Normal Section Bearing Capacity of Ultra High Performance Concrete Beam

The experimental investigation and theoretical analyses were carried through on the uniaxial compressive stress-strain complete curve of Ultra High Performance Concrete(UHPC) and the mechanical behavior of the prestressed UHPC beams.Results show that the UHPC has good compressive deformation performance.The strain at the peak stress of UHPC is about 0.003 5 and the ultimate strain is 0.004 5.UHPC beams have good tensile deformation capacity and crack distribution.The ultimate deformation of UHPC beams is 1/30.1～1/71.8 of the beam span,and the concrete strain distribution of the beam body basically accords with the plane section assumption.The plastic influence coefficient of UHPC beam section is 1.53,which is obtained based on the tensile strength of the initial cracking. Accordingly,formulae for calculating the cracking moment of UHPC flexural member and the ultimate bearing capacity are established to predict the failure mode, the cracking moment and the ultimate moment of UHPC beams.The computed values are of high precision.