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Keywords: smooth particle hydrodynamics, coupled modeling, high temperature, mechanical properties, boundary conditions, simultaneous nonlinear equations.

Summary

Concrete exposed to elevated temperature for example can be subject to material deterioration and consequently failure of such structures is possible. Tunnel linings are such an instant [1].

An increase of temperature above 200°C very dramatically reduces the compressive strength of concretes based on Portland paste.

The tensile strength and the strength in bending tension appear to be very similar.

At a high temperatures chemical decomposition of calcium-silicate-hydrate occurs, which is the main component of the mechanical properties of the concrete.

Splitting and spalling of parts of the concrete are related to different thermal expansion of particular components of the concrete mixture and the disturbed bond between aggregate and stiff cement paste as a consequence of physical and chemical changes. It is especially the phase change of quartz from a triclinic crystal system to the hexagonal system, which happens during the increase of temperature to 570-575°C.

The development of fires depends on very many circumstances: the type of structural material, source and the way of distribution of the fire, system of ventilation, reaction of the affected people, the system and speed of extinguishing the fire and the management of operation all affect the development of fires.

In this paper the combustion of the concrete lining and the rock surrounding the tunnel is solved using the smooth particle hydrodynamics (SPH) method. The results are partly compared with experiments on concrete slabs burned in a furnace. The influence of fibres is observed and the composite with concrete matrix is evaluated after carrying out tests at Innsbruck Technical University, Austria.

The boundary conditions are specified by the time changing source of heat, and the damage in the material is calculated at the time-stages. The SPH method is perfectly suitable for solving such a problem. This method uses relatively less computer time when comparing it with other numerical methods, but generally it suffers from one unpleasant property: inhomogeneous geometrical boundary conditions must be respected in the calculus in a complicated way.

References

1: V. Machovic, F. Kolár, P. Procházka, Š. Pešková and P. Kuklík, "Raman spectroscopy study of interfacial transition zone in cement composite reinforced by PP/PE and basalt fibres", Acta geodynamica et geomaterialia, 2, 63-67, 2006.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 91 PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping, L.F. Costa Neves and R.C. Barros Paper 96 Application of Smooth Particle Hydrodynamics to solving Problems with Exacting Conditions P.P. Prochazka and S. Peskova Department of Mechanics, Czech Technical University in Prague, Czech Republic doi:10.4203/ccp.91.96 purchase the full-text of this paper Full Bibliographic Reference for this paper P.P. Prochazka, S. Peskova, "Application of Smooth Particle Hydrodynamics to solving Problems with Exacting Conditions", in B.H.V. Topping, L.F. Costa Neves, R.C. Barros, (Editors), "Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 96, 2009. doi:10.4203/ccp.91.96 Keywords: smooth particle hydrodynamics, coupled modeling, high temperature, mechanical properties, boundary conditions, simultaneous nonlinear equations. Summary Concrete exposed to elevated temperature for example can be subject to material deterioration and consequently failure of such structures is possible. Tunnel linings are such an instant [1]. An increase of temperature above 200°C very dramatically reduces the compressive strength of concretes based on Portland paste. The tensile strength and the strength in bending tension appear to be very similar. At a high temperatures chemical decomposition of calcium-silicate-hydrate occurs, which is the main component of the mechanical properties of the concrete. Splitting and spalling of parts of the concrete are related to different thermal expansion of particular components of the concrete mixture and the disturbed bond between aggregate and stiff cement paste as a consequence of physical and chemical changes. It is especially the phase change of quartz from a triclinic crystal system to the hexagonal system, which happens during the increase of temperature to 570-575°C. The development of fires depends on very many circumstances: the type of structural material, source and the way of distribution of the fire, system of ventilation, reaction of the affected people, the system and speed of extinguishing the fire and the management of operation all affect the development of fires. In this paper the combustion of the concrete lining and the rock surrounding the tunnel is solved using the smooth particle hydrodynamics (SPH) method. The results are partly compared with experiments on concrete slabs burned in a furnace. The influence of fibres is observed and the composite with concrete matrix is evaluated after carrying out tests at Innsbruck Technical University, Austria. The boundary conditions are specified by the time changing source of heat, and the damage in the material is calculated at the time-stages. The SPH method is perfectly suitable for solving such a problem. This method uses relatively less computer time when comparing it with other numerical methods, but generally it suffers from one unpleasant property: inhomogeneous geometrical boundary conditions must be respected in the calculus in a complicated way. References 1 V. Machovic, F. Kolár, P. Procházka, Š. Pešková and P. Kuklík, "Raman spectroscopy study of interfacial transition zone in cement composite reinforced by PP/PE and basalt fibres", Acta geodynamica et geomaterialia, 2, 63-67, 2006. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £140 +P&P)
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