11 research outputs found
Behavior of a Multi-Story Steel Structure with Eccentric X-Brace
Eccentrically Braced Frames (EBFs) outperform moment-resisting frames in seismically active regions because of their strength, stiffness, energy dissipation, and ductility. Conventional bracing systems, such as X, Y, V, or K types, are utilized to enhance structural integrity. This study employs computational modelling to analyze multi-story steel buildings featuring an eccentric X-brace system. In this investigation, 120 multi-story steel frame buildings were selected. These multi-story structures comprise six-, nine-, and twelve-story geometries. ETABS built a full-scale FE model of multi-story structures. The study's parametric variables are the X-brace eccentricity, steel X-brace section size, and X-braced placement. Steel X-braces may have an eccentricity of 500, 1000, or 1500 millimeters. The ETABS model was validated when its findings matched experimental data. According to the data, the eccentric X-brace increases top-story displacement more for 6-story multi-story structures than for 9- and 12-story ones. Eccentric X-braces reduced lateral stiffness, allowing more significant floor movement. Eccentric and diagonal braces offer less lateral rigidity than concentrically braced frames due to their flexibility. Eccentricity reduces stiffness, even if the X-braced component has a larger cross-section. EBFs may migrate horizontally. Since the EBF absorbs more energy, changing the X-brace section size and eccentricity affects its ductility.
 
Behavior of a Multi-Story Steel Structure with Eccentric X-Brace
Eccentrically Braced Frames (EBFs) outperform moment-resisting frames in seismically active regions because of their strength, stiffness, energy dissipation, and ductility. Conventional bracing systems, such as X, Y, V, or K types, are utilized to enhance structural integrity. This study employs computational modelling to analyze multi-story steel buildings featuring an eccentric X-brace system. In this investigation, 120 multi-story steel frame buildings were selected. These multi-story structures comprise six-, nine-, and twelve-story geometries. ETABS built a full-scale FE model of multi-story structures. The study's parametric variables are the X-brace eccentricity, steel X-brace section size, and X-braced placement. Steel X-braces may have an eccentricity of 500, 1000, or 1500 millimeters. The ETABS model was validated when its findings matched experimental data. According to the data, the eccentric X-brace increases top-story displacement more for 6-story multi-story structures than for 9- and 12-story ones. Eccentric X-braces reduced lateral stiffness, allowing more significant floor movement. Eccentric and diagonal braces offer less lateral rigidity than concentrically braced frames due to their flexibility. Eccentricity reduces stiffness, even if the X-braced component has a larger cross-section. EBFs may migrate horizontally. Since the EBF absorbs more energy, changing the X-brace section size and eccentricity affects its ductility.
The behavior of reinforced lightweight concrete beams with initial cracks
This research examines the performance of reinforced lightweight concrete beams subjected to several degrees of damage (50%, 60%, 70%, and 100%). It can use a sheet made of Carbon Fiber Reinforced Polymer (CFRP) to reinforce. The Full U-wrapping rehabilitation method was tested in the presented experimental program. In this method, CFRP sheets are attached to the bottom only and the side and bottom of the beam section. Experiments proved that the service load (Ps) increases by 7.06 % from a damage level of 50 % to 70 %, rises by 1.21 % from a damage level of 60 % to 70 %, and falls by 3.07 % from a damage level of 100 %. The result also rose for the fortified sample by 11.99%. Increases of 42.67 %, 33.07 %, and 23.73 % in the stiffness ratio (k) were observed at damage intensities of 50, 60, and 70 %, respectively. Damage at lower severity levels is increasing at a faster rate. The ductility of the restored LWC beams is more excellent than the control, as with the stiffness. Damage levels of 50%, 60%, and 70% saw increased ductility of 35.60, 34.92, and 34.69 %, respectively
Numerical Analysis of Reinforced Concrete Circular Columns Strengthening With CFRP under Concentric and Eccentric Loadings
The purpose of this study is to explore the numerical behavior of circular RC short columns with different degrees of confinement with CFRP (0%, 25%, 50%, and 100%) wraps under concentric and eccentric loading. The numerical analysis carried out by using an improved concrete plastic-damage model (CDPM) implemented in ABAQUS software for finite element (FE) analysis. The FE model simulated a total of twenty-four numerical specimens. The findings were matched to published experimental test results in the literature. The findings of the FE model and the experimental data were good similar. As a consequence, the model was found to be valid. The numerical results shows that as load eccentricity increased, the load carrying capacity of columns decreased for unconfined specimens, whereas the decline in strength for confined specimens becomes limited as the degrees of confinement ratio increased. In addition, increasing the CFRP confinement ratio improves the column's load-bearing capability at the same load eccentricity
The behavior of reinforced lightweight concrete beams with initial cracks
This research examines the performance of reinforced lightweight concrete beams subjected to several degrees of damage (50%, 60%, 70%, and 100%). It can use a sheet made of Carbon Fiber Reinforced Polymer (CFRP) to reinforce. The Full U-wrapping rehabilitation method was tested in the presented experimental program. In this method, CFRP sheets are attached to the bottom only and the side and bottom of the beam section. Experiments proved that the service load (Ps) increases by 7.06 % from a damage level of 50 % to 70 %, rises by 1.21 % from a damage level of 60 % to 70 %, and falls by 3.07 % from a damage level of 100 %. The result also rose for the fortified sample by 11.99%. Increases of 42.67 %, 33.07 %, and 23.73 % in the stiffness ratio (k) were observed at damage intensities of 50, 60, and 70 %, respectively. Damage at lower severity levels is increasing at a faster rate. The ductility of the restored LWC beams is more excellent than the control, as with the stiffness. Damage levels of 50%, 60%, and 70% saw increased ductility of 35.60, 34.92, and 34.69 %, respectively
Numerical analysis of RC columns under cyclic uniaxial and biaxial lateral load
U ovom se radu prikazuje numeriÄka analiza konaÄnih elemenata koja je provedena kako bi se ispitalo ponaÅ”anje AB stupova visoke ÄvrstoÄe za sluÄaj dvoosnog i jednoosnog boÄnog pomaka pri konstantnom uzdužnom optereÄenju. NumeriÄka analiza provedena je na 24 modela pomoÄu programa ABAQUS / CAE. Validacijom je utvrÄena dobra podudarnost numeriÄkih i eksperimentalnih rezultata. U okviru parametarske studije odreÄen je koeficijent armiranja uzdužnom armaturom, ukupna ploÅ”tina spona za ovijanje (Ash) te jednoosno i dvoosno cikliÄno posmiÄno optereÄenje. Rezultati numeriÄke analize pokazuju da poveÄanje koliÄine uzdužne armature u sluÄaju jednoosnog i dvoosnog boÄnog optereÄenja dovodi do znatnog poveÄanja maksimalnog i graniÄnog optereÄenja stupova, progiba, broja ciklusa maksimalnog i graniÄnog optereÄenja, te poÄetne krutosti Ki, dok je utjecaj popreÄne armature manje izražen. Otpornost stupova na optereÄenja i deformacije znatno se smanjuje pri nanoÅ”enju dvoosnog cikliÄnog posmiÄnog optereÄenja, u odnosu na jednoosno optereÄenje. Isto tako, taj utjecaj se smanjuje s poveÄanjem udjela uzdužne armature (%Ļl) i vrijednosti Ash.A numerical finite element study is conducted in this paper to examine structural behaviour of high strength RC columns exposed to biaxial and uniaxial lateral displacement histories with constant axial load. The numerical analysis of 24 models was made using ABAQUS / CAE. The comparison between numerical analysis and experimental results shows good agreement through validations. The considered parametric study involves determination of the longitudinal reinforcement ratio, total cross-sectional area of confinement steel (Ash), and uniaxial and biaxial cyclic shear load. Numerical analysis results show that an increase of longitudinal reinforcement for a uniaxial and biaxial lateral historic load will significantly increase maximum and ultimate load of columns, corresponding deflections, number of cycles at maximum and ultimate loads, and initial stiffness Ki, while the effect of transverse reinforcement is less pronounced. The columns load and deformation capacity decreases significantly with application of biaxial cyclic shear load, compared with uniaxial load. Also, this effect reduces with an increase in longitudinal reinforcement ratio (%Ļl) and Ash
Numerical analysis of RC wall with opening strengthened by CFRP subjected to eccentric loads
U radu je provedeno numeriÄko ispitivanje srediÅ”njeg otvora u ab zidovima s CFRP ojaÄanjem i bez njega podvrgnutim ekscentriÄnom vertikalnom optereÄenju s linearnim prirastom. Å est zidnih ploÄa u mjerilu 1 : 2 modelirane su u raÄunalnom programu ABAQUS u svrhu procjene uÄinka ojaÄanja. Analiza je pokazala da na nosivost zida u smislu maksimalnog optereÄenja utjeÄe debljina CFRP-a. UtvrÄeno je da varijacija debljine CFRP-a ima znaÄajan utjecaj na krajnju nosivost, pojavu pukotina, glavnu plastiÄnu deformaciju betona i ekvivalentno naprezanje.Numerical analysis of the central hole in RC walls with and without CFRP, subjected to uniform eccentric vertical line load, is presented in this paper. Six half-scale wall panels were modelled using the ABAQUS software to estimate the strengthening effects. The analysis revealed that the load capacity of the wall in terms of maximum load carrying capacity is influenced by CFRP thickness. It was found that the variation of CFRP thickness greatly influences the ultimate load carrying capacity, crack patterns, principal plastic strain of concrete, and equivalent stress
Numerical analysis of reinforced concrete circular columns strengthening with CFRP under concentric and eccentric loadings
The purpose of this study is to explore the numerical behavior of circular Reinforced Concrete (RC) short columns with different degrees of confinement with Carbon Fiber Reinforced Polymer (CFRP) (0%, 25%, 50%, and 100%) wraps under concentric and eccentric loading. The numerical analysis carried out by using an improved Concrete Damage plasticity (CDP) model implemented in ABAQUS software for finite element (FE) analysis. The FE model simulated a total of twenty-four numerical specimens. The findings were matched to published experimental test results in the literature. The findings of the FE model and the experimental data were good similar. As a consequence, the model was found to be valid. The numerical results shows that as load eccentricity increased, the load carrying capacity of columns decreased for unconfined specimens, whereas the decline in strength for confined specimens becomes limited as the degrees of confinement ratio increased. In addition, increasing the CFRP confinement ratio improves the column's load-bearing capability at the same load eccentricity
Enhancing the flexural performance of lightweight concrete slabs with CFRP Sheets: an experimental analysis
The flexural behavior of lightweight concrete two-way slabs is investigated in this work, with a focus on the strengthening or repairing method of externally attaching carbon fiber-reinforced polymer (CFRP) sheets. Five 1000 mm by 1000 mm by 120 mm reinforced lightweight concrete slab slabs were used in the experiment. Tested one specimen with no strengthening and another with CFRP sheet strengthening and repaired the rest with a single layer of CFRP at damage ratios of 50%, 60%, or 70% of the ultimate load, consciously making each slab crack under bending loads while keeping the exact measurements. As to the experiment findings, the ultimate load capacity increased by 30.3% at the strengthened specimen, 17.7% at the 50% damage level, 12.6% at the 60% damage level, and 10.9% at the 70% damage level. As degradation increases, so does the carrying capacity of LWC slabs. The amount of damage LWC slabs sustain influences their stiffness and flexibility. Effectively repairing the sample, CFRP sheets raised the reinforced concrete slabsā failure stress and stopped the fractures from growing. Reinforced concrete slab failure was increased, and CFRP sheet repairs of the specimens successfully stopped crack propagation
Finite Element Analysis of RC Tapered Beams under Cyclic Loading
This paper presents a numerical investigation to study the effect of variations in displacement history sequence and magnitude on cyclic response of RC tapered (haunched) beams (RCHBs).Five simply supported RCHBs (four haunched and one prismatic) were selected from experimental work carried out by Aranda et al. The selected variables included were five loading history types. The first part of this study focused to verify the finite element analysis with selected experimental work and the second part of this study focused too studying the effect of varying in loading history to the response of RCHBs. The finite element code Abaqus was used in the modeling. The adopted cyclic simulation performance of the selected beams using the plastic- damage model for concrete developed by Lubliner and Lee & Fenves. The constitutive model of plain concrete describing the uniaxial compression response under cyclic loading proposed by Thorenfeldt, and the uniaxial tension response follows the softening law proposed by Hordijk was used in the modeling. Menegotto-Pinto model was used to simulate the steel response. Model verification has shown A good agreement to the selected experimental work. The variations in loading history will decrease the ultimate load and corresponding deflection with increase in the number of cycles at ultimate load