Experimental and Numerical Investigation of Different Types of Jacketing Effect on Retrofitting RC Short Columns Using ECC Concrete

Given the deterioration of civil infrastructure throughout the world, developing more efficient repair and strengthening is essential. Jacketing is one of the most common methods for retrofitting reinforced concrete (RC) columns. Notably, using engineered cementitious composite (ECC) within the jacketing area increases the bearing capacity and significantly enhances the ductility of the columns. The recent development of ECC concrete with suitable compressive strength and higher ductility of about 5 % can significantly enhance the performance of reinforced concrete structures. The behavior of retrofitted RC columns depends heavily on the cohesion between the jacket and the original column as well as the mechanical properties of the jacketing materials. This study investigates jacketed square and circular RC columns using ECC and conventional/normal concrete (NC) using different casing techniques to retrofit RC columns, namely galvanized mesh, U and L-shape joints, removing the cover, core drilling, and integrated models. All specimens were subjected to a compression test. The results indicate that in both square and circular specimens, the use of ECC as a super ductile material and vertical U-shaped elements to connect the longitudinal rebars of the casing and the core leads to much higher ductility and bearing capacity than in NC specimens. These elements also showed suitable ductility because of using ECC as a super ductile material. In order to optimize these methods, finite element analysis (FEA) was conducted using Abaqus software to verify experimental models, as well as a parametric study to achieve an optimum design of the jacketing

Supply Chain Risk Management in the Container Liner Shipping Industry from a Strategic Point of View

One of the most significant current discussions in the container liner shipping industry (CLSI) is supply chain risk management (SCRM). In recent years, there has been an increasing interest in managing risk and reliability in the container supply chain from many viewpoints. This paper reviews the significant literature related to SCRM in the CLSI from a strategic point of view. By integrating the concept of the CLSI, the planning levels of container liner shipping and the concept of SCRM, questions have been raised about risk and uncertainty arising from the external environments (i.e. country-limited scope) and how can these factors influence the organisational reliability and capability of liner shipping operators (LSOs). Another question concerns how uncertain environments can influence the punctuality of containerships. So far, however, no research has been found that answered these questions which make further research is meaningful. For future research, this paper recommends an extensive assessment of a business environment-based risk and an evaluation of organizational reliability and capability of LSOs from the strategic point of view. Finally, it is worth mentioning that there is a research gap in both industry and academia on how to analyse and predict the punctuality of containerships (i.e. arrival and departure) under uncertain environments. Keywords: supply chain risk management, container liner shipping industry, business-environment based risk, organisational reliability and capability, punctuality

Business Environment-Based Risk Model for the Container Liner Shipping Industry

Container liner shipping is a risky industry. There are many unexpected risks and uncertainties in extended journey around the world which can be the result of external events such as political actions, economic situation and natural disasters. The impact of these external risks can be devastating. In this paper, a new business environment-based risk (BEBR) model for prioritising and assessing the external risk criteria in the CLSI, is developed. The term BEBR can be defined as a wider scope of external risks including political risks, economic risks, social risks and natural hazards that directly or indirectly influence the business performances in the CLSI. An analytic hierarchy process (AHP) approach is employed to prioritise the importance of risk criteria and is adapted into a deterministic weight factor in the context of risk impact level. So far, no study has been found that developed this model for the CLSI which highlights a significant research gap to be fulfilled. Based on the test case, the result has shown that economic risks are the most significant main criteria in the BEBR model, followed by political risks, natural hazards and social risks. For future research, this paper recommends a quantitative risk analysis for assessing the targeted or whole risk criteria in the BEBR model. Keywords: business environment-based risk (BEBR), container liner shipping industry (CLSI), analytic hierarchy process (AHP), prioritisation

A risk assessment approach to improve the resilience of a seaport system using Bayesian networks

Over the years, many efforts have been focused on developing methods to design seaport systems, yet disruption still occur because of various human, technical and random natural events. Much of the available data to design these systems are highly uncertain and difficult to obtain due to the number of events with vague and imprecise parameters that need to be modelled. A systematic approach that handles both quantitative and qualitative data, as well as means of updating existing information when new knowledge becomes available is required. Resilience, which is the ability of complex systems to recover quickly after severe disruptions, has been recognised as an important characteristic of maritime operations. This paper presents a modelling approach that employs Bayesian belief networks to model various influencing variables in a seaport system. The use of Bayesian belief networks allows the influencing variables to be represented in a hierarchical structure for collaborative design and modelling of the system. Fuzzy Analytical Hierarchy Process (FAHP) is utilised to evaluate the relative influence of each influencing variable. It is envisaged that the proposed methodology could provide safety analysts with a flexible tool to implement strategies that would contribute to the resilience of maritime systems

An advanced risk analysis approach for container port safety evaluation

Risk analysis in seaports plays an increasingly important role in ensuring port operation reliability, maritime transportation safety and supply chain distribution resilience. However, the task is not straightforward given the challenges, including that port safety is affected by multiple factors related to design, installation, operation and maintenance and that traditional risk assessment methods such as quantitative risk analysis cannot sufficiently address uncertainty in failure data. This paper develops an advanced Failure Mode and Effects Analysis (FMEA) approach through incorporating Fuzzy Rule-Based Bayesian Networks (FRBN) to evaluate the criticality of the hazardous events (HEs) in a container terminal. The rational use of the Degrees of Belief (DoB) in a fuzzy rule base (FRB) facilitates the implementation of the new method in Container Terminal Risk Evaluation (CTRE) in practice. Compared to conventional FMEA methods, the new approach integrates FRB and BN in a complementary manner, in which the former provides a realistic and flexible way to describe input failure information while the latter allows easy updating of risk estimation results and facilitates real-time safety evaluation and dynamic risk-based decision support in container terminals. The proposed approach can also be tailored for wider application in other engineering and management systems, especially when instant risk ranking is required by the stakeholders to measure, predict and improve their system safety and reliability performance

Enabling security and risk-based operation of container line supply chains under high uncertainties

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Application of a collaborative modelling and strategic fuzzy decision support system for selecting appropriate resilience strategies for seaport operations

The selection of an appropriate resilience investment strategy to optimize the operational efficiency of a seaport is a challenging task given that many criteria need to be considered and modelled under an uncertain environment. The design of such a complex decision system consists of many subjective and imprecise parameters contained in different quantitative and qualitative forms. This paper proposes a fuzzy multi-attribute decision making methodology for the selection of an appropriate resilience investment strategy in a succinct and straightforward manner. The decision support model allows for a collaborative modelling of the system by multiple analysts in a group decision making process. Fuzzy analytical hierarchy process (FAHP) was utilized to analyse the complex structure of the system to obtain the weights of all the criteria while fuzzy technique for order of preference by similarity to ideal solution (TOPSIS) was employed to facilitate the ranking process of the resilience strategies. Given that it is often financially difficult to invest in all the resilience strategies, it is envisaged that the proposed approach could provide decision makers with a flexible and transparent tool for selecting appropriate resilience strategies aimed at increasing the resilience of seaport operations

Evaluation of the Seismic Behavior Based on the Performance of Special Steel Moment Frames by Modified Energy Method and Force Design Method

Although conventional methods in seismic design consider such parameters as force, displacement, and ductility, the behavior of a significant number of structures that have been designed and experienced earthquakes shows that the existing criteria are insufficient and more comprehensive ones should be used. In this regard, the energy-based design method may be considered one of the suitable solutions. This method is based on creating a balance between the input and output energy of structures. It is possible to have a more appropriate estimate of the energy input as well as dissipated energy by the structure and use it in the design of the structure. In the modified energy method that has been used in this study, control of items such as the creation of a soft story, establishment of the Strong-Column Weak-Beam concept, the uniform distribution of loads in the members, the nonconcentration of force and local damage, and simultaneous drift control of the structure with the optimal distribution of plastic hinges have been considered. Also, modifications have been made to the energy balance equation. In this paper, 8-, 16-, and 24-story frames with lateral force resisting system of special steel moment frame have been modified by energy method and compared by the design force method of AISC code. Performance level criteria of the ASCE41-17 code have been applied in the design, and the P−Δ effects have also been considered in the nonlinear analysis. The results show that, for the frame which is designed by the energy method, the plastic hinges are created in the upper stories and beams; however, in the frame designed by the LRFD method, several plastic hinges are formed in the columns of the upper stories, and a local mechanism is created. Also, in 8- and 16-story structures, the weight of the structure which is designed by the energy method is less than that obtained by the LRFD method. The results also showed that, in contrast to the energy method, the relationships presented in the codes regarding the Strong-Column Weak-Beam rule cannot prevent local and undesirable mechanisms in severe earthquakes

Risk factors for in-hospital mortality among patients with coronavirus-19 in Isfahan City, Iran

Background: The aim of the study is to explore the risk factors of mortality for hospitalized patients in three designated hospitals in Isfahan province.Materials and Methods: This retrospective cohort study was conducted on all positive coronavirus disease (COVID)-19 patients admitted to Khorshid, Isabn Maryam, and Amin hospitals in Isfahan province. The demographic, clinical, laboratory, and outcome data of patients who were died or discharged from February 24, 2020, to April 18, 2020, were extracted from patient's medical records.Results: Overall 1044 COVID-19 patients were included in this analysis. Based on the findings of this study, older age (& GE;65 years) (adjusted hazard ratio [aHR]: 2.06; 95% confidence interval [CI]: 1.13-3.76), chronic obstructive pulmonary disease (COPD) history (aHR: 2.52; 95% CI: 1.09-5.83), white blood cell (WBC) counts more than 10 x 103/L (aHR: 3.05; 95% CI: 1.42-6.55), Hb level < 13 gr/L (aHR: 2.82; 95% CI: 1.34-5.93), bilateral pulmonary infiltrates (aHR: 2.02; 95% CI: 1.12-3.64) at admission, development of acute respiratory distress syndrome (ARDS) (aHR: 1.87; 95% CI: 1.01-3.47), and intensive care unit (ICU) admission (aHR: 2.09; 95% CI: 1.04-4.18) during hospitalization were risk factors for in-hospital mortality in patients with COVID-19.Conclusions: Multiple factors were found related to the severity and death among COVID-19 patients. We were found that older age (& GE;65 years) with COPD history, high level of WBC, low level of Hb (< 13 g/L), bilateral pulmonary infiltrates at admission, development of ARDS, and ICU admission during hospitalization were identified as risk factors of death among COVID-19 patients. More related studies are needed in the futur

Acute bacterial meningitis in Iran: Systematic review and meta-analysis

<div><p>Introduction</p><p>Bacterial meningitis persists in being a substantial cause of high mortality and severe neurological morbidity, despite the advances in antimicrobial therapy. Accurate data has not been available regarding the epidemiology of bacterial meningitis particularly in developing countries, yet. Indeed, the present systematic review provides a comprehensive data analysis on the prevalence and epidemiology of bacterial meningitis in Iran.</p><p>Methods</p><p>We systematically reviewed articles from 1994 to 2015. The reports which contained the prevalence and etiology of acute bacterial meningitis by valid clinical and laboratory diagnosis were comprised in the present study.</p><p>Results</p><p>Our analysis indicated that <i>Streptococcus pneumoniae</i> (30% [I2 = 56% p < 0.01]), <i>Haemophilus influenza</i> type b (15% [I2 = 82.75% p < 0.001]), coagulase negative staphylococci (CoNS) (14% [I2 = 60.5% p < 0.06]), and <i>Neisseria meningitidis</i> (13% [I2 = 74.16% p < 0.001]) were the most common cause of acute bacterial meningitis among meningitis cases in Iran. Notably, high frequency rates of nosocomial meningitis pathogens were detected in the present analysis.</p><p>Conclusions</p><p>It was magnificently attained that the majority of cases for bacterial meningitis in Iran could be avertable by public immunization schemes and by preventive care to inhibit the broadening of hospital acquired pathogens.</p></div