87,579 research outputs found
Life-Cycle Performance of Deteriorating Structures
No full textThis chapter is aimed at presenting a review of the main principles, concepts, methods, and strategies for life-cycle design and assessment of deteriorating structural systems under uncertainty. General criteria for deterioration modeling are first presented, with emphasis on the effects of corrosion and fatigue in steel structures and chloride-induced corrosion in concrete structures. The timevariant structural performance is then investigated with reference to a set of probabilistic performance indicators, and the structural lifetime assessment and design criteria associated with a reliability target are finally formulated
Experimental validation of nonlinear finite element analysis of PC bridge deck beams based on the results of full-scale load tests
No full textFull-scale load tests on prestressed concrete (PC) deck beams extracted from a dismantled bridge have been performed within the ongoing BRIDGE|50 research project. The results of this experimental activity, along with the outcomes of non-destructive tests and laboratory tests for mechanical characterization of materials, are considered in this paper for the validation of computational structural analysis models based on PC beam finite elements
with distributed nonlinearity and plane-stress finite elements formulated in accordance with the Modified Compression Field Theory. The accuracy of numerical versus experimental results is evaluated under four-point bending for different shear span ratios and by taking into account the contribution of the top concrete slab on the structural response of the tested beams
Survey on Life-Cycle Performance of Civil Structures and Infrastructure Systems
No full textThe Special Project approved by the SEI Technical Activities Division (TAD) Executive Committee for the development of this state-of-the-art report included a survey and an International Workshop on Life-Cycle Performance of Civil Structure and Infrastructure Systems, which was held by invitation only at the ASCE headquarters in Reston, Virginia, on November 10, 2015. The survey was disseminated to selected researchers and experts from universities, industries, engineering firms, and agencies active in the field of life-cycle civil engineering. A brief overview of the main results of the survey are presented in this appendix with emphasis on life-cycle concepts and methods, deterioration and damage evaluation, life-cycle performance indicators, inspection and maintenance procedures, life-cycle cost analysis, and implementation in design practice
Probabilistic structural assessment of RC bridges under corrosion based on efficient simulation methods
No full textThe life-cycle assessment of structural reliability and seismic vulnerability of aging bridges is a key issue for optimal management of critical components of transportation systems. Predictive models of the structural performance should be able to integrate uncertainties associated with material properties and environmental stressors. In a life-cycle context, simulation-based methods relying on time-consuming non-linear structural analyses may require unfeasible computational efforts, especially when mechanical non-linearities are involved in structural response of deteriorating members. This paper presents a computational approach for lifetime structural reliability assessment of deteriorating Reinforced Concrete (RC) structures. The life-cycle numerical estimate of failure probability is evaluated over time based on suitable adaptation of Importance Sampling considering a Stationary Proposal distribution to efficiently select the sample structural models. The proposed methodology is investigated for seismic fragility assessment of a RC bridge pier under corrosion based on non-linear static pushover analysis
Effects of Climate Change on Life-Cycle Performance of Structures and Infrastructure Systems: Safety, Reliability and Risk: Preface
No full textField and laboratory tests for corrosion assessment of existing concrete bridges
No full textMany existing Reinforced Concrete (RC) structures built around the middle of the last century have now reached the end of service life and require maintenance interventions to repair degradation-induced damage, especially due to steel corrosion. The conservation of existing structures and infrastructural facilities is therefore a relevant and urgent problem, particularly bridges and viaducts in view of their social and economic importance. In order to correctly define the restoration interventions and fulfill safety, robustness, and durability requirements, it is necessary to inspect RC structures and assess the state of degradation of materials and corrosion of embedded steel. This paper is aimed at contributing to effective methods, procedures, and criteria for corrosion assessment of existing RC bridges and viaducts. To this purpose, the results of inspections and diagnostics carried out on structural members of bridges subjected to corrosion and exposed to different environmental conditions and microclimates will be presented by focusing on in-field non-destructive testing as well as on chemical, physical and microstructural analyses
Damage modeling and nonlinear analysis of concrete bridges under corrosion
No full textA general approach to nonlinear analysis of concrete bridges under corrosion is presented. This approach is based on the formulation of a three-dimensional reinforced concrete beam finite element which accounts for both mechanical and geometrical nonlinearity. The formulation considers uniform and localized (pitting) corrosion and damage modeling includes the reduction of cross-sectional area of corroded bars, the reduction of ductility of reinforcing steel, the deterioration of concrete strength, and the spalling of concrete cover. The beam finite element is validated with reference to the results of experimental tests carried out on beams with corroded reinforcement. The three-dimensional structural analysis of a reinforced concrete arch bridge under different damage scenarios shows the effectiveness and application potentialities of the proposed formulation for life-cycle assessment and design of concrete bridges exposed to corrosion
Semi-probabilistic methods for the assessment of existing concrete structures: An overview
No full textLife-cycle assessment of the residual performance of existing structures usually involves a wider spectrum of uncertainties compared to a standard approach for designing new structures. The main differences are related to the modification of structural capacity and demand in time, f.i. due to aging and structural deterioration processes. Furthermore, climate change has a significant impact on this evolution. In order to account for these aspects, full probabilistic approaches are often exploited for assessing existing structural systems. However, these methodologies are time-consuming and may require significant knowledge and expertise for numerical implementation. Therefore, the development of semi-probabilistic methodologies for existing structures considering the impact of climate change, including proper validation and calibration for incorporation in design codes and standards, is nowadays of essence. This paper provides an overview of recent accomplishments and available literature regarding semiprobabilistic code formats for the assessment of existing reinforced concrete structures, including insights on how to incorporate climate change effects on these methodologies
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