Giuseppe Brando

Damage Probability Matrices for Three-Nave Masonry Churches in Abruzzi After the 2009 L’Aquila Earthquake

ABSTRACT This article provides the main outcomes obtained downstream from a survey concerning the damage to 64 three-nave masonry churches in Abruzzi resulting from the 2009 L’Aquila earthquake. First, they are classified according to the typological, structural, and architectural features. Next, the main failure mechanisms observed in the immediate aftermath of the 2009 earthquake are identified and analyzed, taking into account both the global structural response and the local mechanisms involving specific parts of the churches. Damage related to the local mechanisms is classified by means of scores based on both the severity and extension of the revealed cracks. The single scores are combined to define an index measuring the global damage of each church. Such indices are therefore associated with six damage levels, the frequencies of which are organized into damage probability matrices. These matrices can be used in order to quantitatively evaluate the damage scenarios that the studied population of buildings revealed after the seismic event, as well as to predict the damage level that could be expected on similar churches for future earthquakes.

Influence of Column Axial Load and Heat Affected Zone on the Strength of Aluminium Column Web in Tension

The component method for aluminium joints has been recently introduced in some codes and guidelines. Nevertheless, it is still in need of some development and improvement, as in some cases it was obtained by adapting the existing formulations that are valid for steel. The current paper presents the main outcomes of a parametric analysis carried out by means of finite element (FE) numerical models for determining the influence of both column axial load and heat affected zone—in the case of welded details—on the structural response of the column web in a tension component. The proposed study integrates previous research carried out by the authors, where the influence of the assumed alloy was investigated and interpreted by corrective parameters expressed as a function of both the material strain hardening and ductility.

Structural Individuation of Damages Occurred on St. Gemma Church in Goriano Sicoli during the 2009 L’Aquila Earthquake

The current paper presents the first part of a study in progress devoted to analyse the St. Gemma church in Goriano Sicoli, which has been seriously damaged by the 2009 L’Aquila earthquake. Firstly, the main effects provoked by L’Aquila Earthquake on ancient historical centres, with particular regard to buildings belonging to the cultural heritage, are described. Then, the St. Gemma church is investigated in detail. The main geometry and structural details of the church are shown and damage occurred during to the seismic event of 6.04.09 is critically analysed and discussed. Finally, the main outcomes of dynamic tests carried out on the damaged church, in order to detect its main natural frequencies and mode shapes, are provided.

The effects of L’aquila earthquake on the St. Gemma church in Goriano Sicoli: part II—fem analysis

In order to integrate the study undertaken in the companion paper, the main outcomes of a linear response spectrum analysis carried out by the FEM numerical model of the St. Gemma church in Goriano Sicoli are presented in current paper. The proposed model has been calibrated on the basis of ambient vibration tests carried out on the building in the damaged state. Numerical model reliability has been proved by its capability to reproduce the crack pattern observed on the church as it was provoked by the occurred earthquake. The structural response of the church has been investigated by interpreting the stress distribution with the aim of understanding the zone where the major stress concentrations occur. The purpose of the study is to provide useful indications on the main structural vulnerability of this type of building in order to extend the main outcomes to similar churches belonging to the same regional area, in order to get appropriate fragility curves.

Seismic vulnerability assessment of historic centers: description of a predictive method and application to the case study of scanno (Abruzzi, Italy)

ABSTRACT In this article, a predictive model for the seismic vulnerability assessment of old Italian historic centers is presented through its direct application to a meaningful case study, the historic center of Scanno, in Abruzzi, Italy. The proposed method is calibrated on the basis of the observations carried out on similar historic centers hit by the 2009 L’Aquila earthquake and is applied in order to provide likely damage scenarios by means of fragility curves. The method is based on the evaluation of a limited number of structural and typological parameters that can be obtained by simple and rapid inspections on buildings. In addition, it is conceived in order to provide useful information on the most effective anti-seismic strategies to be implemented on urban scale for pursuing a global mitigation of the seismic risk and for the application of suitable risk reduction policies. The final aim of the article is to give an applicative vision of the method, by providing instructions on how to judge the features of the buildings that are influential on their seismic behavior, as well as by showing the potentiality of the method itself in providing likely damage scenarios, also with the support of GIS-based representations.

The effects of L’Aquila earthquake on the St. Gemma church in Goriano Sicoli: part I—damage survey and kinematic analysis

The paper deals with the structural response of the St. Gemma church in the small historical centre of Goriano Sicoli, which was stricken by the 2009 L’Aquila earthquake. This church is a typical example of Abruzzi baroque architecture and is representative of a large population of similar samples belonging to a wide territorial area. A detailed survey of the damages provoked by the earthquake on both the whole church and its main macro-elements is presented. Then, the observed mechanisms are interpreted by the implementation of both linear and non linear kinematic analyses. The comparison between the obtained results and the occurred seismic demand allows to justify the revealed state of damage and to prove the reliability of the proposed evaluation procedure. In the companion paper, the main outcomes of a FEM response spectrum analysis are presented in order to investigate the structural vulnerability of the church through a detailed analysis of the local stress distribution.

An Extensive Survey of the Historic Center of Cusco for Its Seismic Vulnerability Assessment

This paper presents the main important typological data collected during an extensive survey carried out on the buildings of the historic center of Cusco, Peru. These data will represent the basis for a future analysis devoted to large scale seismic vulnerability assessment, to develop, in a structured and efficient manner, policies and measures for the seismic risk mitigation. Starting from the collection of available data and from the historical analysis of the urban development of the center, also accounting for earthquakes of the past, the most representative architectural typologies are identified. Moreover, statistical analyses are carried out, in order to detect the most recurrent structural details. On these bases, the main potential fragilities are identified, giving a preliminary idea of the structural behavior of the considered buildings under seismic forces.

A Design Formulation for Dissipative Metal Shear Panels

This paper proposes an analytical formulation for designing dissipative metal shear panels for the seismic protection of buildings. In particular, two types of dissipative shear panels are analyzed. The first is based on the adoption of a material characterized by a low yield strength with the application of transversal stiffeners. The latter is a steel shear plate that is properly weakened by perforations. Both the studied typologies are conceived in order to obtain a low shear elastic strength, so that their dissipative function is activated when the other members of the structure are still in the elastic field, even for high intensity earthquakes. Moreover, they are usually designed in order to postpone the trigger of potential buckling phenomena to the field of high shear inelastic demands. The proposed design formulations put in relation demanded shear stresses and strains. In particular, a unique expression, characterized by different coefficients for the two panel typologies, is given. The validity of the proposed expression is corroborated on the basis of the results of several numerical and experimental analysis.

Comparative Analysis of Dual Steel Frames with Dissipative Metal Shear Panels

This paper deals with the seismic response of dual steel frames with and without dissipative metal shear panels. The main goal is to define possible design criteria, for the seismic protection of new and existing buildings, accounting for the main behavioral peculiarities of metal shear panels.To this purpose, based on a large number of historical records that are selected in order to match the main interesting frequencies, Incremental Dynamic Analyses (IDAs) are carried out on two steel frames. These frames have been first designed in order to satisfy specific performances. Then, they have been improved by imposing stricter design goals that have been complied with the application of dissipative metal shear panels.The obtained outcomes highlight that metal shear panels allow to control properly the collapse mechanisms of the frames. Moreover, they can lead to significant increases of collapse accelerations and to a general reduction of both the permanent and the transient story drifts. The paper concludes with the evaluation of the equivalent q-behaviour factor of both the protected and the un-protected frames. As it could be expected, the most effective shear panels are able to produce stronger increase of behavior factors (up to 150%), due to the larger dissipative capacity of the whole structure.

Analysis of Aluminium Beam-to-Column Joints by the Component Method: Existing Studies and Research Needs

This paper aims at providing an overview on the current state of the art and on possible future developments concerning the component method implementation for the classification of beam-to-column joints belonging to aluminum moment resisting frames.After a brief discussion on the component method theoretical bases, developed in the past to give a feasible calculation procedure for steel joints, recent experimental and numerical studies, carried out for investigating some aluminum components, are presented and discussed. In particular strengths and weaknesses of the current knowledge are put into evidence, also in light of the peculiarities that make aluminum alloys different from steel. The launch of new research fields, aimed at pursuing an update of the current codes dealing with aluminum structures, is therefore proposed.