Relationships among repeated sprint tests and aerobic fitness in adolescent tennis players

The aim of this study was to determine the performance indices (ideal sprint time – IS, total sprint time – TS, and performance decrement – PD) of two repeated sprint test (RST) and to examine their relationships with the aerobic fitness of young tennis players. Fifteen young (age 14.7±1.0 yrs) tennis players performed three tests: an aerobic power test (20 m shuttle run), and two different RST protocols (12×20 m and 12×10 m runs). Peak heart rate was significantly higher in the 20 m protocol compared to the 10 m protocol while no significant difference was found in the PD of the two RST protocols. Significant positive correlations were found between the ISs and the TSs (r=0.946 and r=0.932, respectively), but not between the PDs of the two RST protocols. Significant negative correlations were found between TS and IS and aerobic fitness during the 10 m protocol (r=–0.594 and r=–0.595, respectively) and the 20 m protocol (r=–0.757 and r=–0.716, respectively), but not between PD and the aerobic fitness in both RST protocols. Both short and long RST protocols represent similar anaerobic capabilities. In addition, the aerobic energy system serves as a significant factor in both RST protocols. However, it seems that the involvement of the aerobic system is more significant in the long than in the short repetition RST protocol

Development of Exclusive Seismic Fragility Curves for Critical Infrastructure: An Oil Pumping Station Case Study

Fragility curves are a common tool to appraise the expected damage to critical infrastructure (CI) after an earthquake event. Previous studies offer fragility curve parameters for CI that are suitable for a vast range of systems, without an in-depth examination of the system architecture and subcomponents. These curves are applicable in cases where a thorough analysis is not required or when the information related to a single system is poor. This paper proposes an original approach and presents a comprehensive methodology for developing exclusive fragility curves for critical infrastructure systems. In the proposed methodology, the fragility curves are developed by a decomposition of the system into its main subcomponents and determination of the failure mechanisms. The derivation of the fragility parameters includes failure analysis for each damage state by a Fault Tree Analysis and approximation of the fragility parameters in accordance with the rate of exceedance. The implementation of the methodology is demonstrated by a case study with three alternatives of an oil pumping plant configuration. It was found that a change of a subcomponent has an effect on the derived values of the fragility parameters. Moreover, the variances in the fragility parameters have implications for the effectiveness of each alternative to resist different levels of severity

Seismic Risk Mitigation and Management for Critical Infrastructures Using an RMIR Indicator

Recent earthquake events have highlighted the importance of critical infrastructure (CI) resilience, as a strong correlation was found between economic loss and severity of CI damage. CIs are characterized by a complex structure composed of sub-components that are essential for the continuous performance of the system. CI owners and governments allocate ample resources to retrofitting and upgrading CI systems and components to increase the resilience of CIs and reduce risk in case of seismic events. Governments and decision makers must manage and optimize the retrofitting efforts to meet budget and time constraints. This research presents a probabilistic methodology for CI seismic risk mitigation and management. The risk expectancy is appraised according to an FTA-based stochastic simulation. The simulation includes the development of exclusive fragility curves for the CI and an examination of the expected damage distribution as a function of earthquake intensity and fragility uncertainty of the components. Furthermore, this research proposes a novel RMIR (risk mitigation to investment ratio) indicator for the priority setting of seismic mitigation alternatives. The RMIR is a quantitative indicator that evaluates each alternative’s cost-effectiveness in terms of risk expectancy mitigation. Following the alternative’s RMIR value, it is possible to prioritize the alternatives meeting budget and time constraints. This paper presents the implementation of the proposed methodology through a case study of a generic oil pumping station. The case study includes twelve mitigation alternatives examined and evaluated according to the RMIR indicator

Development of Exclusive Seismic Fragility Curves for Critical Infrastructure: An Oil Pumping Station Case Study

Fragility curves are a common tool to appraise the expected damage to critical infrastructure (CI) after an earthquake event. Previous studies offer fragility curve parameters for CI that are suitable for a vast range of systems, without an in-depth examination of the system architecture and subcomponents. These curves are applicable in cases where a thorough analysis is not required or when the information related to a single system is poor. This paper proposes an original approach and presents a comprehensive methodology for developing exclusive fragility curves for critical infrastructure systems. In the proposed methodology, the fragility curves are developed by a decomposition of the system into its main subcomponents and determination of the failure mechanisms. The derivation of the fragility parameters includes failure analysis for each damage state by a Fault Tree Analysis and approximation of the fragility parameters in accordance with the rate of exceedance. The implementation of the methodology is demonstrated by a case study with three alternatives of an oil pumping plant configuration. It was found that a change of a subcomponent has an effect on the derived values of the fragility parameters. Moreover, the variances in the fragility parameters have implications for the effectiveness of each alternative to resist different levels of severity

Integrating Maintenance Into Seismic Risk Assessment: A Comprehensive Approach to Infrastructure Resilience

A severe seismic event can cause significant damage to infrastructure systems, leading to both direct and indirect severe consequences. Thus, a comprehensive risk management approach is essential for developing earthquake-resilient infrastructure. This study introduces an innovative approach to seismic risk assessment that incorporates maintenance considerations with seismic fragility curves. Our methodology distinctively quantifies the impact of maintenance conditions on seismic risk, providing insights into the dynamic evolution of risk associated with loose maintenance and accelerated deterioration. It suggests that the condition of infrastructure maintenance and its level of deterioration significantly influence seismic resilience. By integrating the Building Performance Indicator (BPI) with deterioration over time, the proposed approach assesses their combined effect on fragility curves to calculate the total risk over the infrastructure's lifecycle (TRLC – Total Risk over Life Cycle). We demonstrate this methodology through a case study of a low-voltage substation in Bik'at HaYarden, Israel. A Monte Carlo simulation was carried out to examine the particular conditions of the substation thoroughly. Additionally, a sensitivity analysis was carried out to better understand how maintenance conditions influence the TRLC over time. Our findings reveal a statistically significant correlation between infrastructure performance and maintenance condition, and their subsequent impact on the TRLC. Notably, we found that loose maintenance conditions significantly increase the uncertainties in seismic risk. This research offers researchers, stakeholders, and decision-makers a novel and comprehensive view on the critical role of maintenance in managing and mitigating seismic risk

A Comprehensive Approach to Earthquake-Resilient Infrastructure: Integrating Maintenance with Seismic Fragility Curves

A severe seismic event can cause significant damage to infrastructure systems, resulting in severe direct and indirect consequences. A comprehensive risk-management approach is required for earthquake-resilient infrastructure. This study presents an innovative approach to seismic risk assessment and aims to integrate maintenance considerations with seismic fragility curves. The proposed methodology uniquely quantifies the impact of maintenance conditions on seismic risk, presenting a dynamic perspective of risk changes attributable to maintenance and deterioration. The methodology hinges on the hypothesis that the maintenance condition of the infrastructure and the level of deterioration impacts the seismic resilience of the infrastructure. The methodology synergizes the Building Performance Index (BPI) and the deterioration over time to evaluate their cumulative effect on fragility curves to estimate the infrastructure’s total risk over the lifecycle (TRLC). This proposed methodology is demonstrated through a case study of a low-voltage substation in Bik’at HaYarden, Israel. A Monte Carlo simulation was carried out for the specific conditions of the analyzed substation. A comprehensive sensitivity analysis was performed to understand better the effect of maintenance conditions over time on the TRLC. Key insights reveal a statistically significant correlation between infrastructure performance and maintenance and their consequential impact on the TRLC. Notably, declining maintenance conditions intensify seismic risk uncertainties. The research proposes to researchers, stakeholders, and decision-makers a novel comprehensive perspective on the indispensability of maintenance for seismic risk management and mitigation

Seismic Risk Mitigation and Management for Critical Infrastructures using an RMIR Indicator

Recent earthquake events have highlighted the importance of critical infrastructures (CI) resilience, as a strong correlation was found between the economic loss and the severity of CIs damage. CIs are characterized by a complex structure composed of sub-components that are essential for the continuous performance of the system. CIs owners and governments allocate ample of their resources in retrofitting and upgrading CIs systems and components to increase the resilience of CIs and reduce the risk they are exposed to in case of seismic events. Governments and decision-makers must manage and optimize the retrofit efforts to meet the budget and time constraints. This research presents a probabilistic methodology for seismic risk mitigation and management in CIs. The risk expectancy is appraised according to an FTA-based simulation. The simulation includes the development of exclusive fragility curves for the CI and an examination of the expected damage distribution as a function of the earthquake intensity. Furthermore, this research proposes a novel RMIR (Risk Mitigation to Investment Ratio) indicator for priority setting of seismic mitigation alternatives. The RMIR is a quantitative indicator that evaluates each alternative's cost-effectiveness in terms of risk expectancy mitigation. Following the alternative's RMIR value, it is possible to prioritize the alternatives meeting the budget and time constraints. This paper presents the implementation of the proposed methodology through a case study of a generic pumping station. The case study includes twelve mitigation alternatives examined and evaluated according to the RMIR indicator