Experimental Research On The Carrying Capacity Of The Prestressed Steel Reinforced Concrete Beam

To order to study the flexure performance of prestressed steel reinforced concrete (PSRC) beam, it was studied from 2 groups, 6 specimens with different sectionsteel configuration and different prestressing degree. Through observing the whole loading process and ultimate state of PSRC beams and SRC beams, normal section yield rule,mean strain,prestressing effect were analysed. The experimentation results show: As the section is arranged reasonably, the failure modes of PSRC beam is similar to RC beam's; The prestressing force can obviously improve crack resistance of the specimens but reduce the ductility a little, then nearly has no effect to yield moment; It's thought that the normal section has yielded when the lower flange of formed steel yielded; It's feasible to analyse the carrying capacity of PSRC beam based on the calculation method of RC beam; When sectionsteel is located in tensile region, it's propitious to control stiffness and deflection of PSRC beam, but the effect to carrying capacity of PSRC beam need farther experimental research. After the experiment on the flexure performance of specimens, the shearing performance of PSRC beam was studied from the specimens, through observing the whole loading process and ultimate state, shear span ratio,prestressing effect,formed steel and stirrup strain were analysed.This paper discusses the calculation method research on the flexural capacity of the normal section and the shearing capacity of the oblique section of the PSRC beam, based on our nation present specification《sSpecification for Design of Steel -Reinforced Concrete Structure》and《Technical specification for steel reinforced concrete composite structures》, and combining the result of 6 experimental beams, educing the calculation formula which is the same with the flexural capacity of the normal section ,and validate the calculation formula of the shearing capacity of the oblique section of the PSRC beam. Contrasting the actual measure value:①"Simple repeat addition method"is only the same with the symmetry collocation along the section height of the steel, and the error is rather big when it is apply to steel reinforced concrete beam;②"Cooperation analytical method"based on plane hypothesis has better applicability and calculation precision for non-symmetry collocation steel, prestressed steel reinforced concrete beam and steel reinforced concrete beam;③The calculation formula which is the same with the shearing capacity of the oblique section of the PSRC beam is similar to those of prestressed reinforced concrete (PRC) beam. In addition, the program is worked out to analyse the nonlinear flexure process and plot the M -φcurves of the specimens in this paper. By comparing the M -φcurves plotted by the program with the test curves, the change of the flexural capacity were analysed when sectionsteel configuration and prestressing degree are changed.