6533b861fe1ef96bd12c5917

RESEARCH PRODUCT

Rocking behaviour of multi-block columns subjected to pulse-typeground motion accelerations

subject

description

Ancient columns, made with a variety of materials such as marble, granite, stone or masonry are an important part of theEuropean cultural heritage. In particular columns of ancient temples in Greece and Sicily which support only the architrave arecharacterized by small axial load values. This feature together with the slenderness typical of these structural members clearlyhighlights as the evaluation of the rocking behaviour is a key aspect of their safety assessment and maintenance. It has to be notedthat the rocking response of rectangular cross-sectional columns modelled as monolithic rigid elements, has been widely investigatedsince the first theoretical study carried out by Housner (1963). However, the assumption of monolithic member, although beingwidely used and accepted for practical engineering applications, is not valid for more complex systems such as multi-block columnsmade of stacked stone blocks, with or without mortar beds. In these cases, in fact, a correct analysis of the system should considerrocking and sliding phenomena between the individual blocks of the structure. Due to the high non-linearity of the problem, theevaluation of the dynamic behaviour of multi-block columns has been mostly studied in the literature using a numerical approachsuch as the Discrete Element Method (DEM). This paper presents an introductory study about a proposed analytical-numericalapproach for analysing the rocking behaviour of multi-block columns subjected to a sine-pulse type ground motion. Based on theapproach proposed by Spanos (2001) for a system made of two rigid blocks, the Eulero-Lagrange method to obtain the motionequations of the system is discussed and numerical applications are performed with case studies reported in the literature and with areal acceleration record. The rocking response of single block and multi-block columns is compared and considerations are madeabout the overturning conditions and on the effect of forcing function’s frequency..