What is a shear wall?
Shear walls are divided into plane shear walls and tube shear walls. Plane shear wall is used in reinforced concrete frame structure, raised slab structure and flat floor system. In order to increase the rigidity, strength and collapse resistance of the structure, reinforced concrete shear walls can be cast-in-place or partially prefabricated. Cast-in-place shear wall and surrounding beams and columns are poured at the same time, which has good integrity. The tube shear wall is used in high-rise buildings, towering structures and suspended structures, and is surrounded by partition walls of elevator machine room, stairwell, equipment room and auxiliary rooms. The tube walls are all cast-in-place reinforced concrete walls, and their stiffness and strength are higher than those of plane shear walls, which can bear larger horizontal loads.
Walls can be divided into load-bearing walls and shear walls according to their mechanical characteristics. The former mainly bears vertical loads, such as masonry walls. The latter mainly bears horizontal load. In the seismic fortification area,
Horizontal loads are mainly caused by horizontal earthquakes, so shear walls are sometimes called seismic walls. Shear walls can be divided into steel plate shear walls, reinforced concrete shear walls and reinforced block shear walls according to structural materials. Among them, reinforced concrete shear wall is the most commonly used.
Cracks in shear walls are common, so how to deal with them? Let me tell you something about it.
Causes of cracks in shear wall
Judging from the mix proportion, strength and construction technology of concrete, it conforms to relevant specifications.
According to the principle of mechanics, the distribution and shape of cracks are different for different reasons. For example, cracks caused by principal stress and secondary stress are mostly distributed at the position of 45 with the long side direction of members, which is often called 45 oblique cracks in engineering mechanics. Through our observation after removing the outer mold, when no external load is applied,
Early cracks have been produced, which are almost perpendicular to the bottom plate and distributed regularly, mostly at the edge of columns or between two columns, which is consistent with the distribution and shape of cracks produced by shear walls in basements of most similar projects. Therefore, it is not difficult to analyze that the causes of shear wall cracks are not caused by stress, but by deformation changes. Qualitative through design: cracks in basement shear wall do not affect the structure. But there are three main reasons:
1, shrinkage deformation of concrete;
2. Structural deformation caused by temperature change;
3. There may be some reasons why there is no expansion joint or post-pouring belt in the basement.
Treatment method of cracks in basement shear wall
1. Open a V-shaped groove with a depth of 15-20mm along the cracks on both sides of the shear wall, and pour epoxy resin into the groove for embedded reinforcement.
2. Add two layers of bonded polyurethane glass fiber net at the crack, each side is 300mm wide, and then waterproof.
Shear walls can be said to bear the weight of the whole house.
The quality of shear wall has a great influence on our life safety. In recent years, natural disasters such as earthquakes have occurred frequently. In this regard, the quality of shear walls must be good to resist natural disasters. Therefore, shear walls should be inspected frequently at ordinary times, and cracks should be handled in time. I hope my introduction is helpful to you.