海洋大气环境下钢筋混凝土梁可预期寿命设计方法
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摘要
基于时变可靠性分析,采用荷载与抗力分项系数,提出了海洋大气环境下钢筋混凝土梁可预期寿命设计方法。首先,基于混凝土中Cl~-传输模型确定了钢筋初始锈蚀时刻;其次,考虑钢筋锈蚀不均匀性对横截面积分布以及钢筋力学性能的影响,计算了锈蚀梁在预期服役寿命内的时变可靠指标;再次,对结构设计的初始目标可靠指标进行调整,从而保证结构在预期服役寿命内的最低可靠指标仍满足现行规范要求。在极限状态设计表达式基础上,通过可靠性分析计算了不同目标可靠指标调整值以及预期服役寿命要求下钢筋混凝土结构各构件梁荷载和抗力(受弯承载力)分项系数。最后通过钢筋混凝土梁的设计算例说明本文方法的有效性。
Based on time-dependent reliability analyses and the load and resistance factor design approach, a design method of expected service life was developed for reinforced concrete(RC) beams under marine atmospheric environment. First, the initial corrosion time of reinforcing bars was determined based on the Chloride ion transport model in concrete; and then, considering the influence of the variability of corrosion on both distribution of cross-sectional area and mechanical properties of rebars, time-dependent reliability indexes of corroded RC beams were calculated during their expected service lives. Besides, the initial target reliability indexes were redefined in order to ensure the reliabilities of RC beams during their entire expected service lives could meet the requirements of the relevant design specifications. Moreover, based on probability and limit states equations, the adjusted value of reliability index, and the load and resistance partial factors were determined for RC beams with different requirements for expected service live. Finally, the validity of the proposed approach was illustrated using several design cases.
Based on time-dependent reliability analyses and the load and resistance factor design approach, a design method of expected service life was developed for reinforced concrete(RC) beams under marine atmospheric environment. First, the initial corrosion time of reinforcing bars was determined based on the Chloride ion transport model in concrete; and then, considering the influence of the variability of corrosion on both distribution of cross-sectional area and mechanical properties of rebars, time-dependent reliability indexes of corroded RC beams were calculated during their expected service lives. Besides, the initial target reliability indexes were redefined in order to ensure the reliabilities of RC beams during their entire expected service lives could meet the requirements of the relevant design specifications. Moreover, based on probability and limit states equations, the adjusted value of reliability index, and the load and resistance partial factors were determined for RC beams with different requirements for expected service live. Finally, the validity of the proposed approach was illustrated using several design cases.
引文
[1] COWI Consulting Engineering and Planners. General guidelines for durability design and redesign: DuraCrete, probabilistic performance based durability design of concrete structures[M].Gouda:CUR, 2000.
[2] 韩宁旭. 以性能和可靠度理论为基础的钢筋混凝土基础设施使用寿命设计及其原理和应用[M]// 邢锋,明海燕.沿海地区混凝土结构耐久性及其设计方法.北京:人民交通出版社, 2004:24. (HAN Ningxu. Performance and reliability based service life design principle and application for reinforced concrete infrastructure[M]// XING Feng, MING Haiyan. Durability and design method of concrete structures in the coastal areas.Beijing:China Communications Press, 2004:24.(in Chinese))
[3] Fédération International du Béton. Model code for service life design[S]. Lausanne: International Federation for Structural Concrete, 2006.
[4] SARJA A. Reliability principles, methodology and methods for lifetime design[J]. Materials and Structures, 2010, 43(1): 261-271.
[5] 李田, 刘西拉. 混凝土结构耐久性设计方法的研究[J]. 建筑结构学报, 1998, 19(4): 40- 45.(LI Tian, LIU Xila. Research on design method of durability of concrete structure[J]. Journal of Building Structures, 1998, 19(4): 40- 45 (in Chinese))
[6] 欧进萍, 侯爽, 周道成,等. 钢筋混凝土结构预期使用期可靠度设计实用方法[J]. 建筑结构学报,2008, 28(5): 120-127. (OU Jinping, HOU Shuang, ZHOU Daocheng, et al. Practical reliability design approach for reinforced concrete structures with expected service time[J]. Journal of Building Structures, 2008, 28(5): 120-127. (in Chinese))
[7] 秦权, 贺瑞, 杨小刚. 在时变结构可靠度领域中有必要澄清一个错误概念[J]. 工程力学, 2009, 26(8): 201-204.(QIN Quan, HE Rui, YANG Xiaogang. Clarification of a wrong concept in the field of time-varying structural reliability[J]. Engineering Mechanics, 2009, 26(8): 201-204.(in Chinese))
[8] 贡金鑫, 赵国藩, 赵尚传.大气环境下锈蚀对钢筋混凝土结构可靠度的影响[J]. 大连理工大学学报, 2000, 40(2): 210-213.(GONG Jinxin, ZHAO Guofan, ZHAO Shangchuan. Influence of corrosion of reinforcement on reliability of reinforced concrete structures in atmospheric environment[J]. Journal of Dalian University of Technology, 2000, 40(2): 210-213. (in Chinese))
[9] BENTZ E C, THOMAS M D A. Life-365 service life prediction model and computer program for predicting the service life and life-cycle costs of reinforced concrete exposed to chlorides[R]. Farmington hills, Michigan: American Concrete Institute, 2008.
[10] 混凝土结构耐久性评定标准:CECS 220:2007[S]. 北京: 中国建筑工业出版社, 2007. (Standard for durability assessment of concrete structures: CECS 220:2007[S]. Beijing: China Architecture & Building Press, 2007.(in Chinese))
[11] STEWART M G, AL-HARTHY A. Pitting corrosion and structural reliability of corroding RC structures: experimental data and probabilistic analysis[J]. Reliability Engineering & System Safety, 2008, 93(3): 373-382.
[12] ZHANG W P, ZHOU B B, GU X L, et al. Probability distribution model for cross-sectional area of corroded reinforcing steel bars[J]. Journal of Materials in Civil Engineering, 2014, 26(5): 822-832.
[13] GU X L, GUO H Y, ZHOU B B, et al. Corrosion non-uniformity of steel bars and reliability of corroded RC beams[J]. Engineering Structures, 2018,167:188-202.
[14] 混凝土结构设计规范:GB 50010—2010[S]. 北京: 中国建筑工业出版社, 2010. (Code for design of concrete structures: GB 50010—2010[S]. Beijing: China Architecture & Building Press, 2010.(in Chinese))
[15] SAETTA A V, SCOTTA R V, VITALIANI R V. Analysis of chloride diffusion into partially saturated concrete[J]. ACI Materials Journal, 1993, 90(5): 441- 451.
[16] ZHOU B B, GU X L, GUO H Y, et al. Polarization behavior of activated reinforcing steel bars in concrete under chloride environments[J]. Construction and Building Materials, 2018, 164: 877-887.
[2] 韩宁旭. 以性能和可靠度理论为基础的钢筋混凝土基础设施使用寿命设计及其原理和应用[M]// 邢锋,明海燕.沿海地区混凝土结构耐久性及其设计方法.北京:人民交通出版社, 2004:24. (HAN Ningxu. Performance and reliability based service life design principle and application for reinforced concrete infrastructure[M]// XING Feng, MING Haiyan. Durability and design method of concrete structures in the coastal areas.Beijing:China Communications Press, 2004:24.(in Chinese))
[3] Fédération International du Béton. Model code for service life design[S]. Lausanne: International Federation for Structural Concrete, 2006.
[4] SARJA A. Reliability principles, methodology and methods for lifetime design[J]. Materials and Structures, 2010, 43(1): 261-271.
[5] 李田, 刘西拉. 混凝土结构耐久性设计方法的研究[J]. 建筑结构学报, 1998, 19(4): 40- 45.(LI Tian, LIU Xila. Research on design method of durability of concrete structure[J]. Journal of Building Structures, 1998, 19(4): 40- 45 (in Chinese))
[6] 欧进萍, 侯爽, 周道成,等. 钢筋混凝土结构预期使用期可靠度设计实用方法[J]. 建筑结构学报,2008, 28(5): 120-127. (OU Jinping, HOU Shuang, ZHOU Daocheng, et al. Practical reliability design approach for reinforced concrete structures with expected service time[J]. Journal of Building Structures, 2008, 28(5): 120-127. (in Chinese))
[7] 秦权, 贺瑞, 杨小刚. 在时变结构可靠度领域中有必要澄清一个错误概念[J]. 工程力学, 2009, 26(8): 201-204.(QIN Quan, HE Rui, YANG Xiaogang. Clarification of a wrong concept in the field of time-varying structural reliability[J]. Engineering Mechanics, 2009, 26(8): 201-204.(in Chinese))
[8] 贡金鑫, 赵国藩, 赵尚传.大气环境下锈蚀对钢筋混凝土结构可靠度的影响[J]. 大连理工大学学报, 2000, 40(2): 210-213.(GONG Jinxin, ZHAO Guofan, ZHAO Shangchuan. Influence of corrosion of reinforcement on reliability of reinforced concrete structures in atmospheric environment[J]. Journal of Dalian University of Technology, 2000, 40(2): 210-213. (in Chinese))
[9] BENTZ E C, THOMAS M D A. Life-365 service life prediction model and computer program for predicting the service life and life-cycle costs of reinforced concrete exposed to chlorides[R]. Farmington hills, Michigan: American Concrete Institute, 2008.
[10] 混凝土结构耐久性评定标准:CECS 220:2007[S]. 北京: 中国建筑工业出版社, 2007. (Standard for durability assessment of concrete structures: CECS 220:2007[S]. Beijing: China Architecture & Building Press, 2007.(in Chinese))
[11] STEWART M G, AL-HARTHY A. Pitting corrosion and structural reliability of corroding RC structures: experimental data and probabilistic analysis[J]. Reliability Engineering & System Safety, 2008, 93(3): 373-382.
[12] ZHANG W P, ZHOU B B, GU X L, et al. Probability distribution model for cross-sectional area of corroded reinforcing steel bars[J]. Journal of Materials in Civil Engineering, 2014, 26(5): 822-832.
[13] GU X L, GUO H Y, ZHOU B B, et al. Corrosion non-uniformity of steel bars and reliability of corroded RC beams[J]. Engineering Structures, 2018,167:188-202.
[14] 混凝土结构设计规范:GB 50010—2010[S]. 北京: 中国建筑工业出版社, 2010. (Code for design of concrete structures: GB 50010—2010[S]. Beijing: China Architecture & Building Press, 2010.(in Chinese))
[15] SAETTA A V, SCOTTA R V, VITALIANI R V. Analysis of chloride diffusion into partially saturated concrete[J]. ACI Materials Journal, 1993, 90(5): 441- 451.
[16] ZHOU B B, GU X L, GUO H Y, et al. Polarization behavior of activated reinforcing steel bars in concrete under chloride environments[J]. Construction and Building Materials, 2018, 164: 877-887.