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Bridges are key parts of transportation networks and hence, their post-hazard condition is vital for the recovery of the regions affected by natural hazards. However, the fact that they are often subjected to more than one destructive natural hazard during their life span resulting in accumulated damage that may influence their capacity has attracted relatively little research interest, while almost no design standards take it into consideration. The multiple hazard events may be successive single events, separated by considerable time intervals (e.g. an earthquake followed by a flood event), combined or cascading multiple-hazard events (e.g, landslide after an earthquake), or even simultaneous events. The main objective of this study is to propose an effective framework for the development of multiple-hazard fragility curves of bridges considering the effect of subsequent events and taking into account different possible damage scenarios of the bridge critical components, i.e. piers, bearings and the abutment-backfill systems. In this framework, the effect of the damage level of the critical components and their interdependence on the fragility assessment for multiple events is examined and compared with the bridge fragility for single events. A pilot case study is also included in the present work, aiming to highlight the effect of the initial damage state on the final fragility estimate of a typical riverine bridge. [ABSTRACT FROM AUTHOR]

The reliable assessment of bridge capacity is necessary in order to ensure the functionality of the roadway network under normal, or emergency operating conditions. Damage due to the interaction with the environment (e.g., corrosion of coastal reinforcement) has been observed in many cases, even in newly built interurban road networks. Therefore, the need for obtaining and including measured data in fragility assessment analysis has emerged. In line with the above, the proposed research introduces a framework for the assessment of bridges considering integrating data obtained with NDTs. The scope of NDTs is to track down the evolution damage on bridges and determine its risk of failure. The work presents a structural damage identification approach that successfully updates a digital twin of the structure. Subsequently the digital twin is used in order to determine the bridge fragility. Fiber modeling is used for creating the digital twin of the structure. Modified uniaxial material laws are applied for the fragility assessment of a deteriorated case study bridge also providing comparative assessment results for the pristine bridge, i.e. without damage. [ABSTRACT FROM AUTHOR]

The acquisition of data regarding the performance of buildings and the use of metrics to understand their performance level are critical for efficient building management. Performance indicators are key elements in this process. They shall be clearly defined and provide the means for easily measuring building performance. These performance indicators should cover all aspects of a building's life cycle including safety, operability and sustainability. To facilitate such a process, it is preferable to group the performance indicators into categories, namely the key performance indicators. In this paper, the key performance indicators for buildings are determined by compiling the identified critical ones in the literature. A case study of an R/C building in Greece is used to quantify the presented metrics focusing mainly on safety. The reliability index indicator is calculated based on the simulation and analysis of a building subsystem. Other key performance indicators relevant to building maintenance are considered on scenario basis. The study has been conducted as part of the IABSE Task Group 5.2. – "Key Performance Indicators: Definition" and provides valuable insight into using quantified metrics for decision‐making in building management. [ABSTRACT FROM AUTHOR]

Bridges are in direct interaction with the environment and thus are exposed to various natural hazards such as earthquakes and floods, that may result in severe damage and substantial direct and indirect losses. The multiple hazard events may be subsequent single events (e.g., a flood event followed by an earthquake) or combined multi‐hazard events (e.g., cascading ground failure event after an earthquake). The effect of multiple hazards on bridge fragility is related to the damage level of the bridge components and the associated failure mechanisms that may compromise the roadway network functionality. The scope of this work is to propose an approach for the multiple‐hazard assessment of bridges considering subsequent events and different damage scenarios of critical bridge components, i.e. piers, bearings and abutments. Therefore, the effect of the damage level of critical bridge components and their interdependence on the fragility assessment for subsequent hazard events is investigated. Different damage scenarios and hazard sequences are studied, providing insight into the damage mechanisms and the accumulation of damage. The approach is applied to the multiple hazard assessment of a case study typical riverine bridge in Greece and the results are comparatively discussed. [ABSTRACT FROM AUTHOR]

Due to soil -structure-interaction (SSI), the seismic lateral structural deformations may be substantially different from the ones traditionally calculated from the fixed-base structure on free-field approach. Additionally, the actual displacements of foundations considering soil compliance are of practical interest in some applications. In the present study, seismic elastic displacement demand of compliant coupled soil- structure (SFS) systems, is investigated through numerical time history analyses. The numerical displacement demand is validated through an analytical solution, comparison between FEM and analytical solution is provided and finally, a practical, simplified approach for displacement evaluation is proposed. The displacements are presented in terms of dimensionless parameters such as soil to structure stiffness ratio 1/σ and slenderness ratio h/B, while closed-form relationships are proposed. [ABSTRACT FROM AUTHOR]

A new methodology for the development of bridge-specific fragility curves is proposed with a view to improving the reliability of loss assessment in road networks and prioritising retrofit of the bridge stock. The key features of the proposed methodology are the explicit definition of critical limit state thresholds for individual bridge components, with consideration of the effect of varying geometry, material properties, reinforcement and loading patterns on the component capacity; the methodology also includes the quantification of uncertainty in capacity, demand and damage state definition. Advanced analysis methods and tools (nonlinear static analysis and incremental dynamic response history analysis) are used for bridge component capacity and demand estimation, while reduced sampling techniques are used for uncertainty treatment. Whereas uncertainty in both capacity and demand is estimated from nonlinear analysis of detailed inelastic models, in practical application to bridge stocks, the demand is estimated through a standard response spectrum analysis of a simplified elastic model of the bridge. The simplified methodology can be efficiently applied to a large number of bridges (with different characteristics) within a road network, by means of an ad hoc developed software involving the use of a generic (elastic) bridge model, which derives bridge-specific fragility curves. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]