Seismic Vulnerability Assessment and Strengthening Interventions of Structural Units of a Typical Clustered Masonry Building in the Campania Region of Italy

Abstract

The present paper aims at inspecting the structural behaviour of a typical masonry aggregate located in the historical centre of Cercola, a municipality in the province of Naples. The clustered building under study consists of four structural units mutually connected to each other made of tuff stone and deformable floors. Two distinct structural units, namely in heading and intermediate places, in both isolated and aggregate conditions, are examined to estimate the influence of structural positions on the global seismic response of the examined case study buildings. For this purpose, non-linear static analyses are performed using the 3MURI software. Pushover analyses are conducted to both evaluate the seismic behaviour of examined structural units and improve their earthquake performances while considering proper retrofit interventions on vertical and horizontal structures. The analysis results are plotted in terms of risk factor, stiffness, and ductility. Finally, a set of fragility functions are derived to point out the structural response of the case study buildings before and after retrofit interventions. From the achieved results, it is highlighted that retrofit interventions improve the structural performances of the buildings, especially those of structural units in aggregate conditions.

Seismic Vulnerability Assessment and Simplified Empirical Formulation for Predicting the Vibration Periods of Structural Units in Aggregate Configuration

“…To estimate the seismic vulnerability of buildings aggregate, it was adopted a specific vulnerability form proposed in [4,28,29], which is based on Benedetti and Petrini's vulnerability index method. The proposed vulnerability form, widely recognized internationally, was appropriately conceived for historical aggregate buildings by adding-to the original form-five new additional parameters, which take into account the effects of the mutual interaction among SUs under seismic action.…”

“…The proposed vulnerability form, widely recognized internationally, was appropriately conceived for historical aggregate buildings by adding-to the original form-five new additional parameters, which take into account the effects of the mutual interaction among SUs under seismic action. In particular, the new parameters were added to the 10 basic parameters used in the past to survey the buildings considered in isolated configuration [4,28,29] (Table 2). The vulnerability index, I V , was evaluated for each SU as the weighted sum of the class selected (for each of the 15 parameters listed in Table 2) multiplied by the respective weight [28].…”

“…The reference case study clustered structural cells are illustrated in Figure 6, where the aggregate configuration effect was modelled taking into account the half part of the units contiguous to the reference one accounting for their contribution in terms of both stiffness and mass. In addition, the behavior of the above-presented SUs was also analyzed in isolated configurations to appreciate the differences in terms of stiffness, ductility, ultimate displacement, and base shear concerning the case of aggregate constructions [4].…”

“…This structural inadequacy generates a drastic increase in terms of global vulnerability and, therefore, of the seismic risk of entire urbanized sectors. Thus, seismic vulnerability represents one of the main elements to be taken into consideration for the protection of historic buildings [4,5].…”

“…Therefore, simplified procedures for simulated modal identification analysis of the inspected buildings are developed. In this regard, many mechanical models are analyzed in several scientific papers [4,5,9], where the uncertainties related to vulnerability factors are often considered to quantify the seismic response of the entire aggregate and to set up appropriate risk mitigation procedures [24,25].…”