Theoretical Analysis And Experimental Study On Semi Assembled Composite Open-web Sandwich Plate Outsourcing U Type Steel Plate

Large span space structure is an important symbol to measure the level of science and technology of a country.It is also a symbol of the degree of civilization development of a country.Therefore,the countries all over the world attach great importance to the research,application,development and innovation of the theory and technology of large span space structure.Space grid stru ctures are three-dimensional structure systems composed of rod element,beam-column element and plate shell element.In the middle of the last century,with the development of industrialization in the modern world,the new structure developed vigorously un der the external condition that the function of large span structures became more and more complicated.At present,there are 38 specific forms of space grid structure in the domestic and foreign places.Space grid structures has become one of the most vit ality in recent years due to its reasonable form,good mechanical performance,beautiful appearance,reasonable economy,and the ability of crossing large space.In order to meet the increasing needs of people,the specific forms of new space grid structures are constantly developed with the continuous development of human society.Large span steel-concrete composite open-web plate is presented in this paper to solve practical problems of the decrease of city land as below: single large span public buildings could be changed to multilayer large span public buildings because more and more people live in the city and the increasing demand of public buildings;with the development of industry and increasing demand of factories,90% of single industrial factories built in the past could be changed to multilayer industrial factories.Large span steel-concrete composite open-web plate which could be applied to multilayer public and industrial buildings is systematically studied in this paper as below:?1?Through the research on the history of space grid structures and process of solving practical problems,large span steel-concrete composite open-web plate is presented and applied to multilayer public and industrial buildings.The basic structure,the connection,the grid form and the basic parameters of this structure are described in detail in this paper.?2?There are three calculation methods for semi-assembled composite open-web plate,including finite element method,quasi-sandwich plate method and practical calculation method.The calculation model,basic assumption,basic equation and solution are analyzed in detail.These methods were used to calculate the practical example and the results are consistent.The static load test was conducted in the laboratory and verified the accuracy of finite element method and practical calculation method in design stage.Quasi-sandwich plate method could be used for scheme selection stage,the finite element method and practical calculation method could be used in the design stage,and all the methods meet the requirements of current standard in China,called Technical specification for space frame structures?JGJ7-2010?.The practical calculation method can be used directly in the design.?3?Compared with the calculation and test results of the components of large span steel-concrete composite open-web plate,we can see that: 1)the calculation for up ribs could use the practical calculation method and one side longitudinal reinforcement of the minimum reinforcement ratio incr ease to 0.4%;2)for the lower ribs,the bearing capacity calculation is priority to choose the form of U plate;3)for the shear key,using local rules?document [106] and [108]?formula is conservative for bearing capacity of the shear key and needs to be improved.?4?Strut and tie theory was used to establish the analysis model for the shear key and take the actual project in the Museum of Guizhou province to build the shear key benchmark model.According to the static and dynamic performance of the sh ear key,its shear bearing capacity is decided by the strut and the formula is V=f_yA_sttan??5?Through reading large amount of documents and research on the comfort evaluation criteria,the comfort evaluation criteria for semi-assembled composite open-web plate are presented.Through the field measurement of two actual projects,and compared with the finite element calculation value,it is concluded that the large span U steel-concrete composite open-web plate is comfortable.?6?Six U steel-concrete composite open-web beams were studied,which four beams were under static load and tow beams were under dynamic load.The results verify that the strut and tie analysis model and shear bearing capacity formula is correct.We can also get the static destruction characteristi cs for U steel-concrete composite open-web plate and the modes between the measured method and finite element method fit well and meet the requirements of the support conditions.