Aims of the numerical analysis were (a) the study of failure modes I and II and (b) the determination of the maximum compressive, tensile and shear stresses that develop under the actions described in Tables 2 and 3. The models are shown in Figures 13 & 14. The clamp tensile strength was chosen equal to 55 MPa, the clamp shear strength 29 MPa and the dowel shear strength 14 MPa (Zambas 1994, Vardoulakis et al. 2002). In the case of the dowel analysis, two force distributions on the marble (applied as surface distributed loads and automatically converted to loads on the corresponding nodes) were selected, namely uniform and triangular. The latter results in higher corresponding stresses ax and ay.
In the case of the clamps, in accordance to the conclusions of the failure modes' analysis, mainly shear (and not tensile) forces were considered. It is however recognized that, in rather extreme situations (such as the explosion), significant tension can also develop parallel to shear, therefore some more complex stress situations were also considered.
In terms of resistances, it is well-known that marble tensile strength values available in the literature present important scattering, attributable to different test procedures as well as to marble anisotropy (Vardoulakis et al. 2002). The values provided by Vardoulakis et al. (2002) were used. Precisely, the tensile strength in the two strong marble directions was found equal to 9.5 and 10.8 MPa respectively, whereas the tensile strength of the marble soft plane was found equal to 5.3 MPa. Consequently, tensile stresses around 5 MPa were considered sufficient to generate cracks inside the marble mass.
The main results of the analysis of the connectors (Toumbakari 2007a, Filippoupolitis 2007) are summarized in Tables 6 & 7. In the case of the clamp, the application of a shear force equal to 15 kN (LC2) at
Table 6. Main results of the clamp analysis.
Table 6. Main results of the clamp analysis.
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