The taxi service in Italy: motivation and outline of the recent reform

This paper presents a quantitative and analytical documentation to the debate on taxi service liberalization. The results of a survey of the Bank of Italy on the main Italian cities show that the supply of taxi is much lower than that of other foreign cities. The paper gives also some quantitative and qualitative evidence of the negative effects on consumers and on the creation of rents deriving from the present taxi regulation. The economic analysis and the positive results of the recent experiences of liberalization in other countries show that a rigid regulation on tariffs and supply, like the one adopted in Italy, lacks a solid analytical as well an empirical basis for support. Likely, the lower availability of taxi in Italy does not reflect only quantity and price regulation but also other characteristics of the regulation itself, such as the prohibition of juridical persons to operate on the market and a decentralized decision process that attributes more consideration to the interests of taxi drivers with respect to those of consumers. The paper also presents some proposal, in the light of the effects of the recent Bersani decree, for a reform of the sector.service liberalization, taxi

Experimental and numerical analysis of a scaled dry-joint arch on moving supports

This paper aims to investigate the response of a scaled segmental dry-joint masonry arch to the settlement of one support. An experimental test and numerical simulations were performed by applying incremental vertical displacements at the right support up to collapse. The experimental test was carried out on a 1:10 small-scale model of the arch made of bi-component composite blocks with dry joints. Numerical simulations were performed using a finite element (FE) micro-modelling approach, where the arch was discretised as a set of very stiff voussoirs connected by nonlinear interfaces. Experimental and numerical results were compared in terms of displacement capacity and collapse mechanisms. The sensitivity of the numerical results to the interface stiffness was also evaluated.Peer ReviewedPostprint (author's final draft

Economic and Environmental Evaluation of a Single-Story Steel Building in Its Life Cycle: A Comprehensive Analysis

In this study, the possibility of applying the Life Cycle Thinking approach to structural design, considering all aspects and phases of the structure's life, is investigated. The idea is to develop a procedure for the analysis of the economic and environmental impacts of structures in their life cycle, including not only ordinary costs along life cycle phases but also the extraordinary costs resulting from damage and anticipated end-of-life caused by unexpected natural hazards. The building performance under extraordinary conditions is calculated according to a time-based Loss Assessment Analysis. Such analysis provides the probable performance of a building and its components over a given period of time, considering all the hazardous events that can occur in that period, the probability of occurrence of each event, and the related effects. The outlined approach is applied to a case study of a single-story steel office building located in Italy. Two LC scenarios, having a duration of 2 years and 50 years, are considered. Results show that contributions of environmental impacts and benefits related to end-of-life management and economic losses for natural hazards are significant and not negligible. It is highlighted that the greatest challenge faced when using such a comprehensive approach is represented by data availability and representativeness that deeply limits the possibility of its implementation

Validation of Simplified Micro-models for the Static Analysis of Masonry Arches and Vaults

Compared to simple masonry walls, numerical modelling of masonry vaulted structures is particularly complex due to their three-dimensional curved geometry and articulated masonry pattern. Moreover, the scarce availability of experimental data makes it difficult to validate numerical models for these types of structures. Recently, the simplified micro-modelling approach has been applied by different authors, despite some intrinsic limits, such as huge numerical effort and adoption of ad-hoc written numerical codes. The aim of this study is to overcome these difficulties by using a commercial software with built-in friction interface models and to validate the proposed simplified-micro model through experimental tests on in-scale specimens of arch and cross vault. The proposed approach has shown promising features: experimental results have been numerically reproduced with a high degree of accuracy, both in case of planar and space structures, with both dry and mortar joints. The final result of the study is a validated modelling strategy that could be confidently applied to real masonry vaulted structures

Seismic in-plane displacement capacity of masonry barrel vaults: the role of constructive aspects

Historic masonry vaults are one of the most vulnerable elements with respect to the seismic action. Cracks are often detected after post-earthquake surveys. However, it is difficult to directly link the observed damage to causes. Different mechanisms can occur during an earthquake, such as in-plane horizontal shear distortion or longitudinal opening/closing of the abutments. These mechanisms are not necessarily associated to a specific crack pattern, since other factors are involved in the determination of the detected crack status. Among these factors, constructive aspects (such as the brick pattern) play a major role. This study aims at investigating the possible correlation between constructive aspects and the crack pattern in barrel vaults subjected to in-plane shear mechanism. Numerical simulations are carried out on an ideal circular vault with a rectangular base of dimensions 3.1x5.3 m, and rise of 1.175 m. Three brick patterns are considered: radial, diagonal and vertical. In order to investigate these aspects, a micromodelling numerical approach has been adopted. Results are presented in terms of ultimate displacement capacity, collapse mechanisms and crack pattern charts

Effects of earthquakes with different nature on the seismic performance of masonry vaults

Past seismic events showed that earthquakes can cause severe damages in masonry vaulted structures, which can lead to significant damage, including fatalities, and heritage and economic losses. Although seismic guidelines suggest the implementation of specific modern strengthening techniques to prevent those seismic losses, many masonry vaulted structures are unreinforced and they are one of the most vulnerable structural elements in monumental buildings, such as churches and palaces. Thus, the present paper focuses on the seismic performance of a numerical model, which simulates an experimental reduced-scale dry-joints vault, through the nonlinear dynamic analysis, by applying several earthquakes of different nature. The numerical model was built based on the discrete element method, where it is possible to simulate the detailed geometrical properties: the interlocking between the blocks, the cuts along the diagonals, the offset of the units and the boundary conditions. Moreover, the model was calibrated based on results obtained from shake table tests. The results of this sensitivity analysis, obtained from the different inputs, are compared in terms of damage patterns.- (undefined

Nonlinear modeling of unreinforced masonry structures under seismic actions: validation using a building hit by the 2016 Central Italy earthquake

A prolonged seismic sequence struck the regions of Central Italy between August 2016 and January 2017, causing several fatalities and widespread damage to the built environment. The main objective of this work was to study the structural and seismic behavior of "Pietro Capuzi" school, located in Visso, in the Marche region, which was severely damaged by the 2016-2017 Central Italy Earthquake. A 3D finite element (FE) model of the entire school was prepared, adopting a macro-modeling approach to represent masonry materials. An eigenvalue analysis was initially performed in order to identify the dominant modes of vibration of the structure and to calibrate the numerical model according to the results of the dynamic identification tests. Afterwards, nonlinear static analyses were performed on the calibrated FE model to evaluate the seismic response of the structure. Finally, the numerical results obtained in terms of crack pattern and failure mechanisms were compared with the damage experienced by the building. The numerical model proved to accurately predict the seismic response exhibited by the structure during the past seismic events

Experimental and Numerical Analysis of Seismic Response of Unreinforced Masonry Cross Vaults

The present paper shows an experimental and numerical analysis to understand the seismic behaviour of unreinforced masonry cross vault. The experimental tests were performed on a 1:5 scale model of a cross vault made of 3D-printed blocks with dry joints. The seismic actions was experimentally simulated as a horizontal force proportional to the vault\u2019s mass by using a quasi-static tilt testing setup. The vault 3D collapse mechanism and its strength expressed in terms of collapse multiplier was investigated, also considering the direction of the seismic action with respect to the vault\u2019s base. The tests results were compared to those obtained from a numerical analysis using a rigid-block model based on 3D limit analysis. The model formulation allows to take into account both associative and non-associative behaviour. A sensitivity analysis on friction angle variation was also investigated to evaluate the accuracy and robustness of the model

Seismic assessment of masonry cross vaults through numerical nonlinear static and dynamic analysis

Masonry vaults represent a pleasant typology of structural horizontal element in traditional architecture and historical buildings, widespread on a large scale along all the European countries, even those characterized by a high level of seismicity. However, they are some of the most vulnerable structural elements particularly under dynamic actions. Therefore, the assessment of their structural safety and the determination of their stress field is a very important task for preservation of historic buildings. Vaults have been studied from an architectural and structural point of view as sequences of arches, and thus extending the use of bidimensional tools of analysis. This assumption can be reliable for the analysis of barrel vaults, but it is not always the most appropriate solution for investigating more complex vaulted systems with a not negligible three-dimensional behavior. The paper presents on the analysis of a particular groin vault, typically found in monumental buildings which will be successively tested during an experimental dynamic campaign on the shake table. Among all the failure mechanisms of this type of vault, the shear failure is one of the most frequently recorded during post-earthquake surveys. The activation of the shear response is caused by asymmetric boundary conditions and difference in stiffness between two sides of the vault, as it occurs in groin vaults covering churches aisles characterized by the presence of a perimeter wall on one side and two columns on the other side. The main aim of the paper is to investigate the seismic response of a brick groin vault simulating the boundary conditions and loadings of an aisle in a three naves church prototype. Static and dynamic nonlinear numerical analyses were performed using a finite element model. The boundary conditions simulate from one side the presence of a perimeter wall and from the other side the two columns between the main and the lateral nave. The role of the infill and- (undefined

Improving and Automating BFV Parameters Selection: An Average-Case Approach

Fully homomorphic encryption is a revolutionary technology that allows arbitrary computations on encrypted data, providing privacy and security. State-of-the-art schemes such as the Brakerski/Fan-Vercauteren (BFV) scheme are based on the Learning with Errors assumption and its variants. Thus, each ciphertext has an error that increases with each homomorphic operation. To maintain correctness, the error must be kept below a certain threshold, which requires a balance between security and computational efficiency. Therefore, choosing optimal, secure, and efficient parameters can be a challenging task, even for experts in a particular scheme. In this paper, we present two major contributions to improve the parameter selection in the BFV scheme. We perform the first average case analysis to estimate the error growth. Our method significantly improves on previous work in terms of accuracy and tightness of bounds. For a circuit with a multiplicative depth of only 3, our bounds are within 1.2 bits of the experimentally observed values while being up to 19 bits tighter than previous analyses. In addition, we take advantage of our theoretical advances and propose the first parameter generation tool for the BFV scheme. Here we add support for arbitrary but use-case-specific circuits, as well as the ability to generate easy-to-use code snippets, making our theoretical work accessible to both researchers and practitioners