Performance‐based earthquake engineering (PBEE) is a probabilistic framework developed to improve seismic risk decision‐making, characterising building performance in terms of metrics such as ...casualties, economic losses and anticipated downtime. Building upon PBEE, expected annual loss (EAL) and collapse safety expressed in terms of mean annual frequency of collapse (MAFC) have been recently proposed as fundamental objectives within an integrated performance‐based seismic design (IPBSD) framework. This article, following the parametric investigations conducted, proposes a refined design loss curve and demonstrates the capabilities of IPBSD to target a certain MAFC and limit EAL through its application to several reinforced concrete case‐study buildings. The performance was evaluated using both incremental dynamic analysis and a storey‐based loss assessment procedure to estimate MAFC and EAL of risk‐targeted designs, respectively. The agreement and consistency of design solutions and intended performance objectives were then checked to demonstrate the validity of the IPBSD framework, with MAFC being effectively targeted and the EAL limited as initially foreseen by the method. Further scrutiny of the results highlighted the validity of the assumptions made in the IPBSD framework and shed further light on the pertinent sources of economic losses, namely the ones deriving from structural and non‐structural elements, when designing buildings, in addition to influential parameters like initial period range and the influence of design engineering demand parameter profiles. This is seen as part of the next‐generation risk‐targeted and loss‐driven design approaches in line with modern PBEE requirements.
•Drift-based fragility functions for FRP-strengthened corner and exterior BCJs.•Relationship between drift and probability of exceeding specified damage state.•Variability of developed fragility ...functions with different BCJs failure modes.•Comparison with available fragility functions for unstrengthen BCJs.•Quantifying the attained losses, along with economic aspects.
Post-earthquake field inspections have outlined the poor seismic performance of non-conforming reinforced concrete (RC) beam-column joints (BCJs) of existing RC buildings. Experimental and analytical studies have demonstrated that the application of externally bonded fiber-reinforced polymers (FRPs) is an efficient and cost-effective strengthening technique to improve the seismic performance of deficient BCJs. However, seismic losses for FRP-strengthened BCJs at different damage states (DSs) are currently not quantified. A potential seismic damage assessment tool is critical to obtain reliable estimations of the effects of FRP strengthening on reducing the expected damage and losses in existing buildings. Therefore, experimental-based fragility functions for FRP-strengthened corner and exterior BCJs at different limit states are proposed in this study. Experimental tests on 70 corner and 28 exterior FRP-strengthened BCJs are first collected. Then, DSs with increasing severity (i.e., light, moderate, and heavy) are defined according to widely recognized studies. These DSs are quantified on the basis of inter-story drift ratios (IDRs). After retrofitting, IDR-based fragility functions are generated for strengthened BCJs classified in terms of failure mode and achieved ductility level. The proposed functions are also compared with fragility functions available for non-conforming and conforming joints obtained from the literature. Finally, an application of the proposed fragility functions within a performance-based earthquake engineering (PBEE) framework for quantifying expected losses (ELs) and the benefits of FRP strengthening of BCJs is showed.
•Structural damage is a mechanism of emission from HFC and CFC banks.•Natural hazards have been found able to induce such mechanism of emissions.•CFC/HFC content can be comparable to GWP of ...buildings’ materials and construction.•CFC content can vastly exceed ODP of buildings’ materials and construction.•Disaster Waste Management can mitigate this mechanism of emission.
Fluorocarbons are an important class of greenhouse gases, currently responsible for a non-negligible share of global emissions. CFCs are known to be linked to the depletion of the stratospheric ozone layer. CFCs and HFCs also have a high GWP. The Montreal Protocol banned the production of CFCs and, more recently, the Kigali Amendment established the phase-out of high-GWP HFCs over the coming decades. CFCs and HFCs banks are expected to continue generating emissions during the present century, however. These banks consist of CFCs and HFCs contained mainly in insulation foams, HVAC and refrigeration systems. It has been demonstrated in practice that structural and other damages caused by natural hazards (NHs) can lead to emissions from such banks. Conventional approaches that include NHs in the Life Cycle Assessment (LCA) of buildings focus mainly on the embodied carbon metric, usually examined as part of the economic input–output procedure. These issues are not considered in LCAs currently applied to Disaster Waste Management. Such methods do not take into account the potential release of high-GWP compounds in the event of extensive damage or collapse, so the related carbon footprint may generally be underestimated. Since CFCs are banned in the vast majority of manufacturing processes, their ozone depletion potential (ODP) based on such an approach is close to zero. This paper describes a recently-proposed framework that incorporates the concept of content release ozone depletion potential (CODP), based on analytical tools that enable this ODP to be taken into account using current methods for conducting LCAs on buildings that include NHs. A case study conducted to test the proposed framework is also reported.
This paper presents a copula-based cloud analysis method for seismic fragility assessment with practical applications for nuclear power plant structures. Copula theory enables the flexible and ...efficient modeling of joint probability density function (PDF) for critical parameters, specifically the intensity measures (IM) and the engineering demand parameters (EDP). It decomposes the joint PDF into the product of marginal PDFs and copula density function, which are then separately fitted to the data. The study showcases the versatility of parameterized joint distribution models in estimating optimal distribution parameters derived from structural seismic analysis data. By utilizing copula functions, the method calculates conditional EDP distributions given IM, facilitating the construction of seismic fragility curves. The research compares various copula models’ suitability for fitting fragility curves, employing methods like Akaike information criterion (AIC) for model selection. The study provides a comprehensive framework for seismic fragility assessment, from random sampling of structural parameters and seismic data to nonlinear finite element modeling and copula-based parametric cloud analysis. The application to prestressed concrete containment vessel (PCCV) structures exemplifies the method’s adaptability. This innovative approach not only highlights the flexibility of copula-based analysis in assessing structural performance under different dynamic scenarios but also offers invaluable insights for performance-based earthquake engineering (PBEE) and safety assessments.
•A novel copula-based cloud analysis approach is proposed, offering a flexible and precise framework for seismic fragility assessment in engineering structures.•The method’s adaptability is demonstrated through its successful application to nuclear power plant structures, showcasing its potential across diverse engineering scenarios.•Various copula models are compared rigorously, providing valuable insights into the most effective copula parameterization for fitting seismic fragility curves.
•Establishment of the relationship between main and aftershock intensities through statistical analysis, laying the foundation for subsequent probabilistic assessments.•Introduction of a multi- ...dimensional fragility analysis method based on vine-copula correlation analysis, circumventing the repetitive calculations and the linear fitting errors associated with traditional fragility analyses.•Conducting a multi-dimensional fragility analysis in the context of nuclear power plants, quantifying the impact of aftershocks on structural fragility and assessing the influence of mainshocks on aftershock fragility.
Seismic resilience of critical infrastructure, such as nuclear power plants, is paramount in ensuring nuclear safety. This study presents a comprehensive analysis of the seismic fragility of nuclear power plants under sequential earthquakes, employing the innovative vine-copula theory. The methodology integrates advanced modeling techniques, including layered shell elements and plastic damage softening constitutive modeling, to capture the intricate behavior of nuclear power plants under seismic loading. The seismic sequence is derived from the Wenchuan earthquake data, considering both mainshocks and aftershocks. A set of random seismic peak ground accelerations (PGAs) is generated based on the distribution of giant earthquake PGAs. Utilizing seismic attenuation theory, corresponding random aftershock PGAs are generated. The resulting mainshock-aftershock sequence, modulated within the real seismic sequence, serves as the input for numerical simulations. The vine-copula theory is employed for multi-dimensional fragility analysis, providing a flexible framework to model the complex nonlinear dependencies among structural response parameters. The vine-copula model is applied to fit seismic response data, allowing the construction of fragility surfaces under sequential earthquakes. This approach, rooted in performance-based earthquake engineering (PBEE), enables a more realistic representation of the seismic risk profile. The findings demonstrate that seismic fragility trends for nuclear power plants increase with higher mainshock and aftershock intensity measures (IMs). The impact of aftershocks on the structural performance, often overlooked in traditional studies, is elucidated through the proposed methodology. The study contributes valuable insights into nuclear safety assessments by quantifying the influence of sequential earthquakes on the fragility of nuclear power plants.
This article aims at identifying the optimal scalar- and vector-valued intensity measures (IMs) for predicting liquefaction triggering and the consequence of liquefaction (i.e. permanent deformation ...of sloping grounds), respectively. A total of 169 ground motions were selected from the NGA-West2 database. Using the selected ground motions as input, one-dimensional dynamic analyses were conducted for generic sloping ground soil profiles consisting of a loose-sand liquefiable layer implemented in OpenSees. The excess pore water pressure ratio and the liquefaction-induced lateral displacement were regarded as the engineering demand parameters (EDPs) of interest. A total of 20 scalar-IMs and 21 vector-IMs representative of various characteristics of seismic loading were evaluated as candidate IMs. The criteria for identifying optimal IMs include consideration for the efficiency, sufficiency, and predictability of the given IMs. An error propagation approach was employed to evalute the overall uncertainty of EDPs under scenario earthquakes using different IMs as predictor variables. Based on the results of extensive comparative analyses, acceleration spectrum intensity (ASI), and the vector of peak ground acceleration and spectral acceleration at 0.3 s (peak ground acceleration (PGA) and Sa(0.3 s), respectively) are identified as the optimal scalar- and vector-IM for liquefaction triggering evaluation, respectively. However, Arias intensity (Ia) and vectors of Ia, cumulative absolute velocity and PGA, Ia are identified as the optimal scalar- and vector-IM for predicting the liquefaction-induced lateral displacements. The optimal IMs identified could be used in performance-based liquefaction hazard evaluations, to assess the liquefaction triggering and consequence of liquefiable sites.
Corrosion-induced deterioration of material properties can noticeably affect the seismic performance of coastal reinforced concrete (RC) bridges in aggressive marine environments, causing significant ...adverse economic and environmental consequences post extreme events. This study systematically investigates the time-dependent seismic performance, resilience, and sustainability of coastal RC bridges. For that purpose, a three-dimensional (3D) nonlinear finite element (FE) framework is developed and combined with the formulation of performance-based earthquake engineering (PBEE) and an economic input-output life cycle assessment (LCA) approach. Seismic resilience and robustness of the coastal RC bridges are subsequently evaluated in terms of the post-earthquake repair cost, repair time, and carbon footprint quantified by CO2. Within this framework, additional analyses are conducted to explore possible retrofit measures, including the use of fiber-reinforced polymer (FRP) reinforcement on the sustainability and resilience of the retrofitted RC bridges. For the presented scenario, it is shown that wrapping bridge columns with FRP composites can effectively increase the moment capacity, thus improving resilience and sustainability by reducing as much as 650 Mg of CO2 for this specific bridge. Overall, the derived insights highlight the need for sustainability, resilience, and potential retrofit analysis of coastal RC bridges in seismically active regions affected by corrosion-induced deterioration.
•A nonlinear 3D FE framework for coastal RC bridges is developed and combined with the PBEE formulation and EIO-LCA approach.•Seismic resilience and sustainability of RC bridges under aggressive marine environments and earthquakes are investigated.•Effectiveness of FRP composites to potentially enhance the performance of bridge columns is thoroughly explored.•Wrapping coastal bridge columns with FRP composites can effectively improve seismic resilience and sustainability.
This is a Discussion of the following article: Cook D., et al. (2023). ASCE/SEI 41 assessment of reinforced concrete buildings: Benchmarking nonlinear dynamic procedures with empirical damage ...observations, Earthquake Spectra, August 2023, Vol. 39, No. 3, pp. 1721–1754.
Coastal bridges are particularly prone to damage caused by prior earthquakes, rendering them more vulnerable to subsequent hazards. The potential occurrence of a near-field tsunami can significantly ...exacerbate this damage, leading to detrimental environmental and economic impacts. Aiming to quantitatively assess these consequences, this study delves into the multihazard resilience and sustainability of a typical coastal Reinforced Concrete (RC) bridge under sequential earthquake-tsunami events. As such, a nonlinear three-dimensional (3D) finite element (FE) framework is established, seamlessly merging the economic input-output life cycle assessment (EIO-LCA) methodology with the principles of performance-based earthquake engineering (PBEE). To minimize the uncertainty in the probabilistic seismic demand model and the subsequent PBEE outcomes, an optimal intensity measure is chosen based on a comprehensive evaluation of efficiency, correlation, and coefficient of variation. Consequently, the multihazard resilience of the coastal RC bridge is assessed according to the repair time, repair cost, and carbon footprint. It is shown that bridges are more vulnerable under sequential earthquake-tsunami events compared to earthquake events alone, leading to notably increased carbon footprints and reduced resilience levels. Overall, the developed framework enhances the assessment of coastal RC bridge performance, providing valuable insights into the consequences for both the environment and socioeconomic aspects resulting from bridge damage during sequential earthquake and tsunami events.
•A framework for multihazard analysis of coastal RC bridges is developed by integrating FE modeling, PBEE, and EIO-LCA approach.•An optimal intensity measure is identified by considering correlation, efficiency, and coefficient of variation.•Multihazard resilience and sustainability of a coastal RC bridge during earthquake-tsunami sequential events is investigated.•Increased bridge susceptibility under earthquake-tsunami events causes increased carbon footprint and decreased resilience.
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