Study On Mechanical Performance And Design Method Of Prestressed Steel Reinforced Concrete Laminated Beams

Prestressed Steel Reinforced Concrete Laminated(PSRCL)beams,whose steel reinforced concrete shells were firstly prefabricated in the shop,after the high strength or high performance concrete of the shells reached the expected design strength,the prefabricated parts were prestressed,and then the prefabricated parts were transported to the site and installed,the inner part concrete constructions were then cast in situ to construct PSRCL beams.PSRCL beams can effectively simplify the construction process in situ,which result in reducing or avoiding the use of temporary support and formwork,and greatly reduce the cost,improve the prefabrication of the building industry.In order to improve the application of the innovative type of PSRCL beams,two types — filled steel type and unfilled steel type — were proposed.Combining with experimental study and theory analysis,the following jobs were carried out:1.The tests of 15 PSRCL beams from two types of PSRCL beams were conducted.The influence of some key parameters such as the prestress ratio,the strength of precast concrete,the prestress order and the layout of prestress reinforcements on the bending performance of PSRCL beams were analyzed respectively.With experimental results and analysis,two sets of calculation methods of the flexural capacity from two types of PSRCL beams were put forward respectively,the calculation results were in good agreement with the test results in general,and one set of the two calculation methods was suggested respectively.2.The tests of 18 PSRCL beams from two types of PSRCL beams were conducted.The influence of some key parameters such as the shear span ratio,the prestress ratio,the layout of prestress reinforcements and the prestress order on the mechanical properties of PSRCL beams were analyzed respectively.With experimental results and analysis,five sets of calculation methods of the shear capatity from two types of PSRCL beams were put forward respectively,the calculation results were in good agreement with the test results in general,and one set of the five calculation methods was suggested respectively.3.With the flexural tests results from two types of 15 PSRCL beams,the influence of some key parameters such as the prestress ratio and the prestress order on the mechanical properties of PSRCL beams were analyzed respectively.Furthermore,with experimental results and analysis,the calculation methods of cracking moment,crack width,stiffness and deformation were established,the calculation results were in good agreement with the test results.4.Through the research of three parts above,the calculation methods of flexural capacity and shear capacity from two types of PSRCL beams were put forward,the calculation methods of cracking moment,crack width,stiffness and deformation from two types of PSRCL beams were also put forward,the design methods from two types of PSRCL beams were formed,which can provide theoretical basis and support for the design and application from two types of PSRCL beams newly proposed.