Abstract
In this research article, we present a comprehensive solution utilizing both linear elastic theory and Artificial Neural Network (ANN) methods to analyze interfacial stress in simply supported beams strengthened with bonded fiber-reinforced polymer (FRP) plates. The study investigates FRP-reinforced damaged RC beams under uniformly distributed loads. In our analytical approach, we account for adherend shear deformations in theoretical analyses by assuming a linear shear stress throughout the thickness of the adherends—a consideration often overlooked in existing solutions. Subsequently, the study validates and compares the results obtained from this approach with those available in the literature. Simultaneously, the ANN technique is employed to predict normal and shear stresses in concrete beams strengthened with FRP plates. In the architecture
of the artificial neural network (ANN), the initial layer serves as the input layer with 15 inputs, followed by a hidden layer consisting of 18 neurons,and finally, two output layers. Within the hidden layer, the activation function utilized is the Transg function. This prediction relies on a dataset comprising over 3339 data points from the current analytical approach and literature sources, including analytical and finite element methods presented in this paper and others from existing literature. The ANN
technique systematically explores various parameters, such as material characteristics, properties, and geometric details of RC beams and FRP plates. Through both the ANN method and computational analysis, the study establishes the significant influence of FRP plates on shear and normal stress. The ANN model showcases robust capabilities in handling extensive datasets and various critical parameters.
Address
Rezki Amara: Laboratory of Structures, Geotechnics and Risks, Department of Civil Engineering, Hassiba Beénbouali University of Chlef, Algeria
Mokhtar Nebab: Laboratory of Structures, Geotechnics and Risks, Department of Civil Engineering, Hassiba Beénbouali University of Chlef, Algeria; Department of Civil Engineering, Faculty of Technology, University of M'Hamed BOUGARA Boumerdes, Algeria
Hassen Ait Atmane: Laboratory of Structures, Geotechnics and Risks, Department of Civil Engineering, Hassiba Beénbouali University of Chlef, Algeria
Zahira Sadoun: Laboratory of Structures, Geotechnics and Risks, Department of Civil Engineering, Hassiba Beénbouali University of Chlef, Algeria
Lazreg Hadji: Department of Civil Engineering, University of Tiaret, 14000, Algeria
Riadh Bennai: Laboratory of Structures, Geotechnics and Risks, Department of Civil Engineering, Hassiba Beénbouali University of Chlef, Algeria
Abstract
The eight-bolt stiffened extended end plate moment (8ES) connection is preapproved for use in intermediate and
special moment frames according to ANSI/AISC 358. Simulated seismic testing indicates that 8ES connections generally
perform well, exhibiting ductile failure modes. Despite this, many studies have found that the beam flange near the stiffener toe is prone to fracture due to the high stress concentration in that area. Recently, a solution to this problem was proposed - an unstiffened eight-bolt extended end plate connection. This removes the stiffener and arranges bolts in an octagonal pattern to eliminate stress concentration and ensure equal force distribution. When using the proposed unstiffened connection with deep wide flange beams (e.g., W-sections of 900 mm nominal depth), detailed finite element analyses performed in this study showed that high strain demands at the beam flange to end plate CJP welds can develop despite improvements. Hence, two additional seismic performance enhancing techniques are analytically evaluated for unreinforced eight-bolt extended end plate connections. The first technique uses heat treatment of specified beam flange regions and reinforcing specified beam web regions. The heat treatment relocates the plastic hinge and thereby lower flange weld strain demands, whereas web reinforcement delays the onset and slows the rate of connection strength degradation. The second technique uses a heavy extended shear tab to relocate the
plastic hinge away from flange weld and slightly delays the onset of strength degradation. Systematic analysis results are developed and presented to demonstrate the enhanced seismic performance of the modified EEP connections and to plan future experimentations and design development.
Key Words
extended end plate connection; extended end plate stiffener; extended shear tab; heat-treated beam section; octagonal bolt arrangement; seismic performance enhancement; web reinforcement
Address
Shahriar Quayyum: Department of Civil & Environmental Engineering, Manhattan University, Riverdale, NY 10471, USA
Machel L. Morrison: Department of Structural Engineering, University of California San Diego, La Jolla, CA 92093, USA
Tasnim Hassan: Department of Civil, Construction & Environmental Engineering, North Carolina State University, Raleigh, NC 27695, USA
Timothy R. Kohany: Department of Civil & Environmental Engineering, Manhattan University, Riverdale, NY 10471, USA
Abstract
This article aims to investigate the thermal and post-buckling issues of magneto electro thermal elastic plates with initial geometric defects. Firstly, the nonlinear vibration equation is derived applying first-order shear deformation plate theory and energy method, which the influence of geometrical nonlinearity and geometric defects of the structure are considered. Then, during the solution process, we take into account three different boundary conditions and employ the Galerkin method to obtain
the thermal buckling loads and thermal post-buckling path. The solution results of this article are well consistent with existing literatures, thus ensuring the reliability of the research. Finally, we are focused on the effects of material properties, electric potential, magnetic potential, geometric defects, and boundary conditions on the thermal and post-buckling responses of MEE plates. The results indicate that when there is initial geometric imperfection (W1=/0) in the MEE plates, as long as the temperature changes, the MEE plates will undergo bending deformation. As the voltage ascends or the magnetic potential descends, the thermal buckling loading and the thermal post-buckling strength will decline accordingly.
Key Words
geometrical imperfection; Magneto-electro-elastic plates; nonlinear; thermal post-buckling
Address
Gui-Lin She and Yu-Jie He: College of Mechanical and Vehicle Engineering, Chongqing University, Chongqing 400044, China
Abstract
A significant quantity of coconut shell waste is produced from coconut product production industries and its proper eradication needs to be investigated. Researchers have suggested using it as a concrete ingredient due to high strength, better modulus properties, high lignin content, low cellulose content, and non-biodegradable. Lignin in coconut shell makes the concrete weather resistant and its low cellulose content absorbs less moisture compared to other agricultural waste. This research is aimed at quantifying the result of partial replacement of the coarse aggregate by coconut shell (CS), and replacing partially the cement by coconut shell ash (CSA) to prepare concrete. CSA possesses high amount of silica reacts with water and calcium hydroxide to form C-S-H gel in concrete. Both cement and coarse aggregate are partially replaced together by 10%, 15% and 20% respectively. It was noticed that the strength in compression has been decreased as the amount of CSA and CS increased. Results indicated that with 15% replacement by CSA and CS, the compressive strength after 7 days is increase by 2.48%; whereas increase in compressive strength after 28 days was 2.81%. When the steel fibers were added the corresponding compressive strength is enhanced by 4.13% and 4.31% after 7 and 28 days respectively. Similarly, the strength in splitting increases to 1.62% and 3.31% for 15% replacement of CS and CSA for 7 and 28 days respectively. Further, this strength is increased by 4.06% and 8.09% for the mix 20% CS and CSA when steel fibres were added. When the replacement is 20%, the concrete became lighter by 17%. The RCPT test results indicated low chloride ion penetration for addition of these two materials.
Key Words
coconut shell ash; coconut shell; concrete; durability; strength
Address
Siddesha Hanumanthappa, T.K. Bharath, H.O. Chethan Naik, Vaishali, D.S. Rajendra Prasad: Department of Civil Engineering, Siddaganga Institute of Technology, B.H. Road, Tumakuru, 572 103, Karnataka, India
A.R. Pradeep: Department of Civil Engineering, Sri Siddhartha Institute of Technology, Tumakuru, Karnataka, India
Abstract
One of the most effective methods for strengthening reinforced concrete columns is applying all-round FRP
composite external coatings. This method significantly enhances the bearing capacity and ductility of the columns. With the eccentricity of the load and curvature in the columns, the direction of the FRP fibers will also be important in strengthening. In this study, 20 circular reinforced concrete columns were examined by considering the three variables: the direction of composite fibers, number of composite layers, and value of eccentricity of the load. Nine columns were experimentally examined with 11 numerical models analyzed using ABAQUS finite element software. The specimens were classified into two groups, eccentricity
value of the load equal to the radius of the column (R) and three times the radius of the column (3R). In each group, the direction of FRP fibers was considered as 0o, 45o, and 90o in relation to the transverse axis of the columns. The numbers of composite layers were also considered as two and three layers. The results revealed in the state of loading with R eccentricity value, the composites are more suitable to be directed at 0o or 90o for strengthening. While loading with 3R eccentricity, use of only 90o composites had the greatest impact on the bearing strength and ductility of columns. Increasing the number of composite layers boosted the bearing capacity and reduced ductility of the columns. Also, the effect of 45o FRPs in loading with R eccentricity is greater than those with 3R.
Key Words
ductility; eccentricity of the loading; fiber elongation; FRP composite; reinforced concrete column; strengthening
Address
Mostafa Habibpour, Jafar Asgari Marnani, Abbas Ghasemi: Faculty of Civil and Earth Resources Engineering, Department of Structure, Islamic Azad University, Central Tehran Branch, Iran
Abolfazl Arabzadeh: Faculty of Civil Engineering and Environment, Department of Structure, Tarbiat Modares University of Iran, Iran
Abstract
Recently, the construction of interlocking mortarless masonry walls as infill panels and/or architectural space partitions has been widely grown in South Africa, East and South Asia due to significant construction speed, reduction of labour cost, easy alignment and environmental friendliness. These innovative construction elements can be used as an appropriate alternative to traditional mortared masonry walls. This paper presents an in-depth seismic performance investigation of different interlocking masonry wall types, including Putra, Tanzanian, Thai, Solbric and Hydraform under lateral load by nonlinear static analysis in earthquake-prone areas. To this end, numerical models of interlocking walls were established in ABAQUS finite element package through micro-scale modeling technique. Then they were validated under the combination of in-plane loading and afterward their seismic capacities were evaluated using pushover method. Furthermore, based on the Iranian seismic design code, the performance of interlocking walls was assessed by inelastic demand spectrum for 475 years return period earthquake. Results revealed that the seismic performance of the interlocking mortarless walls strongly depends on the intensity of vertical load and inelastic response spectra. It was also found that by applying typical surcharge vertical load, just the interlocking walls restricted horizontally and transversely (first group) can be used in low seismicity areas (0.2 g) in all cases.
Key Words
finite element analysis; interlocking bricks; micro-scale modeling; mortarless masonry walls; nonlinear static analysis; seismic assessment
Address
Nima Moradi, Mahdi Yazdani and Seyed Jafar Hashemi: Department of Civil Engineering, Faculty of Engineering, Arak University, Arak, Iran
