| Common treatment methods for deformation joints |
Causes cracking or even destruction. The deformation joint is a construction joint reserved for this case. The deformation joint can be divided into three types: expansion joint, settlement joint and anti-vibration joint. Buildings often deform under the influence of external factors. Vertical joints are usually provided in appropriate parts of the building, and the expansion joint building members may expand and contract due to changes in temperature and humidity. to this end. From the foundation above, the wall, floor slab, roof and other components of the house are disconnected, and the building is separated into several independent parts, so that each part has room for expansion and contraction. The deformation is mainly caused by the temperature change, so the expansion joint is also called the temperature seam. The maximum spacing of a single expansion joint on a building shall be determined according to the building materials, structural form, usage, construction conditions, and changes in local temperature and humidity. The masonry structure is 100,150 meters, and the reinforced concrete structure is 3,575 meters. The concrete is 1020 meters, and there are corresponding regulations in the design specifications of various structures. It is necessary to meet the requirements for deformation of the building structure in the horizontal direction. The expansion joints on the outer wall, in order to prevent wind and rain from entering the room, require the use of elastic water-repellent materials that are not easily extruded. Commonly used materials are asphalt hemp, immersed asphalt wood board, neoprene, foam and so on. The seams must also be covered with galvanized iron, aluminum or plastic sheets. The disposal of the internal wall expansion joint varies with the interior decoration. It can be covered with wooden strips, wood boards, plastic plates, metal plates, etc. Floor floor expansion joints, which can be filled with asphalt and hemp in the seams, and cover the movable cover or rubber strip to prevent dust from falling to the next floor. The expansion joints of the roof are covered with galvanized iron sheets, aluminum sheets or prefabricated reinforced concrete slabs, focusing on waterproofing. Expansion joints in underground buildings, basements, etc., due to waterproof requirements, glass cloth linoleum, rubber sheets, galvanized iron sheets, copper sheets are often placed on the outside or bottom of the waterproof structural layer, and embedded or detachable water is used. Belt (such as rubber, plastic, metal, etc.) and fill the gap with asphalt mortar, asphalt hemp or immersed asphalt wood board. In the cast-in-place monolithic reinforced concrete building, since the concrete has large shrinkage deformation for a period of time after pouring, it will become stable later. This characteristic can be used to divide the long direction along the reinforced concrete structure into several sections. Leave the seam and wait for 12 months after the first phase of construction, then re-water the joint. This temporary temperature shrinkage joint, which is only preserved during construction, has the structure of expansion joints. It is called post-sealing seam, or shrink belt. The width of the post-sealing joint is generally 50100 cm, the spacing of the joints is about 2025 meters, and it should be combined with the joints during construction as much as possible; the filling data of the joints can be made of concrete mixed with aluminum powder. At present, the understanding is not consistent, and the regulations and practices of different countries are different. In the Federal Republic of Germany, the Soviet Union and some Eastern European countries, expansion joints and their maximum spacing problems are set in buildings. Strict expansion joint spacing is used to prevent cracks in the building. Japan, the United States, etc. are considering temperature stress in calculations, and generally no expansion joints are provided. The United Kingdom, France, etc. are more flexible. From the observance of the law in the 20th century, China explored the theory of building expansion joints, and put forward a preliminary theoretical basis to solve some engineering problems. The provisions on the width of expansion joints in China are shown in Table 1 [expansion width]. Or the height, load and structural form of the adjacent parts of the building are quite different. The settlement joint is built on a foundation with different soil properties and different properties. When the depth of the adjacent wall is very different, in order to prevent uneven settlement of the building and even the occurrence of staggered cracking, a vertical gap should be provided at the difference to divide the building into several independent units that can be freely settled. The significant difference between the settlement joint and the expansion joint is that the settlement joint is completely penetrated from the foundation of the building to the roof. The width of the settlement joint is related to the nature of the foundation and the height of the building (Table 2 [Settling Joint Width] The structure of the settlement joint is basically the same as that of the expansion joint, but the method of covering the seam must ensure that two adjacent units can freely settle. In the brick-concrete structure The foundation of the building on both sides of the settlement joint usually adopts two schemes: 1 picking the beam foundation, that is, the foundation of the side wall of the settlement joint is normally set, and the longitudinal wall of the other side is undertaken by the cantilevered picking beam, and the beam end is separately set. The foundation beam and the lightweight partition wall. 2 The double wall scheme is adopted, that is, the load-bearing wall is arranged on both sides of the settlement joint to ensure that each individual unit has a vertical and horizontal wall closed and the structure is good. When the distance between the two load-bearing walls is small, In order to overcome the eccentric stress of the foundation, an independent foundation which is staggered in two rows in a plane arrangement can be used, and the foundation beam of the wall is placed on the wall. The settlement joint also functions as a expansion joint, and the same building can be used in the same building. Combined settings, but expansion joints are not a substitute for settlement joints. Settlement joints in reinforced concrete frame structures usually use double-column cantilever beams or simply supported beams. In the earthquake zone, where expansion joints or settlement joints are installed, the width of the joints should be increased according to the earthquake requirements to prevent the two walls from colliding due to different amplitudes during the earthquake. The anti-seismic joints are required to see the building shockproof. |
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