(北京工业大学城市减灾与防灾防护教育部重点实验室， 北京 100124)

［摘要］应变率效应和尺寸效应是混凝土力学领域重要的基础科学问题。以强度为代表的力学性能指标随应变率增大而提高、随结构尺寸增大则存在劣化的趋势。目前，对应变率效应的研究多采用试验观测的经验方法，现有表征应变率效应强弱的动力增大因子计算模型多基于有限数据拟合，参数缺少物理意义，因此不利于工程实际应用；尺寸效应方面已存在几类基于不同理论框架的模型分析方法，但仍存在较大分歧。结合前期研究工作中建立的具有实际物理意义参数的混凝土抗拉强度动力增大因子计算模型和考虑混凝土材料配合比参数的全局尺寸效应模型，提出了同时考虑应变率效应与尺寸效应影响的普通混凝土名义抗拉强度理论预测方法。研究可为基于性能的大体积混凝土配合比设计方法及其动态强度预测方法提供理论依据。 

［关键词］混凝土；应变率效应；尺寸效应；动态强度；动力增大因子 

中图分类号：TU398-7 文献标识码：A文章编号：1002-848X(2021)17-0122-07

Theoretical prediction method for nominal tensile strength of ordinary concrete considering strain rate effect and size effect 

LI  Dong,  DU  Xiuli,  JIN  Liu 

(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education, Beijing University of Technology, Beijing 100124， China) 

Abstract: Strain rate effect and size effect are important basic scientific problems in the field of concrete mechanics. The mechanical properties represented by strength increase with the increase of strain rate and deteriorate with the increase of structure size. At present, the empirical method of experimental observation is mostly used to study the strain rate effect. The existing calculation models of dynamic increase factor, which represents the degree of strain rate effect, is mostly based on the fitting of limited data, and the parameters lack physical significance. Therefore, it is not conducive to the practical application of engineering. Several types of model analysis methods have been established based on different theoretical frameworks in terms of size effect, however, large differences are apparent. Based on the calculation model of concrete tensile dynamic increase factor with parameters of actual physical significance and the global size effect model considering the design parameters of concrete mix proportion in the previous work, theoretical prediction method for nominal tensile strength of ordinary concrete considering both strain rate effect and size effect was proposed. The research can provide theoretical basis for performance-based mix proportion design method and dynamic strength prediction method of mass concrete. 

Keywords:concrete； strain rate effect； size effect； dynamic strength； dynamic increase factor

*国家重点研发计划专项（2018YFC1504302）。

 作者简介：李冬，博士，研究员，博士生导师，Email: dong.li@bjut.edu.cn；通信作者：杜修力，博士，教授，博士生导师，Email: duxiuli@bjut.edu.cn。