Research On The Mechanical Property Of New-type Precast Grid-beams Floor System With Self-thermal Insulation

Construction industrialization is the inevitable developing trend of construction industry in the future. In order to meet the residential need of free segment and assembly, our research team puts forward the new—type precast grid-beams floor system with self-thermal insulation. This floor system is mainly composed of gird beams, the upper plate and the lower plate, foamed concrete. It not only has the highly prefabricated degree, less operations of cast-in-place concrete, the construction space faster and high economic benefits, at the same time, the new-type floor system has many characteristie,such as heat preservation and heat insulation, sound insulation, light weight, large span. So, researching on the mechanical properties by experiment and theoretical analysis of this new type has the important theoretical significance and important practical value.This paper takes the static test on the 1/2 scale model of the new-type floor system. The new-type floor system consists of six pieces of prefabricated plate, four pillar of prefabrication composite beams and four pillars. Through actual pouring the component of floor and the assembly of floor, it verifies the effectiveness of the pouring sequence and the assembly sequence of the component. Through the static loading test of the test floor, it gets the crack development of the model, analyzes the stiffness changes of floor under the load loading process, tests the vertical bearing capacity of the floor, and inspects the splice performance. It is concluded that the crack development of the new-type of precast gird-beam floor and the solid floor are nearly the same, the vertical bearing capacity is high, and the connection performance of floor is good.By using finite element analysis of single span floor and continuous floor, it is concluded that the bearing stiffness of the single span floor of is small, can be assumed to hinge support; the bearing stiffness of the continuous floor is bigger, can be assumed to semi-rigid bearing, in engineering design takes the ratio of the floor bearing bending moment and bending moment in the cross as 1.15.Through the contrastive analysis of the new-type precast grid-beams floor system with self-thermal insulation, the solid floor, and hollow grid-beams floor, it founds that the deformation of the new-type floor basic accord with flat section assumption, the upper and lower plate works as the whole cross section, so the vertical bearing capacity and vertical stiffness of the new-type floor are higher than hollow grid-beams floor, and the stress of the new-type floor is the same with solid floor.In conclusion, the new-type precast grid-beams floor system with self-thermal insulation, not only realizing the industrialization, energy saving heat preservation, reduce weight, and satisfies the requirement of the supporting body, but also makes the upper and lower plate working as the whole cross section, improves the vertical bearing capacity and vertical stiffness of the new-type floor, so the upper and lower plate can set the monolayer plate steel.By analyzing the results of test results and finite element analysis, this paper draws that the floor stiffness of the test floor and the hollow gird-beam floor are nearly the same. The main reason is that the splicing contact of the test floor early cracks under load, leading to test floor stiffness decrease, and reduced experimental floor rigidity is the same with the hollow gird-beam floor. In the structural design, the span to depth ratio and the detail size of the new floor can be in accordance with the specification of the rules of the hollow grid-beams floor.