The Crack Control Technology Of Over-length Basement Concrete Structure

With the development of the national economy, land supply has become tighter, the construction of the underground garage is growing. Situation underground garage design is: single garage area is growing, the length of the garage is increasing, more and more layers, this is a design problem.In China, the China Institute of Water Resources and Hydropower Research Academician Zhu Bofang had done the research of temperature stress and fracture controlled hydraulic concrete structures as early as1970s; In1980s, Ye Linchang, the director of the national building waterproof association, He Analyzed concrete performance and temperature. In recent years, Professor Wang Tiemeng,a crack control expert, write a book,"engineering structure crack control",In his book,He systematically expounded the mechanism of temperature cracks in the concrete method, crack control of mass concrete structure stress theory.He also put forward the design principle of "Resistance" and "Release", according to the engineering practice that the expansion joint spacing and crack control formula, and provides strong technical support for the designers." The code for design of concrete structure" prescribed temperature expansion length of more than55m should be broken structures is arranged in the middle part of the joint. But, underground garage structure is not pleasant for joints.Designers only take the measures of "after pouring belt" and "expansion agent" to control the crack. It has been proved that these two measures can not prevent the cracks of the over-length basement.It can not find an effective method of calculation to solve the "secondary internal forces". Usually, the calculated internal forces is very large, can not be implemented. This is a major problem for over-length basement.First,this paper describes the harm of basement crack, analyze the causes of cracks,Then through the analysis of engineering concrete in the hardening stage, the temperature variation in the internal situation of structural member.Finally, take the use of "temperature difference of comprehensive calculation" on the over-length basement concrete structure. In this paper, the author tries to make the design and construction of a wide range of technical research combined with their focus on engineering practice, by adjusting the use of the software, the structural arrangement, the calculation parameters selection, calculation and analysis results, and gradually find a solution to the basement cracks some way. During construction services, through on-site construction, survey, measurement and other means, to understand the formation of cracks in the basement of the status, then by analyzing the common problem of the formation of cracks in the basement, to find out ways to solve practical problems.Through the crack research of the over-length basement concrete structure, this article is intended to understand the reasons for the formation of cracks, more importantly, is to be able to provide reference for the The crack control technology of over-length basement concrete structure. By introducing the "temperature difference of comprehensive calculation ",provides a concise, practical calculation method for the structure designer.