高强钢筋混凝土柱受弯性能的尺寸效应研究  

Research on Size Effect of Flexural Properties of High-Strength Reinforced Concrete Columns

作　　者：李振宝[1] 于春义 解咏平 马华[1] 唐贞云[1] LI Zhenbao;YU Chunyi;XIE Yongping;MA Hua;TANG Zhenyun(The Key Laboratory of Urban Security and Disaster Engineering,Ministry of Education,Beijing University of Technology,Beijing 100124,China;College of Exploration Technology and Engineering,Hebei GEO University,Shijiazhuang 050031,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]河北地质大学城市地质与工程学院,石家庄050031

出　　处：《工业建筑》2022年第6期71-78,107,共9页Industrial Construction

基　　金：国家自然科学基金项目(51408378);河北省自然科学基金项目(E2021403007);河北省教育厅重点基金项目(ZD2019026)。

摘　　要：随着混凝土强度的提高,柱受弯极限承载力的尺寸效应更加明显。因此,高强混凝土柱受弯屈服承载力尺寸效应需要进一步的确认。为此,开展了理论剪跨比为4的高强混凝土柱在轴压和单调水平荷载作用下的受弯性能试验。试件的剪跨比、轴压比和配箍率一致,几何尺寸相似比为3∶5∶7。结果表明:柱均为弯曲破坏,并且大尺寸柱保护层混凝土的劈裂效应可能是尺寸效应产生的部分原因;大尺寸柱的相对名义弯曲应力、名义转角、P-Δ效应及受弯屈服承载力的安全储备系数和局部安全储备系数与小尺寸柱相比均有所降低,其存在一定的尺寸效应,并且随着混凝土强度的提高,相对名义弯曲应力和受弯屈服承载力安全储备系数的尺寸效应更加明显;基于试验结果和Ba6ant的Type2类型尺寸效应模型,提出了考虑尺寸效应的受弯屈服承载力计算方法,使大小尺寸构件的安全储备系数趋于一致,进而保证了大尺寸柱受弯屈服承载力计算的安全性。It has been shown that as concrete strength increases,the size effect of ultimate flexural capacity becomes more pronounced in columns.However,the size effect of flexural capacity requires further confirmation for highstrength concrete columns.For this purpose,the high-strength concrete columns with a theoretical shear-span ratio of 4 were subjected to axial and monotonic loading in this study.The shear-span ratio,axial load ratio,and volume ratio of stirrup were consistent.The geometric similarity ratio of components was 3∶5∶7.The experimental results indicated that the failure mode of columns was flexural failure,and the splitting effect of concrete cover for large size columns might be a part reason of size effect.Meanwhile,the relative nominal flexural strength,nominal angle of rotation,P-Δeffect,and safety factors and local safety factors for flexural capacity decreased as section size increased,suggesting that size effect existed.Moreover,the size effect of relative nominal flexural strength and safety factors of flexural capacity was stronger for high-strength columns than for conventional concrete columns.In addition,based on the test results and Bažant’s Type 2 model,the calculation method of flexural capacity was modified to provide a constant factor of safety regardless of column size,indicating that the fluexural capacity was safer for large size columns.

关 键 词：尺寸效应 高强混凝土柱 受弯屈服承载力 安全储备系数 局部安全储备系数 

分 类 号：TU375.3[建筑科学—结构工程]