Journal articles on the topic 'Columns'
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1
Melero Carnero, Laura. "Francisco Ríos Álvarez y su «Mirada en la Lengua»: estructura, temas e ideologías lingüísticas en sus Columnas sobre la lengua (CSL) en La Voz de Galicia." Revista de Investigación Lingüística 25 (December 31, 2022): 129–54. http://dx.doi.org/10.6018/ril.524511.
Abstract:
This article analyses Francisco Ríos Álvarez’s newspaper columns. The aim is to define this columnist’s writing style and its evolution, as well as his linguistic ideology. The study is framed within a line of research that investigates a subgenre of journalistic column called language columns. These are journalistic texts regularly published in a written newspaper, signed by a person of renown and dealing with analyses of language usage (Marimón, 2019b: 13). In order to analyse columns by the said author, a corpus was compiled consisting of 44 texts selected from the three series of columns that he authored. The findings reveal a stylistic, ideological and thematic evolution. Este trabajo analiza las columnas periodísticas de Francisco Ríos Álvarez, con el fin de definir el estilo de escritura y su evolución y la ideología lingüística del columnista. Esta investigación se enmarca dentro del estudio de un subgénero de columna periodística llamada Columnas sobre la lengua: un texto periodístico que se publica regularmente en un periódico escrito, firmadas por una persona de reconocido prestigio y en el que se explican los usos de la lengua (Marimón, 2019b: 13). Para analizar sus columnas, se ha creado un corpus con 44 columnas seleccionadas de las tres series que escribió. Los resultados obtenidos mostraron que existe una evolución estilística e ideológica en sus columnas y en los temas sobre los que escribe.
2
VIRGENS, J. P., R. B. GOMES, L. M. TRAUTWEIN, G. N. GUIMARÃES, and A. P. R. VAZ. "Experimental analysis of eccentrically loaded reinforced concrete columns with an added jacket of self-compacting concrete." Revista IBRACON de Estruturas e Materiais 12, no. 2 (April 2019): 329–36. http://dx.doi.org/10.1590/s1983-41952019000200007.
Abstract:
Abstract This paper presents the experimental study of eccentrically loaded reinforced concrete columns with an added 35 mm self-compacting concrete jacket attached to the column’s most compressed face using wedge bolts. Nine columns with a 2000 mm height were tested under compression and one-way bending until failure. Columns were denominated as original column (PO) with a cross section of 120 mm x 250 mm; reference column (PR) with a cross section of 155 mm x 250 mm, and seven columns with an initial cross section of 120 mm x 250 mm and later reinforced by the addition of 35 mm self-compacting concrete layer and various configurations of wedge bolts. Except for the original column PO, the columns were submitted to a 42.5 mm load eccentricity due to the added concrete layer at the compressed face. Although failure of the wedge bolts did not occur, it was not possible to prevent detachment of the added layer. The results indicate that it is possible to structurally rehabilitate reinforce concrete columns with the use of the strengthening methodology used in this research, resulting in average ultimate load capacity gains of 271% compared to original column’s ultimate load.
3
Shaat, Amr, and Amir Fam. "Axial loading tests on short and long hollow structural steel columns retrofitted using carbon fibre reinforced polymers." Canadian Journal of Civil Engineering 33, no. 4 (April 1, 2006): 458–70. http://dx.doi.org/10.1139/l05-042.
Abstract:
This paper describes the behaviour of axially loaded short and long square hollow structural section (HSS) columns, strengthened with carbon fibre reinforced polymer (CFRP) sheets. Twenty-seven short-column and five long-column HSS specimens were tested. The effect of CFRP sheet orientation in the longitudinal and transverse directions was studied for short columns. For long columns, CFRP sheets were oriented in the longitudinal direction only. A maximum strength gain of 18% was achieved for short columns with two transverse CFRP layers. For long columns, the maximum strength gain of 23% was achieved with three longitudinal CFRP layers applied on four sides. In all CFRP-strengthened long columns, lateral deflections were reduced. Strength gain in long columns was highly dependent on the column's imperfection. As such, no correlation was established between strength gain and number of CFRP layers. CAN/CSA 16-01 equation was modified to account for CFRP through transformed section analysis so that they could be used to predict the axial-load capacity of long columns.Key words: retrofit, steel, HSS, column, FRP, carbon, buckling, strength, stiffness.
4
Rahbar-Kelishami, Ahmad, Hossein Bahmanyar, and Zahra Hajamini. "A novel approach for calculating packed column height based on new correlation of mass transfer coefficient." Polish Journal of Chemical Technology 17, no. 1 (March 1, 2015): 48–54. http://dx.doi.org/10.1515/pjct-2015-0008.
Abstract:
Abstract The calculation of column’s height plays an important role in packed columns precise design. This research is based on experimentally measurement of mass transfer coefficients in different heights of packed column to predict its height. The objective of presented work is to introduce a novel conceptual method to predict column height via new correlation for mass transfer coefficient. As the mass transfer coefficient is decreased with increase of column height, the HTU’s are not constant figures along the column so this new approach is called increasing HTU’s. The results of the proposed idea were compared with other correlations and the conventional method i.e. constant HTU’s. Since the results are in very good agreement with experimental data comparing to conventional method, it seems this approach can be a turning point in design of all differential columns like packed columns. Making use of this method is suggested for design of differential columns.
5
Luo, Wen Wen, Ying Min Li, Ni Na Zheng, and Na Chen. "Numerical Analysis of Seismic Behavior of Masonry Walls Confined by Precast Tie-Columns." Applied Mechanics and Materials 166-169 (May 2012): 2429–35. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2429.
Abstract:
In order to improve the seismic behavior of the rural masonry buildings and reduce the cost and be convenient for construction, a precast tie-column system was put forward, which was suitable for masonry buildings, constructed by fired common bricks or porous bricks. The uniaxial compression constitutive relation of brick masonry was used for simulating the precast tie-column. And this paper analyzed the difference of the seismic behavior of masonry walls which bearing different vertical compressive stress, and confined by cast-in-place tie-columns or precast tie-columns, and whether contain windows or not. The results show that the uniaxial compression constitutive relation used for simulating precast tie-column is reasonable and the seismic behavior of masonry walls confined by precast tie-columns is better than the wall without tie-colums, and equal to those confined by cast-in-place tie-columns.
6
Ibraheem, Rawaa S., and Alaa H. Al-Zuhairi. "A Comparative Study on Behavior of RC Columns Strengthened by CFRP and Steel Jacket." E3S Web of Conferences 318 (2021): 03002. http://dx.doi.org/10.1051/e3sconf/202131803002.
Abstract:
This paper studies the behavior of axially loaded RC columns which are confined with carbon fiber reinforced polymers’ sheet (CFRP) and steel jackets (SJ). The study is based on twelve axially loaded RC columns tested up to failure. It is divided into three schemes based on its strengthening type; each scheme has four columns. The main parameters in this study were the compressive strength of the concrete and steel reinforcement ratio. Furthermore, the results of the experimental test showed a substantial enhancement in the column's load-carrying capacity. When compared to the original columns, the CFRP sheet had a significant effect on improving the ductility of the column by increasing the axial deformation by about 59.2 to 95.7%. On the other hand, the SJ contributed mostly to the column load-carrying capacity, which increased the capacity of RC concrete from 75 to 107%; because of its composite action comparing with the CFRP sheet action in which unidirectional lateral confinement is provided. Both methods produced completely different failure modes. The columns strengthened with CFRP sheet failed by rupture occurring in the sheet fibers. The strengthened with SJ failed due to the buckling that occurred in the steel angles due to the direct contact with the head of the column, and crushing in the concrete has occurred.
7
Niu, Jiangang, Wenming Xu, Jingjun Li, and Jian Liang. "Influence of Cross-Sectional Shape on the Mechanical Properties of Concrete Canvas and CFRP-Reinforced Columns." Advances in Materials Science and Engineering 2021 (May 11, 2021): 1–14. http://dx.doi.org/10.1155/2021/5541587.
Abstract:
Fiber-reinforced polymer (FRP) wrapping has become an attractive strengthening technique for concrete columns. However, the ingress of corrosion into the concrete through the gap of CFRP fiber greatly reduces the durability of concrete and the bearing capacity of specimens. Concrete canvas, a kind of corrosion-resistant and refractory material, is a promising method to enhance durability and carrying capacity. In this study, the concrete canvas (CC) and carbon fiber-reinforced polymer (CFRP) were used to jointly reinforce columns with square cross section, octagonal cross section, circular cross section, and elliptical cross section. The influence of section shape on the strengthening effect of the axial compression column was investigated by the axial compression test. The results showed that the section shape had a significant influence on the reinforcement effect of the axial compression column. The carrying load capacity and ductility coefficient of different columns follow this order: square column < oval-shaped columns < octagonal columns < circle columns. The increased amplitude of bearing capacity for the different columns with the increase of CC layers follows this order: square columns < oval-shaped columns < circle column < octagonal columns. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 129%, 155%, 150%, and 139% for the square, octagonal, circular, and elliptical columns, respectively. The octagonal column has the largest increase range. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 348%, 318%, 310%, and 296% for the square, octagonal, elliptical, and circular columns, respectively. The square column has the largest increase range. The stress concentration phenomenon of all section shapes was weakened after the CC was used. The application of the CC on CFRP-reinforced columns improves column ductility significantly, with some degree of increase in bearing capacity.
8
Al-Shwaiter, Abdullah, and Ziyad Al-Gaboby. "Behavior of Rubberized Concrete-Filled Square Steel Tube Under Axial Loading." Journal of Science and Technology 24, no. 1 (June 30, 2019): 23–39. http://dx.doi.org/10.20428/jst.v24i1.1572.
Abstract:
The purpose of this paper is to investigate the behavior of rubberized concrete-filled steel tube (RuCFST)analytically by using ABAQUS 6.12-1 software for square columns under axial loading. Twelve specimens modeled with various variables which are rubber content as replacement percentage from natural aggregate (0%, 5% and 15%), tube thickness (3mm and 6mm) and columns’ length (1.5m and 3.0m). The results showed an adoption model of RuCFST columns subjected to axial force in elastic and plastic properties of steel and concrete gives a good agreement between numerical and references experimental results. Also, the results showed a reduction in column capacity with increasing rubber content. In contrast, the results showed an increase in the columns’ compression capacity with increasing the thickness from 3 to 6mm. In addition, columns’ lengths have no significant effect on compression capacity, although the corresponding shortening increased with increase column’s length.
Keywords: Rubberized concrete, Infilled steel tube, Finite element, Axial loading and ABAQUS.
9
Al-Shwaiter, Abdullah, and Ziyad Al-Gaboby. "Behavior of Rubberized Concrete-Filled Square Steel Tube Under Axial Loading." Journal of Science and Technology 24, no. 1 (June 30, 2019): 23–39. http://dx.doi.org/10.20428/jst.24.1.2.
Abstract:
The purpose of this paper is to investigate the behavior of rubberized concrete-filled steel tube (RuCFST)analytically by using ABAQUS 6.12-1 software for square columns under axial loading. Twelve specimens modeled with various variables which are rubber content as replacement percentage from natural aggregate (0%, 5% and 15%), tube thickness (3mm and 6mm) and columns’ length (1.5m and 3.0m). The results showed an adoption model of RuCFST columns subjected to axial force in elastic and plastic properties of steel and concrete gives a good agreement between numerical and references experimental results. Also, the results showed a reduction in column capacity with increasing rubber content. In contrast, the results showed an increase in the columns’ compression capacity with increasing the thickness from 3 to 6mm. In addition, columns’ lengths have no significant effect on compression capacity, although the corresponding shortening increased with increase column’s length.
Keywords: Rubberized concrete, Infilled steel tube, Finite element, Axial loading and ABAQUS.
10
Zhang, Xun Zhong, Ru Heng Wang, and Wei Hu. "Analysis on Seismic Performance of Frame Columns Reinforced with Wing Walls." Applied Mechanics and Materials 166-169 (May 2012): 1691–95. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.1691.
Abstract:
Through the ANSYS finite element method, the seismic performance of frame columns reinforced with wing walls has been analyzed, indicating that the wing wall reinforcement can effectively improve the lateral stiffness and remarkably increase the bearing capacity of columns. With the wing wall reinforcement, the envelop area of the column’s hysteresis curve increases, and the bearing capacity improves, however, the shrinking phenomena of the curve suggests that the ductility of the section reduces. When the centerline of the additional wing wall coincides with that of the original column, the hysteresis curve inclines to be full, thus advising overlapping the centerline of the wing wall with that of the original column.
11
Patel, Nishiben, Krishna R. Gupta, and Milind J. Umekar. "An Overview of Monolithic Column: Types, Parameters and Applications." Journal of Drug Delivery and Therapeutics 12, no. 4-S (August 15, 2022): 223–31. http://dx.doi.org/10.22270/jddt.v12i4-s.5521.
Abstract:
The column is the main component for chromatographic separation. Nowadays, monolithic columns are graining more popularity in the field of separation media for liquid chromatography. The monolith columns possess great potential as compared to the conventional packed column in terms of preparing complex mixtures. These columns provide various properties like higher permeability, high-efficiency fast separations, high flow rate with lower backpressure, fast mass transfer kinetics with a high binding capacity. It is categories into three columns and they are organic monolithic column, inorganic monolithic column and hybrid monolithic column and all three types of monolithic column differ through their porous properties. In this review, the various advantage of the high-efficiency monolithic column with recent advances, the origin of the concept, the various parameter of the monolithic stationary phase and the application of monolithic columns are illustrated. It is better column in comparison of selectivity, reproducibility and performance.
Keywords: Monolithic column, Packed columns, Inorganic and organic monolithic column, Column parameters, Pharmaceutical Applications
12
Ahmed, Ali, Ahmed Mohammed Youssef Mohammed, and Koichi Maekawa. "Performance Comparison of High Strength Reinforced Concrete Circular and Square Columns Subjected to Flexural Controlled Cyclic Loading." Civil Engineering Journal 7, no. 1 (January 1, 2021): 83–97. http://dx.doi.org/10.28991/cej-2021-03091639.
Abstract:
In existing design practices selection of circular or square column shape mostly depends upon architectural needs rather than structural behavior. The behavior of equivalent area (circular and square), high strength reinforced concrete columns is reported to be same under monotonic loading conditions but their behavior under fatigue loading is not well-established. This paper presents the comparison of high strength reinforced concrete circular and square equivalent area columns’ performance (load-deflection behavior) under fatigue loading. Columns were casted in four configurations: square and circular shapes and with and without shear stirrups. Experimental results showed that in case of columns without shear stirrups, the square column resisted 38% more loading cycles as compared to circular column while the maximum deflection was 78% more than the circular column. Similarly, in case of columns with shear stirrups, square shaped column resisted 55% more loading cycles with only 5% more maximum deflections as compared to circular column. The results show that the square columns might be considered more ductile as compared to circular columns under the application of cyclic loading conditions like wind forces or seismic forces. Therefore, it might be concluded that square columns should be recommended for highly seismic regions as compared to circular columns with equivalent area. Doi: 10.28991/cej-2021-03091639 Full Text: PDF
13
Fenollosa, Ernesto, Iván Cabrera, Verónica Llopis, and Adolfo Alonso. "Non-linear Analysis of Slender High Strength Concrete Column." Civil Engineering Journal 5, no. 7 (July 18, 2019): 1440–51. http://dx.doi.org/10.28991/cej-2019-03091343.
Abstract:
This article shows the influence of axial force eccentricity on high strength concrete columns design. The behavior of columns made of normal, middle and high strength concrete with slenderness values between 20 and 60 under an eccentric axial force has been studied. Structural analysis has been developed by means of software which considers both geometrical and mechanical non-linearity. The sequence of points defined by increasing values of axial force and bending moment produced by eccentricity has been represented on the cross-section interaction diagram until failure for each tested column. Then, diagrams depicting the relationship between failure axial force and column's slenderness have been drawn. The loss of bearing capacity of the member for normal and middle strength columns when compared with the bearing capacity of their cross-section is more noticeable as axial force eccentricity assumes higher values. However, this situation reverses for high strength columns with high slenderness values. On the basis of results obtained, the accuracy level for the moment magnifier method was checked. Despite the good concordance in most of the cases, it was verified that the moment magnifier method leads to excessively tight results for high strength concrete columns with high slenderness values. In these specific cases, a coefficient which amends the column rigidity is proposed so as to obtain safer values.
14
Nguyen Thai, Linh, Manh Nguyen Duc, and Ha Nguyen Hai. "Analysis of impacting factors for soil-cement column combined high strength geogrid." Transport and Communications Science Journal 72, no. 1 (January 25, 2021): 9–15. http://dx.doi.org/10.47869/tcsj.72.1.2.
Abstract:
Soil-cement column combined with geogrid on top or Geogrid Reinforced Pile Supported (GRPS), is used to construct structures on soft ground. Because of its high tensile capacity, the geogrid is spread on the top of the soil-cement column to form a soft transmission layer, increasing the capacity transferred to the columns, reducing a part of the load transmitted to the soft soil between the columns. The numerical analysis results of the GRPS with a high strength geogrid showed four major factors affecting transmission the efficacy of the column (Ef) and the tensile force of the geogrid including effective vertical load (v’); the ratio of the distance between the columns and the column’s diameter (s/D); the ratio of the elastic modulus of the soil-cement column to the deformation modulus of soil (Ec/Es); the tensile stiffness of the geogrid (J). The efficacy of the column (Ef) increases rapidly with an increase in effective vertical load (v’) from 0.23 to 0.44. In contrast, the transmission efficiency (Ef) decreases from 0.60 to 0.37 when s/D increased. When the ratio Ec/Es > 150 and J > 8000 kN/m, the tensile force of the geogrid tends not to change much.
15
Propika, Jaka, Dita Kamarul Fitriyah, and Yanisfa Septiarsilia. "Analisa Perbandingan Kolom Komposit Inside Steel dan Outside Steel terhadap Kapasitas Tahanan Aksial dan Momen." Reka Buana : Jurnal Ilmiah Teknik Sipil dan Teknik Kimia 5, no. 2 (September 22, 2020): 62. http://dx.doi.org/10.33366/rekabuana.v5i2.1947.
Abstract:
ABSTRAK Penggunaan kolom komposit telah banyak digunakan di berbagai bangunan bangunan tinggi. Dan pada umumnya, Kolom komposit dibagi menjadi 2 macam, yaitu kolom komposit inside steel dan outside steel dengan struktur baja terbungkus oleh beton disebut dengan kolom inside steel atau bisa saja disebut Concrete Encased Column. Sedangkan untuk baja yang berisi beton disebut dengan kolom outside steel atau juga disebut Concrete Filled Column. Penggunaan struktur kolom komposit outside steel sebagai kolom utama dalam mendukung beban lateral pada struktur rangka bangunan belum lazim digunakan dalam perkembangan konstruksi saat ini. Oleh karena itu, perlu dilakukan analisa kekuatan dari 2 macam kolom komposit agar diketahui jenis kolom komposit yang paling efektif dan memiliki kekuatan paling tinggi. Perhitungan yang dilakukan dengan menggunakan perhitungan manual pada kolom komposit inside steel dan outside steel yang berbentuk kotak, sedangkan untuk perhitungan dengan menggunakan program CSICOL dilakukan pada seluruh kolom komposit. Hasil nilai ØPn dan ØMn kemudian dibandingkan antara perhitungan manual dengan program CSICOL. Hasil perhitungan menunjukan bahwa kemampuan kolom komposit outside steel lebih baik dibandingkan kolom komposit inside steel dengan menggunakan standar volume dari ukuran kolom komposit inside steel kotak 400x400 mm. Kolom komposit outside steel berbentuk bundar dengan diameter 431 mm lebih unggul sebesar 17 % dalam menahan gaya aksial nominal (ØPn) dibandingkan semua tipe kolom komposit yang lain. Sedangkan kolom komposit outside steel berbentuk kotak dengan ukuran 405.70x405.70 mm lebih unggul menahan momen nominal (ØMn) sebesar 10,5 % dibandingkan semua tipe kolom komposit yang lain.Kata kunci : kolom komposit; inside steel (concrete- encased column); outside steel (concrete-filled column)ABSTRACT The use of composite columns has been widely used in various high-rise buildings. Composite columns are generally divided into two types: composite columns inside steel and outside steel columns with a steel structure wrapped in concrete called an inside steel column (concrete encased column), while steel containing concrete is called an outside steel column (concrete-filled column). The use of a composite column structure outside steel as the main column in supporting lateral loads in the building frame structure is not yet commonly used in current construction developments. Therefore, it is necessary to consider the strengths of 2 types of composite columns to know which type of composite column is the most effective and has the highest strength. Calculations are performed using manual calculations on composite columns inside steel and outside steel in the form of a box, while calculations using the CSiCOL program are carried out on all composite columns. The results of the ØPn and ØMn values are then compared between manual calculations and the CSiCOL program. The calculation results show that the composite outside steel column's ability is better than the inside steel composite column by using a standard volume from the size of the composite column inside steel box 400x400 mm. The round composite outside steel column with a 431 mm diameter is 17% superior in withstanding nominal axial force (ØPn) than all other composite column types. While the outside steel composite column in the form of a box with a size of 405.70x405.70 mm is superior to withstand the little moment (ØMn) by 10.5% compared to all other types of composite columns.
16
Redecki, Michał, and Bronisław Gosowski. "The influence of the torsional restraint of crane column brackets on their critical load capacity." MATEC Web of Conferences 262 (2019): 09009. http://dx.doi.org/10.1051/matecconf/201926209009.
Abstract:
The paper presents the results of numerical parametric studies conducted on laterally restrained steel I-columns with a single stepped asymmetric change in their cross-section. Such elements are used as a part of the outermost columns in the transversal system of steel halls with cranes. The columns are usually braced along their length with wall girts, which in a properly structured hall system have a significant effect on the columns’ load bearing capacity and determine their axis of rotation. The main aim of the presented studies is to determine the impact of parameters, such as longitudinal load distribution on the upper and lower segment of the column, the number of pointed lateral bracings and their distance to a column's external flange, and also the application of torsional restraint on the critical load capacity. Results are presented as surfaces or contour maps, in which the ordinates represent the critical loads with regards to the analysed parameters. The paper ends with practical conclusions.
17
Lei, Min, Zihao Wang, Penghui Li, Liyi Zeng, Hongyao Liu, Zhidong Zhang, and Huicheng Su. "Experimental Investigation on Short Concrete Columns Reinforced by Bamboo Scrimber under Axial Compression Loads." Advances in Civil Engineering 2020 (September 29, 2020): 1–12. http://dx.doi.org/10.1155/2020/8886384.
Abstract:
The paper presents bamboo scrimber bars as a reinforcing material instead of steel reinforcement in low-strength concrete columns. Twelve short concrete columns with different reinforcements are tested under axial compression load to study the axial compressive behavior of short concrete columns reinforced by bamboo scrimber. Three columns are reinforced concrete columns, and the other nine columns are bamboo scrimber reinforced concrete columns. The failure process, bearing capacity, axial deformation, and strain of the specimens are compared and analyzed. The results show that the bonding performance between the bamboo scrimber bars by surface treatment and low-strength concrete is excellent. In low-strength concrete columns, the material properties of bamboo bars play more thoroughly than those of steel bars. When the bamboo reinforcement ratio is increased, the concrete column ductility is significantly improved, but the bearing capacity of the concrete column is not increased. The bamboo scrimber bars with the size of 10 mm × 10 mm or 15 mm × 15 mm can be used as longitudinal bars of low-strength concrete columns. The ductility of the short concrete column with 2.56% bamboo scrimber reinforcement is close to that of the short concrete column with 0.72% steel reinforcement.
18
Liu, Shihao, Wenhua Ye, Peihuang Lou, Weifang Chen, Jungui Huang, and Lili Xiao. "Bionic Design for Column of Gantry Machining Center to Improve the Static and Dynamic Performance." Shock and Vibration 19, no. 4 (2012): 493–504. http://dx.doi.org/10.1155/2012/545931.
Abstract:
In order to improve the machining accuracy of a gantry machining center, structural bionic design for column was conducted. Firstly, the bionic design method for stiffener plate structure was established based on distribution principles of gingko root system. The bionic design method was used to improve column structure of the gantry machining center, and three kinds of bionic columns were put forward. The finite element analysis on original and bionic columns indicates that the mass of the column with the best bionic stiffener plate structure is reduced by 2.74% and the first five order natural frequencies are increased by 6.62% on average. The correctness of column's bionic design method proposed in this paper was verified by the static and dynamic experiments. Finally, the bionic principles for stiffener plate of column were concluded, which provides a new idea for updating traditional design concepts and achieving lightweight structure of machine tool components.
19
FERREIRA, D. B., R. B. GOMES, A. L. CARVALHO, and G. N. GUIMARÃES. "Behavior of reinforced concrete columns strenghtened by partial jacketing." Revista IBRACON de Estruturas e Materiais 9, no. 1 (February 2016): 1–21. http://dx.doi.org/10.1590/s1983-41952016000100002.
Abstract:
This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column) e PR (reference column). The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.
20
Halding, Philip Skov. "Reduction of the Carbon Footprint of Precast Columns by Combining Normal and Light Aggregate Concrete." Buildings 12, no. 2 (February 15, 2022): 215. http://dx.doi.org/10.3390/buildings12020215.
Abstract:
To reduce the global emission of CO2 from the building industry, researchers, architects and manufacturers must consider new ways of constructing precast concrete buildings. Modern concrete columns and walls are not optimized to the applied load, and there is potential to save material. By creating a stronger column core and a lightweight concrete cover, it is possible to reduce the carbon footprint. A method is proposed to calculate such eccentrically loaded columns of two or more materials. The analytical method is developed for straight columns and columns with Entasis. Production of curved Entasis columns is possible by using textile molds due to the low mold pressure from the light aggregate concrete. Two column types are load tested to confirm the method. The CO2 emission is calculated for some column examples, and it shows that an optimized column geometry often leads to a reduced carbon footprint compared to regular columns. The concept is especially efficient for slender columns. Furthermore, the external light aggregate concrete layer ensures protection against fire if high-strength concrete is applied as the column core.
21
Li, Kai Wen, Zhi Yang Li, Xin Wan, and Fei Liu. "Non-Linear Numerical Simulation on Hysteretic Behavior of SRC Columns." Applied Mechanics and Materials 723 (January 2015): 382–86. http://dx.doi.org/10.4028/www.scientific.net/amm.723.382.
Abstract:
In order to study the mechanics properties to of concrete columns with embedded steel, two groups contrasting analysis models referring to SRC column and RC column are established by using finite element software ABAQUS. Both Static and cycle force are conducted. Analytical results show that bearing capacity and deformation ability of steel embedded reinforced concrete columns (SRC) under static loading are obviously higher than those of the reinforced concrete column (RC). Under the cycle force, the hysteresis circles of the SRC columns are fuller than RC column. The capability of energy consumption of the SRC columns is almost 1.4 times more than the RC columns. Further axial pressure coefficient and stirrup ratio are considered as parameters to study hysteresis characteristics, energy dissipation and the influence of the skeleton curve of SRC columns. The analytical results demonstrate that the hysteresis characteristics and energy dissipationare different with the changes of axial pressure coefficient. Meanwhile, the stirrup ratio of SRC column has little effect on energy dissipation. The study results have some value on the design and application of the SRC columns.
22
Wu, Jing, Fa Zhou Wang, Wen Yang, and Qing Jun Ding. "Load Carrying Capacity Analysis of Multi-Spiral Reinforced Concrete Column." Advanced Materials Research 150-151 (October 2010): 441–46. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.441.
Abstract:
The behavior of confined concrete is highly dependent on the confinement type of transverse reinforcement, spiral hoops are generally believed to have better confined effect in concrete than rectangular hoops. It is verified through experiments and the oretical calculations that multi-spiral confined concrete columns have better mechanical properties than single spiral columns, the multi-spiral significantly increase the column’s strength, plasticity, ductility and anti-seismic capability. Based on the three-direction stress law of confined concrete, the load carrying capacity of the rectangular cross section concrete column with multi-spiral is analysed in this paper, and the calculated equation of the load carrying capacity is proposed, which provide a theory and calculation basis for multi-spiral confined concrete column design and research.
23
Shukla, Shubham, and M. V. Waghmare. "Strengthening of RC Column Using GFRP." International Journal for Research in Applied Science and Engineering Technology 10, no. 3 (March 31, 2022): 1217–24. http://dx.doi.org/10.22214/ijraset.2022.40866.
Abstract:
Abstract: In construction industry, engineers try to find new, better, economical material. Today there are several new techniques observed in the industry. In recent years, the construction industry has seen an increasing demand to reinstate, rejuvenate, strengthen and upgrade existing concrete structures. This may be attributed to various causes such as environment degradation, design inadequacies, poor construction practices, lack of regular maintenance, revision of codes of practice, increase in loads and seismic conditions etc. One of the technique used is the wrapping of damaged and newly constructed columns with GFRP. As GFRP has the properties like high strength, light weight, resistance towards chemicals and salt water, it can be moulded into complex shapes, requires low maintenance etc. The behaviour of fibre reinforced polymer on different shapes of column has been extensively studied, but much less is known about concrete in FRP confined damaged columns. In this project a total of 21 columns are casted, out of which 3 columns are conventional columns, 9 columns are damaged & 9 are newly constructed columns. The columns are wrapped with single, double and triple layer of GFRP. An average increase of 33.21% is observed in damaged single layer wrapped GFRP column and 51.64% in damaged double layer wrapped GFRP column and 62% in damaged triple layer wrapped GFRP column. Similarly, 46.93% of increase in newly constructed single layer wrapped GFRP column and 72.56% of increase in newly constructed double layer wrapped GFRP column and 90.23% of increase in newly constructed triple layer wrapped GFRP column. Keywords: GFRP, damaged column, newly constructed column.
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Krishna, Himanshu, and Prince Yadav. "Study the Seismic Behavior of Special Columns in Multi-Story (G+4) Building for Seismic Zone III." International Journal for Research in Applied Science and Engineering Technology 10, no. 8 (August 31, 2022): 749–53. http://dx.doi.org/10.22214/ijraset.2022.46215.
Abstract:
Abstract: Columns are RC building structural elements that are primarily subjected to axial load and moments as they transport them from the superstructure to the substructure. Columns of various shapes and sizes are used. Popular column shapes include square, rectangular, and circular columns, as well as L-shaped, T-shaped, and (+) shaped columns, which are uncommon but provide more interior space than commonly used column shapes. This study aims to examine the seismic performance of multistory G+4 buildings with Rectangular columns and building with specially shaped columns. According to IS Code 1893(part 1):2016, the proposed buildings are analyzed using equivalent static analysis for zone III in soil condition 3. ETABs are used to analyze the models. After analysis, we conclude that buildings having special columns are safer and have more space as compared to the regular shaped column buildings
25
Krishna, Himanshu. "Study the Behavior of Special Columns on Multi Storey Building for Seismic Ground Motions." International Journal for Research in Applied Science and Engineering Technology 10, no. 7 (July 31, 2022): 2011–14. http://dx.doi.org/10.22214/ijraset.2022.45642.
Abstract:
ABSTRACT: Columns are RC building structural elements that are primarily subjected to axial load and moments as they transport them from the superstructure to the substructure. Columns of various shapes and sizes are used. Popular column shapes include square, rectangular, and circular columns, as well as L-shaped, T-shaped, and (+) shaped columns, which are uncommon but provide more interior space than commonly used column shapes. This study aims to examine the seismic performance of multistorey G+10 buildings with Rectangular columns and building with specially shaped columns. According to IS Code 1893(part 1):2016, the proposed buildings are analyzed using equivalent static analysis for zone IV. ETABs are used to analyze the models. After analysis, we conclude that buildings having special columns are safer and have more space as compared to the regular shaped column buildings
26
Yusuf, Hamzah, Akhmad Azis, Sugiarto Badaruddin, Andi Muhammad Subhan Saiby, Zulvyah Faisal, and Zubair Saing. "Physical modeling of sand columns application in recharge reservoir to prevent seawater intrusion." Water Supply 22, no. 2 (October 26, 2021): 2170–78. http://dx.doi.org/10.2166/ws.2021.365.
Abstract:
Abstract This study aims to provide visual evidence by the physical simulation to demonstrate the sand column performance of a recharge reservoir to control seawater encroachment and confirm some previous studies. In this analysis, a two-dimensional sand tank illustrates the sand column's role in overcoming seawater intrusion. Besides using dyes, the sand tank is also fitted with sensors to observe the length of seawater penetration. Furthermore, the simulation using SEAWAT numerical modeling is used as a reference in this analysis. The criteria analyzed were the number of sand columns, the reservoir water level, and the isochlors concentration. The results revealed a reasonably close match between physical and computational modeling. It was also found that the more sand columns and the higher the reservoir water level, resulted in the decrease of seawater penetration length that occurred. Physical and computational modeling findings indicated that the optimal results are derived using three sand columns with an RMSE value of 0.76. The seawater infiltration length decreased to 84.72% relative to sand column-free conditions at a reservoir water level of 15.0 cm.
27
Xu, Ying, and Bi Qin Dong. "An Industrialized Multi-Layer Precast Concrete Frame Building with Middle-Joint Beams and Columns." Advanced Materials Research 163-167 (December 2010): 1849–53. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1849.
Abstract:
An industrialized multi-layer precast concrete building with middle-joint beams and columns frame system has been developed by China VANKE CO., LTD. The building is the first industrialized multi-layer precast concrete building for experimental purpose in China. A middle-joint beams and columns method has been utilized with beams and columns split in the middle place. The whole frame structure is then integrated into a unity through precast beams, precast columns, and reliable cast-in-place column-column and beam-beam joints. This paper presents the key points and difficulties during the building design process, introduces the structural design of column-column and beam-beam joints, and analyses the advantages and weaknesses of middle-joint beams and columns frame system.
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Teddy, Livian, Gagoek Hardiman, N. Nuroji, and Sri Tudjono. "The New Method in Calculating Columns and Beams Dimensions That Meets Requirements of The Strong Column-Weak Beam and Non-Soft Story." Journal of Architectural Design and Urbanism 1, no. 2 (March 27, 2019): 1. http://dx.doi.org/10.14710/jadu.v1i2.4492.
Abstract:
Situated at an earthquake prone area, buildings planning in Indonesia must implement earthquake resistant building principles. One of these principles is determining dimensions of columns and beams in the process of architectural designing.This act eventually affects the behaviour of the strong column-weak beam and the probability of bending failure due to soft story. At present time, there are no simple rules architects can use in calculating the dimensions of beams and columns that meet the criteria for strong column-weak beam and non-soft story. This paper is an effort to provide an input to the architects in designing the dimensions of the columns and beams. This research is a review result of three theories namely: 1). The theory of columns and beams preliminary design, 2). The theory of the strong column-weak beam concept, and 3). The theory of soft story and column slenderness. Those theories were then synthesized into a spreadsheet. To meet the criteria for strong column-weak beam and non-soft story, the following procedures must be done : 1). Determine the columns’ dimensions according to 0.15% of the columns’ cumulative tributary area, 2). Determine the beams’ dimensions according to 1/12 of the beams’ span and the beams’ plastic modulus, 3). Determine the columns’ dimensions and the columns’plastic modulus, 4). Determine the columns’ height based on the column slenderness criteria, and 5). Compare the columns plastic modulus and the beams plastic modulus and check whether they meet the criteria “the columns’plastic modulus ≥ 1.2 * the beams’ plastic modulus”.
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Masia, Mark J., and Nigel G. Shrive. "Carbon fibre reinforced polymer wrapping for the rehabilitation of masonry columns." Canadian Journal of Civil Engineering 30, no. 4 (August 1, 2003): 734–44. http://dx.doi.org/10.1139/l03-015.
Abstract:
The use of carbon fibre reinforced polymer (CFRP) wrapping to strengthen existing cracked masonry columns was investigated experimentally. The study was aimed at quantifying the increase in strength that can be achieved and assessing the effect of column size on the strength increase. Eighteen columns were tested, with three different square cross-sectional sizes (290 mm × 290 mm, 390 mm × 390 mm, 490 mm × 490 mm) and two different types of clay masonry unit. Six columns were constructed in each size, two columns using unit type 1 and four columns using unit type 2. Strengthening was achieved by wrapping the square section columns directly with a single-layer CFRP laminate or by wrapping the columns after first casting a circular concrete jacket around the column. The latter treatment was applied to two of the small-sized columns and two of the intermediate-sized columns. All other square section columns were wrapped directly. Significant strength increases were achieved, particularly when the columns were provided with the cylindrical concrete jacket. These preliminary tests indicate that the use of CFRP wrapping is an effective technique for rehabilitating damaged masonry columns. Decisive conclusions could not be made regarding the effect of column size (cross-sectional area) on the strength increase achieved. Further tests together with nonlinear finite element modelling aimed at duplicating the experimental observations would greatly enhance the information provided by the current tests.Key words: masonry, columns, rehabilitation, strengthening, fibre reinforced polymer, experimental.
30
Hirata, Yukio. "Column technology for packed capillary columns." Journal of Microcolumn Separations 2, no. 5 (September 1990): 214–21. http://dx.doi.org/10.1002/mcs.1220020503.
31
Shendrik, V. A. "STRUCTURAL EVALUATION OF REINFORCED CONCRETE COLUMN WITH COMPOSITE GFRP SHELL -- A STRUCTURAL ELEMENTOF BRIDGE PIER." Russian Journal of Building Construction and Architecture, no. 2(50) (May 21, 2021): 74–84. http://dx.doi.org/10.36622/vstu.2021.50.2.006.
Abstract:
Statement of the problem. It’s considered the problem of developing a methodology for structural evaluation of hybrid design - a reinforced concrete column combined with external composite GFRP (glass-fiber-reinforced-plastic) shell. This hybrid design is intended for bridge piers. Results. As a result of a study, theoretical relationships were formulated to determine the longitudinal and transverse stresses and relative deformations of hybrid column structural elements. The developed formulas take into account the cooperation of triaxial compressed concrete core and an anisotropic composite GFRP shell. Conclusions. The obtained theoretical dependences of the hybrid column’s elements behavior make it possible to develop a structural evaluation methodology of bridge piers hybrid columns. The findings of the investigation are proposed to be applied in the structural evaluations of the bridges piers hybrid columns with composite GFRP elements.
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Sivakumar, V., D. McKelvey, J. Graham, and D. Hughes. "Triaxial tests on model sand columns in clay." Canadian Geotechnical Journal 41, no. 2 (April 1, 2004): 299–312. http://dx.doi.org/10.1139/t03-097.
Abstract:
Vibro-stone columns can improve the bearing capacity and reduce the settlement of foundations. Their performance depends on the strength of the column material, reinforcement method of column installation, type of in situ soil, area replacement ratio, and column length. This paper examines the behaviour of small laboratory specimens of soft clay (undrained shear strength ≈ 30 kPa) reinforced with sand columns when tested under known boundary stress conditions. Two series of tests were carried out on kaolin specimens (diameter 100 mm, height 200 mm) in a triaxial cell. In the first series, specimens were reinforced with a 32 mm diameter column of sand, 80, 120, 160, or 200 mm long. Columns were installed by (i) compacting moist sand into a prebored hole or (ii) freezing a column of moist sand before inserting it into a prebored hole. In the second series, columns were reinforced with geo-grids before installation. The specimens were subjected to (i) uniform loading in which the load was applied over the entire surface area of the specimen or (ii) foundation-type loading in which only a small area in the centre of the specimen was loaded. Under uniform loading, the specimens containing a full-depth column were significantly stronger than specimens without columns. Specimens with single, partially penetrating columns installed by wet compaction were weaker than specimens without columns. When frozen columns were installed, strengths increased progressively. Under foundation-type loading, bearing capacities increased with an increase in column length. Geo-grid reinforcement produced significant increases in load-carrying capacity.Key words: ground improvement, undrained shear strength, consolidation, stress path.
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Mohamed Sayed, Ahmed, Mohamed Mohamed Rashwan, and Mohamed Emad Helmy. "Experimental Behavior of Cracked Reinforced Concrete Columns Strengthened with Reinforced Concrete Jacketing." Materials 13, no. 12 (June 24, 2020): 2832. http://dx.doi.org/10.3390/ma13122832.
Abstract:
Reinforced concrete (RC) columns often need to be strengthened or rehabilitated to allow them to carry the loads applied to them. In previous studies, RC columns have been strengthened by jacketing, without considering the occurrence of cracking. In this study, the behavior of RC columns strengthened externally by jacketing after cracking is analyzed. The accuracy of the existing models was verified by analyzing the performance of fifteen RC columns with different cross-sections to determine the effect of new variables, such as the column size, amount of steel reinforcement, and whether the column was cracked or not, on the effectiveness of strengthening. The analysis demonstrated that this strengthening technique could effectively improve both the ductility and strength of RC column cross-sections. The results indicate that the model suggested by the ACI-318 code can predict the ultimate load capacity of RC columns without strengthening, or strengthened by RC jacketing before or after cracking, with higher accuracy and material efficiency. The RC columns without strengthening met the safety limit of the ACI-318 model. However, for strengthened columns, a reduction coefficient must be used to enable the columns to meet the safety limit, with values of 94% and 76% for columns strengthened before and after cracking, respectively. Furthermore, strengthening after cracking affects the ultimate load capacity of the column, with 15.7%, 14.1%, and 13.5% lower loads for square, rectangular, and circular columns than those strengthened before cracking, respectively.
34
Shima, Hiroyuki. "Simple Approximate Formulas for Postbuckling Deflection of Heavy Elastic Columns." Applied Sciences 10, no. 20 (October 14, 2020): 7163. http://dx.doi.org/10.3390/app10207163.
Abstract:
Columnar buckling is a ubiquitous phenomenon that occurs in both living things and man-made objects, regardless of the length scale ranging from macroscopic to nanometric structures. In general, analyzing the post-buckling behavior of a column requires the application of complex mathematical methods because it involves nonlinear problem solving. To complement these complex methods, this study presents simple analytical formulas for the large deflection of a heavy elastic column under combined loads. The analytical formulas relate the concentrated load acting on the tip of the column, the column’s own weight, and the deflection angle of the column through a simple mathematical expression. This can assist in obtaining an overall picture of the post-buckling behavior of heavy columns from an application point of view.
35
Marzon, Marzon, Mukhlis Islam, and Elhusna Elhusna. "ANALISIS PENAMPANG KOLOM BETON BERTULANG PERSEGI PANJANG BERLUBANG." Inersia, Jurnal Teknik Sipil 10, no. 2 (January 29, 2019): 1–12. http://dx.doi.org/10.33369/ijts.10.2.1-12.
Abstract:
Installation of pipes (conduit) in the building columns often found in reinforced concrete structures. The installation of pipes inside the columns is utilized as sanitary and mechanical electrical pipes. The case research in this study is to analyze the rectangular column with the applied research type (applied/pratical research). This research aims to analyze the impact of the holes on square rectangular columns. This calculation consists of 675 samples with differentconcrete compression strength (f'c), reinforcement area, holes area, and the dimensions of the column. Analysis of the calculation of hollow rectangular columns using the stress-strain relationship equation developed by Hognestaad. The results of the analysis on hollow rectangular columns resulted in a decrease column capacity. The largest decrease of the rectangular column capacity occurred on holes area of 7%, with concrete compression strength 30 MPa, and dimensions of the column 450 x 1800 mm which is 16.97%.
36
Hashemi, Fereshteh, and Faezeh Jafari. "Finite element analysis and neural network investigation of box columns under climate change." Pollack Periodica 16, no. 1 (March 25, 2021): 83–89. http://dx.doi.org/10.1556/606.2020.00085.
Abstract:
AbstractThe behavior of box-shaped columns under heating is investigated. For this purpose, the various sections of thin-wall box-shaped columns were modeled and verified in different temperature ranges by ABAQUS software. The results of this research showed that increasing the thickness leads to increase the buckling stability of column under temperature change. Since the behavior of column will be better than thinner columns under climate change because of the increase in the modulus of elasticity. The solid columns have better buckling stability than hollow columns in normal conditions.
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Fiorelia, Natashya Evangeline, Anthony Dharma Wibowo, Natanael Leonard Lae, Allison Ang, and Oki Krisbianto. "Types of High-Performance Liquid Chromatography (HPLC) Columns: A Review." FoodTech: Jurnal Teknologi Pangan 5, no. 1 (May 25, 2022): 1. http://dx.doi.org/10.26418/jft.v5i1.57334.
Abstract:
Some chemical analysts, especially those working in the food sector, often find it difficult to choose the HPLC columns for their research. Every so often they tend to modify their method to fit whatever HPLC column available in their laboratory instead of looking for the column type best suited to their experiments. Other than that, HPLC column types are often very limited discussed in the class. This is particularly disadvantageous for those who have sufficient access to select the HPLC column they need for the best result. The lack of insight into the types of HPLC columns available in the market also influenced their decision to select the right column in their analysis to a large extent. This article briefly reviews the differences between the commonly used Particle-Packed Columns with the newer yet less frequently used Monolithic Columns. The types of HPLC columns based on polarity, molecular size, and the electrical charge will be described further, along with the working principle of the columns in brief and various examples of options available on the market. Lastly, the uses of HPLC columns in the food industries are also described. This review is expected to contribute to the field of chemical analysis, such as food analysis.
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Moitinho, Maria da Luz Ribeiro, and Cláudio Santos Ferreira. "Sedimentation in parasitological coproscopy." Revista do Instituto de Medicina Tropical de São Paulo 34, no. 3 (June 1992): 255–58. http://dx.doi.org/10.1590/s0036-46651992000300013.
Abstract:
A sedimentation technique is described, in which a fecal suspension is placed on top of an aqueous sucrose solution of specific gravity 1.015 g/cm³. Using 100 by 15 mm test tubes, duplicate gravity sedimentation experiments were made using homogenized fecal suspensions (single-columns) and fecal suspensions placed on top of clear columns (double-columns). Egg- and cyst-counts, and turbidity determinations were made in the sediments obtained after definite time intervals. Most Ascaris lumbricoides, Trichuris trichiura and Ancylostomidae eggs sedimented within 20 minutes in single - and between 30 and 60 minutes in double-columns. Giardia duodenalis cysts required longer periods to sediment in double - than in single-columns; after 180 minutes (the maximum period of observation), double-column sediments produced 60.0% of the counts of single-columns. Double-column sediments were consistently less turbid than single-column ones
39
Zhao, Jin You, and Shi Chang Teng. "Design Method of Horizontal Braces Unlocated at Middle of Columns with Fixed-Ended Column Base." Applied Mechanics and Materials 351-352 (August 2013): 803–7. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.803.
Abstract:
A large number of column-bracing systems for the horizontal braces unlocated at middle of columns with fixed-ended column base were modeled and analyzed by second-order analysis using finite element method, in which the random combination of the initial imperfections between columns and horizontal braces was well considered by Monte Carlo method. According to the analysis results, two kinds of instability modes of column-bracing system have been found, probability density function of the horizontal bracing forces unlocated at middle of columns with fixed-ended column base is established based on probability statistics, and the design formula of horizontal braces unlocated at middle of columns are also proposed.
40
Tantrapongsaton, Warakorn, and Chayanon Hansapinyo. "Impact Response of Reinforced Concrete Columns with Different Axial Load under Low-Velocity Impact Loading." Key Engineering Materials 803 (May 2019): 322–30. http://dx.doi.org/10.4028/www.scientific.net/kem.803.322.
Abstract:
Building collapses from the seismic pounding of two adjacent buildings have been found in many past earthquakes. For the two buildings with different story height, the pounding induces impact load and local stress at column mid-height where the provided column reinforcement is normally lesser than the column’s edge. This paper aims to investigate the impact responses of reinforced concrete columns with different axial load and shear capacity by using numerical simulation method. Sixteen reinforced concretes columns were subjected to an impact load created by dropping 300 kg hammer at the height of 1,200 mm above the mid-span of the column. Every specimen has an identical cross section of 220 mm by 220 mm, with 3,000 mm of clear span length. Both ends of the column were fully restrained. The magnitude of the axial load varies from 0% to 40% of the ultimate axial capacity of the concrete section. Shear reinforcement spacing varies from @200 mm to @60 mm. It is found that the axial loads have a great effect on the impact responses of the RC columns. The specimens with high axial load yield higher peak impact force value and less mid-span deflection. Shear cracks were observed on the specimens with low axial force, but the cracks were relatively decreased when increasing the axial load.
41
Al-Mashaykhi, Mustafa, Belal Alsubari, Mazin Abdulrahman, and Aayat Hussein. "Punching Strength of Reactive Powder Reinforced Concrete Flat Slabs." TJES: Vol. 28, No.3 28, no. 3 (April 7, 2021): 35–74. http://dx.doi.org/10.25130/tjes.28.3.03.
Abstract:
This research is devoted to investigating experimentally the punching shear strength of reactive powder concrete slabs under monotonic loading. All slabs have the same flexural reinforcement and same dimensions (1000mm length,600mm width,50mm thickness). The experimental program includes casting and testing of sixteen slabs tested under monotonic loading. The major parameters adopted in the current research include the shape of column (circle, square), column size (twocolumn sizes), number of columns (one, two), and the distance between two columns (3d,5d,7d). Results showed that, the slabs with circular column sections have slightly higher ultimate load than those with square column sections. An increasing column area increases the load of punching shear failure. It was found that the ultimate failure load for slabs with two columns is greater than the slabs with one column. Related to the effect of distance between the two columns for monotonic, it was found that the slabs maximum load reaches the maximum value at distance between the two columns equal to(7d) for a circular section with a diameter of 85mm and 113mm and square section with dimensions of (100*100)mm. While the maximum failure load reaches the maximum value when the distance between two columns (d) for a square section with the dimension of (75*75)mm. Related to the crack patterns, it was noticed that for slabs with larger columns sections with the distance between columns equal to 7d, the failure zone extended (in a large direction) to the slab sides.
42
Nicolae, Marilena. "Complex Systems of Distillation Columns Used in the Production of the Propylene Oxide." Revista de Chimie 68, no. 1 (February 15, 2017): 28–34. http://dx.doi.org/10.37358/rc.17.1.5382.
Abstract:
Complex systems of distillation columns were intensively studied within last decades and continue to show interest for researchers and for industrial application. The first designed complex distillation column with heat integration was the Petlyuk column and the development of complex systems of columns continued up to dividing wall columns (DWC) which are increasingly being used in industry. DWC are usually used to separate three products, components or fractions, from a multicomponent mixture. This study attempts to find the best fitting of complex systems of columns in the process of propylene oxide (PO) obtaining using the method of propylene chlorination and presents a proposed variant of separation which can lead to a reduced energy consumption. The fabrication of PO through this method lead to a multicomponent mixture which is separated in two main products: propylene oxide (PO) and heavier components containing as valuable compound 1,2 dichloropropane (DCP). Both products, PO and DCP, have important uses in the chemical industry. The study of complex schemes of columns used for PO separation was assessed by simulation using a simplified method based on Fenske � Underwood - Gilliland correlation (F.U.G.) [1]. The systems studied in this work include the following configurations of columns: column with prefractionator, column with partially coupled prefractionator, the Petlyuk column, the dividing wall column, column with side striper, column with side rectifier, the direct and the indirect sequence.
43
Lei, Zi Xue, Yu Hang Han, San Sheng Dong, and Jun Qing Guo. "Analysis of Seismic Performance of RC Frames with Centrally Reinforced Columns." Advanced Materials Research 671-674 (March 2013): 1319–23. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.1319.
Abstract:
A centrally reinforced column is a new type of RC columns, formed by providing a reinforcement skeleton at the central part of the cross section of an ordinary RC column. Tests have shown that as compared with an ordinary RC column, this type of columns has a higher load carrying capacity and ductility. From the pushover analysis of a frame composed of ordinary RC columns and one consisting of centrally reinforced columns, their seismic performance under seismic load of 9-degree intensity was studied according to Chinese code, including target displacements, story-level displacements, interstory drifts, appearance and development of plastic hinges. The results indicate that although the dimensions of cross sections of columns in the frame with centrally reinforced columns are smaller than those of the ordinary frame, the former still has a higher overall load carrying capacity and seismic performance than the latter.
44
Indah, Shinta, Denny Helard, and Dian Ramadhan. "Penerapan kolom adsorpsi seri dengan adsorben sekam padi pada penyisihan logam seng (Zn) dari air tanah." Jurnal Riset Kimia 12, no. 1 (April 3, 2021): 19–26. http://dx.doi.org/10.25077/jrk.v12i1.389.
Abstract:
To increase the performance of continuous adsorption with rice husks as adsorbent in Zn removal from groundwater, a series of fixed bed column was applied. The experiments were carried out at the acrylic columns having diameter of 7 cm, column height of 19.5 cm, bed height of 13.5 cm and flow rate of 2 gpm/ft2 (310 mL/minute) for 540 minutes. The number of columns used were 3 columns arranged in series and the rice husk used were in their original size (1-2 mm). The influent concentration of Zn metal was 7.62 mg/L. The results showed that the use of column adsorption in series increased the removal efficiency of Zn by rice husks, from 33.21% using 1 column to 51.70% with 3 columns. The adsorption capacity of Zn obtained when using 3 columns in series was 3.542 mg/g. In addition, the use of adsorption columns in series can also prolong the saturation of the adsorbent, thereby extending its service life. The overall research results demonstrated that column the adsorption in series with rice husk as an adsorbent has the potential to be applied to remove heavy metals from groundwater.
45
Ma, Li Jie, Jin Yu Zhang, and Shao Jie Wang. "The Seismic Performance Study of Steel Pipe Concrete Column in the Absence of Beam Floor System." Advanced Materials Research 446-449 (January 2012): 2331–35. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.2331.
Abstract:
Architecture is the concrete columns with steel pipe flat floor slab, the 100mm × 100mm of steel pipe concrete column is in the center of the floor. The variation of moment and horizontal anti-force under horizontal displace of steel concrete columns are researched, and the steel columns working are analyzed, from that we can know steel concrete column in the slab-column structure has a good deformability under earthquake.
46
Yin, Zhan Zhong, Qiang Wang, Ya Xiong Liang, and Zong Rui Hu. "The Ultimate Bearing Capacity of Partial Concrete Encased Steel Strengthened Column." Applied Mechanics and Materials 215-216 (November 2012): 796–99. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.796.
Abstract:
The finite element modes of composite columns were built. The nonlinear analysis of the common steel column and the partial concrete encased steel composite columns were conducted. The load-displacement curves were getting. The strength of partial concrete encased steel Strengthened columns was much higher than the common steel column. Finally, Construction design suggestions and theory study of the type of partial concrete encased steel composite columns are advanced according to the results of analysis and computer simulation.
47
Liu, Laijun, Song Lei, Fangwen Wu, Weiwei Lin, Kai Peng, and Xiangyan Fan. "Experimental Study on Seismic Performance of Precast Columns Repaired with CFRP Fabrics." Materials 15, no. 21 (October 24, 2022): 7443. http://dx.doi.org/10.3390/ma15217443.
Abstract:
Earthquakes worldwide highlight the seismic vulnerability of reinforced concrete (RC) bridge columns. RC bridges are likely to collapse or lose service function due to damage to the bridge columns from strong earthquakes. Rapid repair of RC bridge columns is of great significance for maintaining traffic lines for emergency rescue work after earthquakes. In this study, an improved rapid repair method was developed to restore the bearing capacity of a damaged precast column after earthquake damage. A cyclic loading test was performed to simulate the seismic loading. The original column and the repaired column were both tested. The test results showed that the bearing capacity of the repaired columns was increased by 8%, and the energy dissipation capacity was 53% higher than that of the original column. The ductility decreased because the test for the repaired specimen ended in advance. The initial stiffness of the repaired columns was reduced, but the stiffness was significantly developed in the later loading stage. The rapid repair method proposed in this study exhibited an excellent effect on restoring the seismic resistance of the damaged columns.
48
Lai, Zhi Peng, and Shao Hua Guo. "Mechanism Analysis on Concrete Column’s Recovery Strengthening." Advanced Materials Research 941-944 (June 2014): 707–11. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.707.
Abstract:
This paper deals with the behavior of concrete columns actuated by SMA wires winding around the column’s cylindrical surface, when the concrete column are constrained and driven in circumferential direction by the SMA wires, the column’s ultimate bearing capacity and axial deformation are mainly studied. Both theoretical research and finite element simulation are carried out. The results indicate that, the SMA’s limited recovery in reverse transformation by heating can generate circumferential prestress, which will improve the concrete column’s ultimate bearing capacity and control its deformation, so as to realize the concrete column’s recovery strengthening.
49
Wu, Bo, Zhou Hong, Gui-He Tang, and Chao Wang. "Fire Resistance of Reinforced Concrete Columns with Square Cross Section." Advances in Structural Engineering 10, no. 4 (August 2007): 353–69. http://dx.doi.org/10.1260/136943307783239336.
Abstract:
Calculation of the fire resistance of 480 square cross section normal strength concrete (NSC) columns and 480 high strength concrete (HSC) columns, made with siliceous aggregate, is presented in this paper. The variables considered in the study include concrete strength (NSC and HSC), dimension of column cross section, axial load ratio, load eccentricity ratio (i.e., ratio of load eccentricity to dimension of column cross section), and steel ratio (i.e., ratio of longitudinal reinforcement to cross-sectional area of column). Explosive spalling of HSC exposed to fire is also considered approximately. Simulation results show that: (1) increasing the dimension of column cross section, reducing the axial load ratio, and reducing the load eccentricity ratio are all effective measures for improving the fire resistance of both NSC and HSC columns subjected to concentric axial load or eccentric axial load; (2) increasing the steel ratio has no significant influence on the fire resistance of concentrically loaded NSC and HSC columns, but has some positive effect on the fire resistance of eccentrically loaded NSC and HSC columns; (3) explosive spalling of HSC has a significant detrimental influence on the fire resistance of HSC columns. Based on simulation results, a simplified formula is empirically developed to enable determination of the fire resistance of both NSC and HSC columns, and is shown to be applicable to concrete columns with square cross section.
50
Alkhorshid, Nima, Gregório Araújo, and Ennio Palmeira. "Geosynthetic Encased Column: comparison between numerical and experimental results." Soils and Rocks 44, no. 4 (November 21, 2021): 1–12. http://dx.doi.org/10.28927/sr.2021.073121.
Abstract:
The use of granular column is one of the ground improvement methods used for soft soils. This method improves the foundation soils mechanical properties by displacing the soft soil with the compacted granular columns. The columns have high permeability that can accelerate the excess pore water pressure produced in soft soils and increase the undrained shear strength. When it comes to very soft soils, the use of granular columns is not of interest since these soils present no significant confinement to the columns. Here comes the encased columns that receive the confinement from the encasement materials. In this study, the influence of the column installation method on the surrounding soil and the encasement effect on the granular column performance were investigated using numerical analyses and experimental tests. The results show that numerical simulations can reasonably predict the behavior of both the encased column and the surrounding soil.