rest of the shear wall should be structurally strengthened.

3) When the bottom layer cancels part of the shear wall, a conversion layer should be set.

4) In order to avoid sudden changes in stiffness, the thickness of the shear wall should be changed according to the stages, and the thickness should be reduced to 50-l00mm each time, and should not be too large, so that the stiffness of the wall should be changed uniformly and continuously. The change of thickness and the change of concrete strength grade should be staggered floors.

5) When the thickness changes, both sides should be adducted at the same time. The exterior wall and elevator hall wall can be retracted on one side only.

The reason for the problem is very detailed, and the standard basis for the reinforcement protective layer is the design and construction specifications of reinforced concrete.

The problem of the wall is good to say, the main problem is the floor slab, if the leakage phenomenon is very common, it is a greater safety hazard, should be negotiated with the developer to solve.

The upstairs analyzed the reasons in great detail, so I won't say much.

The stipulation is the "Concrete Structure Code" (if the landlord is a layman, you can consult the 03G101-1 atlas, this is convenient, for those who are engaged in construction all understand, have seen), for the local exposed ribs, the landlord still accepts it, it is impossible to smash the components for the local exposed ribs, because then the re-structural construction may make the seismic resistance, stress, etc. is not as strong as the original exposed ribs. Of course, it has to be said that the continuous corrosion of the steel bars without the concrete protective layer eventually leads to the accelerated destruction of the building structure.

Most of the solutions are to increase the protective layer by plastering and protecting the steel bar. It is necessary to believe that under normal circumstances, the house is not so easy to collapse, and the general architectural design service life is 50 years, but in essence, it has not been lived in for 50 years.

If possible, just check out, but if you can't do it, you can only call the developer to lose money or find the local construction department to solve it. In the end, it's still the same sentence: if you stay, you can rest assured, and you won't cross.

The situation you are talking about is that the protective layer of the rebar is small or not! The protective layer of the main reinforcement of the shear wall stipulated by the state is not less than 20mm, and the protective layer of the roof is not less than. You should go to the developer to solve the problem.

The leakage is obviously influential, and the supervisor sees it and is looking for trouble again. . . It's pouring that I didn't adjust the rebar. . . It is estimated that there is no reinforcement protection pad block. It's serious...

It is also possible that the template is left by the tension, and it is nothing, and you can see it clearly, if the point shape is the tension, if it is the line type, it is the leaking rib.

Unified Standard for Acceptance of Construction Quality of Construction Projects GB50300-2001 "Code for Acceptance of Construction Quality of Concrete Structure Engineering" GB50204-92 You can go to the library to buy two such specifications, which have corresponding content, which can completely show that your house has a big mistake in the construction process.

The construction unit is based on the drawings to the construction, the drawings have a description, the design of the protective layer thickness of the root ring, the strength of the concrete and so on.

Leakage occurs from time to time in construction, which is an abnormal normal phenomenon, and it can be understood if there is less. The shear wall is not rusted on the plaster, and the rust point of the floor may be caused by the horse's pedal, if it is the main reinforcement, it is a quality problem.

The reasons for the insufficient thickness of the protective layer of the shear wall are as follows: 1. The rust removal of the steel bar is not complete when the steel bar is poured at the beginning; 2. When the formwork is supported, there is no cushion protective layer cushion block or the cushion block falls off; 3. The alkali content of concrete is large, and the corrosion of steel bars is serious.

There is no good way to deal with it, you use oxalic acid to brush the wall to try, and when it dries, you can scrape the putty and brush the paint.

Shear walls with a wall thickness of more than 140mm should be two rows of steel bars. The reinforcing bars are arranged on both sides of the wall, and the distance from the rebar to the outer skin of the wall should be 15mm.

Claim it, it's not a problem to get tens of thousands of dollars.

Then get rid of the house.

Let's change houses.

This house is extremely unsafe.

The outermost layer of steel bars and shear walls shall not be lower than centimeters is made by national building standards. Different layers of environmental protection are also different.

There are a lot of embroidery points, which may be that the protective layer is not enough.

Construction quality issues. Find a developer

In the process of applying codes to design, structural engineers often encounter difficulties in recognizing certain code provisions.

The operability of the solution and the answer to the provisions is not strong, or some engineering difficulties that are not covered by some specifications. Experts with rich design experience are specially invited to combine their understanding and experience in actual engineering, combined with the relevant provisions of the specification and engineering examples, to deeply analyze the difficulties of the specification, and give alternative methods and design suggestions for the problems that cannot be directly applied to the specification, so as to help designers make reasonable and economical engineering design.