Experimental results of concrete under dynamic exposure preceded by long-term static load

21st International Scientific Conference on Advanced in Civil Engineering "Construction - The Formation of Living Environment"

土木建筑工程

Tsvetkov, Konstantin^1 ; Bazhenova, Alexandra^1

Moscow State University of Civil Engineering, Yaroslavskoe shosse, 26, Moscow

129337, Russia^1

关键词: Computational model;    Deformation rates;    Longitudinal deformation;    Moscow State University;    Practical calculation;    Static and dynamic loads;    Stress-strain diagram;    Transverse deformation;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/365/5/052024/pdf
DOI  :  10.1088/1757-899X/365/5/052024

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

Experimental study aimed at evaluation of static preload impact on concrete strength and deformation characteristics had been carried out in 2014-2017 in laboratory of Strength of Materials Department of Moscow State Institute of Civil Engineering. The paper briefly presents the research technique, outcome and suggests its interpretation. Authors feature of the methodology is an absence of unloading when applying the dynamic load with stress growth rate of 450 MPa/sec and destruction time of approximately 0.8 sec after static preload with value of 0.3, 0.7 and 0.8 of prism strength. The use of portable dynamic module which was has been designed and built by Igor Bezgodov, engineer of Moscow State University of Civil Engineering, made it possible to complete the experiment. Investigation of samples under short- term static load of the same level and reference samples under static and dynamic load without preloading was carried out concurrently. The data obtained include strength values and stress-strain diagrams which allowed estimating the coefficients of longitudinal and transverse deformation and ultimate deformation. The authors suggest that long-term static preload does not affect the dynamic strengthening factor, which remained between 1.17 and 1.30 regardless of preload level. At the same time preloading changes stress-strain diagram significantly. Diagrams for various loading modes are combined on single figure to demonstrate their features. The coefficients of longitudinal and transverse deformation related to significant fragments of diagrams are presented in tables and compared to each other. Loading rate considerably lowers ultimate deformations under dynamic impact. Relatively low-level preloading does not modify longitudinal deformations perceptibly, however, at preloading level of 0.8 longitudinal deformations increase significantly and almost match the ones under static loading. The authors conclude that comparison of diagrams points out on necessity of taking deformation rate growth and static preload level into consideration in practical calculations of concrete and reinforced concrete constructions. Thus, the research contributes to the development of computational models of concrete and reinforced concrete.