Stress Analysis And Crack Control Of Two-way Super-long Structure With Multi-Tower Considering Concrete Shrinkage And Cooling Effect

With the acceleration of urban construction,land resources is becoming very rare and land costs in the cost of developers is getting higher and higher.Structure is developing into the sky.At the same time,we are accelerating the development of structures into underground space.Due to the use of functional needs,underground space often interlinked,forming a two-way super long structure.However,the upper structure often been designed as single-tower,naturally forming a two-way super long structure with towers,such as huge community and large-Commercial complex.Due to the use of functional requirements such as waterproof,there is no structural expansion joints in this kind of structure in underground space.In the case of structural cooling and concrete shrinkage,the structure will produce a large tensile stress and then lead to structural cracking.Therefore,it is necessary to study stress distribution law of two two-way super long structure with towers under the action of structure chilling and concrete shrinkage,and then take effective measures to control crack.This paper study the following structures using the finite element software Sap2000,taking the Changsha Meiqi project as the research background.These structures are: The single-tower structure locates the end of the two-way super long structure.The single-tower structure locates the central of the two-way super long structure.22 towers are arranged in the two-way super long structure.The internal force of the tower and the floor is studied by comparing and analyzing the internal forces of the beam,floor and column.In order to study the lowest temperature of the basement in winter,the team measured the indoor and outdoor temperature difference of three projects in Chongqing.Finally,through the use of groove seam and post-pouring joint,expansion concrete measures,the paper control the Changsha Meixi Lake project crack.Through this study,we draw the following conclusions:(1)The horizontal temperature stress of the independent tower under the cooling effect mainly concentrates on the connection part between the shear wall and the foundation wall,The deformation and horizontal stress of the floor are mainly concentrated on the first and second floor.(2)The tower has a large anti-side stiffness compared to the frame column.When the tower is arranged at the end of the structure,the non-moving point of the structure will approach the tower,which greatly reduces the lateral displacement of the large chassis frame near the tower.And increase the column top displacement of the distal two-way super-long structure.Increase the internal force of the whole frame beam and the plate,and reduce the internal force of the frame near the tower.The influence of the tower on the frame's large chassis diverges outwardly in a parabolic shape.The influence of the large chassis on the tower is mainly concentrated on the upper two layers of the large chassis and the shear wall beneath the large chassis.The bottom of the tower shear wall has the maximum tensile stress,and it is the most easily cracked area.(3)When the tower is arranged in the middle of the structure,the tower has little effect on the large chassis,and its main influence area is near the tower.For the tensile stress in the X direction,the existence of the tower will reduce the tensile stress on the left and right sides of the tower and increase tensile stress of the large chassis on both sides of the upper and lower sides of the tower.For the tensile in the Y direction,the existence of the tower will increase the tensile stress on the left and right sides of the tower and reduce tensile stress of the large chassis on both sides of the upper and lower sides of the tower but little effect.(4)The influence of the number of floors on the structural temperature stress can be neglected when the tower is more than two layers of the two-way super-long structure,which has little effect on the temperature stress of the two-way super long structure.(5)The column top displacement and column end bending moment is greatly reduced,when the tower is araanged.The stress on the floor of the multi-tower enclosed area will increase significantly.Groove can significantly reduce the structural temperature stress,with its structural crack control,it should try to penetrate the entire long structure,in order to avoid the end of the groove stress concentration.The tension between the towers is large,it is appropriate to use after the pouring and groove joints to release the concrete shrinkage and temperature stress,groove layout,should be between the middle of the tower.In subunits formed by dividing the two-way super-long structure from the groove,the tower should be in the middle of the sub-unit to reduce the temperature stress of the sub-unit.