Now showing 1 - 8 of 8
  • Publication
    Steps toward a probabilistic framework for tunnelling damage
    Globally, the high rates of urbanization over the past century have spurred unprecedented levels of tunnel construction. With each tunnel installation, there is a large affiliated risk for damage to aboveground structures, especially those of unreinforced masonry. Such damage (and the subsequent costs and litigation) occur, despite huge sums committed to construction monitoring and pre-tunnel mitigation. Arguably, damage still happens because the wide range of parameters and the extent of their variability are not sufficiently considered in the risk assessment process. To address these uncertainties, a probabilistic framework for the large-scale risk assessment of existing, unreinforced masonry buildings subjected to bored tunnelling is proposed by the Urban Modelling Group (UMG) at the University College Dublin (UCD). This paper summarizes the initial steps needed to achieve such a framework.
  • Publication
    The Effect of Uncertainty on the Prediction of Building Damage Due to Tunnelling-Induced Settlement
    Prediction of the response of buildings to tunnelling-induced settlement for the extent of a tunnel route is a complex task due to the heterogeneous nature of ground conditions, variable tunnelling operations, and unknown building parameters. Consequently, there are generally uncertainties associated with building damage predictions. This paper presents a probabilistic numerical methodology to investigate the effect of uncertainties for the damage prediction of masonry buildings due to tunnelling-induced settlement. The methodology is employed to provide a Class C1 prediction for a previously documented case history. The results demonstrate the uncertainties that have a significant influence in terms of the building response prediction and, furthermore, provide a quantitative risk assessment for masonry buildings due to nearby tunnelling.  
  • Publication
    Generation of a Building Typology for Risk Assessment due to Urban Tunnelling
    Major underground infrastructure projects are often located beneath dense urban environments in an effort to relieve congested areas. The effects of urban tunnelling works can impinge on hundreds, if not thousands of structures, many of which a re historically significant. Tunnel-induced ground movements can result in significant building damage and, therefore, require an accurate risk assessment of the existing built heritage and the selection of appropriate preventative measures. Damage prediction techniques extend from traditional empirical and analytical methods to modern computational modelling techniques. A common requirement for many damage assessment methodologies is the development of a building typology. Such typologies can provide critical information where measured drawings, particularly of structural elements (e.g. floor and wall thickness), are not otherwise available. This study begins to establish a building typology for a historic area of Dublin's city centre for which an underground railway system has been planned.
  • Publication
    Pioneering Real-time Computational Models for Building Damage Prediction During Adjacent Tunnel Excavation
    Numerical modelling is commonly employed prior to tunnel excavation to estimate surface settlements and to predict the response of adjacent structures. Unfortunately, geotechnical and building parameters are difficult to determine for the large geographical extent of a tunnelling project. As such, parametric values for modelling purposes are frequently assumed and are rarely revised to provide updated predictions as field data becomes available. Given advances in 'real time' data availability from subsurface- and surface-based monitoring systems, the question arises of how to better fully exploit this data for improved adjacent building protection. To achieve this, integration of numerical models into the monitoring process to provide updated 'real time' building response predictions is explored. This paper extends existing frameworks which utilize geotechnical field data to provide 'real time' predictions to also include building considerations.
  • Publication
    Evaluation of risk assessment procedures for buildings adjacent to tunnelling works
    (Elsevier, 2014-02) ;
    Risk assessment procedures for underground projects form a key component of pre-construction efforts since resulting ground movements may cause damage to adjacent structures. Particularly for urban tunnelling works, surface settlements may impinge on a vast number of structures and can result in significant lawsuits unless the appropriate building protection measures are implemented. Although the understanding of tunnelling induced building damage has advanced greatly in recent decades, damage and litigation persist. Hence, this paper reconsiders the pre-construction risk assessment procedures undertaken during the generation of an Environmental Impact Statement (EIS) by formally including considerations relating to a building's historical significance, present usage, and current physical condition. In doing so, a holistic approach to risk assessment is proposed, allowing for project resources to be targeted towards buildings that are most at risk. This is demonstrated through a Class A prediction for a section of an upcoming underground railway system in which 14% of the selected study area of 220 buildings are identified to be at risk. Results are compared to those produced by the official EIS where building vulnerabilities are considered in isolation from the damage prediction assessment and just 5% of buildings are considered to be at risk. The proposed methodology offers a standardised procedure for incorporating both cultural and physical aspects of each building, thereby providing a more systematic, comprehensive procedure for pre-construction risk assessment than previously available.
      1661Scopus© Citations 50
  • Publication
    A semi-random field finite element method to predict the maximum eccentric compressive load for masonry prisms
    An accurate prediction of the compressive strength of masonry is essential both for the analysis of existing structures and the construction of new masonry buildings. Since experimental material testing of individual masonry components (e.g., masonry unit and mortar joints) often produces highly variable results, this paper presents a numerical modelling based approach to address the associated uncertainty for the prediction of the maximum compressive load of masonry prisms. The method considers a numerical model to be semi-random for a masonry prism by adopting a Latin Hypercube simulation method used in conjunction with a parametric finite element model of the individual masonry prism. The proposed method is applied to two types of masonry prisms (hollow blocks and solid clay bricks), for which experimental testing was conducted as part of the 9th International Masonry Conference held at Guimarães in July 2014. A Class A prediction (presented before the tests were conducted) was generated for the two masonry prisms according to the proposed methodology, and the results were compared to the final experimental testing results. The root mean square deviation of the method for prediction of eccentric compressive strength of both types of prisms differed by only 2.2 KN, thereby demonstrating the potential for this probabilistic approach.
      578Scopus© Citations 21
  • Publication
    A Systematic Approach for Large-scale, Rapid, Dilapidation Surveys of Historic, Masonry Buildings
    (Taylor and Francis, 2012-05-16) ;
    Dilapidation surveys may require extensive resources to achieve detailed accounts of damage for intervention purposes or may involve only limited resources but be restricted to an extremely rapid assessment (e.g. post-earthquake, life-safety inspection). Neither provides a holistic, cost-effective approach for evaluating the general health of a large number of structures, as is needed for urban planning, historic designation determination, and risk assessment due to adjacent works. To overcome this limitation, index images are introduced for a systematic approach for rapidly conducting large-scale, dilapidation surveys of historic masonry buildings. This method, the University College Dublin Inspection Method (UCDIM), is tested against both a detailed inspection and an alternative rapid approach to determine accuracy and resource intensiveness through its application by three inspectors of various levels of experience to six buildings in the city centre of Dublin, Ireland. The UCDIM provided a damage ranking of ρ = 0.94 for all inspectors, regardless of experience, except when painted or rendered façades were included. The UCDIM, when compared to detailed inspection provided a high level of reliability, cost savings of approximately 90% and several months of time savings since interior access was not required.
      685Scopus© Citations 9
  • Publication
    A Multi-hazard Risk Assessment Methodology, Stress Test Framework and Decision Support Tool for Transport Infrastructure Networks
    (Elsevier, 2016-06-27) ;
    Natural hazards can cause serious disruption to societies and their transport infrastructure networks. The impact of extreme hazard events is largely dependent on the resilience of societies and their networks. The INFRARISK project is developing a reliable stress test framework for critical European transport infrastructure to analyse the response of networks to extreme hazard events. The project considers the spatio-temporal processes associated with multi-hazard and cascading extreme events (e.g. earthquakes, floods, landslides) and their impacts on road and rail transport infrastructure networks. As part of the project, an operational framework is being developed using an online INFRARISK Decision Support Tool (IDST) to advance decision making approaches, leading to better protection of existing transport infrastructure. The framework will enable the next generation of European infrastructure managers to analyse the risk to critical road and rail infrastructure networks due to extreme natural hazard events. To demonstrate the overarching risk assessment methodology developed in the project, the methodology is demonstrated for two case studies, which comprise portions of the European TEN-T network; a road network in the region of Bologna, Italy and a rail network extending from Rijeka to Zagreb in Croatia. This paper provides an overview of the INFRARISK multi-hazard risk assessment methodology and a brief introduction to the case studies, as the project is currently ongoing.
      345Scopus© Citations 17