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This study focuses on developing strength reduction factor R μ spectrum, a maximum inelastic displacement (MID) estimation method and a displacement-based design method for single-degree-of-freedom (SDOF) bilinear structures with self-centering viscous-hysteretic devices (SC-VHDs). The effects of design parameters on R μ spectrum are statistically investigated under near-fault pulse-like ground motions (NFPG) and far-field ground motions (FFG), and its prediction formula is fitted according to the statistical data. Following proposed R μ spectrum, a MID estimation method and a performance-based design method are proposed, respectively. Next, three SC-VHD frames are designed step-by-step to verify the proposed design method, and then their MIDs are calculated step-by-step to validate the MID estimation method. Finally, a risk assessment is conducted on a SC-VHD frame and a conventional frame to compare their collapse performance and the performance exceeding 0.2% residual drift in the probability framework. The results indicate that R μ spectrum is primarily affected by the ductility ratio, period and viscous damping ratio, while the parameters of ring springs have little effect on it. R μ spectrum under the NFPE is significantly lower than that under the FFE except for periods from 0.2 s to 0.6 s. The R μ spectrum formula and the MID estimation method both have errors that are typically less than 10%. The designed SC-VHD frame can achieve the target performance, and its probability of collapse and exceeding 0.2% residual drift in a period of 50-year is significantly smaller than that of the conventional frame. • Strength reduction factor spectrum is developed for self-centering viscous-hysteretic systems. • A maximum inelastic displacement estimation method is proposed. • A displacement-based design method is proposed. [ABSTRACT FROM AUTHOR]

A new efficient approach for uncertainty quantification of pipeline structural response undergoing reverse-slip fault rupture displacements in sand is presented using multi-fidelity Gaussian processes. Uncertainty quantification problems generally take large numbers of scenarios to be analysed considering variations in the influencing parameters. Analysing large numbers of computationally expensive detailed geo-technical numerical models is practically not feasible. Hence, a multi-fidelity approach employing Gaussian process is proposed to tackle this problem which combines the accuracy of a relatively few number of detailed geo-technical numerical models and the efficiency of large numbers of simplified numerical models to track the uncertainty response. The detailed model utilizes a previously validated pipe-soil finite element (FE) model including a non-linear sand constitutive model implemented in finite element software ABAQUS. The simplified model utilizes beam element pipe and bi-linear soil springs. The multi-fidelity model is first trained using data from high-fidelity and low-fidelity model analyses, thereafter cross-validated and subsequently used to quantify uncertainty in the peak compressive strains generated and to identify the most sensitive input variables. Finally, fragility curves are derived for a site specific pipe-soil fault rupture problem. [ABSTRACT FROM AUTHOR]

Generally, in designing nonlinear energy sink (NES), only uncertainties in the ground motion parameters are considered and the unconditional expected mean of the performance metric is minimized. However, such an approach has two major limitations. First, ignoring the uncertainties in the system parameters can result in an inefficient design of the NES. Second, only minimizing the unconditional mean of the performance metric may result in large variance of the response because of the uncertainties in the system parameters. To address these issues, we focus on robust design optimization (RDO) of NES under uncertain system and hazard parameters. The RDO is solved as a bi-objective optimization problem where the mean and the standard deviation of the performance metric are simultaneously minimized. This bi-objective optimization problem has been converted into a single objective problem by using the weighted sum method. However, solving an RDO problem can be computationally expensive. We thus used a novel machine learning technique, referred to as the hybrid polynomial correlated function expansion (H-PCFE), for solving the RDO problem in an efficient manner. Moreover, we adopt an adaptive framework where H-PCFE models trained at previous iterations are reused and hence, the computational cost is less. We illustrate that H-PCFE is computationally efficient and accurate as compared to other similar methods available in the literature. A numerical study showcasing the importance of incorporating the uncertain system parameters into the optimization procedure is shown. Using the same example, we also illustrate the importance of solving an RDO problem for NES design. Overall, considering the uncertainties in the parameters have resulted in a more efficient design. Determining NES parameters by solving an RDO problem results in a less sensitive design. [ABSTRACT FROM AUTHOR]

• A novel Stochastic XFEM (S-XFEM) algorithm is proposed. • S-XFEM couples H-PCFE with XFEM. • S-XFEM can be used for stochastic fracture propagation and reliability analysis. • Results obtained are accurate and efficient. We present a novel stochastic extended finite element (S-XFEM) method for solving fracture mechanics problems under uncertainty. The proposed S-XFEM couples XFEM and a novel multi-output Gaussian process based machine learning algorithm, referred to as the hybrid polynomial correlated function expansion (H-PCFE). With this approach, the underlying stochastic fracture mechanics problem is decoupled into multiple classical fracture mechanics problems. Since solution of a classical fracture mechanics problem is computationally expensive, we utilize the H-PCFE model as a surrogate to emulate the behavior of the system. Training samples required for training the H-PCFE model are generated by using the XFEM. Because of the intrinsic capability of XFEM in providing a mesh insensitive solution, the proposed approach can provide reasonable result from a coarse mesh. On the other hand, H-PCFE is capable of providing highly accurate solution from very few training samples. Overall, the proposed S-XFEM is highly efficient in solving stochastic fracture mechanics problems. The proposed approach is used for solving three stochastic fracture mechanics problems. Different case studies involving reliability analysis and stochastic fracture propagation have been reported. The procedure yields highly accurate results for all problems, indicating its possible applications to other large scale systems. [ABSTRACT FROM AUTHOR]

Nonlinear structural response of buried continuous pipeline undergoing strike-slip fault rupture, i.e., where soil masses get displaced in the horizontal plane along a fault line, is studied in a detailed manner. A detailed analysis technique employing ABAQUS/Standard with implicit formulation to study the behavior of buried continuous pipelines crossing fault movements is proposed and established with suitable validations. A three-dimensional nonlinear finite element (FE) model including both material and geometric nonlinearities is used for this study. Firstly, a non-linear sand constitutive model is adopted and implemented in commercial FE package ABAQUS. The adopted material model is validated with available experimental tri-axial test results. This material model is thereafter suitably calibrated to develop a FE model of buried pipeline undergoing fault rupture for a specific large-scale experimental test. The study identified important soil strength parameters from direct shear soil tests conducted for the large-scale test program and converted them suitably with respect to the adopted sand constitutive model. The FE model is then validated against full-scale experimental results. It is observed that the developed FE model yields highly accurate results in comparison to available numerical results for this experiment. Analysis results indicated that, consideration of sand non-linear mobilized shear strength appropriately in numerical modelling may result in significantly improved prediction of generated pipeline strains with increasing fault displacements. • A detailed 3D FE model for simulating buried pipelines undergoing fault rupture in sand is developed. • The FE model is found is yield superior results as compared to other FE models available in the literature. • The nonlinear material model adapted for sand is found to yield an excellent match with the tri-axial test results. • The material model is incorporated within ABAQUS by using USDFLD. • It is expected that the methodology presented here will be useful in performing strain hazard analysis of pipelines. [ABSTRACT FROM AUTHOR]

This study focuses on developing probabilistic inelastic displacement ratio C R demand spectra for single-degree-of-freedom (SDOF) self-centering viscous damper (SC-VD) systems subjected to near-fault forward-directivity ground motions. In addition, this study presents a procedure for calculating the mean annual frequency (MAF) of the maximum inelastic displacement demand exceeding a specific displacement while considering the forward-directivity pulse effect to determine the maximum inelastic displacement demand hazard of the SC-VD structural system under near-fault forward-directivity ground motions. First, the effect of ground motion characteristics on C R demand is investigated. A probabilistic distribution model describing the probabilistic distribution of C R demand is then established. The effect of structural characteristics on key parameters in the probabilistic distribution of C R demand is investigated, and calculation models for key parameters are established. Based on the probabilistic distribution model and the calculation models for key parameters, the probabilistic C R demand spectra are developed. Finally, by combining the probabilistic C R demand spectra and the probabilistic seismic hazard analysis with the forward-directivity pulse effect, the procedure for calculating the MAF of the maximum inelastic displacement demand exceeding a specific displacement is presented to determine the maximum inelastic displacement demand hazard. The results indicate that the effects of ground motion characteristics should be treated as random variables, and that the Gamma distribution can reasonably describe the probabilistic distribution of C R demand. The proposed probabilistic C R demand spectra can reasonably estimate the actual C R demand, especially when R is large. Besides, the procedure for calculating the MAF of the maximum inelastic displacement demand exceeding a specific displacement is demonstrated to be effective in assessing the maximum inelastic displacement demand hazard through a set of SDOF SC-VD example systems. • A probabilistic distribution model of inelastic displacement C R demand is proposed. • The effect of structural characteristics on the probabilistic C R demand is studied. • A probabilistic C R demand spectrum under near-fault ground motions is developed. • A framework for calculating the inelastic displacement seismic hazard is proposed. [ABSTRACT FROM AUTHOR]

Prestressing in wood connection, due to frictional forces, improves mechanical properties of the connection. This paper presents novel friction-based connectors, and corresponding tests at the connection and system levels. The friction-base connector is composed of a softwood or hardwood dowels inserted into the wood-based material and tightened to generate frictional force. Long-term performance was evaluated by stress relaxation tests and time-dependent connection tests. To evaluate dynamic performance of shear walls with friction-based connectors, shake table tests were conducted. The shake table tests showed that the restoring force characteristics of the wood friction shear walls were bilinear reflecting the behaviors of the friction-based connectors. The strength degradation of the wood friction shear walls due to cyclic input was small that more seismic inputs could be applied before any significant damage to the wood friction shear wall. Results of stress relaxation tests, for periods of 1 to 3 years, showed that the stresses were maintained at 70–90% under uncontrolled environment. On the other hand, the results of time-dependent connection tests, for 1 to 6 years, showed high initial clamping stresses caused large performance loss, but high performance could be maintained when tightened below the allowable stress for sustained loading. • Experimental studies of friction connectors using wooden dowels were conducted. • Shear walls with the connectors showed high seismic performance in shake table tests. • Long-term performance was evaluated by stress relaxation and time-dependent connection tests. • Experimental results suggest the connectors have a high potential for practical use. [ABSTRACT FROM AUTHOR]

Abstract Introduction : The safety of oil and gas pipelines is an increasing concern for the public, government regulators, and the industry. A safety management system cannot be efficient without having an effective integrity management program (IMP) and a strong safety culture. IMP is a formal document (policies, planning, scheduling, and technical processes) while safety culture is a measure of views, beliefs, and traditions about safety. For regulatory authorities and O&G companies, assessing the effectiveness of both the IMP and safety culture through regulatory audits is a daunting task with indistinct findings. Method : An integrated framework based on regulatory audits is developed to assess the maturity of safety culture based on IMP efficacy through risk-based approach by using failure mode and effect analysis (FMEA). The framework focuses on three distinct aspects, the probability of failure occurrence in case of the non-compliance of regulatory and program requirements, severity of non-compliance, and effectiveness of the corrective actions. Results : Program requirements and performance indicators are translated into assessment questions which are grouped into 18 IMP components. Subsequently, these components are linked with four safety culture attributes. Sensitivity analysis revealed that four IMP components, i.e., organizational roles and responsibilities, policy and commitment, risk assessment, and training and competency, significantly affect the safety culture maturity level. Conclusions : Individual assessment of IMP and safety culture in O&G sector consumes extensive time and efforts in the auditing process. The framework facilitates the process by pursuing common criteria between IMP and safety culture. The O&G companies and regulator can prioritize the improvement plans and guidelines using the framework's findings. Practical applications : The integrated framework developed in this research will improve the existing assessment mechanism in O&G companies. The framework has been effectively implemented on a case of 17 upstream O&G pipeline-operating companies in the province of British Columbia, Canada. [ABSTRACT FROM AUTHOR]

Highlights • The performance of a mass-timber building under tornado-like vortex is assessed. • A 34 m tall mass-timber building is structurally designed using wind tunnel test data. • Straight-line and tornadic wind loads are obtained from experimental tests. • Dynamic structural analyses are carried out in time domain. • The vulnerability of drift sensitive components of mass-timber building is estimated. Abstract Tall mass-timber buildings utilize engineered wood panels to form their main gravity and lateral load resisting systems, which makes them lighter and more flexible than buildings made from concrete, masonry or even steel. In general, drift sensitive components of tall mass-timber buildings could be susceptible to damages due to increased deflection when subjected to extreme wind storms like violent tornadoes. This paper assessed the structural performance of a multi-story mass-timber building, which was designed using the customary 1-in-50 years design wind speed of the 2010 National Building Code of Canada with a load factor of 1.4, under experimentally simulated tornado-like wind fields. In the study, wind loads were obtained from laboratory simulations of tornado-like wind field and atmospheric boundary layer flow at Western University, Canada. Tornadic wind loads from the laboratory tests were scaled to five Enhanced Fujita wind speeds, representing various levels of damage. Dynamic structural analyses were carried out in time-domain to include the possible amplification due to the dynamic component of the excitation and assess floor level inter-story drift and shear force demands for various parameters. The varied parameters were tornado intensity level, the orientation of the building (aerodynamic direction), and critical damping ratio. Based on the obtained results, the vulnerability of drift sensitive components of the study building under tornado-like wind field was estimated. It is shown that strong tornadoes may pose significant damage to drift sensitive non-structural components of multi-story mass-timber buildings. Finally, roadmaps to improve the design of mass-timber buildings in tornado-prone areas are forwarded. [ABSTRACT FROM AUTHOR]

Industrial buildings often have irregularities due to operational and complex industrial process. In this paper, a thermal power plant with mass and vertical irregularities was designed with the 2010 ASCE and AISC design codes. Subsequently, a parametric study was undertaken on simplified braced frames to quantify the impact of mass and vertical irregularities, as well as their combined effect. Detailed numerical models were developed in Open System for Earthquake Engineering Simulation platform. With a high seismicity level in China, ground motions were selected and nonlinear time-history analyses were performed. Subsequently, probabilistic seismic demand models, seismic fragilities, and risks were developed for different performance levels. The results show that the vertical irregularity generated larger detrimental effect than mass irregularity, and need more attention in structural design. Collapse risk increased the most due to the combined effect of mass and vertical irregularities. Furthermore, under small earthquake intensities, the thermal power plant with the combined irregularities had higher risk in functional disruption. [ABSTRACT FROM AUTHOR]

• Without any binder, SFRCR-ECC can be sprayed with a certain pressure to achieve good adhesion to steel surfaces at high temperatures without peeling. • After 210 min open-fire test, 3 CFST columns sprayed with SFRCR-ECC coating all maintained good integrity, while no large-scale falling of SFRCR-ECC coating occurred, with good thermal stability. • Due to the excellent thermal insulation performance of SFRCR-ECC, the fire resistance limit of CFST columns with 30 mm thick SFRCR-ECC exceeds 210 min. The conventional spray-applied fire-resistive material meets the basic fire resistance requirements. However, it has limited strength and ductility, and poor bonding with the substrate, consequently, it will not deform with the main structure and reduces the fire resistance performance. A multifunctional spray-applied, fire-resistive and corrosion-resistive Engineered Cementitious Composites (SFRCR-ECC) has been developed to overcome these defects. Material properties of SFRCR-ECC coating were initially investigated, as well as the ISO-834 standard fire test of CFST columns sprayed with SFRCR-ECC coating were carried out. The effects of SFRCR-ECC coating thickness and the load ratio of the columns to the fire resistance limit were preliminarily explored, while the damage of the specimens after the open fire test, the temperature distribution and the axial deformation of CFST columns were obtained. The open fire test results also proved that SFRCR-ECC has excellent fire resistance performance as a new sprayable fire resistant material. [ABSTRACT FROM AUTHOR]

Onshore and offshore wind power technologies have seen unprecedented growth. For wind farms located in areas prone to earthquake, seismic analysis and design of wind turbines are required to guarantee their safety and economy. This paper proposes a procedure to establish design response spectra for wind turbines by modifying the 5%-damped design response spectra in codes for traditional buildings. This modification entails short service life and low structural damping ratio of wind turbines. The damping modification factors (DMFs) are developed for the quantile spectra to account for the excessive fluctuations of low-damped spectra. Besides, the critical modal periods of the wind turbine are applied in the procedure, leading to much more accurate results of the DMFs at these periods. The design seismic intensity is modified to make an identical seismic risk for the wind turbines and buildings, leading to economical design of wind turbines. A case study is conducted for a monopile-based offshore wind turbine to illustrate and demonstrate the proposed approach. Comprehensive discussions are also included on establishment of DMFs for wind turbines with various damping ratios and different substructures. The results indicate that the proposed DMFs have a high accuracy at the critical modal periods of the wind turbine, and the DMFs corresponding to different damping ratios and various quantile values can be efficiently derived according to the developed regression models. • Seismic intensity is modified considering the service life of wind turbines. • Accuracy of DMF is improved by considering the modal periods of wind turbines. • Excessive fluctuation of low-damped spectra is considered in DMFs. [ABSTRACT FROM AUTHOR]

Reinforced concrete frames with unreinforced masonry infill walls represent a widely adopted building system. During seismic events, infill walls, usually considered as non-structural elements, may significantly affect the characteristics of the system in terms of in-plane stiffness, strength, and energy dissipation capacity. The assessment of framed structures infilled with unreinforced masonry walls has been investigated since the 1950s. Developing reliable numerical models of infill walls has become an important issue since then. The analytical simplified model based on equivalent diagonal struts is often used to assess the infilled frames response. The nonlinear behavior of the equivalent diagonal strut is usually described by constitutive laws that account for the stiffness, the strength and the hardening or softening behavior of the infill. The present work focuses on the evaluation of various parameters needed to define the monotonic and hysteretic response of infill walls modelled by equivalent struts. In order to select a simple and reliable analytical model that suitable for representing the infill wall response, different strut formulations and hysteretic models have been analysed in detail and used to reproduce several experimental tests available in the literature. The numerical analyses are performed by means of the OpenSees computer program. Three uniaxial material models available in OpenSees are used to assess their capability in reproducing the experimental hysteretic response. Finally, from the comparison among different models and between numerical and experimental results, suggestions are made to properly model the in-plane non-linear response of infills. [ABSTRACT FROM AUTHOR]

• The seismic behavior of perimeter diagrid concrete core (PDCC) structures has been systematically evaluated. • A comprehensive study of the failure modes of PDCC was conducted by measurements and observations of the shaking table tests. • The investigation of the shake table tests is beneficial to comprehensively understand the seismic performance of a PDCC structural system. Perimeter diagrid concrete core (PDCC) is a structural system used for high-rise building applications. Quantifying their seismic safety is of interest to owners and decision makers due to the lack of the comprehensive understanding of the seismic performance of the high-rise PDCC structure. To systematically evaluate the seismic performance, a 36-story PDCC structure has been assessed using 1/20 scaled shake table tests. In addition, a detailed nonlinear finite element model (FEM) of the PDCC structure was built for comparison and analysis with the shaking table test. The damage to the perimeter diagrid bracings, the RC structural walls, the diagonal beam, under earthquake excitations have been assessed and discussed systematically based on the experimental and numerical results. The analysis result shows that the PDCC structure has a high performance under the earthquake load that can be used as an efficient seismic force-resisting system. Under the action of horizontal earthquakes, the axial force of the diagonal braces on the same floor varies greatly, and the axial force of the diagonal brace is related to the number of other diagonal braces on its axis. In terms of seismic damage to the perimeter diagonal braces, the most severe seismic damage is concentrated in the diagonal braces with higher axial forces, while the damage to other diagonal braces with smaller axial forces is less severe. And the seismic damage of diagonal bracing has a tendency to expand to other surrounding diagonal braces. [ABSTRACT FROM AUTHOR]

In order to model the spatial correlations of seismic performances within a portfolio of buildings, an approach based on multiple-output Gaussian random field is proposed in this paper. Seismic performances, including engineering demand parameters, economic loss, repair time, and collapse state, are modeled as functions of latent Gaussian random fields. The correlations of seismic performances are specified by the kernel functions of Gaussian random fields, whose hyperparameters are determined by using Gaussian process regression. After applying the proposed method to a spatially distributed building portfolio, it is demonstrated that overlooking spatial correlations may lead to an underestimate of the probability of occurrence of extreme seismic losses. • Gaussian random field is applied to model spatial correlation of seismic losses. • Correlation is specified by kernel functions. • Hyperparameters are determined using Gaussian process regression. • Cross-correlation is modeled by multiple-output Gaussian random field. [ABSTRACT FROM AUTHOR]

• The dynamic and long-term performance of a connector using a wood friction is investigated. • The dynamic performance of shear walls with the connectors was compared with that of conventional shear walls in shake table tests. • Friction tests of the connections and the wall were periodically conducted along with stress relaxation tests of wood. • Experimental results suggest that the connectors have a high potential for practical use in indoor environments. This paper presents the results of shake table tests and periodical friction tests to evaluate the dynamic and long-term performance of a novel connector using a wood friction (friction-based connectors). The friction-based connectors are a quite simple system in which the wood is bolted transversely to generate friction force. The shake table tests showed that the type of hysteresis loop of the wall with the friction-based connectors exhibited a bilinear, and significantly reduced the maximum response displacement even when the conventional walls were combined. In addition, more than 60% of the total energy was absorbed by the wall with friction-based connectors, even the load bearing ratio of the wall was about 30%. The periodical friction tests of the connectors and the wall with the friction-based connectors indicated that the friction forces were mostly linked to the relaxation behavior of wood, and although the friction forces were significantly affected by humidity fluctuations, long-term friction forces were expected to be maintained. [ABSTRACT FROM AUTHOR]

• Probabilistic framework to estimate the downtime (DT) of power and telecommunication systems following an earthquake. • General decision support framework to use under emergency conditions. • Identification of key parameters influencing the recovery time of infrastructure systems. • Bayesian networks model deals with the uncertainties of the DT rational and irrational parameters. • Three case studies demonstrating the applicability of the proposed framework with a sensitivity analysis. Natural and human-made disasters can disrupt infrastructures even if they are designed to be hazard resistant. While the occurrence of hazards can only be predicted to some extent, their impact can be managed by increasing the emergency response and reducing the vulnerability of infrastructure. In the context of risk management, the ability of infrastructure to withstand damage and re-establish their initial condition has recently gained prominence. Several resilience strategies have been investigated by numerous scholars to reduce disaster risk and evaluate the recovery time following disastrous events. A key parameter to quantify the seismic resilience of infrastructures is the Downtime (DT). Generally, DT assessment is challenging due to the parameters involved in the process. Such parameters are highly uncertain and therefore cannot be treated in a deterministic manner. This paper proposes a Bayesian Network (BN) probabilistic approach to evaluate the DT of selected infrastructure types following earthquakes. To demonstrate the applicability of the methodology, three scenarios are performed. Results show that the methodology is capable of providing good estimates of infrastructure DT despite the uncertainty of the parameters. The methodology can be used to effectively support decision-makers in managing and minimizing the impacts of earthquakes in immediate post-event applications as well as to promptly recover damaged infrastructure. [ABSTRACT FROM AUTHOR]

We introduced shape memory alloy (SMA) assisted nonlinear energy sink (NES) with negative stiffness for seismic vibration mitigation. The ability of dissipating energy through a hysteretic phase transformation of its microstructure triggered by cyclic loading is a notable feature. To utilize this feature, the nonlinear spring within NES is replaced by a SMA based spring. The nonlinear material behavior of SMA spring is modeled by the Greaser - Cozzarelli model utilizing the super-elastic effect of SMA. In order to ensure robust performance of the proposed controller, the tuning parameters of SMA assisted NES with negative stiffness are determined by solving a robust design optimization problem. To solve the RDO problem in an efficient manner, blind Kriging has been used as a surrogate model. A number of parametric studies are carried out to illustrate the robustness of the proposed controller. The results obtained clearly demonstrate the enhanced and robust performance of the proposed SMA enhanced NES with negative stiffness. • A novel Shape memory alloy (SMA) based nonlinear energy sink (NES) with negative stiffness and sliding friction is proposed. • Tuning parameter of the proposed controller is estimated using surrogate based robust design optimization under uncertainty. • The performance of the proposed controller is assessed comparing controller without and with sliding friction. • The proposed controller with sliding friction is found to be more robust. • Re-centering properties of SMA is captured. • Enhancement of performance of proposed controller is established by comparing performance of conventional and hysteretic NES. [ABSTRACT FROM AUTHOR]

Inter-story isolation (ISI) is a passive control technique that involves the placement of seismic isolation devices between stories. Multiple isolation layers installed at different story levels can reduce the response of the isolation devices, while maintaining control of the primary building. A multi-objective optimization (MOO) study is conducted in this paper to select the optimum stories of installation and the effective stiffness and damping properties of specified number of isolation layers. The maximum standard deviations of inter-story drift ratio (ISDR) and isolation drift, derived from random vibration analysis (RVA) of a shear-building model are used as the objective functions of the optimization problem, thus accounting for the seismic responses of both the primary building and the isolation devices. To solve the resulting mixed-integer problem, the combinations of integer variables are fully enumerated and a continuous-variable sub-problem is solved for each combination. Four metaheuristic and one derivative-free algorithms are comparatively assessed for solving the continuous-variable multi-objective sub-problems corresponding to the combinations of the integer variables. Along with the optimal trade-offs between the response objectives, multi-objective optimization reveals trends in response with varying isolation configuration as well as the enhancement of the ISI building performance with increasing number of isolation layers. • Multi-objective optimization (MOO) of inter-story isolated buildings. • Consideration of multiple isolation layers at different stories of multi-story buildings as means to reduce isolation drift. • Comparative assessment of four metaheuristic and one derivative-free MOO algorithms Identification of optimal stories of installation and for specified number of isolation layers. • Performance enhancement assessment with increasing number of isolation layers for the case study building model. [ABSTRACT FROM AUTHOR]

The bio-geophysical effects of land cover classes are considered to be an important factor in land surface temperature variations between urban and suburban areas. This means that major cities are significantly warmer than surrounding suburban or rural areas, which is known as the Urban Heat Island (UHI) effect. The aim of this study was to assess and analyze the spatiotemporal variation, correlation and impact of UHIs on Mekelle city (1990-2020) using remote sensing techniques. The study's primary objective was accomplished using the a number of techniques, including the extraction of LULC classes, estimation of the seasonal LSTs, assessment of UHI and UTFVI, and showing the relationship between LULC and LST as well as the interactions between UHI, UTFVI, and urban LULC classes. By analyzing TIRs/OLI thermal band data after calibrating uncertainty in the images and validating it using the concept of theoretical relationships and least squares fitting method, estimates of local LST, UHI (both in Mekelle and periphery rural areas), and UTFVI were obtained. The result of standard multiple regression models showed that impervious urban land surface, built-up areas, and dry bare soil highly contribute and influence variation at LST intensity caused for the formation of UHI in the study area. The result showed that the maximum UHI value in Mekelle city was 2.73 °C during the dry season in 1990. It decreased slightly to 2.53 °C in 2000 and then increased regularly to 2.83 °C and 2.98 °C in 2010 and 2020, respectively. To determine the city's UHI status in comparison to eight selected peripheral suburban areas, a trend analysis has been done. The UHI intensity of Mekelle city was higher relatively to that of most of the periphery suburban districts, particularly in 2020 (both dry and rainy seasons); this could be due to the city's explosive growth. It's worth noting that the research area affected by the urban heat island effect has grown over time, and as a result, the study area also has severe microclimate conditions that primarily damage the quality of urban life and create the worst conditions for thermal discomfort. The results of this study provide major conceptual understandings of how improper distribution and use of urban land affects the urban environment and fuels the creation of the UHI and thermal discomfort phenomena. Hence policy makers and urban planners should consider the effects of LST and UHI and integrate UHI comprehensive mitigation strategies with urban development patterns, and current and projected local climate changes in order to create sustainable urban environments, cities, and communities. In conclusion, compared to the conventional method, satellite remote sensing provides a faster and more efficient method for researching LST and UHI., (© 2023 The Authors.)

The 2020 National Building Code of Canada (NBCC) seismic hazard model (SHM) marks a comprehensive update over its predecessor (NBCC 2015). For different regions in Canada, this will have an impact on the design of new buildings and performance assessment of existing ones. In the present study, a recently developed hybrid building system with reinforced concrete (RC) moment-resisting frames and cross-laminated timber (CLT) infills is assessed for its seismic performance against the latest SHM. The six-story RC-CLT hybrid system, designed using the direct displacement-based method, is located in Vancouver, Canada. Along with very high seismicity, southwestern British Columbia is characterized by complex seismotectonics, consisting of subduction, shallow crustal, and in-slab faulting mechanisms. A hazard-consistent set of 40 ground motion pairs is selected from the PEER and KiK-net databases, and used to estimate the building's seismic performance. The effects of using steel slit dampers (associated with large hysteresis loops) and flag-shaped energy dissipators (associated with the recentering capability) are investigated. The results indicate that the hybrid system has good seismic performance with a probability of collapse of 2-3% at the 2475-year return period shaking intensity. The hybrid building with steel slit dampers exhibits a collapse margin ratio of 2.8, which increases to 3.5-3.6 when flag-shaped dissipators are used. The flag-shaped dissipators are found to significantly reduce the residual drift of the hybrid building. Additionally, the seismic performance of the hybrid building equipped with flag-shaped dissipators is found to improve marginally when the recentering ratio is increased., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2022.)

This study presents a city-wide seismic risk assessment of single-family wooden houses in Victoria, British Columbia, and Canada. The novelty and uniqueness of this study include considerations of detailed building-by-building exposure model for residential houses, current national seismic hazard model for Canada, and rigorous seismic fragility modeling of wooden houses based on nonlinear dynamic analysis of structures subjected to mainshock-aftershock sequences. A full consideration of stochastic event scenarios in probabilistic seismic risk analysis allows the identification of critical scenarios from overall regional seismic risk perspectives and provides valuable insights in informing earthquake disaster risk management actions. Outputs from the developed catastrophe model for Victoria are compared with the empirical model that was developed based on insurance claim data from the 1994 Northridge earthquake. Results of the seismic loss calculations highlight the importance of seismic resistance of the existing houses and of aftershock effects. The integrated use of the outputs from the advanced catastrophe model facilitates risk-based identification of critical earthquake scenarios, which are useful for different stakeholders for earthquake risk management purposes., (© 2020 Society for Risk Analysis.)