A method for large-scale vulnerability assessment of historic towers

Abstract

The methods commonly pursued for vulnerability or risk analysis, when carried out at large scale (territorial, regional), are mainly based on qualitative parameters, due to the necessity of processing a huge number of structures. As a matter of fact, the final target of these methods is the correlation of the most representative parameters of the structural behaviour, so as to finally rank the same structures according to their level of vulnerability or associated risk.These methods are undoubtedly effective for large-scale analyses and statistical elaborations, although affected by a certain level of subjectivity. Moreover, the vulnerability is commonly defined by hybrid indices (more often obtained as score assignment or expert opinions) that do not represent physical entities.A validation of these methods can be pursued by data on earthquake damage, which are very helpful for calibrating the analysis and formulating fragility curves.Experimental data and in situ investigations can also help to enhance the effectiveness of the method and to finally calibrate the same results.These are particularly needed for very slender structures, as towers and similar structures, the behaviour of which is strongly influenced by the dynamic performance.This paper presents a new method, named Vulnerability of Towers (VULNeT), for assessing the seismic vulnerability of slender structures (particularly towers) according to two different levels of accuracy. The method is based on qualitative parameters, collected through a new survey form, on purpose developed with an online data storage, capable of running speedy analyses.Once the method has been introduced, some applications on different samples are shown and the result compared with those of other recent works obtained from the literature on the topic.The final part of this paper provides a general framework on possible enhancements of VULNeT. Data on the dynamic behaviour of the structure obtained through experimental campaigns and structural modelling are introduced, and these are conceived for validating the results achieved as well as to check the feasibility of the possible failure mechanisms included in the form.

Simplified risk assessment of immovable cultural heritage assets

“…A descrição e a definição detalhada do processo de avaliação da fragilidade sísmica e a consequente avaliação do nível de dano esperado para as várias classes arquitetónicas consideradas é apresentada de forma individual em [2]. Salienta-se, no entanto, que os procedimentos estabelecidos são baseados em [3][4][5][6][7][8], no caso de construções da classe arquitetónica CA1, em [9][10][11][12], no caso de construções da classe arquitetónica CA2, em [13][14][15][16][17][18][19], no caso de construções da classe arquitetónica CA3, e em [20][21][22][23], no caso de construções da classe arquitetónica CA4.…”

A framework for the simplified risk analysis of cultural heritage assets

“…The procedure developed for cultural heritage units of class CA2 is similar to that of class CA1. For class CA2, the procedure is based on the classification and weighted average of 12 parameters related to the type of structural system, the characteristics of the masonry, the lateral strength of the structure, the slenderness of the structure, the type of foundations and soil conditions, the construction position and interaction with respect to its surroundings, plan and vertical regularity factors, the type and arrangement of openings, the type of floor and roof systems, the state of conservation of the structural system and the existence of non-structural falling hazards [78][79][80][81]. The procedures developed for cultural heritage units of classes CA3 and CA4 are different than those of classes CA1 and CA2 since they are mostly based on simple mechanics-based approaches.…”

Seismic Vulnerability Assessment of Slender Masonry Structures

“…These structures are characterized by their notable slenderness and also represent one of the main differences from most of the historic structures or even ordinary buildings [1]. These structures are scattered over different countries with different densities and features.…”

“…Unfortunately, several historical constructions suffered partial or total collapse in the course of time due to earthquakes, fatigue, deterioration, soil movements, etc. The occurrence of these unexpected and unavoidable events has demonstrated that historical slender masonry structures are one of the most vulnerable structural types to suffer strong damage or collapse [1]. These losses are simply not quantifiable in economic terms, as nether lives nor can cultural heritage be reinstated by post-earthquake reconstruction plans.…”

“…These structures are featured by their notable slenderness and also represent one of the main differences from most of the historic structures or even ordinary buildings [1].…”