摘要
针对某高速公路改扩建工程中墩柱的钢筋锈蚀、混凝土剥落露筋等病害以及部分伸缩墩的墩柱存在竖向裂缝、环向裂缝的问题,从全寿命周期角度考虑,采用UHPC增大截面加固法对墩柱塑性铰区域进行加固处理。在原有C40混凝土加固方案的基础上,设计考虑了UHPC强度(120 MPa和140 MPa)、UHPC加固层厚度(8 cm和10 cm)、墩柱设计直径(1.0 m、1.2 m、1.4 m和1.5 m)以及加固层是否配筋4种因素影响的加固方案。利用XTRACT软件分析了加固墩柱截面M-N曲线和M-φ曲线,研究了UHPC强度、加固层厚度、墩柱直径及加固层是否配筋对墩柱截面力学性能的影响。最后,从结构性能、耐久性、混凝土用量及美观性等方面综合对比分析了不同加固方案的加固效果。结果表明:UHPC强度对加固墩柱截面性能影响不大,墩柱承载力随着UHPC加固层厚度的增大而增大;对于不同设计直径的墩柱结构,加固10 cm厚度的UHPC与加固20 cm厚度的C40混凝土均可达到相同的承载能力水平;加固层配筋能够提高墩柱承载力,但8 cm厚UHPC配筋加固远不如10 cm厚UHPC加固效果。相较普通混凝土,利用UHPC加固能够减少或免除墩柱的维修,大幅降低养护成本,降低工程全寿命造价。
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-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 l
作者
许祥贵
赵兴华
张智博
韩笑
XU Xianggui;ZHAO Xinghua;ZHANG Zhibo;HAN Xiao(The Fourth Engineering Co.,Ltd.,of CCCC First Highway Engineering Co.,Ltd.,Nanning 530031,China;CCCC Highway Bridge National Engineering Research Center Co.,Ltd.,Beijing 100120,China)
出处
《混凝土》
CAS
北大核心
2024年第4期178-182,191,共6页
Concrete
基金
中国交通建设集团有限公司科技研发项目(KJYF-2022-A-01J)
中交一公局集团有限公司科技研发项目(2020-A-11)。
关键词
超高性能混凝土
增大截面加固法
加固层厚度
截面力学性能
全寿命周期
UHPC
increased section reinforcement method
reinforcement layer thickness
section mechanical properties
entire life cycle
