AN EXPEDITIOUS PARAMETRIC APPROACH FOR CITY INFORMATION MODELING AND FINITE ELEMENT ANALYSIS

Abstract. The mitigation of seismic risk passes through the assessment of seismic hazard of urban fabrics on a given territory. Statistical methods and damage probability matrices are currently used to facilitate seismic safety knowledge and assessment operations. These methods, despite being fast and low cost, often return results that differ from reality and prone to the expertise of the operator. Indeed, in order to have more accurate information it is necessary to conduct Finite Element Analysis (FEA). However, this type of analysis requires considerable surveying and modeling time and therefore are not easily applied to the urban scale. The key to implement this analysis at the territorial scale lies in the way of acquisition of urban data (geometric and informative) and their management within appropriate modeling environments that allow their treatment. Currently, the information modeling paradigms used for urban data collection and management are either time and resource consuming (HBIM) or overly simplified (GIS). In this research we investigate the potential of City Information Modeling (CIM) in a parametric environment (with reference to CityGML standards) combined with urban survey procedures. Aim of the work presented here is the definition of a parametric modeling protocol that allows, in a short time, the acquisition, modeling and finite element structural analysis of urban aggregates

Simulation of the Out-of-Plane Behaviour of URM Walls by Means of Discrete Macro-Element Method

The seismic response of masonry structures without box-type behaviour is given by a complex interaction between in-plane and out-of-plane behaviours. Previous earthquakes demonstrated that out-of-plane failure mechanisms represent the main cause of structural collapses of UnReinforced Masonry (URM) and historical structures. Previous experimental and analytical studies, investigating the out-of-plane behaviour of URM structures, mostly considered the effects of one-way bending moment. In this regard, recent experimental campaigns and numerical simulations have been conducted in order to investigate the out-ofplane behaviour of masonry walls subjected to two-way bending. These investigations have demonstrated the complexity of this mechanism and stressed the need for accurate numerical tools capable of providing reliable predictions in terms of ultimate strength and failure mechanisms. This paper focuses on the assessment of the dynamic behaviour of a U-shape URM prototype, subjected to shaking table tests, by means of a simplified computational strategy denoted as Discrete Macro-Element Method (DMEM). In this investigation, a comparison between experimental and numerical results was conducted in order to validate the capabilities of the proposed modelling approach. Subsequently, a parametric analysis was carried aiming at determining the influence that masonry mechanical properties, and additional model parameters, have on the out-of-plane nonlinear dynamic response of URM masonry structures

In-plane Behaviour of an Iron-Framed Masonry Façade: Comparison between Different Modelling Strategies

The ‘baraccato’ system is a construction technique with genius earthquake resilient features, used for the reconstruction of the historical city centres in the South of Italy after the catastrophic events occurred in the 18th-19th centuries. A very interesting example of such a building typology is represented by the Church of Santa Maria Maddalena, located in the municipality of Casamicciola Terme of the Ischia Island and built in 1896, after the catastrophic earthquake of 1883. The church is characterized by a mixed ‘baraccato’ system mainly made of yellow tuff block masonry walls strengthened by iron profiles or wooden elements. The reduced damage suffered by the church after the seismic event of 21st August 2017 evidenced the good behaviour of such a mixed structural system, especially into avoiding out-of-plane mechanisms. The presence of the iron-framed system is even more challenging in the definition of the modelling strategies for the structural analysis of the church. Thus, the choice of an appropriate numerical strategy to be used for nonlinear simulation should be properly investigated since the interaction between the frame elements and the elements representing the masonry walls has to be considered. As a first step of the structural analysis of the whole church, the in-plane behaviour of the main façade of the Church of Santa Maria Maddalena is analysed in this paper, with the aim to evaluate the efficacy of different modelling strategies. In particular, the study considers different models according to Finite and Discrete Element strategies available within DIANA FEA [1] and 3DMacro [2] software, respectively. Non-linear static analyses are carried out by means of both software and the obtained results are compared and discussed with the aim of extending them to the study of the whole church

A model for pushover analysis of confined masonry structures : implementation and validation

Confined masonry (CM) is a typical building technique in Latin American countries. This technique, due to its simplicity of construction and similarity with traditional practices of reinforced concrete building, presents a potential of use in European regions with moderate-to-high seismicity. However, most of the procedures for seismic design in codes for Latin America are force-based, which appears to be inadequate due to the high dissipative response observed for CM. This paper presents a simplified numerical-analytical approach to model CM structures using pushover analysis, aiming to apply performance-based design procedures. First, a data mining process is performed on a database of experimental results collected from lateral tests on CM walls to adjust prediction models for the wall shear strength and to determine the input relevance through a sensitivity analysis. Then, an analytical model of CM structures for pushover analysis is proposed with basis on a wide-column approach that employs an adaptive shear load-displacement constitutive relation. The proposed method is compared with a discrete element model that represents explicitly the confinements-masonry interaction, against the experimental results obtained in a quasi-static test of a full-scale tridimensional CM structure. The accuracy of the predictions from both methods is very satisfactory, allowing to capture the base shear-displacement envelope and also the damage patterns of the structure, thus, demonstrating the ability of the methods to be used in performance-based seismic assessment and design of CM buildings.The first author acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) through the Ph.D. Grant SFRH/BD/41221/2007

An Interdisciplinary Approach for the Experimental Assessments of the Seismic Safety of Artworks

Recent seismic events occurred in areas rich of ancient remains and full of cultural and artistic heritage in terms of artworks. Earthquakes may damage buildings, but the vibrations may also induce the uplift and overturning of their content, implying irreparable loss of cultural values. The seismic assessment of objects is usually tackled modelling them as rigid blocks. This paper focuses on statues, which generally present a very complicated geometry, and proposes a general methodology involving different disciplines, for their experimental seismic assessment. The methodology is here applied to the masterpiece of “Paolo Orsi” museum in Syracuse (Italy), that is the “Venere Landolina”. Due to the complexity of statues, traditional techniques cannot be considered reliable for a proper geometry reconstruction; therefore, Terrestrial Laser Scanner (TLS) and Unmanned Aerial System (UAS) technologies are here employed to obtain a highly detailed and complete digital model. Aiming at providing a low-cost scaled physical model of the statue, a wooden specimen has been arranged employing a Computer Numerical Control (CNC) milling machine, cutting off disks from flat panels which are then superimposed and glued, progressively reconstructing the actual geometry of the statue. The specimen, able to approximately reproduce the scaled actual geometry, was then tested on a shaking table with ground motions compatible with those expected for the site where the statue is located. The obtained results are finally correlated with those expected for the real scale statue

New perspectives in silicon micro and nanophotonics

In the last two decades, there has been growing interest in silicon-based photonic devices for many optical applications: telecommunications, interconnects and biosensors. In this work, an advance overview of our results in this field is presented. Proposed devices allow overcoming silicon intrinsic drawbacks limiting its application as a photonic substrate. Taking advantages of both non-linear and linear effects, size reduction at nanometric scale and new two-dimensional emerging materials, we have obtained a progressive increase in device performance along the last years. In this work we show that a suitable design of a thin photonic crystal slab realized in silicon nitride can exhibit a very strong field enhancement. This result is very promising for all photonic silicon devices based on nonlinear phenomena. Moreover we report on the fabrication and characterization of silicon photodetectors working at near-infrared wavelengths based on the internal photoemission absorption in a Schottky junction. We show as an increase in device performance can be obtained by coupling light into both micro-resonant cavity and waveguiding structures. In addition, replacing metal with graphene in a Schottky junction, a further improve in PD performance can be achieved. Finally, silicon-based microarray for biomedical applications, are reported. Microarray of porous silicon Bragg reflectors on a crystalline silicon substrate have been realized using a technological process based on standard photolithography and electrochemical anodization of the silicon. Our insights show that silicon is a promising platform for the integration of various optical functionalities on the same chip opening new frontiers in the field of low-cost silicon micro and nanophotonics

Numerical Modelling of Masonry Arches Strengthened with SFRM

The adoption of effective strengthening techniques of historical constructions is one of the most widely debated aspects in structural engineering. Within this topic, the application of steel fiber reinforced mortar (SFRM) has been recently proposed as a low invasive and effective way to obtain a considerable structural benefit in the safety of existing masonry structure. To this purpose, in this paper the experimental results obtained on a circular masonry arches are presented. The considered specimens, subjected to a vertical increasing static load, is tested in the unstrengthened and strengthened configurations, and is part of a wider experimental campaign. After presenting and discussing the experimental results, they are compared with those relative to numerical simulations conducted by means of a discrete macro-element (DME) strategy, based on a simple mechanical scheme, able to model the nonlinear behavior of masonry structures with a limited computational effort. Such an approach is here extended to model the SFRM strengthening technique accounting for the main failure mechanisms associated to the combined presence existing masonry and the additional strengthening layer applied at the intrados of the arch. Numerical and experimental results demonstrate the efficacy of the proposed retrofitting strategy both in terms of bearing capacity and increase of ductility

preliminary results of principe predictors of resistance to immunotherapy with nivolumab niv study in advanced pretreated non small cell lung cancer apnsclc investigating the role of an immune genomic signature igs including jak2 jak3 pias4 ptpn2 stat3 ifnar2 alterations

n/