Expansion joints in the project construction has a huge role, why do we have to set the expansion joint for the following reasons:
The building is influenced by the temperature change due to thermal expansion and contraction, the temperature stress in the internal structure, when the building length exceeds a certain limit, the building level changes more or structure change is large, building caused by large deformation and crack expansion and contraction. To prevent the occurrence of such a situation, often along the length direction of the building at a distance or gap in the structure type change, buildings will be disconnected.
Requirements: the building of the wall, floor, roof and other parts of the ground above all open. The basic part of the temperature changes due to the smaller, so it does not need to be disconnected.
According to the length of the building, structure type and the rigidity of the house and roof have set the temperature or heat insulation layer to consider. Among them, the building length is mainly related to the temperature stress accumulation size; structure type and roof stiffness is mainly related to temperature stress effect on other parts of the structure is easy to transfer and whether or not. Set the temperature or the heat insulation layer is related to the structure directly affected by the influence of temperature stress.
Spacing of expansion joints
(1) the distance between the frame and the expansion joint of the frame shear wall can be based on the numerical value of the frame structure and the shear wall structure in the concrete layout of the structure。
(2) when the roof has no heat preservation or heat insulation measures, the shrinkage of concrete is larger or the distance between the expansion joints should be reduced due to the longer construction exposure time。
(3) in the climate dry region, the structure of the hot and heavy rain in summer, the distance between the expansion joints is reduced.
To increase the maximum distance of the expansion joints, or even without expansion joints, the key is how to reduce the temperature stress and concrete shrinkage stress, as well as how to improve the crack resistance of concrete components.
Construction measures and construction measures for the appropriate distance between the expa
1, the top, bottom, side gable and longitudinal wall temperature variation of large parts of the increase of reinforcement ratio;
2, the top layer of insulation measures to strengthen the external thermal insulation layer;
3, each 30-40M spacing set aside after the construction of the pouring belt, bandwidth 800 - 1000MM, reinforced with lap joints, after pouring concrete should be poured two months after;
4, the top floor of the structure with a small stiffness or the top of the structure of the local temperature, the structure is divided into a short length of section;
5, the use of small shrinkage of cement, reduce the amount of cement, adding a suitable admixture in the concrete;
6, to improve the structure of the floor of each floor reinforcement ratio or the use of partially prestressed.