Deformation joints of walls, what is deformation joints

Deformation joints include expansion joints, settlement joints and shockproof joints, which are used to ensure that the house can have some free expansion and contraction when the temperature changes, the foundation is uneven settlement or the foundation is uneven, so as to prevent the wall from cracking and structural damage. When the height, load and structural form of the adjacent parts of the house are very different and the foundation is weak, the house may produce uneven settlement, resulting in cracks in some weak parts. The function of the settlement joint is to prevent the uneven subsidence of the building, which is generally disconnected from the bottom of the foundation (which is also the main difference between the expansion joint and the settlement joint), and runs through the full height of the building.

The settlement joint should have a foundation and a brick wall on each side. The principle of setting the settlement joint is:

1) Complex plane and body shape turning parts of the building;

2) The height and load of the building are quite different;

3) the appropriate part of the excessively long building;

4) There are significant differences in the compressibility of foundation soil;

5) The methods of foundation treatment are obviously different;

6) The different types of foundations of buildings and the junction of the houses built in stages. In order to prevent the destruction of the house, the house is divided into several independent parts with simple shape and uniform structural stiffness by using shockproof joints. The width of the seismic joint is determined according to the height of the building and the intensity of the area, and the minimum gap size is 50mm 70mm.

There should be walls on both sides of the joint, and the gap should start from the top surface of the foundation and run through the full height of the building. In the fortified area, when the building needs to be equipped with expansion joints or settlement joints, it should be treated as a seismic joint.

The deformation joint is set up by the building considering the uneven settlement, so it will run through the building, so that the internal and external walls will exist, but the wall at the deformation joint is not necessarily a load-bearing wall, which depends on the structural design.

The deformation joint is to avoid the gap set on the building due to the influence of temperature changes, uneven settlement of the foundation, etc.

Deformation joints are a general term for expansion joints, settlement joints, and shockproof joints. Buildings are often deformed under the action of external factors, leading to cracking and even destruction. A deformation joint is a construction joint that is reserved for this situation.

As the houses built by people cover an area larger and larger, and the structure becomes more and more complex, the magical deformation joint has been produced in accordance with the development of the times, and its appearance provides a certain guarantee for the safety of the house we live in now, and has become an important part of our lives.

In house construction, the expansion joint is to consider that the building is too long, when the temperature changes, the substructure such as the substructure buried in the soil inner wall foundation or the strip foundation or box foundation under the column is less affected by the temperature deformation, so that the lower part of the superstructure is more affected by the constraint than the above, so when the temperature changes, it may lead to the cracks of the superstructure, and the expansion joint can ensure that the main stressed members are not damaged due to temperature stress. Expansion joints in bridge structures prevent temperature stresses from generating excessive additional stresses in superstatically determined structures, leading to structural damage. Expansion joints can effectively control the cracking of concrete in the construction of large-volume concrete.

In summary, expansion joints are installed at small loads in order to reduce the adverse effects of temperature stress.

Settlement joints are set up to prevent cracks or damage in the superstructure caused by uneven foundation settlement, such as in the case of many differences in floor height, or uneven foundation soil or connection between old and new buildings. The settlement joint needs to disconnect the foundation, but the expansion joint can be uninterrupted, so the settlement joint can also be used as an expansion joint.

Shockproof joints are to prevent the stiffness of the two parts of the superstructure from being different and the vibration frequency and deformation in the ** are inconsistent and cause serious seismic damage. The anti-seismic joints should be of sufficient width, otherwise they will collide due to the different vibration periods and phase angles of the two parts of the house, which will lead to more serious consequences.

The deformation joint is a joint reserved in the building structure of large shopping malls, factories and commercial houses, in order to prevent the house from collapsing due to ultra-width.

Both the interior and the exterior walls are available.

Reasons for wall deformation:

1. Material problems.

Due to the light bulk density of lightweight blocks, it has great advantages over red bricks when used as non-load-bearing walls, but it also has its disadvantages, one is that the shrinkage rate is larger than that of clay bricks, and with the reduction of water content, the material will produce a large dry shrinkage deformation, which is easy to cause cracks of different degrees;

Second, the secondary shrinkage of the block after moisture, the shrinkage of the material will expand after moisture, and the dry shrinkage deformation will occur after dehydration, causing cracks in the wall; Third, the tensile and shear strength of block masonry is poor, only 50% of that of clay bricks;

Fourth, the quality of the block is unstable. Due to the defects of the block itself, some cracks are caused, such as the inverted figure-eight cracks symmetrically distributed in the middle of the longitudinal walls inside and outside the house, the oblique cracks or vertical cracks that appear on the side of the window sill on the first to second floors of the building, the horizontal cracks and horizontal corner cracks that appear under the roof ring beam, and the vertical cracks that appear on the large wall surface with heavy bottom and lighter top.

2. Design issues.

The designer attaches great importance to the strength design and ignores the anti-crack structural measures. For a long time, people are accustomed to all kinds of cracks in masonry structures, and the designers generally make the necessary calculations in terms of strength, and most of them refer to national standards or standard atlases for structural measures, and rarely put forward relevant anti-crack requirements and measures alone, and do not investigate or summarize the feasibility of these measures.

3. Construction problems.

The construction unit lacks training and practice, and the construction methods, tools, mortar, etc. all follow the practice of clay sintered bricks, lack of experience in masonry height and humidity control, and the horizontal ash joints and vertical ash joints are not full in the construction process, which weakens the tensile and shear resistance of the wall and the instability of the masonry level of the workers all lead to cracks in the wall.

Deformation joints usually exist in both exterior and interior walls, mainly because buildings are often deformed under the action of external factors, resulting in cracking and even destruction. A deformation joint is a construction joint that is reserved for this situation.

Deformation joint is to avoid the building due to temperature changes, uneven settlement of the foundation, etc.

Deformation joints can be divided into three types: expansion joints, settlement joints, and shockproof joints, which are available on both interior and exterior walls, and not only on walls.

Building components will expand and contract due to changes in temperature and humidity and other factors. For this purpose, vertical gaps are usually set up in the appropriate parts of the building, and the walls, floor layers, roofs and other components of the house are connected from the foundation.

Classification of wall deformation joints: cover plate type, card lock type, seismic type, rubber embedded flat type, V-shaped.

The cover plate type wall deformation joint is suitable for the flat joint of the expansion joint of the external wall of the building, which is fixed on the front of the wall joint on both sides, and the slide bar is moved to ensure the free expansion and contraction of the central plate, which is widely used in the expansion joint of the external wall. Exterior wall deformation joint cover plate type EM can be used in 75-500mm joint width, can also be customized according to the needs of the product, the company also has a variety of specifications of the base to choose from (ordinary type, embedded rubber strip type, heightened and thickened type), fully meet the needs of the majority of construction, deformation joint cover plate color can be customized spraying, spraying process can be selected powder or fluorocarbon, cover thickness is 1mm-4mm for selection. The cover plate type deformation joint can be made of aluminum alloy or stainless steel.

Lock-type wall deformation joint device EL is telescopic by a freely moving L-shaped central plate, one side of the central plate is fixed on the pedestal surface of the building, and the other side is pressed between the aluminum alloy pedestals, and its horizontal state can be maintained when the building is telescopic and deformed, the aluminum alloy pedestal specifications are 10mm*40mm and 10mm*50mm are optional, and the thickness of the central cover plate is proportional to the width of the seam, and the common specifications are 1mm.

The rubber embedded flat wall deformation joint is characterized by a combination of high-elasticity thermoplastic strips and aluminum alloy frames, which can withstand the settlement, expansion and contraction of the building, and the deformation of the building in all aspects. The inner layer is equipped with an elastic hose to ensure excellent dust and high waterproof performance and seismic resistance, and the surface of the exterior wall is smooth and beautiful after installation. The requirements for the internal treatment of the expansion joint are high, keep the top and bottom straight, can withstand the heavy and elastic and all-round deformation of the building, has excellent waterproof performance and seismic performance, and the outer rubber can match the color of the exterior wall.

The V-shaped wall deformation joint is made of V-shaped products by bending the middle of the flat plate, and the building is subjected to V-shaped force when the building expands and contracts, and the advantage is not limited by the straightness of the joint.

Exterior wall deformation joints need to be inspected first, the structural details should be checked, installed in the center of the deformation joint, the adhesive should be applied, and the base should be placed into the notch.

1. Check the notch.

Before installation, the notch should be carefully inspected to see if it meets the product requirements, the excess part should be chiseled, the defective part should be repaired, and the part that is too deep and too wide should be reinforced with straight ribs to ensure the straightness and firmness of the notch.

2. View the construction details.

The floor floor deformation joint installation road should meet the requirements of the structural details of this atlas, if it cannot be satisfied, it should be made of groove or abutment, and fixed with expansion bolts with the main structure of reinforced concrete. The minimum depth of embedding is 40mm with the expansion bolt of M6 and 50mm with the expansion bolt of M8.

3. Install in the center of the deformation joint.

During installation, the center of the deformation joint is taken as the base point, and according to the selected model, the two sides are lofed according to the requirements of the atlas to determine the position of the fixed aluminum alloy base. Use the same method to determine the position of the expansion bolt, and the spacing meets the requirements of the installation drawing. Install the fire barrier belt according to the actual requirements.

4. Adhesive brushing.

Brush the gap with a special base adhesive on both sides of the base and the waterstop, and lay the waterstop flat on the concrete base and compact it with corresponding tools. After the waterstop is fixed, there shall be no bubbles or openings in the joint parts of the concrete on both sides.

5. Put the base into the notch.

Put the aluminum alloy base into the notch, adjust the design elevation, make the longitudinal slope and cross slope consistent with the decorative surface, and fix the aluminum alloy base with expansion bolts.

The exterior wall is well protected by the finished product

Individual seams should be filled with caulking glue and scraped flat. Special attention should be paid to the joint treatment of roof joints. Special nodes and accessories are specially processed by the manufacturer.

For details, please refer to the flat joint diagram of roof deformation joints. Handle two different types of deformation and installation according to the node diagram. For details, please refer to the connection structure between roof deformation joints and exterior walls.

At this stage, how can construction enterprises carry out the construction of internal wall deformation joints? What are the construction precautions? The following is the relevant content of the professional construction terminology of the interior wall deformation joint practice of Zhongda Consulting, and the basic situation is as follows:

The structure of deformation joints and expansion joints must meet the requirements of deformation of the building structure in the horizontal direction. In order to prevent wind and rain from intruding into the room, the expansion joints on the exterior wall are required to be filled with elastic, water-repellent materials that are not easy to be extruded. Commonly used materials are asphalt hemp wire, asphalt-impregnated wood wool board, neoprene, styrofoam, etc.

The seam must also be covered with galvanized iron sheet, aluminum plate or plastic plate.

At this stage, the practice of building interior wall deformation joints mainly includes: (1) metal cover plate type exterior wall deformation joint method (2) metal lock type exterior wall deformation joint method (3) rubber embedded flat exterior wall deformation joint method (4) seismic type exterior wall deformation joint method four construction methods, in the construction of interior wall deformation joint, the precautions are as follows:

If the drawings do not indicate a series of models of exterior wall deformation joints, the construction party should take the initiative to ask the designer for a detailed description of the node, or communicate with the manufacturer of the deformation joints, and confirm the model of the exterior wall deformation joints based on the atlas of the exterior wall deformation joints to prevent blind construction, leaving the owner with hidden dangers in the quality of the exterior wall deformation joints.

1) The two sides of the iron sheet of the cover seam of the settlement joint of the outer wall are fixed, and the long round hole is made of insufficient arc and the expansion joint node is mixed up, when the uneven settlement of the wall on both sides occurs, the vertical expansion and contraction of the iron sheet of the cover joint is insufficient, so that the wall on both sides of the vertical joint is broken, or the fixed steel nail is separated from the iron sheet, forming a quality hazard.

2) The deformation joint of the exterior wall, especially the deformation joint dominated by uneven settlement, when the overlapping cover joint of two small corrugated aluminum alloy plates is adopted, the middle part of the overlap of the two plates is riveted with rivets, instead of the oblong vertical sliding hole, which can not be freely expanded, and it is easy to cause the surface layer of the wall on both sides of the vertical joint to be cracked due to improper treatment, forming a potential quality hazard.

3) The expansion joints or seismic joints of the exterior wall are made of arc-shaped stainless steel plates, but the arch arc is insufficient, which can not meet the expansion and contraction requirements of the wall due to temperature changes or the action of the wall, forming a hidden quality hazard. Songbi.

4) The decorative surface layer at the deformation joint of the mixed wall is covered on the outer surface of the iron sheet of the cover joint, which causes the ash of this part of the finish to be not firmly bonded and forms a hidden quality hazard.

5) If the iron sheet of the cover seam is not fixed firmly, it is directly fixed on the brick masonry with steel nails.