Experimental Study on Shear Behavior of Externally Prestressed UHPC Beams Without Stirrups
In order to study the shear behavior of externally prestressed ultra-high performance concrete(UHPC)beams without stirrups,three externally prestressed UHPC beams without stirrups were fabricated.The shear behavior of the test beams was investigated by four-point loading with three shear span ratios of 1.44,2.56 and 3.67,respectively.The load-displacement relationship,load-strain relationship,failure mode,and ultimate shear bearing capacity of the experimental beam were obtained.The experimental results show that the shear failure modes of externally prestressed UHPC beams without stirrups all exhibit brittle failure.As the shear span ratio increases,the specimens are failed by diagonal compression,shear compression and shear tension.The larger the shear span ratio,the less diagonal cracks and the smaller the angle of inclination.The ultimate shear capacity of the test beams also decreases with the increasing shear span ratio and the decreasing trend becomes slower.Based on the ultimate equilibrium method,the formulae for calculating the shear capacity of externally prestressed UHPC beams without stirrups are derived.The shear capacity of fourteen unbonded prestressed UHPC beams is verified,which is of good applicability.
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