Seismic Analysis of Historic Masonry Buildings: The Vicarious Palace in Pescia (Italy)

Recent Italian earthquakes have underlined the need for wide monitoring and safety assessment of architectonical heritage. This has emerged also from requirements of the new Italian Technical Recommendations for buildings. Within this subject the paper investigates the seismic vulnerability of a specific monumental masonry building: the Vicarious Palace (Palazzo del Vicario) in Pescia, a small town near Florence. The structural behavior of the Palace was investigated using a finite element model in which the non-linearities of the masonry were considered by proper constitutive assumptions. The seismic behavior was evaluated by the pushover method, according to the Italian Technical Recommendations. The results were compared with the ones obtained by a simplified approach based on the kinematic theorem of limit analysis. Comparisons of the expected seismic demand vs the seismic capacity of the Palace confirm the weakness of this type of building to suffer extensive damage under earthquakes, as frequently observed in similar construction typologies. Additionally, the comprehension of the structural behavior under seismic loading allows the identification of a proper retrofitting strategy

Time-History Seismic Analysis of Masonry Buildings: A Comparison between Two Non-Linear Modelling Approaches

The paper presents a comparison between two numerical modelling approaches employed to investigate the seismic behavior of unreinforced masonry buildings with flexible diaphragms. The comparison is performed analyzing a two-story prototype tested on a shaking table at the CNR-ENEA research center of Casaccia (Italy). The first numerical model was built by using the finite element (FE) technique, while the second one was built by a simplified macro-element (ME) approach. Both models were employed to perform non-linear dynamic analyses, integrating the equations of motion by step-by-step procedures. The shaking table tests were simulated to analyze the behavior of the prototype from the initial elastic state until the development of extensive damage. The main results of the analyses are discussed and critically compared in terms of engineering parameters, such as accelerations, displacements and base shears. The effectiveness of both models within the investigated typology of buildings is then evaluated in depth

An Integrated Geometric and Material Survey for the Conservation of Heritage Masonry Structures

This paper reports the knowledge process and the analyses performed to assess the seismic behavior of a heritage masonry building. The case study is a three-story masonry building that was the house of the Renaissance architect and painter Giorgio Vasari (the Vasari’s House museum). An interdisciplinary approach was adopted, following the Italian “Guidelines for the assessment and mitigation of the seismic risk of the cultural heritage”. This document proposes a methodology of investigation and analysis based on three evaluation levels (EL1, analysis at territorial level; EL2, local analysis and EL3, global analysis), according to an increasing level of knowledge on the building. A comprehensive knowledge process, composed by a 3D survey by Terrestrial Laser Scanning (TLS) and experimental in situ tests, allowed us to identify the basic structural geometry and to assess the value of mechanical parameters subsequently needed to perform a reliable structural assessment. The museum represents a typology of masonry building extremely diffused in the Italian territory, and the assessment of its seismic behavior was performed by investigating its global behavior through the EL1 and the EL3 analyses

PROBA-3 mission and the Shadow Position Sensors: Metrology measurement concept and budget

PROBA-3 is a space mission of the European Space Agency that will test, and validate metrology and control systems for autonomous formation flying of two independent satellites. PROBA-3 will operate in a High Elliptic Orbit and when approaching the apogee at 6·104 Km, the two spacecraft will align to realize a giant externally occulted coronagraph named ASPIICS, with the telescope on one satellite and the external occulter on the other one, at inter-satellite distance of 144.3 m. The formation will be maintained over 6 hrs across the apogee transit and during this time different validation operations will be performed to confirm the effectiveness of the formation flying metrology concept, the metrology control systems and algorithms, and the spacecraft manoeuvring. The observation of the Sun's Corona in the field of view [1.08;3.0]RSun will represent the scientific tool to confirm the formation flying alignment. In this paper, we review the mission concept and we describe the Shadow Position Sensors (SPS), one of the metrological systems designed to provide high accuracy (sub-millimetre level) absolute and relative alignment measurement of the formation flying. The metrology algorithm developed to convert the SPS measurements in lateral and longitudinal movement estimation is also described and the measurement budget summarized

Uno studio numerico sul coefficiente di forma b del criterio di rottura a taglio per fessurazione diagonale per pannelli in muratura ordinaria

Nella memoria, dopo aver richiamato i meccanismi di rottura dei pannelli murari previsti dalle nuove norme tecniche per le costruzioni (D.M. del 14/01/2008 e Circolare Ministeriale del 02/02/2009), viene presentata un’indagine numerica sul valore del coefficiente di forma b del criterio di rottura a taglio per fessurazione diagonale. I risultati delle analisi mostrano che i valori di tale coefficiente sono più elevati di quelli della formulazione semplificata adottata nella norma, con riduzione del valore del taglio ultimo. Viene proposta una nuova formulazione per il coefficiente b e ne vengono mostrati gli effetti analizzando la risposta strutturale di tre pareti piane di muratura ordinaria con differenti snellezze delle fasce di piano. A tale scopo si confrontano i risultati di analisi di spinta ottenuti con modelli agli elementi finiti ed a telaio equivalente. Questi ultimi sovrastimano la resistenza delle pareti con le fasce di piano più alte e l’effetto è amplificato dall’adozione dei valori del coefficiente b proposti nella norma. ABSTRACT After reporting the failure criteria for unreinforced masonry panels provided by the new Italian Recommendations, the paper presents a numerical study aimed to investigate the shape factor b. This coefficient is used to evaluate the ultimate shear strength of masonry panels in the failure criterion with diagonal cracking. The numerical results show that the computed values of the b factor are higher than those proposed by the rules and a new formulation is given. The effects of this formulation are subsequently investigated by analysing the seismic response of three masonry façades by means of pushover analyses. Results show that the shear strengths obtained applying the equation for b given by Italian Recommendations do not appear conservative