Simplified Design Procedure for Reinforced Concrete Columns Based on Equivalent Column Concept

Afefy, Hamdy M.,El-Tony, El-Tony M. Korea Concrete Institute 2016 International Journal of Concrete Structures and M Vol.10 No.3

Axially loaded reinforced concrete columns are hardly exist in practice due to the development of some bending moments. These moments could be produced by gravity loads or the lateral loads. First, the current paper presents a detailed analysis on the overall structural behavior of 15 eccentrically loaded columns as well as one concentrically loaded control one. Columns bent in either single curvature or double curvature modes are tested experimentally up to failure under the effect of different end eccentricities combinations. Three end eccentricities ratio were studied, namely, 0.1b, 0.3b and 0.5b, where b is the column width. Second, an expression correlated the decay in the normalized axial capacity of the column and the acting end eccentricities was developed based on the experimental results and then verified against the available formula. Third, based on the equivalent column concept, the equivalent pin-ended columns were obtained for columns bent in either single or double curvature modes. And then, the effect of end eccentricity ratio was correlated to the equivalent column length. Finally, a simplified design procedure was proposed for eccentrically loaded braced column by transferring it to an equivalent axially loaded pin-ended slender column. The results of the proposed design procedure showed comparable results against the results of the ACI 318-14 code.

Hazard Analysis and Risk Assessments for Industrial Processes Using FMEA and Bow-Tie Methodologies

Afefy, Islam H. Korean Institute of Industrial Engineers 2015 Industrial Engineeering & Management Systems Vol.14 No.4

Several risk assessment techniques have been presented and investigated in previous research, focusing mainly on the failure mode and effect analysis (FMEA). FMEA can be employed to determine where failures can occur within industrial systems and to assess the impact of such failures. This research proposes a novel methodology for hazard analysis and risk assessments that integrates FMEA with the bow-tie model. The proposed method has been applied and evaluated in a real industrial process, illustrating the effectiveness of the proposed method. Specifically, the bowtie diagram of the critical equipment in the adopted plant in the case study was built. Safety critical barriers are identified and each of these is assigned to industrial process with an individual responsible. The detection rating to the failure mode and the values of risk priority number (RPN) are calculated. The analysis shows the high values of RPN are 500 and 490 in this process. A global corrective actions are suggested to improve the RPN measure. Further managerial insights have been provided.

Hazard Analysis and Risk Assessments for Industrial Processes Using FMEA and Bow-Tie Methodologies

Islam H. Afefy 대한산업공학회 2015 Industrial Engineeering & Management Systems Vol.14 No.4

Several risk assessment techniques have been presented and investigated in previous research, focusing mainly on the failure mode and effect analysis (FMEA). FMEA can be employed to determine where failures can occur within industrial systems and to assess the impact of such failures. This research proposes a novel methodology for hazard analysis and risk assessments that integrates FMEA with the bow-tie model. The proposed method has been applied and evaluated in a real industrial process, illustrating the effectiveness of the proposed method. Specifically, the bowtie diagram of the critical equipment in the adopted plant in the case study was built. Safety critical barriers are identified and each of these is assigned to industrial process with an individual responsible. The detection rating to the failure mode and the values of risk priority number (RPN) are calculated. The analysis shows the high values of RPN are 500 and 490 in this process. A global corrective actions are suggested to improve the RPN measure. Further managerial insights have been provided.

Capacity Magnification by Imposing Composite Action of Precast Concrete Flanged Girders

Hamdy M. Afefy,Nesreen M. Kassem,Salah El-Din F. Taher 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.7

This paper presents an experimental study in order to verify the efficiency of different connecting techniques in improving thehorizontal shear resistance of composite concrete flanged beams. The studied composite beams consisted of precast concrete websinterconnected with precast concrete flanges. Different connecting techniques had been considered; namely, plain/reinforced Ultra-High-Performance Strain-Hardening Cementitious Composites (UHP-SHCC) shear pockets, UHP-SHCC shear buckets in the flangeaccommodated extended steel dowels from the web, unbonded internal steel fasteners and intermediate shear intrusions. Eightcomposite flanged beams incorporating different connecting techniques along with three reference beams; monolithic, successivelycast flanged beam and unconnected web/flange beams were prepared and tested up to failure under two cycles of non-reversalrepeated loading. Furthermore, the push-off test method was employed in order to determine the horizontal shear resistance of theused connecting techniques. Each technique came up with advantages and disadvantages. Therefore, it is a matter of compromise todecide the most appropriate technique according to the necessary criteria (ultimate capacity or ductility). Finally, the horizontal shearresistances were calculated based on the experimental findings and compared with the stipulated resistances in the ECP 203-2007and the ACI 318-14 design codes. It was found that the design codes’ values showed conservative results.

Simplified Design Procedure for Reinforced Concrete Columns Based on Equivalent Column Concept

Hamdy M. Afefy,El-Tony M. El-Tony 한국콘크리트학회 2016 International Journal of Concrete Structures and M Vol.10 No.3

Axially loaded reinforced concrete columns are hardly exist in practice due to the development of some bending moments. These moments could be produced by gravity loads or the lateral loads. First, the current paper presents a detailed analysis on the overall structural behavior of 15 eccentrically loaded columns as well as one concentrically loaded control one. Columns bent in either single curvature or double curvature modes are tested experimentally up to failure under the effect of different end eccentricities combinations. Three end eccentricities ratio were studied, namely, 0.1b, 0.3b and 0.5b, where b is the column width. Second, an expression correlated the decay in the normalized axial capacity of the column and the acting end eccentricities was developed based on the experimental results and then verified against the available formula. Third, based on the equivalent column concept, the equivalent pin-ended columns were obtained for columns bent in either single or double curvature modes. And then, the effect of end eccentricity ratio was correlated to the equivalent column length. Finally, a simplified design procedure was proposed for eccentrically loaded braced column by transferring it to an equivalent axially loaded pin-ended slender column. The results of the proposed design procedure showed comparable results against the results of the ACI 318-14 code.

New Optimization Model for Multi-Period Multi-Product Production Planning System with Uncertainty

Asmaa A. Mahmoud,Mohamed F. Aly,Ahmed M. Mohib,Islam H. Afefy 대한산업공학회 2019 Industrial Engineeering & Management Systems Vol.18 No.4

The focus of this study is to develop a multi-period multi-product (MPMP) production planning system with uncertainty, and products demand (seasonal demand) uncertainty. Mainly, the problem aims reach the production levels ofeach product according to the uncertain demand for various periods, which depend on constraints of capacity, inventory, and resources. An analytical model proposed for this problem that can be categorized into two classes: non-linearand stochastic. The objective is to minimize the summation of variable production costs. As uncertain demand is adynamic stochastic data process in the planning horizon, it is considered as a tree model. Each stage in the demandtree model is related to a cluster of a period time. Hence, depending on the tree model for the fluctuation demand;Two-Stage Stochastic Programming (TSP) model is presented as an alternative for all demand scenarios. In some ofthe reviewed articles validation of the analytical model were missing, while other studies were missing either manufacturing set up costs or assumptions of seasonal demand. Therefore, this study proposes TSP model using SamplingAverage Approximation method (SAA) that is suitable for a production planning system in any manufacturing environment considering seasonal demand using optimization program (Lingo 16) to solve the mathematical model. Further, investigation of seasonal demand is performed using the multiplicative seasonal method, and the model validation was checked using Mathworks Matlab R2015a (64-Bit) considering manufacturing set up costs. Finally, somerecommendations for future research are suggested.

An Efficient Maintenance Plan Using Proposed Framework of RCM Made Simple Approach

Eman K. Abd Elhalim,Ragab K. Abdel-Magied,Islam H. Afefy,Mohamed F. Aly 대한산업공학회 2019 Industrial Engineeering & Management Systems Vol.18 No.2

Reliability Centered Maintenance (RCM) is an effective maintenance strategy and a powerful tool for industrial system enhancement. In this paper, a Framework of RCM is proposed. RCM Made Simple approach is adopted instead of classical RCM to overcome its complexity. A comprehensive analysis is carried out using the proposed Framework which generates a maintenance plane for industrial systems. This analysis is applied on a real case study. The results revealed which component could be critical, potentially critical, commitment, or run to failure. Moreover, it presented the function of each component, failure modes, failure effects and its consequence on the system, failure causes, PM task required, PM frequency for each task, and how to prevent each failure cause. The Framework that proposed in this paper could be adopted as a simple approach to enhance the Reliability, Availability, and Maintainability (RAM) of the industrial systems.