Periodic Reporting for period 2 - INFRASTAR (Innovation and Networking for Fatigue and Reliability Analysis of Structures - Training forAssessment of Risk)
Periodo di rendicontazione: 2018-05-01 al 2020-04-30
Civil infrastructures are the basis of socio-economic wealth for modern societies and concrete is the most used material in volume in the world. However, a series of limitations hamper innovative solutions in the asset management of infrastructures. One of the most prevalent issues that directly influences the life expectancy of concrete structures, is fatigue. Although fatigue has been investigated for years for steel structures, recent findings suggest that concrete structures are also significantly subjected to fatigue that could lead to failure. A second issue relates to the current technological means to measure fatigue on structures like bridges and wind turbines, as these are outdated, imprecise and inappropriate. Finally, while structural reliability methods have been widely applied in some industrial applications, e.g. offshore oil and gas structures, practical application of probabilistic methods still needs theoretical and practical developments.
INFRASTAR aims to develop knowledge, expertise and skills for optimal and reliable management of structures. The generic methodology is applied to bridges and wind turbines in relation to fatigue, offering the opportunity to deal with complementary notions while addressing three major challenges: 1) advanced modelling of concrete fatigue behaviour; 2) new non-destructive testing methods for early aged damage detection; and 3) probabilistic approach of structure reliability under fatigue.
The project provided comprehensive work on innovative sensing techniques and a better connection to damage indicators (data fusion). Refined models and methods of the loading and behaviour of structural members have been elaborated. The potential cost- and material savings using reliability- and risk-based methods for existing structures demonstrated in the case studies will contribute to decreasing the Levelized Cost Of Energy in wind energy and to increased sustainability.
INFRASTAR aims to develop knowledge, expertise and skills for optimal and reliable management of structures. The generic methodology is applied to bridges and wind turbines in relation to fatigue, offering the opportunity to deal with complementary notions while addressing three major challenges: 1) advanced modelling of concrete fatigue behaviour; 2) new non-destructive testing methods for early aged damage detection; and 3) probabilistic approach of structure reliability under fatigue.
The project provided comprehensive work on innovative sensing techniques and a better connection to damage indicators (data fusion). Refined models and methods of the loading and behaviour of structural members have been elaborated. The potential cost- and material savings using reliability- and risk-based methods for existing structures demonstrated in the case studies will contribute to decreasing the Levelized Cost Of Energy in wind energy and to increased sustainability.
WP1 provided work on 2 innovative sensing techniques. ultrasonic monitoring using embedded transducers, and data evaluation by the CWI technique provided early age damage indicators. A crack detection system based on fibre optics has been developed providing quantitative data on crack opening with a quality not seen before. A scheme to combine several features has been provided. This gives a better connection to damage indicators and can be implemented into real bridge monitoring systems. A methodology on how to use existing sensing techniques for the management of existing bridges has been proposed. It has been applied to a real bridge in service and showed that the bridge may stay in service much longer than expected without further intervention.
WP2 provided analysis of data on bridge deck behaviour and a methodology for long-term monitoring. The effect of road traffic loading was investigated with the combination of wind loading. The fatigue behaviour of UHPFRC strengthened with steel rebars was investigated experimentally. Fatigue damage process was identified using refined optical methods. Issues related to the foundation in reinforced concrete of offshore wind turbine (OWT) towers have been investigated. Existing advanced numerical models for the analysis of wind turbine foundations have been extended. A reliable tool to the foundation designers is provided to deliver cost-effective and low-risk offshore wind turbine foundations. The fatigue behaviour and safety of reinforced concrete tower shafts and foundations using reliability methods have been analysed concluding that fatigue partial safety factors can be reduced without compromising structural safety. Fundamental aspects for practical applications of probabilistic methods were validated.
WP3 provided important contributions, e.g. the new developments related to the Value Of Information, as research background for practical applications for risk-informed reassessment and planning of inspections and operation & maintenance of existing bridges and wind turbines, and as basis for standardization, e.g. the probabilistic model for fatigue of concrete.
WP2 provided analysis of data on bridge deck behaviour and a methodology for long-term monitoring. The effect of road traffic loading was investigated with the combination of wind loading. The fatigue behaviour of UHPFRC strengthened with steel rebars was investigated experimentally. Fatigue damage process was identified using refined optical methods. Issues related to the foundation in reinforced concrete of offshore wind turbine (OWT) towers have been investigated. Existing advanced numerical models for the analysis of wind turbine foundations have been extended. A reliable tool to the foundation designers is provided to deliver cost-effective and low-risk offshore wind turbine foundations. The fatigue behaviour and safety of reinforced concrete tower shafts and foundations using reliability methods have been analysed concluding that fatigue partial safety factors can be reduced without compromising structural safety. Fundamental aspects for practical applications of probabilistic methods were validated.
WP3 provided important contributions, e.g. the new developments related to the Value Of Information, as research background for practical applications for risk-informed reassessment and planning of inspections and operation & maintenance of existing bridges and wind turbines, and as basis for standardization, e.g. the probabilistic model for fatigue of concrete.
The engineering methods and tools are applicable for the design and assessment of structural components of new and existing bridges and wind turbines. These engineering methods and tools are readily available for implementation in structural engineering practice. If applied accordingly, assessment of existing bridges and wind turbine structures will be improved leading to more realistic results regarding the future use of existing structures and the design of new structures, following the guiding theme “Getting more out of structures”:
- Replacement of structures can be postponed or even avoided. In this way, existing bridges and wind turbine infrastructure may serve for a second, long service duration. Value is added to existing bridges and wind turbines that our ancestors passed on this generation. Also, the embodied energy and CO2-emissions, as well as the raw material already used in existing structures are preserved.
- The proposed engineering methods contribute to the optimization of the design of new bridges and wind turbine structures. Unnecessary conservatism is removed. It may be expected that fewer resources will be needed to build new bridges and wind turbines. New technologies including the novel UHPFRC building material allow to simplify and accelerate the construction process leading to less energy and material consumption and to enhance durability. Technical advantages lead to lower environmental impact and life-cycle costs when compared to traditional construction
In conclusion, economic and environmental benefits may be realized by harnessing the present research. Overall, the works performed have the potential to contribute to socio-economic impact by improving the sustainability of bridges and wind turbines.
- Replacement of structures can be postponed or even avoided. In this way, existing bridges and wind turbine infrastructure may serve for a second, long service duration. Value is added to existing bridges and wind turbines that our ancestors passed on this generation. Also, the embodied energy and CO2-emissions, as well as the raw material already used in existing structures are preserved.
- The proposed engineering methods contribute to the optimization of the design of new bridges and wind turbine structures. Unnecessary conservatism is removed. It may be expected that fewer resources will be needed to build new bridges and wind turbines. New technologies including the novel UHPFRC building material allow to simplify and accelerate the construction process leading to less energy and material consumption and to enhance durability. Technical advantages lead to lower environmental impact and life-cycle costs when compared to traditional construction
In conclusion, economic and environmental benefits may be realized by harnessing the present research. Overall, the works performed have the potential to contribute to socio-economic impact by improving the sustainability of bridges and wind turbines.