The Study Of The Cracks Based On The Steel Preheating Steel And Concrete Composite Shear Wall During The Construction

At present, the development of China’s construction industry and construction technology level is rising. Across the country are gradually emerging super high-rise buildings, and became a local landmark. In the high-rise buildings, the shear wall of the lower part of the steel plate concrete composite shear wall. Composite wall in order to meet the high strength of the structure, high pumping performance and other requirements, the use of high-strength and high-performance concrete. However, high strength and high performance concrete in the pouring process, due to the large amount of cement, produce a lot of heat of hydration, the early temperature shrinkage deformation is quite obvious, due to the constraint effect exists between concrete and steel plate, the stud, where is easy to produce larger stress and cracking of the structure of the development of serious adverse. So in the field of construction engineering construction technology, steel plate concrete composite shear wall structure concrete cracking problem has been a major problem in the industry.Now, in practical engineering, the method of preheating steel plate is used, in which the method is to preheat the pipe to the pipe, and the hot water can be used to preheat the steel plate. The main principle of the steel preheating is to the steel plate heat up ahead, to produce a certain pre expansion, as far as possible to shear wall steel plate and concrete shrinkage tends to be consistent, to control caused by the mutual constraint of the two uncoordinated deformation and lead to concrete cracking. The hot water pipe construction technology of steel preheating there are many uncertain factors, it is worth to explore, and constantly improve the anti-crack construction technology of the steel-concrete composite shear wallThe development of the finite element software promotes the generation of a large number of numerical analysis software. In this paper, the ANSYS finite element software is used for the numerical simulation of steel plate concrete composite shear wall. Successively simulates and analyses the heat of hydration of concrete with the rule of the development of the age, concrete and stud the stress variation with the age, and preheating plate technology, concrete principal stress change of the force. Finally, the following conclusions are drawn:(1) Preheating plate can effectively weaken the concrete main force, reduce the risk of cracking of concrete wall with steel plate shear wall. Previous studies have come to the preheating plate suitable time and suitable temperature, this paper verifies the availability of the theory, and on the water on the plate layout is explored. The results showed that if the volume of total volume of water layout is too small, the steel preheating adverse effect, between concrete and steel plate still exist larger uncoordinated deformation of concrete still appeared different degrees of cracks. The analysis results show that the total volume of the water pipe should not be less than 0.417 of the total volume of the steel plate. In the actual construction process, it is suggested that the range is between 0.45 and 0.625.(2) considering the constraints between the studs and concrete stress, obtained in the age of 1.5 days to five days in, constraints between the studs and concrete tensile stress has exceeded the tensile strength of concrete, cracking, cracks appeared, in the subsequent temperature drop stage, due to the constraint tensile force reduction, the growth of cracks tend to be small, if the width of the cracks is reduced to a small enough, so that cracks appear a certain degree of closure.(3) Under the action of hydration heat, the steel plate combined shear wall has experienced two processes: rapid heating and slow cooling.In this process, due to the combination of the wall in the air to the external release of heat, the external temperature is low, the inside and outside of the concrete with a large temperature difference.(4) ANSYS finite element software to simulation plate- concrete composite shear wall water of heat temperature changes with age, is also capable of simulating the composite wall early changes of stress and strain, and the simulation results have a certain reference value to the actual engineering.