EFFECT OF TRANSVERSE BASE RESTRAINT ON THE CRACKING BEHAVIOR OF MASSIVE CONCRETE
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Abstract
The effect of considering the third dimension in mass concrete members on its cracking behavior is investigated in this study. The investigation includes thermal and structural analyses of mass concrete structures. From thermal analysis, the actual temperature distribution throughout the mass concrete body was obtained due to the generation of heat as a result of cement hydration in addition to the ambient circumstances. This was performed via solving the differential equations of heat conduction and convection using the finite element method. The finite element method was also implemented in the structural analysis adopting the concept of initial strain problem. Drying shrinkage volume changes were calculated using the procedure suggested by ACI Committee 209 and inverted to equivalent temperature differences to be added algebraically to the temperature differences obtained from thermal analysis.
Willam-Warnke model with five strength parameters is used in modeling of concrete material in which cracking and crushing behavior of concrete can be included. The ANSYS program was employed in a modified manner to perform the above analyses. A thick concrete slab of 1.5m in thickness and 10m in length was analyzed for different widths 2, 4, 8, and 10m to produce different aspect ratios (B/L) of 0.2, 0.4, 0.8, and 1.0 respectively. The results of the analyses show an increase in cracking tendency of mass concrete member as the aspect ratio of the same member is increased due to the effect of transverse base restraint. Accordingly, such effect cannot be ignored in the analysis of base restrained mass
concrete structures subjected to temperature and drying shrinkage volume changes.
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References
* ACI Committee 207, “Effect of Restraint, Volume Change, and Reinforcement on Cracking in Massive Concrete”, (ACI 207.2R-95). American Concrete Institute, Detroit, 1999, 26 pp.
* ACI Committee 209, “Prediction of Creep, Shrinkage, and Temperature Effects in Concrete Structures”, (ACI 209R-92), (Reapproved 1997). American Concrete Institute, Detroit, 1999, 47 pp.
* ANSYS 5.4 Inc., “ANSYS Theory Reference”, Eighth Edition, SAS IP, Inc. 1997, Chapter 4 pp. 48-56.
* Carlson, R. W., “Drying Shrinkage of Large Concrete Members” ACI Journal, Proceedings, Vol. 33, January-February 1937, pp.327-336.
* Cook, R. D., Malkas, D. S., and Plesha, M. E., “Concepts and Applications of Finite Element Analysis”, John Wiley and Sons Inc., Third edition, 1989, 630 pp.
* Fung, Y. C., “Foundations of Solid Mechanics”, Prentice-Hall Inc., Englewood Cliffs, New Jersey, 1965, 525 pp.
* Holman, J. P., “Heat Transfer”, Fourth Edition, 1976, McGraw-Hill. Kammouna, Z. M., “Development of A Mathematical Model for Creep of Concrete with Reference to Baghdad Climate”, M.Sc. Thesis, Baghdad University, College of Engineering, 2001, 90 pp.
* Willam, K. J., and Warnke, E. D., “Constitutive Model for the Triaxial Behavior of Concrete”, Proceedings, International Association for Bridge and Structural Engineering, Vol. 19, ISMES, Bergamo, Italy, p. 174 (1975).