Numerical analysis of the settlement induced damage to Palazzo Loggia in Brescia

One of the main causes of failure of historic buildings is represented by the differential settlements of foundations. Finite element analysis provides a useful tool for predicting the consequences of given ground displacements in terms of structural damage and also assesses the need of strengthening techniques. The actual damage classification for buildings subject to settlement bases the assessment of the potential damage on the expected crack pattern of the structure. In this paper, the correlation between the physical description of the damage in terms of crack width and the interpretation of the finite element analysis output is analyzed. Different discrete and continuum crack models are applied to simulate an experiment carried on a scale model of a masonry historical building, the Loggia Palace in Brescia (Italy). Results are discussed and a modified version of the fixed total strain smeared crack model is evaluated, in order to solve the problem related to the calculation of the exact crack width.

Computational modelling of building damage due to tunnelling

Underground constructions in soft ground may lead to settlement damage to existing buildings. In The Netherlands the situation is particularly complex, because of the combination of soft soil, fragile pile foundations and brittle, unreinforced masonry façades. The tunnelling design process in urban areas requires a reliable risk damage assessment. In the engineering practice the current preliminary damage assessment is based on the limiting tensile strain method (LTSM). Essentially this is an uncoupled analysis, in which the building is modelled as an elastic beam subject to imposed Greenfield settlements and the induced tensile strains are compared with a limit value for the material. The soil-structure interaction is included only as a ratio between the soil and the building stiffness. In this paper, a coupled approach is evaluated. The soil-structure interaction in terms of normal and shear behaviour is represented by interface elements and a cracking model for masonry is included. This project aims to improve the existing damage classification system for masonry buildings subjected to tunnel-induced settlement, in order to evaluate the necessity of strengthening techniques or mitigation measures.

Coupled analysis of building damage due to tunnelling

Excavation works in urban areas require a preliminary risk damage assessment. In historical cities, the prediction of building response to settlements is necessary to reduce the risk of damage of the architectural heritage. The current method used to predict the building damage due to ground deformations is the Limiting Tensile Strain Method (LTSM). This method is based on an uncoupled soil-structure analysis, in which the building is modelled as an elastic beam subject to imposed greenfield settlements and the induced tensile strains are compared with a limit value for the material. This approach neglects many factors which play an important rule in the response of the structure to tunneling induced settlements. In this paper, the possibility to apply a settlement risk assessment derived from the seismic vulnerability approach is considered. The parameters that influence the structural response to settlements can be defined through numerical coupled analyses which take into account the nonlinear behaviour of masonry and the soil-structure interaction.

Numerical analyses of tunnel-induced settlement damage to a masonry wall

Settlements due to underground construction represent a risk for the architectural heritage, especially in The Netherlands, because of the combination of soft soil, fragile pile foundation and brittle, un-reinforced masonry façade. Modelling of soil-structure interaction is fundamental to assess the risk of building damage due to tunnelling. This paper presents results of finite element analyses carried out with different models for a simple masonry wall. Focus is paid on the comparison between coupled, uncoupled and semi-coupled analyses, in which the soil-structure interaction is represented in different ways. In particular, the implementation of a soil-structure interface model in the numerical analyses is analysed, in order to asses its validity. The aim of the research project is the development of a damage classification system for different building typologies.