Research On Construction Technology Of Reinforced Concrete Structure Reinforced Without Support

China’s construction industry has developed rapidly since the founding of the People’s Republic of China,but limited by the technical level and material resources at that time,and after many years of operation,a large number of structures need to be reconstructed and expanded.Among them,the reconstruction and expansion of reinforced concrete structure is huge,the common reinforcement construction of concrete structure is generally carried out by the support method,but many reconstruction and expansion projects are limited by site factors,facing the problem that there is no place to set up support for construction.Aiming at the problem that the traditional support method can not be used in the reinforcement and transformation of reinforced concrete structures due to the limitation of the site,this paper proposes a new no-support construction technology for the reinforcement of reinforced concrete structures supported by the embedding steel bar technology,in order to deal with the problem of insufficient construction space.In this paper,through the pull-out test and finite element simulation,the influence factors of the pull-out force of the system and the simulation selection of the template and the parameters of the steel bar under different working conditions are analyzed.This paper first introduces the system composition,force transfer mechanism of the construction technology and the related theories of embedding steel bar technology,as well as the external load of the system-concrete pouring side pressure calculation method.A total of 75 pull-out tests were designed with the diameter of steel bar,depth of steel bar,strength of concrete and structure type as variables.The failure modes and pull-out forces of different specimens were analyzed and counted,and the influence of the above four factors on the ultimate pull-out force of steel bar structure was analyzed:The depth of the embedding steel bars determines the failure mode of the specimen,and the increase of the embedding bars depth can greatly increase the ultimate pull-out force of the specimen,and the larger the diameter of the embedding steel bars is,the greater the lifting value of the pull-out force is.The enhancement of concrete strength has obvious effect on the specimens with shallower embedding steel bar depth.With the increase of the diameter of the reinforcement steel bar,the increase of the pull-out force will be greater for the component with the greater the depth of the reinforcement steel bar.Secondly,the finite element modeling of the drawing and formwork system of the embedding steel bars is carried out,the establishment of the concrete plastic damage model is introduced in detail,and the causes of various types of damage forms in the drawing of the embedding steel bars are analyzed.The simulation results are in good agreement with the pull-out test of the embedding steel bars.The strength,stiffness and overall construction system of steel formwork under different working conditions are checked and calculated,which provides suitable formwork parameters and the selection of embedding steel bar parameters for different construction conditions.Finally,taking the reinforcement of reinforced concrete abutment in the Changchun to Lalinhe section of Jingha highway reconstruction and expansion project as an example,this paper introduces the practical application of the construction technology of reinforced concrete structure without support,and introduces the corresponding construction technology,which solves the construction problems of reinforced concrete structure under the factors of insufficient space for erecting supports.