Research And Application Of Jointless Construction Technology Of Ultra-large Area Concrete Ground Structure

With the development of national economy, the building which has ultra-length and ultra-wide in size, has got more and more application in such fields as large-scale public buildings , industrial factory buildings , marts and so on,. According to the integrity of the building and structure, function of use and demand of limited time for a project, we put forward the requirement of jointless construction to the ultra-large area concrete ground structure of the building. But in the past, the codes adopted expansion joints and post-pouring zone to solve the problem of temperature stress and shrinkage stress, The researches to the ultra-large area concrete ground structure without set joint(jointless construction) ,which was out of the prescript of codes, were relatively deficient, so its application was limited greatly. The design and construction mainly depended on past practical experiences, which caused a large number of wastes and hidden dangers in projects. So this research in this paper has important actual project value.Base on the summarization and analyses of the current researches at home and abroad, the paper discusses the feasibility on theory to the ultra-area concrete ground structure from the theory of concrete strain-cracking, combine the industrial factory of changsha cigarette factory 20520m2 concrete ground structure, and the on-the-spot test to the project lasted nearly two months, make every efforts to establish a set of ultra-large area concrete ground structure temperatures stress and shrinkage stress analytical calculation method, puts forward the corresponding design method and construction craft. The main research contents include the following several respects:1) Analyze the theory of strain-cracking and stress calculation method of ultra-large area concrete ground structure, select calculation modal that is closed to ultra-large area concrete ground structure, and calculate interval construction [L] of jointless construction, and prove the feasibility on theoretically.2) Use the relation between shrinkage, creep, temperature and concrete stress, combine the project of changsha cigarette factory, carried on construction stage cracking fracture checking computations analyze. Use finite element analysis program ANSYS, carry on cracking fracture checking computations analyze under normally use stage difference temperature in difference seasonal.3) From the design, materials, construct craft and temperature to stress test on- the-spot, analyze the cracking control measures, prove to material selection, mix ratio design and optimizing, concrete placing and cure etc in practice, and the on-the-spot test(temperature and stress in construction stage) to the project lasted nearly two months, conclude the temperature and stress change rule during the course of construction.The research of this paper based on theory and practice, makes grate efforts to conclude succinct effective ultra-area concrete ground structural design and comparatively perfect construction control measure, and form a set of effectual methods, which has certain guidance and suitable value to the familiar projects in the future.