The Study Of Overlength Basement Concrete Structure Crack Control Measures

Along with the booming development of China's overall strength and economic construction in recent years, the demand of biggish area concrete structures is growing and the large planar size building rapidly emerge. But in city, people tend to develop a large scale of underground space because of the problems of land deficiency for construction and "parking difficulty". For the reason of underground engineering have waterproof demand, it is difficult to setup permanent expansion joints in basement concrete structure than the over ground part. Therefore, it rarely set permanent expansion joint in the concrete structure design of basement in present. The cancel of permanent expansion joints in the concrete structure of basement provides good conditions for use, but it also brings a problem which must be solved in concrete structure design of basement that the seamless and the crack prevention research of the overlong concrete structure basement.Firstly, the analysis of cracking reasons, fracture type, crack harm of concrete structure have been done in this paper, and also the material selection, structure design, construction technology and insulation technology have been discussed to research the crack-proof technology of super-long basement concrete structure.Secondly, it takes the pilot project Shenyang Heng Long plaza as an example to study the seamless concrete structure. Shenyang Heng Long plaza is super-length structure, but doesn't set expansion joints after various comprehensive consideration which has brought great benefits to construction effect, structure layout and function etc,. The analysis of long-term shrinkage of concrete and temperature effect proves that the scheme of does not set expansion joints in the structure is completely feasible.Adopting ETABS V9.0.8 structure analysis software, carry out the model analysis to study the effects of the seamless design (mainly temperature and shrinkage effect) which mainly includes vertical component internal force analysis, floor stress analysis, beam stress analysis and basic floor analysis. Then the anti-cracking measures, such as setting post-cast strip, setting expansion strengthening belt, setting the reinforcing steel bar and so on, are suggested according to the calculation results. This subject is adopted a set of post-cast strip, expansion strengthening belt, the setting of the reinforcing steel bar area, increase tectonic reinforcement and other countermeasures. These strategies and measures can be met according to the actual situation and the calculating data.Finally, this paper lists several engineering examples and sums up a series of experience according to the different features of the project which provide the reference to super-long concrete structure basement.