Vol 9 Issue 2 October 2021-March 2022

Abstract: The main objective of this study is to know the effect of sea water and high temperature on the rods made of fiberglass, Experimental work Three concrete slabs were made, mixed with different percentages of seawater 0%, 50% and 100%, and fiber bars were used to reinforce these samples The length of the fiber rod was 160 cm with a diameter of 12 mm, and 12 rods were placed in each direction to be in the form of a net in the sample. These samples were exposed to a temperature of 300 degrees and the exposure time was 60 minutes.

Keywords: FRP; temperature; and seawater.

Title: Study of the Effect of Seawater on Fiber Bars Used to Reinforce Concrete Slabs When Exposed to High Temperatures

Author: Magdy Mahmoud Mohamed Genidi, Khaled samy Abdallah, Amal Hasanin Ibrahim, Ismail mohamed abouelwafa ahmed

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: Information on site specific measured oceanographic data such as wind generated waves, currents is seldom available and plays an important role in offering solution to various coastal engineering problems. Due to unanticipated difficulties during field measurement campaigns, it has been observed that measured data for some specific duration is missing or lost. In such circumstances, data driven methods are essential to predict the missing data and its use to calibrate the physical model and to offer engineering solution to the project. Present study investigates the applicability of one of the popular recently developed artificial intelligence (AI) model named as long short-term memory (LSTM) in predicting current data in a macro tide dominated Thane creek and the significant wave height (H_s) for Floating Storage & Regasification Unit (FSRU) structure. The results indicate that LSTM networks formed based on data of 7/15 days of current/tide, can predict current data for 8/10 days with root mean square error (RMSE) of 0.091 and 0.09 respectively. Study also reveals that for location in Thane creek, LSTM prepared on the basis of 8 days of H_s data is able to predict H_s for 33 hours with RMSE value of 0.14.  Based on the predicted data, current data is used to calibrate the physical tidal model to determine flow conditions for proposed FSRU in Thane creek and also operable condition (Hs). The study reveals that FSRU needs to be aligned at 33° N and hence LSTM network was found to be useful in design of waterfront structures.

Keywords: Artificial intelligence, current, LSTM, oceanographic data, significant wave height.

Title: Prediction of oceanographic data using LSTM network: A case study for FSRU in Arabian Sea

Author: A. Basu, A.A. Purohit, K.A. Chavan

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: This experimental investigation was focused on the study of compressive behavior of steel fiber reinforced concrete (SFRC) subjected to different sustained elevated temperature ranging from 100⁰ C to 400⁰ C. In order to evaluate the effect of elevated temperature on M40 grade SFRC steel fibers of length 30 mm were used. Specimens were casted by using 0%, 1%, and 2% volume fractions. Data obtained from laboratory test results showed that residual strength varied inversely with the quantity of fibers at all levels of sustained elevated temperatures. The compressive toughness of SFRC was also evaluated to investigate the mechanical properties of SFRC at sustained elevated temperatures of 100⁰ C, 200⁰ C 300⁰ C and 400⁰ C. Test results showed that increase in the volume of steel fibers does not have significant variation in compressive strength at room temperature whereas it is observed that there is a decreasing trend in the residual compressive strength of SFRC up to sustained elevated temperature of 400⁰ C.

Keywords: steel fiber reinforced concrete (SFRC), residual strength, mechanical properties.

Title: TOUGHNESS OF STEEL FIBER REINFORCED CONCRETE AT VARIOUS ELEVATED TEMPERATURE

Author: Mahesh Prabhu, Vivek Bindiganavile, Narayana Suresh

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: Composite column systems have become popular in tall building construction due to combining the rigidity and formability of reinforced concrete with the strength, ductility, and speed of construction of structural steel to produce an economic structure. This paper presents an experimental study to get more knowledge about the characteristics and the fire resistance of encased composite concrete columns. Three-scale three reinforced composite concrete columns were constructed and tested up to failure under direct fire at 500◦C for two hours. The experimental program Consists of three specimens with 150 mm in diameter and 1500 mm in height, the first specimen (CIG 500 ͦc) reinforced by steel bars and built-up section have 7 gaps with a diameter of 5cm at the section web, the second specimen (CIB 500 ͦc) reinforced by steel bars and built-up section have 56 bolts and finally, the third specimen (CIP 500 ͦc) reinforced by steel bars and built-up section has 14 welded metal plate. The performance of the tested composite columns specimens is evaluated based on the crack pattern, first crack, failure load, ductility. Moreover, the experimental results are shown a proportional relationship between the degree of temperature and residual strength, causing the residual strength to decrease by 18.29 %. The result shows that the failure load for the encased composite column by plates (CIP 500 ͦ c column) was much greater than the load-carrying capacity of other composite columns, this is due to the high capacity of steel material which is found inside the column. After exposure to a degree of fire 500 ◦ C, the encased composite column by plates steel shows that the failure load is higher than the failure load for the encased composite column by gaps and bolts by 29.7% and 8.17% respectively.

Keywords: encased composite; concrete columns; fire exposure; civil engineering.

Title: Behavior of Encased Composite Concrete Columns under Fire Exposure

Author: Mohammed E. Elghobary, Ahmed Bakhit, Fouad Khairallah, Hala Mamdouh

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: Glass bars for concrete reinforcement, known as glass fiber-reinforced polymers (GFRPs), are new natural inorganic materials with distinct mechanical properties that have been used recently in the construction field. Generally, the FRPs bars have no yield before the brittle failure as steel bars and their behavior, when exposed to fire, is still under investigation, this paper presents an experimental study to get more knowledge about the characteristics and the fire resistance of a concrete beam reinforced using GFRPs. Three-scale concrete beams were constructed and tested up to failure under direct fire at 500 ◦C for an hour. Shear span-to depth ratio is the main parameter of this study. Beam (B1) had distance from face of support 670 mm ,beam (B2) had distance from face of support 250 mm and beam (B3) had distance from face of support 500 mm .All beams had 30 mm concrete cover , exposed to fire for an hour and three GFRPs  reinforcement bars were used. The results are discussed in terms of load capacity, cracking behaviour, and failure modes.

Moreover, the experimental results are compared with theoretical calculations according to the ACI code and other codes. The results show that when distance from face of support over effective depth greater than 2.5 the beams act as slender beams while distance from face of support over effective depth less than 2.5 the beams act as arch action. Our results also showed that when distance from face of support over effective depth 2.02 the failure load incress by percent 60.3% and beam failure as shear failure while distance from face of support over effective depth 1.01 the failure load incress by percent 221.7% and beam failure as flexural failure . More studies are needed to justify our observations in details and determine their applicabilities under different conditions.

Keywords: Shear span, Concrete Beams, Depth ratio, GFRP bars.

Title: Effect of SHEAR SPAN-TO DEPTH RATIO of Concrete Beams Reinforced with GFRP bars on Shear under fire Exposure

Author: M. A. OSMAN, Hala Mamdouh, Ahmed H. Ali, Hamdy. M. Mohamed, T.S.kamal

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: The main objective of this Thesis is study the performance of seawater concrete beams reinforced with glass fiber rebars (GFRP) when using seawater as mixing or curing water. Experimental Work includes three beams were tested with rectangular section its dimensions (200 * 500 * 2200) mm, divided into two groups, using different mixing water (F)or(S) represent as fresh water and natural seawater respectively with using ordinary Portland cement in all mixes . We studied the effect of using seawater on flexural capacity of tested beams in fist group, while the second group showed the effect of changing curing water from fresh water to seawater. Analysis of test results shows that the use of seawater in concrete mixtures will become possible in the future. The pattern of cracks, final mode of failure, and deformational characteristics were recorded. Finally, analysis of test results were reported.

Keywords: seawater; performance; GFRP; Freshwater.

Title: Experimental Study On Performance of Seawater Concrete Beams

Author: Mohamed .H.S .Metwally, Magdy.M.M. Genidi, Amal H.Ibrahim, Usama Ali Ali Ebead

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: This paper presents an experimental study on twelve reinforced concrete (RC) slabs strengthened with carbon, glass, basalt fiber reinforce polymer (CFRP) laminate/sheet under four-point bending, aiming to reveal the effects of the bond-dependent coefficient, (Km) on the load-carrying capacity of strengthened the slabs at debonding failure (i.e. debonding strength). For the purpose, the test specimens are such designed to explore effects of several important factors, including modulus of elasticity of the fibers, the thickness of the used fibers, and the number of layers. The experimental results showed that the number of plies and thickness of the carbon laminate/sheet are strongly influences the debonding strengths of the strengthened slabs. It was also found that the (A_fiber /A_steel) ratio is major parameter that affects the performance of strengthened slabs.

Keywords: FRP, debonding, concrete, slabs, strengthening.

Title: Enhancement the efficiency of FRP External strengthening system of RC Flexural Member

Author: Azza.Abdelrashed, T.Aly, W. Ibrahim, M. Meged

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: The main objectives of this research are to study experimentally, analytically and numerically the effectiveness of the proposed external strengthening techniques to resist punching shear of reinforced concrete flat slabs. The finite element (FE) analysis software program (ANSYS V. 19) was used to create the models and investigate the effects of some parameters on punching shear of reinforced concrete flat slabs. Eight variable parameters are taken into consideration during study full scale flat slab models to account the influence of: (1) concrete compressive strength f_cu; (2) reinforcing steel yield strength f_y; (3) slab thickness (t_s); (4) shear studs and stirrups diameter (D_b); (5) shear studs (stirrups) spacing /t_s ratio (S_b/t_s); (6) shear studs stirrups spacing/t_s ratio (D/ t_s); (7) main steel ratio/m _{max (} m /m _max); (8) top steel ratio/m _max (m` /m _max).The numerical results were compared with the analytical results calculated from ECP 203-2017 [1] and ACI 318-19 [2]. The comparison showed a great match between the numerical results and the results of the two codes, especially ACI 318-19 [2].

Keywords: Punching shear, experimental, external strengthening, ANSYS program, numerical analysis.

Title: Comparison between Experimental, Nonlinear Finite Element Analysis Results and International Codes for Reinforced Concrete Flat Slabs Strengthened Using Different Techniques to Resist Punching Failure

Author: Hanna F. H. Habeb, Ahmed A. Mahmoud, Alaa G. Sherif, Magdy M.M. Genidi

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: Freshwater, will be scarce and could be very difficult to obtain in some regions of the world. According to the report of the World Meteorological Organization (WMO), more than half of the world’s population will not be able to get enough drinking water by 2025. In the concrete industry, several billion tons of freshwater are used annually in mixing, curing, and cleaning around the world. and to saving freshwater, using seawater as the mixing water in concrete should be investigated seriously. So, in this research, we made several mixtures. So, in this research, we made mixtures with different proportions (0%,50%, 100%) of seawater, and the use of ordinary cement and sulfate-resistant cement, as well as fresh water and seawater in the treatment, and using glass fiber rebar replace steel rebar. The pattern of cracks, final mode of failure, and deformational characteristics (deflection, and steel tensile strain) were recorded. Finally, analysis of test results and recommendations were reported.

Keywords: GFRP; seawater; freshwater; and OPC & SRC cement.

Title: THE STUDY OF THE EFFECT OF USING SEAWATER IN FLAT SLABS REINFORCED WITH FIBER REBARS

Author: Usama Ali Ali Ebead, Magdy.M.M Genidi, Adel M. Soliman, Asem Elsayed Ali M.Selem

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: A two-dimensional (2D), Computational Fluid Dynamics (CFD) model was used to study tornado-wind force interaction with a smooth, thin-cylinder structure having a radius less than the tornado radius and little roof area.  They are widely used as wind turbine support towers in tornado-prone areas.  The Navier-Stokes equations were approximated with a Finite-Difference method.  Simulations were performed to determine the minimum required grid resolution to prevent divergence of the program, replicate known straight-wind force coefficients, and determine tornado-wind force coefficients.  The ratio of the core, forced-vortex tornado radius to the cylinder diameter (r_core/D) was increased with constant tornado and translation velocities to determine the tornado drag and lift force coefficients (C_d and C_l).  The rotational velocity strength (V_tan) and r_core were then simultaneously increased to determine their effects on C_d and C_l.  Tornado-wind force coefficients C_d and C_l were corrected for velocity and combined to determine a single tornado-wind force coefficient (C).  The combined coefficient was compared to published force coefficients, including ASCE 7, for straight-wind.  Force coefficients for tornados approached constant values when r_core exceeded 15D.  Tornado-wind force coefficients were 2-3 times the published values for straight-wind.

Keywords: Tornado Wind, Force Coefficient, CFD, Thin-Cylinder.

Title: Wind Mill Reliability: Determining Tornado-Wind Force Coefficients for Thin-Cylinder Structures with Computer Modeling

Author: Quentin S. Ragan, R. Panneer Selvam

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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Abstract: Procurement is a key activity in organization and major activity in the economies both developing and developed countries. Their management has contributed to the success of projects and overall performance of organizations. However, there are several challenges in the implementation of this activity and for that reason different strategies developed and deployed. Procurement is characterized by inventory management, volume ordering and adherence to best practices that safeguard the organization from losses. These activities vary in their outcomes depending on what procurement strategy has been chosen. This study sought to investigate the effect of centralized procurement systems on performance of construction companies in Rwanda. with specific reference to Real Contractors Ltd. The study used a sample of 55 participants including staff of financial, procurement and marketing departments. The study adopted the correlational research design. A questionnaire with open-ended questions was used to collect data. Data was analyzed using descriptive statistics (frequencies, mean and standard deviation) and inferential statistics (correlational and regression analyses) along with the use of SPSS which was used in all calculations and creation of tables. The findings revealed that Real Contractors Ltd. has been able to obtain higher organization performance as a result of centralized purchasing timeliness, quality of goods and services, and customer satisfaction the study also found that inventory management is essential in ensuring that adequate supplies are within the firm’s storage to support continuous production process. The study recommends that the firm should enhance the bulk ordering process by undertaking a value chain analysis which will help the firm in selecting suppliers who will foster the firm savings and enhance its economies of scale.

Keywords: Centralized Procurement, Organization performance and Inventory Management.

Title: CONSIDERING CENTRALIZED PURCHASING SYSTEMS AS A PREDICTOR FOR PERFORMANCE OF CONSTRUCTION SECTOR IN RWANDA USING A CASE OF REAL CONTRACTORS LTD

Author: Rugamba Evariste, Rugira Filipo

International Journal of Civil and Structural Engineering Research  

ISSN 2348-7607 (Online)

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