Universal size effect of concrete specimens and effect of notch depth
The universal size effect law of concrete is a law that describes the dependence of nominal strength of specimens or structure on both its size and the crack (or notch) length, over the entire of interest, and exhibits the correct small and large size asymptotic properties as required. The main difficulty has been the transition of crack length from 0, in which case the size effect mode is Type 1, to deep cracks (or notches), in which case the size effect mode is Type 2 and fundamentally different from Type 1. The current study is based on recently obtained comprehensive fracture test data from three-point bending beams tested under identical conditions. In this test, the experimental program consisted of 80 three-point bend beams with 4 different depths 40, 93, 215 and 500mm, corresponding to a size range of 1:12.5. Five different relative notch lengths, a/D = 0, 0.02, 0.075, 0.15, 0.30 were cut into the beams. A total of 20 different geometries (family of beams) were tested. The present paper will use these data to analyze the effects of size, crack length. This paper presents a studying to improve the existing universal size effect law, named by Bazant, using the experimentally obtained beam strengths for various different specimen sizes and all notch depths. The updated universal size effect law is shown to fit the comprehensive data quite well.
Abusiaf HF, Barr BIG, Şener S (1997). Application of the Torsional Damage Test in High Strength Concrete. Fourth International Conference on Civil Engineering, Tehran, Iran, 355-362.
Abusiaf HF, Şener S, Barr BIG (1996). Size effect in eccentrically loaded compact specimens. Concrete Technology for Developing Countries, Fourth International Conference, Eastern Mediterranean University, North Cyprus, 631-639.
Barr BIG, Abusiaf HF, Şener S (1998). Size effect and fracture energy studies using compact compression specimens, RILEM, Materials and Construction, 31(1), 36-41.
Bazant ZP (1984). Size effect in blunt fracture: Concrete, rock, metal, Journal of Engineering Mechanics, ASCE, 110, 518-535.
Bazant ZP, Planas J (1998). Fracture and Size Effect in Concrete and Other Quasibrittle Materials. CRC Press, Boca Raton, FL.
Bazant ZP, Yu Q (2009). Universal Size Effect Law and effect of crack depth on quasi-brittle structure strength. Journal of Engineering Mechanics, ASCE, 135, 78-84.
Carpinteri A, Chiaia B, Ferro G (1995). Multifractal scaling law: an extensive application to nominal strength size effect of concrete structures. Atti del Dipartimento di Ingegneria Strutturale, 2(2), Politechnico de Torino, Italy.
Çağlar Y, Şener S (2015). Size effect for notched, unnotched concrete beams, XIX. National Mechanics Conf., August 24-28, Trabzon, Turkey.
Çağlar Y, Şener S (2016). Size effect tests of different notch depth specimens with support rotation measurements. Engineering Fracture Mechanics, 157, 43-55.
Duan K, Hu X, Wittmann FH. (2003). Boundary effect on concrete fracture and non-constant fracture energy distribution. Engineering Fracture Mechanics, 70, 2257-2268.
Duan K, Hu X, Wittmann FH (2006). Scaling of quasi-brittle fracture boundary and size effect. Mechanics of Materials, 38, 128-141.
Hoover CG, Bazant ZP (2014). Universal size-shape effect law based on comprehensive concrete fracture tests. Journal of Engineering Mechanics, ASCE, 140, 473-479.
Karihaloo, B. L. Abdalla, H. M., Xiao (2003). Size effect in concrete beams. Engineering Fracture Mechanics, 70, 979-993.
Şener S, Çağlar Y, Belgin ÇM (2014a). Size effect tests for Type I and Type II, 11th International Congress on Advances in Civil Engineering, 51, Istanbul, Turkey.
Şener S, Belgin ÇM, Çağlar Y, Hasanpour R, Topgül S, Boduroğlu VB, Negin M, Çağlar NM (2014b). Size effect tests and fracture mechanics analysis of concrete with carbon nano tubes. Technical report for TUBITAK, 111M374, Istanbul, Turkey.
Şener S, Şener KC (2016). Universal size effect studies using three point beam tests, The First European and Mediterranean Structural Engineering and Technology Conference, and published in Interaction between Theory and Practice in Civil Engineering and Construction, 67-72.
Weibull W (1939). The phenomenon of rupture in solids. Proc. R. Swedish Inst. Eng. Res., 153, 1-55.
Peer-review under responsibility of the organizing committee of ACE2016.
- There are currently no refbacks.