The Research On The Design And Constructional Testing Of Unbonded Prestressed Concrete Transfer Beam

With the ceaseless increasing amount of high-rise buildings and super high-rise buildings in and out of China, architectural structures has been developing towards long-span and large-space buildings, which has led to more and more complicated service functions. Thus, transfer floors and transfer beams are required to be set at the major locations in architectural structures, that is, designing a complicated architectural structure with a transfer floor. However, in the design of transfer floor structure and transfer beams it is commonly adopted to enlarge dimensions of cross sections and the amount of reinforcement for a transfer floor and a transfer beam at the cost of increasing height of the building and engineering cost, which should be modified and improved. In the latest years the design method of unbonded prestressed concrete transfer beam with a long span has been also utilized. The research and application on this design method is very finite since this design is involved in mechanics, material, structure, and management etc. Especially quite a lot of problems should be researched and solved in the design and construction so as to guarantee the safety and reliability of this kind of structure.In this paper Xixi Engineering in Beijing taken for example, the design and construction features of unbonded prestressed concrete transfer beam structure with a long span is explained; through the comparison between computed analysis and real measured analysis on site, the distribution law of internal stress and invert arch value during construction are investigated. The main work is as following. â‘  The definition, structural types, feature and development survey of beam transfer floor structure are simply expounded, and the load bearing characteristic of prestressed concrete transfer beam structure is analyzed in detail. In the meanwhile, the design and constructional survey of Xixi Engineering is introduced. (2) On the basis of the above research, the design and constructional technology are further studied for a prestressed concrete transfer beam structure with a long span. (3) For three unbonded prestressed concrete transfer beams, select a section respectively at two ends, midspan and one third of length, then array ten strain gauges respectively in this sections; array eight electronic displacement meters at the bottom (tension zone); the strains of concrete and invert arch values of beams caused by pretension are really tested for these three beams, which are compared to the calculated values. It shows that they are in a good agreement which verifies that the design method presented in this paper is simply feasible and has an application prospect. Besides, the constructional technologies and methods for this type of structure are deeply researched, from which some instructive conclusions and suggestions are obtained and these will establish a basis for design and construction of this kind of structure in the future.