1 Assistant Professor, Department of Civil Engineering, Universidad de Medellin-Colombia, e-mail: jmgarcia@udem.edu.co
2 Associate Professor, Department of Civil Engineering, Universidad de Medellin-Colombia, e-mail: rbonett@udem.edu.co
3 Assistant Professor, Department of Structural and Geotechnical Engineering, Pontificia Universidad Católica de Chile, e-mail: ledezma@ing.puc.cl
ABSTRACT
The structural behavior of concrete masonry is influenced by the mechanical properties of the constituent materials. The compressive strength of masonry is the most important parameter in the design of masonry structures and it primarily depends on the strength of the individual block units. Mathematical modeling of structures with masonry walls requires the material properties (compressive strength and modulus of elasticity) and constitutive relationships of masonry and its constituents. Code for design masonry structures gives the formulas for calculating the average axial compressive strength of concrete masonry. In these formulas, there are many unknown parameters to predict real compression behavior in the masonry, because the parameters of these formulas are related to the type of block materials.
An experimental investigation was performed to generate the complete stress-strain curves of hollow concrete blocks in uniaxial compression with nominal strength (10 MPa) made of local materials. A number of empirical and analytical models available in the literature of the complete stress-strain curve for concrete under uniaxial compression are reviewed and discussed using the published experimental data.
Based on experimental data, a new model with emphasis on compressive strength is proposed to generate the complete stress-strain relationships for hollow concrete block. The proposed model fit the experimental data with excellent agreement and it is capable of predicting the behavior of normal and high strength hollow concrete block. The proposed empirical model can be employed in the non-linear finite element analysis and design procedures of concrete masonry structures.
KEYWORDS: stress-strain curve, compressive strength, elastic modulus, hollow concrete block, masonry
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