Experimental and numerical investigation of compression shear fracture and size effect of reinforced concrete structural elements

IV SUMMARY PhD Thesis EXPERIMENTAL AND NUMERICAL INVESTIGATION OF COMPRESSION-SHEAR FRACTURE AND SIZE EFFECT OF REINFORCED CONCRETE STRUCTURAL ANALYSIS Ragıp İNCE Fırat University Graduate School of Natural and Applied Sciences Department of Civil Engineering 1998, Page: 140 The design of Reinforced Concrete structural elements has not yet been well defined as desired because of their complex behaviour. However, the existing numerical and experimental research studies provide promising results for future. The presented study was devided into two main groups as numerical and experimental studies. This is because of the importance of both numerical simulations and experiments in materials research. For this purpose, the reinforced concrete beams at a/d=1.5 ratio and without shear reinforcement were tested and the results were applied to existing size effect theories. Afterwords, a new lattice modelling technique was developed over existing informations about lattice modelling in literature. These developments were made based on basic fracture mechanics concepts on concrete. The other important feature of the developed lattice modelling was the consideration of heterogeneity of concrete structure as meso-level modelling. The newely developed model was applied to three most popular fracture mechanics concepts for concrete namely TWO-PARAMETER MODEL, EFFECTIVE CRACK MODEL and THE SIZE EFFECT MODEL. It was concluded that the developed model well agrees with these existing models, than the research extended to the modelling of reinforced concrete behaviour. Beside the requirement of higher computer memory and faster CPU's of the improved lattice model than the other existing models, it performs much better definition and provides more realistic results. Because it is possible to model the concrete without any simplifications on the heterogen structure. It was concluded that the improved lattice model is capable of better modelling of concrete and reinforced concrete. Particularly it must be pointed out that the reinforced concrete model is the first application in lattice theory so far. KEY WORDS: Concrete, Reinforced Concrete beams, Fracture Mechanics of Concrete, Size Effect, Numerical Materials Modelling, Lattice Modelling