scholarly journals PVC Plastic Tube with Concrete Infill Strengthened with FRP: A State-of-the-art Review

2020 ◽  
Vol 9 (4) ◽  
pp. 196-204
Author(s):  
Nwzad Abduljabar Abdulla
Keyword(s):  
Research Work ◽  
Concrete Columns ◽  
Absorption Capacity ◽  
Fiber Reinforced Polymers ◽  
Structural Members ◽  
Lateral Loads ◽  
Energy Absorption Capacity ◽  
Plastic Tube ◽  
Reinforced Polymers ◽  
Compression Members

The strength and energy absorption capacity of concrete compression members are a significant concern when considering the structural performance under axial and lateral loads. A lot of methods and different techniques have been proposed in the past to improve the behavior of concrete columns under the applied loads. One such technique is the concrete filled-plastic tube (CFPT) strengthened externally with fiber-reinforced polymers (FRP). Such a system can improve the durability of the structural members. A review of the research work on the durability of the new system under axial and flexural loads is presented. Moreover, a comparison and a brief discussion of the reported results are displayed.  

scholarly journals Behavior of Columns Confined With FRP Fabrics under Repeated Lateral Loads

2019 ◽  
pp. 1-19
Author(s):  
Hesham A. Haggag ◽  
Nagy F. Hanna ◽  
Ghada G. Ahmed
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Axial Load ◽  
Axial Loading ◽  
Concrete Columns ◽  
Fiber Reinforced Polymers ◽  
Lateral Loads ◽  
Reinforced Concrete Columns ◽  
Reinforced Polymers ◽  
Axial Capacity

The axial strength of reinforced concrete columns is enhanced by wrapping them with Fiber Reinforced Polymers, FRP, fabrics.  The efficiency of such enhancement is investigated for columns when they are subjected to repeated lateral loads accompanied with their axial loading.  The current research presents that investigation for Glass and Carbon Fiber Reinforced Polymers (GFRP and CFRP) strengthening as well.  The reduction of axial loading capacity due to repeated loads is evaluated. The number of applied FRP plies with different types (GFRP or CFRP) are considered as parameters in our study. The study is evaluated experimentally and numerically.  The numerical investigation is done using ANSYS software. The experimental testing are done on five half scale reinforced concrete columns.  The loads are applied into three stages. Axial load are applied on specimen in stage 1 with a value of 30% of the ultimate column capacity. In stage 2, the lateral loads are applied in repeated manner in the existence of the vertical loads.  In the last stage the axial load is continued till the failure of the columns. The final axial capacities after applying the lateral action, mode of failure, crack patterns and lateral displacements are recorded.   Analytical comparisons for the analyzed specimens with the experimental findings are done.  It is found that the repeated lateral loads decrease the axial capacity of the columns with a ratio of about (38%-50%).  The carbon fiber achieved less reduction in the column axial capacity than the glass fiber.  The column confinement increases the ductility of the columns under the lateral loads.

Seismic Upgrading of a Masonry Church with FRP Composites

2016 ◽  
Vol 866 ◽  
pp. 119-123 ◽  
Author(s):  
Gabriele Milani ◽  
Rafael Shehu ◽  
Marco Valente
Keyword(s):  
Seismic Performance ◽  
Fiber Reinforced Polymers ◽  
Seismic Action ◽  
Structural Elements ◽  
Lateral Loads ◽  
Reinforced Polymers ◽  
Preliminary Results ◽  
Existing Structures ◽  
Frp Composites ◽  
The Church

This paper presents some preliminary results of seismic analyses performed on a masonry church located in Emilia-Romagna (Italy). The church suffered damage during the seismic events occurred in 2012 and some seismic upgrading interventions by means of Fiber Reinforced Polymers (FRPs) are proposed. The behavior of the church is investigated under horizontal loads simulating a seismic action defined in accordance with Italian Code indications. The preliminary results of the numerical analyses performed on the church in the unretrofitted configuration put in evidence both the insufficient strength of some structural elements when subjected to lateral loads and a typical failure mode of the façade. Two seismic upgrading interventions with FRP composites are simulated in order to increase the seismic performance of the church. Such interventions are carried out according to the provisions of Italian Code for FRP strengthening of existing structures. Numerical results show that a proper seismic upgrading intervention by means of FRP composites is effective to improve the seismic performance of the church.

scholarly journals Thermomechanical Characterization of CFRPs under Elevated Temperatures for Strengthening Existing Structures

Fibers ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 80
Author(s):  
Christina Papadimitriou ◽  
Lazaros Melidis ◽  
Lambros Kotoulas ◽  
Nikolaos Makris ◽  
Konstantinos Katakalos
Keyword(s):  
Thermal Loading ◽  
Elevated Temperatures ◽  
Tensile Load ◽  
Concrete Columns ◽  
Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Existing Structures ◽  
Structural Reinforcement ◽  
Constant Tensile Load

Fiber-reinforced polymers (FRP) are rapidly gaining acceptance from the construction sector due to their large effectiveness. They are mainly used as confining reinforcement for concrete columns and as tensile reinforcement for concrete beams, columns and slabs. FRPs are already used to a large extent for applications such as bridges and parking lots, where elevated temperatures are not the main risk. Their increasing use as structural reinforcement is hampered by the concern related to their behavior at elevated temperatures as the relevant research is deficient. Thanks to the significant advantage of FRPs’ mechanical properties, further investigation into the influence of heating on their mechanical behavior may solve many doubts. The present study examines the influence of temperatures, ranging among 50, 100 and 250 °C, on the tensile strength of FRP laminates with carbon fibers (CFRP). In addition, the resistance of CFRP specimens to low-cycle thermal loading at the temperatures of 50, 100 and 250 °C under constant tensile load was investigated. The experiments were carried out in the laboratory of Experimental Strength of Materials and Structures of Aristotle University of Thessaloniki.

scholarly journals An Overview of Pros and Cons of Zipper Braced Frames

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 106-110
Author(s):  
A Roshan ◽  
R Farahoni
Keyword(s):  
Absorption Capacity ◽  
Elastic Behavior ◽  
Structural Members ◽  
Braced Frames ◽  
Energy Absorption Capacity ◽  
Soft Story ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Pros And Cons ◽  
Bracing System

The chevron bracing system provides the highest level of stiffness and average ductility by using the yield or buckling of braces. This system demonstrates weak post-buckling behavior while other structural members such as beams, columns and joints show elastic behavior. As a result of bracing buckling at a story, the unbalancing force acts perpendicular on the middle of the beam span and results in the concentration of damage on that story. Consequently, the affected story becomes prone to the soft story mechanism and the structure collapses eventually. In order to prevent this problem, it is possible to place vertical elements (zippers) between beams so that the head of bracings are connected at height and the resulting unbalancing force in the story is transferred to upper stories. Such a frame is known as the zipper frame. With a proper zipper configuration, it is possible to address the problems and weaknesses of the chevron bracing frame. Therefore, zipper frames can become proper substitutes for this type of bracing systems. By using the chevron element in the chevron bracing and turning it into a zipper frame, it is possible to increase the strength, ductility and energy absorption capacity of such frames.

Study of Energy Absorption Characteristics of Square Tube With Composite Cellular Core

2018 ◽  
Author(s):  
Muhammad Ali ◽  
Eboreime Ohioma ◽  
Khairul Alam
Keyword(s):  
Energy Absorption ◽  
Compressive Loading ◽  
Absorption Capacity ◽  
Structural Members ◽  
Tubular Structures ◽  
Tube Material ◽  
Energy Absorption Capacity ◽  
Core Tube ◽  
Energy Absorbing ◽  
Deformation Modes

Square tubes are primarily used in automotive structures to absorb energy in the event of an accident. The energy absorption capacity of these structural members depends on several parameters such as tube material, wall thickness, axial length, deformation modes, locking strain, crushing stress, etc. In this paper, the work presented is a continuation of research conducted on exploring the effects of the introduction of cellular core in tubular structures under axial compressive loading. Here, the crushing response of composite cellular core tube was numerically studied using ABAQUS/Explicit module. The energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, crushing stroke, and energy curves were discussed. The composite cellular core tube shows promise for improving the crashworthiness of automobiles.

Crack Resistance RC Columns Strengthened by CFRP System

2021 ◽  
Vol 878 ◽  
pp. 127-133
Author(s):  
J. Selejdak ◽  
Y. Blikharskyy ◽  
R. Khmil ◽  
Z. Blikharskyy
Keyword(s):  
Crack Resistance ◽  
Experimental Testing ◽  
Experimental Studies ◽  
Concrete Columns ◽  
Fiber Reinforced Polymers ◽  
Tension Zone ◽  
Carbon Fiber Reinforced Polymers ◽  
Rc Columns ◽  
Reinforced Polymers ◽  
Compression Load

This paper presents the experimental testing of eccentrically compressed reinforced concrete columns. There are experimental results of crack resistance of non-strengthened (control) and strengthened RC columns in the tension zone. The columns were strengthened by carbon fiber reinforced polymers (CFRP). As a result of experimental studies with the columns strengthened by CFRP, we obtain that the width of their crack decreased by an average of 33%. The eccentric compression load of the crack’s appearance increased from 40 kN to 60 kN for strengthened columns.

The Influence of Concrete Surface Preparation when Fiber Reinforced Polymers with Different Anchoring Devices are Being Applied for Strengthening R/C Structural Members

2011 ◽  
Vol 82 ◽  
pp. 600-605 ◽  
Author(s):  
G.C. Manos ◽  
Konstantinos Katakalos ◽  
V. Kourtides
Keyword(s):  
Bearing Capacity ◽  
Surface Preparation ◽  
Concrete Surface ◽  
Fiber Reinforced Polymers ◽  
Structural Members ◽  
Fiber Reinforced ◽  
Load Bearing Capacity ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Frp Strips

The aim of this study is to investigate the influence of concrete surface preparation when either steel or carbon fiber reinforced polymers (FRP) are applied for strengthening applications of R/C members. The present study also investigates the anchorage or not of the applied FRP strips on the volume of concrete. For this purpose special concrete specimens were fabricated and were used to attach CFRP or SRP strips with or without anchoring and with or without contact surface treatment. The experimental results indicate that the concrete surface preparation is important and results in an increase of the load bearing capacity when the FRP strip is not anchored. When an anchoring device is employed, the concrete surface preparation is of no significance. With a properly designed anchoring device, a significant increase in the bearing capacity was observed and the failure was that of the fracture of the FRP strips for all such specimens. The highest FRP material exploitation was achieved in the specimen that utilises the patented anchoring device together with two layers of SRP strips. Debonding of the FRP strips, or failure of the anchoring device, results as was to be expected, in relatively unsatisfactory FRP material exploitation.

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