Issue 50

I. Dakanali et alii, Frattura ed Integrità Strutturale, 50 (2019) 370-382; DOI: 10.3221/IGF-ESIS.50.31 375 Figure 7: The time variation of the load and the LVDT indications for two characteristic tests of each experimental class. curves for 2 nd class tests are presented in Fig.6c. The curve has a linear segment till the maximum load when a slight load drop occurs. After that, the load continues to increase. This is due to the friction as the bar is sliding through the remaining hole’s length. It is important that after the bar’s extraction from the marble block, the bars from all 2 nd class tests present a characteristic cone of marble around them (Fig.6b), which does not appear after the tests of 2 nd class (Fig.6d). The load from 3 rd class tests increases linearly till the maximum load, after that a slight drop appears and the load remains relatively constant. The connection does not lose totally its integrity due to the friction between the paste-bar complex and the marble, as the frame is pushing inwards the bar. 1 st class A B C A B C (b) (a) 2 nd class A B C A C B (c) A B A B 3 rd class