Open Access

ABSTRACT

Size effect studies on a notched plain concrete beam using initial stiffness method

B.K. Raghu Prasad¹, T.V.R.L. Rao¹, A.R. Gopalakrishnan¹

1 Department of Civil Engineering, Indian Institute of Science, Bangalore, India.

The International Conference on Computational & Experimental Engineering and Sciences 2009, 9(3), 179-196. https://doi.org/10.3970/icces.2009.009.179

Abstract

A simple numerical method namely Initial Stiffness Method using finite element method has been employed to study the size effect which is prominent in concrete structures. Numerous experimental investigations performed on notched plain concrete beams subjected to three point or four-point bending have revealed the fracture process to be dependent on size of the structural member. It was found that, the nominal stress at maximum load decreases as the size of the structure increases. The nominal stress at failure on the characteristic dimension of structure is termed as size effect. This has also been explained in energy concepts as, the fracture energy G_f decreases with increase in structure size. This size effect is explained with regard to three parameters, namely, nominal stress at failure, post-peak slope of the load-displacement diagram and softening slope parameter α. The results obtained from the analysis of three point bend specimen of varying sizes using initial stiffness method, also confirms the size effect of concrete structures.

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Keywords

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