Study on the cross-sectional performance of UHPC reinforced pier columns considering the entire life cycle
In response to the problems of steel bar corrosion,concrete peeling and exposed reinforcement in the piers and columns of a certain highway renovation and expansion project,as well as vertical and circumferential cracks in some expansion piers and columns,from the perspective of the entire life cycle,the UHPC increased section reinforcement method is adopted to reinforce the plastic hinge area of the piers and columns.On the basis of the original C40 concrete reinforcement plan,the design considers four factors:UHPC strength(120 MPa and 140 MPa),UHPC reinforcement layer thickness(8 cm and 10 cm),pier column design diameter(1.0 m,1.2 m,1.4 m and 1.5 m),and whether the reinforcement layer is reinforced.The M-N curve and M-φ curve of the reinforced pier column section were analyzed using XTRACT software.The curve was used to study the effects of UHPC strength,reinforcement layer thickness,pier column diameter and whether the reinforcement layer is reinforced on the mechanical properties of the pier column section.Finally,a comprehensive comparative analysis was conducted on the reinforcement effects of different reinforcement schemes in terms of structural performance,durability,concrete dosage and aesthetics.The results show that the strength of UHPC has little effect on the cross-sectional performance of reinforced pier columns,and the bearing capacity of pier columns increases with the increase of the thickness of UHPC reinforcement layer.For pier column structures with different design diameters,both reinforced UHPC with a thickness of 10 cm and reinforced C40 concrete with a thickness of 20 cm can achieve the same level of bearing capacity.The reinforcement layer reinforcement can improve the bearing capacity of pier columns,but the reinforcement effect of 8 cm thick UHPC reinforcement is far inferior to that of 10 cm thick UHPC reinforcement.Compared to ordinary concrete,using UHPC reinforcement can reduce or eliminate the maintenance of pier columns,significantly reduce maintenance costs,and lower the overall life cycle cost of the project.
UHPCincreased section reinforcement methodreinforcement layer thicknesssection mechanical propertiesentire life cycle
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