İnşaat Mühendisliği Bölümü Koleksiyonu

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https://hdl.handle.net/20.500.12939/75

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An advanced mixed finite element formulation for flexural analysis of laminated composite plates incorporating HSDT and transverse stretching effect
(Springer, 2025) Kanığ, Doğan; Kutlu, Akif
The modeling and analysis of laminated composite plates are performed using a unified Higher Order Shear Deformation Theory (HSDT) that accounts for transverse stretching effect. The adopted unified HSDT formulation allows the implementation of various shear functions. To derive a weak form from the generalized displacement fields of HSDTs, a variational principle is applied within a two-field mixed approach. The stationarity of the functional for laminated plate structures is obtained through the application of the Hellinger-Reissner variational principle. Hence, displacements and stress resultants, namely two independent fields, are included in finite element equations. Four-noded, quadrilateral elements are employed for the discretization of the plate's domain. While the generated functional initially had C1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C<^>{1}$$\end{document} continuity, benefiting from the two-fields property of the mixed finite element formulation, integration by parts is performed that results with a functional requiring only C0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C<^>{0}$$\end{document} continuity. To effectively capture the nonlinear and parabolic variation of transverse shear stress, it is determined that even with varying functions, the results are theoretically consistent with the elasticity method and the employed HSDT model. Also, when compared to the theories that are already accessible in the literature, for the bending behavior of composite plates, incorporating the stretching effect converges the exact results for laminated composite plates more than the studies where that effect is neglected.
Effective expressions for the estimation of the first and third natural periods of minarets based on extensive and comprehensive parametric modal analyses
(Elsevier Ltd, 2025) Erkal, Aykut; Hilmi, Zahraa Husham Ibrahim
This paper investigates the modal behaviour of minarets by conducting parametric modal analyses with a comprehensive set of geometric and material properties and critically proposes effective expressions to estimate the first and third natural periods of minarets. To make this unprecedented attempt, firstly, previously studied 52 minarets were examined to systematically select the geometric and material properties of 189 representative minarets. Subsequently, numerical models of these 189 minarets were created and assigned with the selected values for height, cross-sectional area, moment of inertia, modulus of elasticity, and mass density. Then, modal analysis was applied to each representative minaret to obtain modal characteristics to see the effect of each variable. Next, an iterative optimization algorithm was used to establish four effective expressions for the first and third natural periods, considering the effect of five and three variables. Finally, the performance of the proposed expressions was checked with 35 of the previously studied minarets whose dynamic characteristics are available. The results demonstrated a satisfactory level of accuracy. For example, the expression for the fundamental period with 5 variables presented discrepancies mostly far less than 19 % for 28 minarets of a total of 35 minarets. © 2025 Institution of Structural Engineers
A novel spring-actuated low-velocity impact testing setup
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Küçük, Mesut; Hejazi, Moheldeen; Sari, Ali
Evaluating the behavior of materials and their response under low-velocity dynamic impact (less than 30 m/s) is a challenging task in various industries. It requires customized test methods to replicate real-world impact scenarios and capture important material responses accurately. This study introduces a novel spring-actuated testing setup for low-velocity impact (LVI) scenarios, addressing the limitations of existing methods. The setup provides tunable parameters, including adjustable impactor mass (1 to 250 kg), velocity (0.1 to 32 m/s), and spring stiffness (100 N/m to 100 kN/m), allowing for flexible simulation of dynamic impact conditions. Validation experiments on steel plates with a support span of 800 mm and thickness of 5 mm demonstrated the system’s satisfactory accuracy in measuring impact forces (up to 714.2 N), displacements (up to 40.5 mm), and velocities. A calibration procedure is also explored to estimate energy loss using numerical modeling, further enhancing the test setup’s precision and utility. The results underline the effectiveness of the proposed experimental setup in capturing material responses during low-velocity impact events.
Laboratory investigation of the effect of de-icing solutions on moisture susceptibility of hot mix asphalt with biomass fibers
(Springer, 2024) Saedi, Sepehr
The probability of freezing in roads exposed to snow and rain requires ice removal operations to reduce the potential dangers. Lack of maintenance and ice removal can lead to swelling, formation of transverse cracking and stripping pavements phenomenon. Due to the numerous disadvantages of using solid calcium chloride for de-icing, researchers worldwide are still seeking alternative methods to minimize its impact on infrastructure and the environment.In line with the mentioned research, this study was conducted to reduce the effect of deicing solutions on moisture damage, which is one of the most important reasons for reducing the lifespan of hot mix asphalt pavements. Liquid anti-icing and de-icing materials that can be used include calcium chloride, magnesium chloride, and sodium chloride. In using de-icing solutions, beside considering the environmental and economic aspects, it is also important to evaluate the potential damage of such material on asphalt surfaces. To begin the research phase, asphalt mixtures were prepared using the Marshall design method, combining basalt aggregates with bitumen PG 58 - 16, and limestone aggregates with the same bitumen specification. Following this, 0.3% hemp fiber was added to the mixtures, and 78 Marshall samples were prepared for testing. To initiate the research stages, asphalt samples were first prepared using two types of aggregates, basalt and limestone, containing 0.3% hemp fibers. Then, the prepared samples were subjected to sodium chloride, calcium chloride, and magnesium chloride solutions after undergoing 5 freeze-thaw cycles. They were subsequently tested under various moisture sensitivity tests. The results indicated that, in addition to the significant environmental damage caused by sodium chloride, it has a severe impact on reducing the resistance of both types of asphalt mixtures against moisture-related distress. Among the tested solutions, Cacl2 has the lowest impact on reducing the resistance of mixtures against moisture-related distress. Considering its lower environmental impact and relatively cost-effectiveness, it can be considered as a suitable option for de-icing operations in cold and snowy regions, which can also help reducing the maintenance costs of asphalt pavements.
Assessment of haditha dam surface area and catchment volume and its capacity to mitigate flood risks for sustainable development
(International Information and Engineering Technology Association, 2024) Hasan, Raad F.; Seyedi, Mohsen; Alsultani, Riyadh
The purpose of this study is to assess Haditha Dam’s catchment area and accessible surface area in order to guarantee that these regions can hold water without being at risk of floods. Using topographic data, the study simulated the two-dimensional catchment area and flow area below the dam. The monthly increase in water storage was then computed using the water balance equation and HEC RAS software. These increments were used to determine the required flow that might be utilized to run the dam more efficiently. Significant outflows were found at the start of the operational year. These volumes will probably cause water to accumulate, water levels to increase quickly, and heights to climb. In order to make sure that these regions can store water without running the danger of flooding, the goal of this study is to assess the catchment area of a contemporary dam and its accessible surface area. The study generated a two-dimensional catchment region and flow area below the dam using topography data. The water balance equation and HEC RAS software were then used to determine the monthly increase in water storage. The necessary flow that could be utilized to run the dam as effectively as possible was calculated using these increments. This assessment provides a comprehensive analysis of the dam’s capacity to manage water storage efficiently and mitigate flood risks, contributing to sustainable water management practices.
Impact of train-induced vibrations on residents’ comfort and structural damages in buildings
(Springer, 2024) Seyedi, Mohsen
The rapid growth of urbanization and the progress of industrialization have resulted in the construction of over or near-track buildings. Train-induced ground-borne vibrations have attracted attention because they can damage buildings and cause residents discomfort. This study conducted a series of finite element analyses on three 5-story concrete framed buildings, which were subjected to the passage of trains at various speeds. One of the buildings was modeled as an over-track building, whereas the other two buildings were located in close proximity to the track but at different distances. The present study investigated the impact of train speed and track-to-building distance on the acceleration and velocity responses of buildings. The comparison of residents’ comfort levels and the structural safety of buildings against potential damages was conducted using international standards as the controlling criteria. Furthermore, an efficient mitigation technique was implemented, involving the utilization of open trenches with different depths between buildings and the railway track. This approach was employed with the aim of minimizing the detrimental impacts caused by trains-induced vibrations. The findings indicated that the over-track building was impacted by the train-induced vibrations more than near-track buildings. Furthermore, it was shown that although the passage of high-speed trains can disturb the comfort of building residents and potentially cause some structural damage to buildings, it did not lead to any significant story drifts in the structures. Finally, the minimum required depth of open trenches to mitigate train-induced vibrations was computed for every type of buildings and train speeds.
An empirical function to predict the liquefaction-induced uplift of circular tunnels
(2024) Seyedi, Mohsen
Tunnels buried in liquefiable soils are prone to liquefaction-induced uplift damage during strong earthquakes. Studying the parameters that affect the liquefaction-induced uplift of tunnels is crucial for enhancing the seismic resilience of tunnels, minimizing potential damage, and ensuring the safety of critical infrastructure during strong earthquakes. This study investigates the effects of tunnel diameter (D), burial depth (H), and amplitude of input shaking at the base of the soil layer (amax) on the liquefaction-induced uplift of circular tunnels using numerical simulation. A comprehensive parametric study was conducted to investigate the effect of the H/D ratio and the value of amax on the dynamic responses, such as uplifts and internal forces in the lining of the tunnel. Using the numerical results, an empirical function was proposed to estimate the liquefaction-induced uplift of circular tunnels buried in liquefiable, loose soils. Finally, the results predicted by the proposed function were compared with those of a shaking table test and a centrifuge experiment. It has been demonstrated that the burial depth of a tunnel has the greatest impact on its seismic performance. Under identical input motion, increasing the burial depth of a tunnel with a 5-m diameter from 5 to 10 m resulted in a 270% increase in uplift and increased the internal forces in the tunnel lining, noticeably.
A plastic hinge method for static pushover analysis of 3D frame structures
(Taylor and Francis Ltd., 2024) Damcı, Erdem; Öztorun, Namık Kemal; Çelik, Tuncer
In this paper, a nonlinear elasto-plastic analysis method under incremental external loads is presented to determine static pushover curves of 3D frame structures. Geometric nonlinearity is taken into account with stability functions, and the nonlinear behaviour of material is considered by plastic hinge hypothesis. Improved matrices and matrix operations for 3D frame elements are given, and the results obtained from a six-storey 3D frame, which is used as a benchmark example, are given comparatively with the related studies. Furthermore, in order to perform these analyses with the developed algorithms, the upgraded computer program TUNAL is used to present pushover curves of a 2-storey RC building for an assumption on torsional stiffness caused by plastic hinges. It is shown that the proposed methodology and the computer program give accurate and reliable results.
Internal erosion and permeability of Na CMC-treated and PAM-treated geosynthetic clay liners
(2023) Özhan, Hakkı O.; Erkal, Aykut
This paper investigates the occurrence of internal erosion and the variation of the permeability of geosynthetic clay liner (GCL) with respect to its geotextile component, polymer type and polymer amount added to its bentonite component, hydraulic head, and subgrade material by performing extensive triaxial permeability tests on the GCL specimens. To do this, Na carboxymethyl cellulose (CMC) and polyacrylamide (PAM) were treated with the bentonite component of the GCLs. Then, the GCLs were placed over poorly graded gravel (GP) and poorly graded sand (SP). Consequently, they were tested with two different woven geotextile components under the hydraulics heads of 0.3 m and 10 m. Results showed that only GCLs tested with woven geotextile, having lower tensile strength, lower mass/area and lower thickness over the gravel at a hydraulic head of 10 m, experienced internal erosion. Critically, Na CMC and PAM treatment caused 2-2.5 orders of magnitude decrease in the permeability. Actually, 2% Na CMC and 1% PAM treatment by dry mass were found to be the optimum polymer contents. Both the environmentally friendly biopolymer Na CMC and the synthetic polymer PAM can effectively be treated with Ca bentonite to enhance the hydraulic performance of the GCLs.
Seismic responses of an isolated long-span bridge using frequency domain and time dependent procedures
(2023) Sarıtaş, Fevzi; Hasgür, Zeki
Seismic behavior of an isolated bridge is analyzed in the frequency domain under the effects of non-stationary ground motions. For dynamic solutions, different ground environments are considered by simulating non-stationary quakes that can be represented from bedrock to soft ground level. In the simulations, power spectral functions and filtered white noise model are adopted for spectral densities of the earthquake excitations. Various computer algorithms have been developed for earthquake simulations, establishing the bridge finite element model and stochastic solutions. Twenty simulated ground motions are used for each soil profile and the parameters of Rayleigh dispersion are estimated by evaluating the system responses for each ensemble. A number of peak response factors dependent on soil conditions are presented for seismic responses. In addition, extreme value distributions of the responses are shown with the probability of exceeding functions and tables. The responses are discussed for the specific exceedance level of probabilities used in probabilistic design process. The stochastic analyses generally yielded responses consistent with time domain solutions. Exceedance probability functions of the peak responses were obtained in a close relationship. However, the probability distributions of the responses decomposed for the soft soil case and they displayed a wider dispersion even for low exceedance levels. The peak responses are expressed with some exceedance probabilities. In the estimation of response variations, this study showed the practicality of the frequency domain method and the results revealed higher peak response factors and variances for softer soil conditions. Furthermore, this study indicated that the frequency domain procedure is an effective tool in the obtaining of nonstationary seismic responses.
The management of construction projects in Iraq and the most important reasons for the delay
(2023) Musawi, Layth A. L.; Naimi, Sepanta
In Iraq, there is a vast construction movement. Still, it is accompanied by many problems, the most important of which is the delay in completing projects during the specified time. The time must be optimized by adopting the leadership practice and dedicating it to the benefit of performing the process and functions of the project. The research aims to identify the most important reasons and factors that affect the project delivery process within the specified period. The investigation initially dealt with the most important previous studies, on this subject, by researchers, then touched on the concept of construction projects, their types and details. A questionnaire containing reasons for the delay was identified and divided into several items. It concluded that the most common reasons for delays are delays in laboratory testing of materials, assignment of works to the lowest bidder, contractors' financial incompetence, and high building materials prices. The most crucial factor is to streamline building material inspection procedures, set up inspection laboratories on several occasions and assess the contractor's effectiveness and ability to implement before the project is referred financially. Organizations and individuals should coordinate their work between the construction departments to prevent any issues that may arise during completing tasks.
Verification of reaching the regulatory limit for the release of radioactive liquid waste in nuclear medicines
(Polskie Towarzystwo Inzynierii Ekologicznej (PTIE), 2023) Alfayyadh, Linda; Naimi, Sepanta; Mizban, Fadhil; Al-Hamami, Naheel; Alguraibawi, Marwah
The research was conducted at one of Iraq’s nuclear medical facilities in Baghdad, which uses radioactive iodine (I-131) to treat thyroid patients, the major purpose of this research was to meet the national legal limit for the release of radioactive liquid waste into the environment, a high purity germanium reagent radiation detector was used to evaluate nine iodine I-131 samples. From 2021 and 2023, the concentration of waste prior to storage and disposal was between 24498 Bq/L and 5.7 Bq/L. Short-lived radionuclides, such as I-131 with an 8.04-day half-life, may be released into the sewage system in line with Iraq’s Nationally Approved Limits and Austria’s International Atomic Energy Agency (IAEA). Moreover, it is stored for 10 times the half-life, or four months, until the choice to release it into the environment is made.
Based BIM techniques to clash detection for construction projects
(International University of Sarajevo, 2023) Abdalhameed, Braa F.; Naimi, Sepanta
Building Information Modeling (BIM) has brought about a qualitative change in the design and management of construction projects because it represents a digital simulation of the physical characteristics of the building, and this increases its efficiency before the actual construction begins. In Iraq, most construction projects still use CAD two-dimensional drawing for the purpose of the implementation process, especially government projects, and this causes many problems due to the difficulty of communication between the various disciplines involved in the design and misunderstanding during implementation. This type of problem is reduced by combining BIM drawings prepared by designers and making them into a single model. In this process of merging conflicts are found using BIM tools such as Autodesk Navisworks. There are three main types of detection. This article includes how a clash detector can help improve clashes in the design phase before starting to construct a specific building using BIM applications and focuses on hard detection type (overlap of a particular element with the others). The methodology involved in this research is to study an educational building (24-classroom model school) consisting of structural and architectural BIM models only, clash detection analysis is done using Autodesk Revit and Autodesk Navisworks Manage software.
Investigation of concrete properties using recycled waste concrete aggregate
(International University of Sarajevo, 2023) Mohammed, Suha
There are several environmental, economic, and energy reasons why RC is gaining popularity around the world. Key environmental problems include the potential for groundwater contamination due to the washing out of fresh concrete brought back from project sites, as well as the loss of natural sources of high-quality aggregate materials. The RC concrete (RCA) impact on the fundamental characteristics of traditional concrete is investigated besides the effect of different ratio effects of water-cement (w/c). The concrete as crushed rubble obtained from several Iraqi demolition sites and landfills is utilized to examine the properties of (RCA). This work utilized sand as natural, and concrete as crushed from various sources as aggregates around Baghdad city. A total of forty-five concrete mixtures were cast into nine groups. Groups were created to examine the impact of recycled coarse aggregate (CA) quality/content, dosage of cement, and w/c ratio. Strengths of compressing and splitting, and modulus of elastic tests were conducted. The findings demonstrated that the concrete rubble (CR) may be turned into recycled aggregate (RC) and utilized in the concrete manufacturing with qualities adequate for the vast majority of structural concrete applications in Iraq. Furthermore, the concrete strength has decreased by 6% to 30%, depending on the proportion of RC utilized to replace natural aggregate and the w/c ratio.
Deprem etkileri altındaki farklı tiplerde çelik yapıların STASTEEL ve SAP2000 kullanılarak karşılaştırılması
(2022) Naimi, Sepanta; Peker, Önder
Çalışma kapsamında uygulamada sıkça kullanılan StaSTEEL ile referans olarak SAP2000 paket programları kullanılarak, simetrik ve L formunda asimetrik kat şekline sahip üç katlı, on katlı ve on beş katlı çelik yapılar ile bu yapılardan farklı tek katlı bir sanayi yapısı modeli, iki paket program ile çözümlenmiştir. Literatürde, StaSTEEL ile yapılmış çalışma bu araştırma yapıldığı sırada hiç bulunmamaktadır. Çalışma içerisinde incelenen bina tipi toplam 7 adettir. Analiz sonucu elde edilen kat ağırlıkları, doğal titreşim periyotları ve elemanlar üzerinde oluşan eksenel, kesme ve moment gerilmeleri bakımından paket programların sonuçlarının karşılaştırılması yapılmıştır. Ayrıca programların ara yüzleri incelenerek kullanıcı için veri girişi, sonuçların irdelenmesi ve çıktılar konusunda ihtiyacın nasıl ve ne kadar karşılandığı araştırılmıştır. Yapı çözümlemeleri için 2019 yılında yürürlüğe giren Türkiye Bina Deprem Yönetmeliği’nde belirtilen kurallar kullanılmıştır. İki paket programın çözümleme sonuçlarının birbirine benzer olduğu gözlenmiştir. Simetrik ya da asimetrik, az katlı veya çok katlı fark etmeksizin oluşan iç kuvvetlerde N, V ve M için en büyük farklar sırasıyla %3, %3,5 ve %2,7 mertebelerindedir. Bununla birlikte StaSTEEL programının gerek veri girişi gerekse sonuçların irdelenmesi konusunda daha kolay olduğu gözlenmiştir. Ayrıca hazırlanan hesap raporlarının daha detaylı ve görselliği yüksek olduğu sonucuna varılmıştır
Automation of cost control process in construction project building information modeling (BIM)
(International University of Sarajevo, 2022) Khaleel, Amjed; Naimi, Sepanta
This research is carried out to investigate the critical role of BIM technology in estimating the construction project cost with higher accuracy than the manual method of budget evaluation. A construction project case study is selected, presenting a commercial complex in Al-Anbar, Al-Ramadi, Iraq. A comparative analysis is conducted to compare the accuracy of the REVIT software (BIM technology) with the manual calculation method. The major research findings revealed that using the BIM technology via the REVIT software provided a more effective approach and practicality than manual calculations of steel, concrete, and other architectural components. In addition, the findings confirmed that the accuracy of cost estimation using BIM technology via REVIT software is better than manual calculations. The reason is the elimination of human errors during the calculations process. Thus, accurate results can be obtained from the REVIT software. Also, the research outputs indicated that using the BIM technology can save much time, effort, and cost needed to calculate the cost of the construction project compared to the manual cost estimation of the construction project.
The effect of geogrid reinforcement of embankment over soft foundation
(International University of Sarajevo, 2022) Mohammed, Shams A.; Naimi, Sepanta; AbdulKareem, Ahmed H.
This paper deals with the usage of geogrids for soil improvement utilizing the PLAXIS 3D FE program's numerical analysis approach. Because of the low shear strength and instability of soft clay soils, reinforcement has been used to improve clay soils. The reinforcement mechanism was analyzed on the basis of results and output. The results of the program outputs are shown in PLAXIS. The reinforcement has little effect in the case of horizontal displacement and vertical displacement, but only a significant effect on the safety factor. This paper also deals with improving soft clay soil using stone columns. The main objective is to reduce settlement and increase the carrying capacity of the soil and shorten the consolidation period. The work investigates geogrid-reinforced stone columns that improved the behavior of soft clay soils under the influence of loading and construction. Underwent soil the stone columns testing covered with a geogrid and traffic load of 50 kpa. The improved method of using stone columns and PLAXIS 3D was used to create the FE model. The results concluded that the comparison results gave an improvement rate of up to 50 % of the improvement for the stone-column-reinforced clay soil in the construction phase.
Numerical investigation of precast reinforced concrete beam–to–column joints by replaceable damper
(2022) Dehqan Nezhad, Yalda; Naimi, Sepanta
This study aimed to investigate the precast reinforced concrete beam-to-column joints behaviors through the replaceable damper under cyclic loading. The precast concrete specimens have been embedded with steel reinforcement and specially shaped connectors. After the application of the replaceable damper under cyclic loading, the energy dissipation shaped very well and increased the bearing capacity of precast specimens. The precast concrete beam–to– column joints were designed and analyzed to compare with the traditional reinforced concrete (RC) specimen. The analysis result of the loading based on the controlled displacement method showed that the precast specimen model with a damper has more hysterical behavior than the traditional RC frame. Also, the specimen (PS-1) is passed the 2.7% chord rotation, which showed higher performance, than the traditional RC specimen. The efficiency of the PS-1 specimen with a special connection has been elaborated with the finite element method (FEM) and simulated by ABAQUS software.
Seismic strengthening of sub-standard RC columns through a novel hybrid thin jacketing method
(fib. The International Federation for Structural Concrete, 2021) Narlıtepe, Furkan; Kian, Nima; Demir, Uğur; Demir, Cem; Ilki, Alper
In this study, a novel hybrid thin jacketing method, in which fiber-reinforced polymer (FRP) sheets are used together with conventional steel reinforcing bars and cement-based repair mortar for strengthening of sub-standard full-scale columns, is proposed. The application of the method is comprised of three parts, i) cover concrete is removed and additional longitudinal steel reinforcing bars are installed with anchors to the foundation, ii) cover concrete is re-formed using repair mortar and iii) columns are wrapped externally in transverse direction with carbon FRP (CFRP) sheets. The major advantages of this strengthening method are unaltered dimensions of columns after strengthening and ease in application. Within the scope of the study, two full-scale sub-standard reinforced concrete (RC) columns were tested under reversed cyclic lateral displacements simulating seismic actions. One of the columns was tested prior to strengthening while the other was tested after strengthening with the specified hybrid thin jacketing method. Three special features of the specimens tested in this study are i) insufficient transverse steel reinforcement with large spacing and ii) high axial load to capacity ratio 0.75 and iii) high shear force corresponding to moment capacity to shear capacity ratio of 0.62 and 0.80 according to ACI 318-19 (2019) and Turkish Building Earthquake Code (TBEC, 2018), respectively. Based on TBEC (2018), columns had a Ve/(fctmbd) ratio of 1.12 indicating a high shear demand, where, Ve, fctm, and d are the shear force corresponding to moment capacity, direct tensile strength of concrete, and effective depth of the section. In addition, the ratio of transverse reinforcement area to the minimum required transverse reinforcement area according to ACI 318-19 (2019) and TBEC (2018) was 0.19 and 0.77, respectively. The experimental findings showed that the proposed easy-to-apply hybrid thin jacketing method is effective in terms of enhancement of seismic performance of sub-standard RC columns.
Numerical investigation on flexural behavior of rc beams wıth large web opening externally strengthened wıth CFRP lamınates under cyclıc load: Three-poınt bendıng test
(2022) Abulqasim, Shahlla Abbas; Noori, Abdul Qader Nihad; Çelik, Tuncer
In the current paper, the effect of carbon fiber reinforced polymer (CFRP) laminates on the flexural strength of reinforced concrete beam (RCB) with the web opening in the flexural zone was investigated using a numerical method. The main aim of the current work is to model the reinforced concrete beam strengthen by two shape of CFRP laminates (2- layer and U-shape), to observe the influences of CFRP on the flexural strength of the beam. To this end, cyclic loading was applied to investigate the flexural behaviour of the Twelve RC beams under the cyclic loading. All beams kept the same dimensions length, breadth, and depth (2400 × 300 × 200) mm were modeled in the finite elements adopted by ABAQUS software. Steel bars have been used for both flexural strengthening and stirrups. A Three-point bending tests were performed using cyclic loading. Furthermore, the effect of web openings with different sizes (Side length of 40, 60, 75% of the breadth) on the flexural behavior of RC beams was investigated in detail. The flexural strength, local analysis, and ductility of the base beam and CFRP reinforced beam were analyzed. The results of the simulations revealed that the CFRP laminates enhanced the strength of the base beam significantly.

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