Loading...
Search for:
concrete-filled
0.007 seconds
Investigating the behavior of circular concrete filled PVC tube columns under concentric and eccentric load using FEM
, Article Asian Journal of Civil Engineering ; Volume 22, Issue 4 , 2021 , Pages 589-603 ; 15630854 (ISSN) ; Khaloo, A ; Hassanpour, S ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The purpose of this research is to investigate the response of concrete-filled composite tube column under concentric and eccentric loads. To evaluate the influence of PVC pipe on the behavior of concrete-filled composite tubes, concrete-filled PVC pipe (CFPT) were modeled by ABAQUS software. The results demonstrate that the presence of the PVC pipe makes the concrete column more ductile and have a significant effect on the stress–strain curve of the CFPT after the peak strength, in a way that the confinement increased by raising the thickness of PVC pipe, but the confinement effect of the PVC pipe decreased by the increment of the column diameter and compressive strength of the concrete...
Investigating the behavior of circular concrete filled PVC tube columns under concentric and eccentric load using FEM
, Article Asian Journal of Civil Engineering ; Volume 22, Issue 4 , 2021 , Pages 589-603 ; 15630854 (ISSN) ; Khaloo, A ; Hassanpour, S ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The purpose of this research is to investigate the response of concrete-filled composite tube column under concentric and eccentric loads. To evaluate the influence of PVC pipe on the behavior of concrete-filled composite tubes, concrete-filled PVC pipe (CFPT) were modeled by ABAQUS software. The results demonstrate that the presence of the PVC pipe makes the concrete column more ductile and have a significant effect on the stress–strain curve of the CFPT after the peak strength, in a way that the confinement increased by raising the thickness of PVC pipe, but the confinement effect of the PVC pipe decreased by the increment of the column diameter and compressive strength of the concrete...
Parametric Investigation of Behavior of Moment Connections to CFST Columns
, M.Sc. Thesis Sharif University of Technology ; Khalu, Alireza (Supervisor)
Abstract
In recent years use of concrete filled steel tube column structures has been increased due to their several advantages. In these columns the steel tube provides confinement for the concrete core of the column, so it increases axial strength and flexibility of the concrete core, and prevents spalling of the concrete. On the other hand the concrete core delays the local buckling steel tube and increases its bearing capacity. In addition, these columns have higher stiffness and strength than typical concrete columns due to placement of steel in farthest point of column cross section. The steel tube besides its structural role acts as framework for the concrete core and reduces time and cost of...
Behavior of Ring-confined Concrete-filled Steel Tubular Columns
, M.Sc. Thesis Sharif University of Technology ; Khalu, Alireza (Supervisor)
Abstract
Recently concrete filled steel tubular columns developed in the construction industry. In these types of columns, concrete and steel have efficient and complementary performance because of proper confinement provided by steel tube for concrete which leads to increase strength and ductility of concrete, also concrete prevents local and inward buckling of steel tube. CFST columns have several advantages over conventional reinforced concrete columns such as elimination of formwork and reinforcement, rapid construction, decrease in the column dimensions and saving extra floor space and also improvement in the load-carrying capacity, ductility and energy absorption ability. Despite the above...
Nonlinear Analysis of Structures with Concrete Filled Steel Tubular Columns
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
In recent years using concrete and steel together in buildings and bridges to mix their advantages and compensate disadvantages is very common especially in seismic zones. Using Concrete Filled Steel Tubular (CFST) columns is one of these methods. In these columns, steel tube has longitudinal and lateral reinforcement role for helping concrete core to resist against bending moment, shear and tension. Steel tube also creates confinement in concrete and increase compressive strength and prevents concrete from spalling. Concrete core increases stiffness of column and reduces capability of inward local buckling. Behaviors of CFST columns are influenced by loading, characteristics of materials...
The fiber element technique for analysis of concrete-filled steel tubes under cyclic loads
, Article Structural Engineering and Mechanics ; Volume 14, Issue 2 , 2002 , Pages 119-133 ; 12254568 (ISSN) ; Aval, S. B. B ; Saadeghvaziri, M. A ; Sharif University of Technology
Techno-Press
2002
Abstract
A beam-column fiber element for the large displacement, nonlinear inelastic analysis of Concrete-Filled Steel Tubes (CFT) is implemented. The method of description is Total Lagrangian formulation. An 8 degree of freedom (DOF) element with three nodes, which has 3 DOF per end node and 2 DOF on the middle node, has been chosen. The quadratic Lagrangian shape functions for axial deformation and the quartic Hermitian shape function for the transverse deformation are used. It is assumed that the perfect bond is maintained between steel shell and concrete core. The constitutive models employed for concrete and steel are based on the results of a recent study and include the confinement and biaxial...
Numerical Analysis of Behavior of Concrete-Filled PVC Tubular Column
, M.Sc. Thesis Sharif University of Technology ; Khalou, Alireza (Supervisor)
Abstract
Concrete Filled Polyvinyl Chloride (PVC) Tube (CFCT) technique has attracted significant research attention in recent years. PVC offers a number of advantages such as low costs and excellent properties like 1- high electrical insulation; 2- high resistance for abrasion; 3- low diffusion for humidity; 4- remarkable resistance to water, bases, acids, alcohols, oils; 5- large elongation at break; 6- low creep deformation; 7- workability including (cutting); 8- consistency; and 9- excellent corrosion resistant, durability and mechanical stability. The PVC tube acts as a longitudinal and transverse reinforcement and serves as a formwork which simplifies construction and reduces erection time. The...
The effects of elevated temperatures on the performance of concrete-filled pultruded GFRP tubular columns
, Article Thin-Walled Structures ; Volume 169 , 2021 ; 02638231 (ISSN) ; Khaloo, A ; Azizmohammadi, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Usage of concrete-filled pultruded glass fiber-reinforced polymer (GFRP) tubes (CFPGT) as columns can increase the service life of structures. However, marine structures such as oil platforms are always prone to fire because of the low resistance to the elevated temperatures. The purpose of this investigation is to evaluate the effects of concrete core strength (30 and 60 MPa), and exposure temperature (25, 100, 200, 300, and 400 °C) and time (60 and 120 min) on the compressive and bond behavior of CFPGTs. The properties of unexposed and exposed concrete core, pultruded GFRP hollow tubes, and CFPGTs were determined via compressive and disk-split tests. Also, the push-out test was used to...
Response of concrete-filled polyethylene tubes under in-service thermal cycles in marine environments
, Article Marine Structures ; Volume 85 , 2022 ; 09518339 (ISSN) ; Khaloo, A ; Azizmohammadi, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Concrete-filled polyethylene (PE) tubes (CFPT) are composite systems using the polyethylene tubes as confinement for the marine structures in the splash zone to extend the service life of structures subjected to harsh environments. However, thermal cycles in marine environments can affect the behavior of such composite systems. This paper evaluates the effect of concrete infill strength (30 MPa and 60 MPa), the number of thermal cycles (50, 100, and 150 cycles) ranging from 25 °C to 60 °C, and thermal cycle type (type A and B) on the compressive and bond response of CFPTs. Characteristics of control and conditioned concrete infill, PE tubes, and CFPTs were obtained by means of compression...
Numerical Study of Stiffener Effects on Composite Shear Wall Performance
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
Concrete filled double-steel-plate (CFDSP) composite wall is a new lateral resisting system that recently used in design and strengthening of high-rise buildings. This CFDSP composite wall is composed of concrete filled steel tubular columns at the two boundaries and concrete filled double-steel-plate wall body. The main advantage of this system is the interaction between steel and concrete which delays local buckling of steel plates. Also, steel jacket increases the strength of concrete in result of confinement effects. Furthermore, these systems have lower thickness compared to ordinary concrete shear walls. Hence, they have less structural weight which reduces the earthquake force....
Experimental Study on the Behavior of the Expansive Concrete-filled UPVC Tube Columns Confined with GFRP Wraps under Pure Compression
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
Lateral confinement is a proven method of increasing strength, stiffness and ductility of concrete columns. This is attributed to a created tri-axial stress state in the concrete core due to the confinement resulting in a higher level of endurable deviatoric stress. Plastic pipes are able to create such a confining medium in concrete-filled UPVC tube (CFUT) columns and therefore they can provide the concrete with some benefits of concrete filled steel tube (CFST) column system. Besides, these pipes are cheap, light and they are also easy to handle. Furthermore, they are resistant to corrosion or other forms of deterioration and recyclable and in this aspect, they are...
Progressive Collapse Analysis of Structures with Concrete Filled Steel Tubular Columns
, M.Sc. Thesis Sharif University of Technology ; Khalu, Alireza (Supervisor)
Abstract
Today, Progressive Collapse analysis of Structures has a great rule in predict and preventing of overall collapse of structures due to local damage to few elements. After World Trade Center collapse, Progressive collapse analysis became more important. According to better ductility of Concrete Filled Steel Tubular Columns, because of existence of core concrete confinement, it is prospected that using this type of columns will lead to better resistance against progressive collapse. In this study, structures with concrete filled steel tubular columns will be examined in progressive collapse. In addition, in this study, a numerical model was proposed to model concrete filled steel tubular...
Performance of polypropylene fiber reinforced concrete-filled UPVC tube columns under axial compression
, Article Construction and Building Materials ; Volume 231 , 20 January , 2020 ; Khaloo, A ; Borhani, M. H ; Tale Masoule, M. S ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This paper aims to study the behavior of UPVC-confined columns reinforced with polypropylene fibers under axial compression. A sum of 42 column specimens has been tested, including 18 Unconfined Concrete Cylinders (UCC) and 24 confined Concrete-Filled UPVC Tube (CFUT) specimens. To investigate the sensitivity of these columns to various parameters, different levels of material volumes have been used, which include two concrete strengths of 40 and 50 MPa, two tube grades of PN6 and PN10, and three polypropylene fiber content of 0, 1 and 3 kg/m3 of the concrete mixture. The influence of each variable on the ultimate strength, ductility and confinement effectiveness of the specimens have been...
Evaluation of Seismic Performance of Composite Moment Frame with Steel-Concrete Composite Column and Steel Beam Utilizing Fragility Curves
, M.Sc. Thesis Sharif University of Technology ; Bakhshi, Ali (Supervisor)
Abstract
The purpose of this research is to investigate the seismic behavior of plane moment resisting frame consisting of steel-concrete columns and steel I beams utilizing fragility curves. Due to the great influence of the column type in seismic performance of structure. To reach an optimal system, different types of steel-concrete composite columns has been used in the models and the fragility curve of each one is compared. Steel-Concrete composite columns can be divided into three types: (1) concrete filled steel tube (CFT), (2) steel reinforced concrete (SRC) and (3) new combinations of (1) and (2). Due to the abundance of the use of concrete filled steel tube (CFT) and steel reinforced...
Formation and Development of Plastic Hinges in Structures With Concrete Filled Steel Tubular Columns Using Nonlinear Static Analysis
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
concrete-filled steel tube offers many practical advantagescompared withconventional structural systems. The concrete infill provides stiffness and strength in compression and restrains local and global buckling. The inelastic deformation capacity of the CFT system is increased by the confinement of the concrete fill by the thin, ductile steel tube, and this significantly contributes to the seismic performance.
In this research, Formation and development of plastic hinges in CFST frames using pushover analysis was investigated. Different frames with rectangular and circular column and I beam weredesigned and Using nonlinear finite element analysis, interaction between steel and concrete...
In this research, Formation and development of plastic hinges in CFST frames using pushover analysis was investigated. Different frames with rectangular and circular column and I beam weredesigned and Using nonlinear finite element analysis, interaction between steel and concrete...
Numerical Study of the Effect of Reduced Beam Section on the Behavior of Steel-Concrete Composite Beam-to-Column Joints
, M.Sc. Thesis Sharif University of Technology ; Mofid, Masoud (Supervisor)
Abstract
In this research, factors affecting the behavior of reduced-cross section steel (RBS) connection to the compound column (CFT) has been investigated. After verifying the accuracy of the numerical simulations performed by finite element software, with a compatible three-dimensional model, several steel beam-to-column connections are modeled to the composite column and the distance effect of the reduced cross section on the column and reduction radius was studied on the behavior of the beam connection with the cross section reduced to the composite column. The results show that in all connections, in which the cross section of the beam is reduced, compared to the connections in which the beam...
Compressive Performance of Concrete Confined with UPVC Pipes
, Ph.D. Dissertation Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
This study presents an experimental and numerical investigation on the compressive behavior of a new type of composite column which consists of both solid and hollow concrete-filled UPVC tube with and without GFRP wraps.Composite construction has been often more economical than traditional concrete construction, because this system realizes the most effective use of concrete, and composite members in the structural system.The enormous potential of using plastic tubes in composite systems will be illustrated by this research. It is an economical type of column in construction.This research aims to study the behavior of UPVC-confined columns under axial compression. A sum of 132 specimens are...
Compressive and Bond Behavior of Concrete-Filled Pultruded GFRP and PE Tubes Under Elevated Temperatures
, Ph.D. Dissertation Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
Concrete-filled GFRP and PE tubes are composite systems using the polymeric tubes as confinement for the marine structures to extend their service life. However, elevated temperatures and thermal cycles in marine environments can affect the behavior of such composite systems. In this investigation, the effect of elevated temperatures and thermal cycles on the performance of concrete-filled pultruded GFRP tubes (CFPGT) and concrete-filled polyethylene tubes (CFPT) is assessed, respectively. For this, different parameters such as concrete core strength (30 and 60 MPa), exposure temperature (25, 100, 200, 300, and 400°C), time exposure (60 and 120 min.), number of thermal cycles (50, 100, and...
Numerical Modelling on Effects of Elevated Temperatures on the Performance of Concrete-filled Pultruded GFRP Tubular Columns
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
Concrete-filled FRP tubes have gained popularity among structures in areas with harsh environmental condition. Despite their unique material properties such as resistance to corrosion, noticeable axial stiffness, and durability, FRP materials have poor resistance to elevated temperatures. This paper presents numerical investigations on the behavior and capacity of concrete-filled pultruded GFRP tubes (CFGFTs) after exposure to elevated temperatures under concentric compression. Variables in this study were the tube’s thickness of 3, 5, and 7mm, the infill concrete’s compressive strengths of 30 and 60MPa, and the exposure temperature of 25, 100, 200, 300, and 400°C. The results in this study...