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This paper presents a procedure for the application of a multifractal spectrum to analyse vibration signals obtained during static bending tests of selected fibre reinforced polymer matrix composite materials. The analyses were designed to determine the failure course of the composites tested under bending conditions. Non-stationary changes occurring in the signals include low- and high-energy symptoms of progressive damage in materials, which are difficult to identify and interpret, especially in the early stages. Determined using fractal leaders, the multifractal spectra of the vibration signals calculated for the different stages of the bending test allowed qualitative identification of the changes caused by progressive damage with different energy responses. In addition, the quantitative measures of change in the characteristics of the multifractal spectrum determined clearly indicated the changes occurring in the recorded signals. It can be concluded from the research that the proposed signal processing method based on a multifractal spectrum determined from non-stationary vibration signals is sensitive to changes occurring in these signals. [ABSTRACT FROM AUTHOR]

This article explores the behavior of short beam specimens made from a titanium/fiber-reinforced polymer (FRP) hybrid sandwich material. The study compares the flexural characteristics of specimens with FRP skins and titanium skins, which were manufactured using additive manufacturing processes. Three-point bending tests were conducted to evaluate the mechanical properties of the specimens. The results provide insights into the fracture mechanisms and performance of the hybrid sandwich material. The study found that titanium-skinned specimens had the highest strength, while aramid and carbon fiber skins had comparable mechanical characteristics. The article also includes micrographs of the fracture surfaces and compares the performance indexes of the different specimens. [Extracted from the article]

Research related to stab-resistant armour is focused on developing a low-weight flexible stab-resistant armour. Various materials and methods have been used to reduce the overall bulk but managing the flexibility and bulk with improved stab resistance is still a challenge for the researchers. In this study, flexible stab-resistant material for stab-resistant personal protective equipments (PPEs) has been developed by using shear thickening fluid (STF) treated fabric made of multicomponent yarns and ultra high molecular weight polyethylene (UHMWPE) laminate composite. The stab resistance and comfort behaviour like flexural rigidity and areal density were investigated with respect to number of layers and different STF concentrations according to VPAM KDIW-2004 and respective standards for flexural rigidity. Laminate-Woven hybrid composite was developed to reduce the bulk of the panel while maintaining the required protection level. [ABSTRACT FROM AUTHOR]

Precision machining of Fibre Reinforced Polymer (FRP) Composites needs to be explored further while addressing advanced engineering applications. However, force and temperature-driven damages while machining FRP composites, due to the non-homogenous and low thermal conducting behaviour of fibre-matrix interfaces, place the barrier in this direction. Surface machining using abrasive wheels has been projected as a promising option for fine removal of material in FRPs. However, conventional dry grinding strategy exhibited high grinding force due to continuous interaction of abrasive cutting edges, leading to accumulation of heat at the grinding interface. As the cutting action is continuous, heat dissipation also becomes difficult in this situation. Temperature-driven damages on composite matrix and subsequent failure of reinforced fibres were serious concerns in this case. Although attempted in some situations, usage of cutting fluids was not recommended fully due to wetting effects and agglomeration of swarf that hinder the grinding efficiency. Eccentric Sleeve Grinding (ESG), using an intermittent-progressive cuttings scheme, is proposed in this work as a potential dry grinding strategy for FRPs. Control of heat accumulation through progressive cutting strategy and enhancement of heat dissipation through intermittency in cutting cycle appears to be the unique characteristics of ESG. Experimentation of ESG on carbon fibre reinforced composite samples showed promising grinding temperature reduction, which was justified through a significant reduction in grinding forces, surface defects and roughness. [ABSTRACT FROM AUTHOR]

Many researchers worldwide have extensively used fibre-reinforced polymer (FRP) strengthening materials to enhance the shear and flexural strengths of reinforced concrete (RC) beams. However, Studies on strengthening of RC beam subjected to combined torsion and bending moment using both spiral and vertical strip configuration of CFRP that explored in this study is rare. This study aims to demonstrate the behaviour of RC beams strengthened with FRP sheets (strips) with different configurations and subjected to combined actions of torsion and bending moment. Eight beams with a dimension of 15 × 25 × 200 cm were cast. One of the beams was not strengthened, but the others were strengthened with carbon FRP. The angle of twist at torque intervals, first cracking torque, ultimate torque and ultimate twist angle of the conventional and strengthened beams during the testing process were compared. Results showed a significant improvement in the torsional performance of RC beams using carbon FRP. The fully wrapped beams performed better than the beams with strip wrapping due to the influence of various wrapping configurations. Amongst the wrapping configurations of FRP fabrics, the 45° spiral strip wrapping configuration was the most effective for RC beam strengthening in terms of torsion resistance. Reinforced concrete (RC) beams strengthened with fiber reinforced polymer composite were tested under combined bending and torsional moment; The effect of composite orientation, spacing and number of plies on the torsional response; Ultimate torsional moments of RC beams; Twist angle of rotation of control and strengthened beams; Analytical prediction for CFRP material contributions to the ultimate torsional moment of strengthened RC beam. [ABSTRACT FROM AUTHOR]

This paper presents the geometry and material distribution influence on energy absorption systems and failure mode of glass epoxy tubes and carbon epoxy tubes in order to improve the structural performances. Experiments were carried out on different types of composite tubes subjected to axial compression load. After collecting the results of the crushing and drawing the load–displacement curve, the initial failure load, maximum crushing load and average load were found. From these parameters, the crashworthiness parameters were calculated. The comparison results between the parameters showed that the best structure of the glass epoxy tubes was the circular tube with eight layers, where produced the highest specific energy absorption at a value of 21.23 kJ/kg. [ABSTRACT FROM AUTHOR]

Integrating foil sensors into fibre-reinforced plastics offers the advantage of making manufacturing measurable with spatial resolution and thus simplifies quality control. One challenge here is the possible negative influence of the integrated sensors on the mechanical behaviour of the structure. This article shows how the different parts of a film sensor influence important mechanical strength parameters of fibre composites. A comparison of two thermoplastic carrier films shows that by choosing polyetherimide (PEI) instead of polyimide (PI), a considerably more advantageous failure behaviour of the composite is achieved. While integrated PI films reduce the interlaminar shear strength by 68%, no impairment is noticeable due to PEI films. For the critical energy release rate, PEI-based film sensors even lead to a significant increase, while a significant deterioration of 85% can be observed for PI-based sensors. However, not only the film substrate plays a decisive role for the interlaminar shear strength, but also the sensor structures themselves. In this article, sensor structures made of gold were investigated. The decisive parameter for the impairment seems to be the area share of gold structures in the sensor. For a sensor pattern made of gold lines with an area filling of 50%, a reduction of the interlaminar shear strength of up to 25% was observed depending on the angle between the shear stress and the gold lines. No impairment was observed for sensor structures with less gold area. The results show that PEI substrates can be a superior alternative for sensor integration into fibre composites and suggest that there is a trade-off between sensitivity and degradation of mechanical properties when designing interdigital sensors. [ABSTRACT FROM AUTHOR]

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describe, how multiple CAE Analysis Simulations were evaluated to verify the influence of the filler in polymer matrix, by checking the differences in weight, density and maximum limit on tensile analysis(MPa) for each polymer composite (PA-MWCNT & PA-CF). Fibre reinforced polymer (FRP) composites were incorporated at different loadings of 10 wt. %., 20 wt. %., and 30 wt. %. Statistical Analysis results, reveals that high tensile limit has been achieved, when the addition of 30 wt. % of CF filler in the PA66 polymer matrix has been added. This paper explore the potential for a novel type of composite material incorporating carbon fibre (CF) and multi walled carbon nanotube (MWCNT). Recent work has shown that notable improvements in mechanical performance are achievable in reinforced polymers [1]. [ABSTRACT FROM AUTHOR]

Near-surface mounted reinforcement system using fibre reinforced polymer bars has been widely considered as an accepted system for strengthening of reinforced concrete columns, particularly with respect to increasing the flexural resistance. It involves cutting grooves into the concrete cover and bonding laminates inside the grooves with fillers (either epoxy resin or cement mortar) ensuring proper bond between fibre reinforced polymer laminate and concrete to prevent premature failure (debonding of laminate). Near-surface mounting does not require extensive surface preparation and takes minimum installation time than externally bonded fibre reinforced polymer. Unlike conventional fibre reinforced polymer jacketing technology, the efficiency of near-surface mounted bars does not depend on the geometry of the column cross-section as well. Previous experimental studies indicate that strengthening using near-surface mounting increases the lateral strength capacity and energy dissipation capacity of reinforced concrete columns. However, the scope of employing a strengthening system for structural retrofits is constrained by the limitations of the material used for strengthening. The lack of adequate confinement results in reduced ductility and energy dissipation capacity for columns strengthened using near-surface mounted technique, particularly under increased loading eccentricities. Jacketing of columns using fibre reinforced polymer increases confinement; however, the efficiency was observed to be reduced at increased loading eccentricities. Similarly, the flexural capacity and drift capacity under low levels of axial load were not observed to be significantly enhanced by the use of fibre reinforced polymer jacketing. Previous studies have indicated that a combination of these two systems could provide effective behaviour for reinforced concrete columns under eccentric loading. Therefore, this research focuses on utilizing a combination of these two methods in the form of a hybrid fibre reinforced polymer reinforcing system consisting of near-surface mounted bars and fibre reinforced polymer confinement to study the structural response of strengthened reinforced concrete columns under eccentric axial compression. [ABSTRACT FROM AUTHOR]

Fibre reinforced polymer (FRP) is extensively applied in the field of maintenance and reinforcement. In the actual reinforcement of concrete structures, most reinforced concrete (RC) members are in a cracked state and the existing calculation methods seldom consider the initial damage of concrete, especially the effect of severe damage on the crack of RC members. Therefore, it is necessary to propose a model for accurately evaluating the crack width of the repaired different damage state concrete members with carbon fiber reinforced plastic (CFRP) sheet. This study presents an experimental investigation on the crack behaviors of the CFRP sheet flexural-strengthened pre-damaged RC beams based on the results of an experimental program involving ten specimens. The influence of the pre-damaged level, reinforcement ratio and CFRP sheet strengthening layer on the crack development, failure characteristics, crack spacing and crack width is analyzed and discussed. Taking into account the influence of the CFRP sheet strengthening layer and pre-damaged level, a formula for predicting the average crack spacing is proposed, and then an analytical model for the crack width prediction of the flexural-strengthened high pre-damaged beams is established based on the calculation model of the crack width of the ordinary RC beams. The predicted results agree well with test values including data of this study and experimental data of 64 sets of references. [ABSTRACT FROM AUTHOR]

Lack of post-yield stiffness and corrosion resistance could inevitably result in a considerable loss of seismic performance for steel reinforced concrete (RC) piers. Fibre reinforced polymer (FRP) reinforcement can provide high tensile strength and protection from corrosion. To achieve a better post-yield stiffness and durability for piers, FRP/steel double-reinforced configurations were designed by the proposed flexural-capacity design method. A seismic fragility assessment was also conducted to investigate the effectiveness of design parameters, namely the ultimate tensile strength of FRP reinforcement, elastic modulus of FRP reinforcement, and ratio of steel reinforcement for a double-reinforced configuration to that for a steel RC configuration ( ρ steel / ρ prototype ). The results demonstrated that the FRP/steel double-reinforced piers satisfied the mentioned objectives, while the fragility of these piers was a 30.2% less than that of conventional steel RC piers. A 79.9% higher median PGA at the collapse damage state was achieved, when the elastic modulus of FRP reinforcement changed from 164 to 80.7 GPa. An increase in the median PGA of 34.8% can be achieved along with the increase of the ultimate tensile strength of FRP reinforcement. When ρ steel / ρ prototype was approximately 66%, FRP reinforcement exhibited the highest effectiveness on the seismic performance of piers. [ABSTRACT FROM AUTHOR]

Increasing importance is being attached to materials in the life-cycle of a building. In the Netherlands, material life-cycle assessments (LCA) are now mandatory for almost all new buildings, on which basis the building is then awarded a building environmental performance or MPG [Milieuprestatie Gebouwen] score. The objective of this study is to reduce the environmental–economic (shadow) costs of precast reinforced concrete (RC) beams in a conventional Dutch office building, thereby improving its MPG score. Two main optimizations are introduced: first, the amount of concrete is reduced, designing a cavity in the cross-section of the beam; second, part of the reinforcement is replaced with a fibre reinforced polymer (FRP) tube. The structural calculations draw from a combination of several codes and FRP recommendations. Hollow FRP-RC beams (with an elongated oval cavity), and flax, glass, and kenaf fibre tubes yielded the lowest shadow costs. In particular, the flax tube obtained shadow costs that were 39% lower than those of the hollow RC beam (with an elongated oval cavity); which also contributed to decreasing the shadow costs of other building components (e.g., facade), thereby reducing the MPG score of the building. However, this study also shows that it is important to select the right type of FRP as hemp fibre tubes resulted in a 98% increase in shadow costs. [ABSTRACT FROM AUTHOR]

This article describes the use of fibre reinforced polymer composites to increase the strength of an isotropic metallic cylindrical shell against elephant's foot buckling. This form of buckling occurs when a cylindrical shell structure is subjected to high internal pressure together with an axial force, such as those that may occur in tanks and silos. It is particularly relevant to tanks under seismic action. Although fibre reinforced polymer composites have been widely applied to different types of structures under several loading conditions, its use to strengthen thin steel cylindrical shells has been very limited. Here, a non-linear elasto-plastic finite element idealisation is used to explore the strengthening effect of a fibre reinforced polymer strip on a thin cylinder. The optimum size and position of the fibre reinforced polymer sheet were obtained and empirically formulated. This study has shown that the strength after repair is sensitive to minor changes in the fibre reinforced polymer parameters so that a close adherence to the optimum parameter values is very desirable. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the experimental and the analytical results of pultruded glass fiber reinforced polymer sheet pile panels subjected to flexural loading. Full scale four-point flexural tests were conducted up to failure on five sets of joined pairs of glass fiber reinforced polymer Z-pile panels by placing them flat-wise. The influences of transverse and longitudinal fiber volume fraction, span-to-depth ratio and steel plate on the carrying capacity and deformability were discussed. The test results displayed that increasing the fibre transverse and longitudinal volume fraction was helpful for tearing control at the flange-web junction on the compressive side, thus obviously enhancing the load capacity and the flexural rigidity of fiber reinforced polymer sheet pile panels. The additional steel plate improved the rigidity of fiber reinforced polymer sheet pile panels, but the load capacity increased insignificantly due to the debonding of steel and glass fiber reinforced polymer interface. The span-to-depth ratio has little influence on the ultimate load due to the local failure but large deformation occurred in the long-span specimen. Based on classical laminate theory for anisotropic materials, a new equation was proposed to calculate the flexural and shear rigidities of glass fiber reinforced polymer sheet pile panels with corrugated section, in addition to applying classical Timoshenko beam theory. The theoretical results agree well with those obtained from the experiments. [ABSTRACT FROM AUTHOR]

As the use of fibre reinforced polymer materials in bridge construction is becoming more popular, appropriate joining techniques, particularly for field joints, are necessary. Bolted joints are a common method for joining fibre reinforced polymer structures. The main advantage of bolted joints is their detachability, but they have a number of shortcomings. On the one hand, hole clearances, which are needed to facilitate on-site assembly, reduce the stiffness and joint efficiency. On the other hand, it is not possible to rely on the beneficial effects of bolt pre-defined tension loads, i.e. load transfer in friction, due to the considerable losses of bolt tension caused by the creep deformation in the composite material. To tackle these problems, a solution utilising metallic inserts in the hole is proposed in this paper. A series of experimental tests have been conducted to investigate the effect of inserts on the bolt-tension relaxation, the stiffness and the load-bearing behaviour of joints. Finite element analyses were also employed. The study demonstrates several benefits of the inserts: the bolt tension relaxation is minimised, the load transfer by friction may be feasible to be utilised in the bridge service state and the joint efficiency is increased in terms of stiffness and strength. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical properties of high impact polypropylene composite reinforced with pineapple leaf fibre from the Josapine cultivar as a function of fibre loading. PLF was extracted by using a pineapple leaf fibre machine and then an alkaline treatment was conducted to enhance the properties. Samples of the composite were fabricated with 100 mm fibre length with five different fibre loadings of PLF (30, 40, 50, 60 and 70 wt%). The fabrication was made by a compression moulding technique with unidirectional fibre orientation. Related tests such as tensile, hardness and density tests were conducted to determine the effect of fibre loading. The experimental data showed that the composite with the 60 wt% fibre loading offered the highest value of tensile strength, which was about 309%, and the Young’s modulus was about 540% compared to 0 wt% of PLF loading. Meanwhile, the hardness and density of the PLF/PP composites showed very similar values, with small increments from 30 wt% up to 70 wt% PLF loading compared to 0 wt% of PLF loading. The highest values are 65.38 Shore-D and 1.002 g/cm³ respectively. The results also revealed that PLF from the Josapine cultivar with alkaline treatment greatly influences the mechanical properties of PLF/PP composite. [ABSTRACT FROM AUTHOR]

This paper presents an experimental research on timber columns with externally bonded fibre reinforced polymer sheets, which consist of aramid fibre reinforced polymer, carbon fibre reinforced polymer and basalt fibre reinforced polymer. This is to provide a strengthening solution to upgrade the structural behaviour and load carrying capacities of such columns under the influence of fractured wood texture. In total, 14 columns were constructed and tested, consisting of 8 circular timber columns and 6 square ones. Besides, three columns of such two section types with knag were reinforced by wrapping of carbon fibre reinforced polymer sheets and tested. The failure mode was analysed, as well as the fracture surface. Externally bonded fibre reinforced polymer sheets were found to be very effective in upgrading the compressive strength of the columns strengthened. The enhancement on load carrying capacities by fibre reinforced polymer reinforcement is in the range of 69-103% for the specimens with a circular section and of 35-83% for the ones with a square section. The test results also show that better ductile behaviour and higher ultimate load carrying capacities were obtained for the columns with externally reinforcing of fibre reinforced polymer sheets. However, there is a great reduction in ultimate loading capacities on columns with fractured wood texture, and the cracks were found on the fracture surface because of the fibres near the cracks being compressed. [ABSTRACT FROM AUTHOR]

In this paper, micromechanical modelling and simulation were performed for unidirectional fibre reinforced composites subjected to transverse and in-plane shear by finite element method. Representative volume element consisting of fibre, matrix and interface was established for the simulation, considering random fibre distribution. The two dominant damage mechanisms of fibre reinforced composites, matrix plastic deformation and interfacial debonding were taken into account in the simulation. Periodic boundary conditions were applied to the representative volume elements. The simulation results indicate that the failure behaviour of the composites under transverse shear is dominated by matrix plastic damage, while the in-plane shear damage is initiated by interfacial debonding and then ultimate failure is caused by matrix damage. Fibre distribution is found to have a more significant effect on the failure behaviour of the composites under transverse shear than in-plane shear. The predicted in-plane shear strength and failure strain show reasonable agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Research into carbon fibre reinforced polymers (CFRP)'s application to steel as a retrofitting technique has shown very promising results for improving mechanical properties. However, the limitation of these materials in a corrosion inducing environment has generally been overlooked. In this study, the interaction of CFRP and steel in extreme weather conditions and the material characteristics in causing localised corrosion (e.g. pitting) were investigated, with the primary aim of quantifying pit depth. Pits are known to initiate fatigue cracks in steels. Steel tiles placed in direct contact with different varieties of CFRP were exposed to 5% NaCl solutions at two temperatures for different durations. The specimens were microscopically examined to find the existence of pits, their depth and density. Steel with prior grinding suffered negligible pitting, whereas the sand-blasting created distinct isolated regions where pitting was more commonly witnessed. However, the most relevant observation was that even after 6 months of exposure to the aggressive NaCl environment, whatever pitting occurred, it was found not to be overly critical in reducing the mechanical strength of the CFRP/steel bonds. [ABSTRACT FROM AUTHOR]

The specific properties of fibre reinforced polymers give them a lot of advantages over traditional materials but the long life of polymeric composites poses serious environmental threats raising sustainability concerns. The other issue of importance concerning the innovators and environmentalists in the mass usage of this material is its health impacts on human beings. This paper thus attempts to highlight and surface out the issues related to fibre reinforced polymers’ sustainability and their health impacts on human beings, by reviewing past studies on the subject, to examine critically the extensive body of published data, prior observations and ideas on the subject in order to identify and analyse those features that are intrinsic and unique to fibre reinforced polymers. This would thus serve as a conceptual model for future research on fibre reinforced polymer composites sustainability and health concerns. [ABSTRACT FROM AUTHOR]

Fibre reinforced polymer is consisted of matrix and reinforcement, which are the deciding factors of mechanical properties. The fibre orientation is dependent on the parameters of material, such as fibre diameter, length, and interaction between fibres (which is interpreted as fibre content), and moulding factors like moulding closure speed, moulding pressure, moulding temperature, etc. Owing to fibre orientation, compression moulded product becomes inhomogeneous and anisotropic, which influences mechanical properties significantly. Therefore, optimal quantitative value of fibre content and orientation is derived to improve tensile strength and shock absorption. Tensile strength of fibre reinforced polymer at 0° orientation is constantly increased along with fibre content and orientation. When fibre orientation is isotropic, tensile strength at 0° direction and the one at 90° direction are same. However, the tensile strength ratio at 90° direction decreases when composite becomes anisotropic ( J is increased). This can be elucidated as the result of the glass fibre filament separation when load is applied perpendicular to the longitudinal direction of filament. Therefore, tensile strength ratio at 90° orientation decreases with fibre content. In conclusion, higher strength can be achieved when fibre used in fibre reinforced polymer is less than the large number of fibres in yarn. [ABSTRACT FROM AUTHOR]

ABSTRACT FRP bars are made of innovative materials, and use of these bars in residential and commercial buildings and infrastructure could result in their increased applications. This requires establishment of fire resistance of the FRP bar RC. This paper describes the results of a parametric study that was carried out on hybrid and carbon FRP bar RC beams. The influence of concrete strength and load ratio on the high temperature performance of beams was investigated. The study used finite element modelling and was conducted with the help of numerical models that were calibrated previously by the authors against the data of experimentally tested beams. It was found that the beam strength and stiffness reduce in the same proportion between two consecutive load ratios and are nearly uninfluenced by the concrete strength. The amount of load was found to be a critical factor for the beam thermal resistance. Preliminary guidance for FRP RC beam design in fire situation is provided on the basis of findings of the study. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A broad class of structural problems has been recognized as being non-conducive to the use of conventional state-of-the-art structural analysis techniques involving the finite element method. This class of problems includes long fibre reinforced polymer structural members having non-uniform, continuously variable material properties and cross-sectional geometry. A novel composite leaf spring is being developed (Thunder Composite Technologies, Ltd.), which will likely prove to be superior to the conventional leaf springs that it aims to replace. However, this new spring belongs to the aforementioned class of problems and will therefore necessitate unconventional and highly complex design and analysis techniques due to the anisotropy and non-homogeneity of its constituents. As such, a design and analysis software tool was developed to be capable of collecting user stipulated parameters and performance specifications, generating a design that is capable of meeting these requirements and performing a high-fidelity structural analysis on the resulting design in order to verify its performance. The following paper summarizes the engineering science and programming methodologies employed by this design tool and discusses how similar methodologies could be employed in the design and analysis of other structural members that reside within this class of problems. [ABSTRACT FROM AUTHOR]

Construction sector is one of the largest markets for fibre reinforced polymers (FRPs) globally. FRP composites are used in a wide range of applications in construction ranging from rehabilitation of existing structures to the full-scale use for new projects because of the benefits they provide over conventional building materials. Such advantages include but not limited to lightness, high mechanical performance and possibility of production in any shape, ease of installation and lesser requirement for supporting structure, controlled anisotropy, high specific strength and specific stiffness. All these multifarious features of FRPs are knocking the doors for new avenues of myriad applications in the Construction Industry, but unfortunately polymeric composites are susceptible to heat and moisture when operating in changing environmental conditions dispelling the biggest myth of them being invincible. The heat response of FRPs is also a major issue of importance in dictating the fate of FRPs future acceptability and applicability. This paper thus attempts to review the specific areas of the current utilization trend of FRPs in the Construction Industry and draw their advantages to support the future applications in a variety of construction processes. It is also being attempted to juxtapose the applicability and the durability concerns of FRPs in a single literature for assessing the versatility and scope of FRPs, by shedding light on the past available studies on the related matter. [ABSTRACT FROM AUTHOR]

An efficient frame finite element (FE) is developed and applied for nonlinear analysis of reinforced concrete beams flexurally strengthened with externally bonded fibre reinforced polymer (FRP) strips/plates. The developed nonlinear model is able to capture different failure modes associated with concrete crushing and cracking, yielding of steel, FRP rupture and intermediate crack-induced debonding of FRP sheets/plates. The element is formulated using force interpolation concept and a simple approach based on application of discrete springs and linear interpolation of bond forces along the element axis is adopted to take account of shear-slip. The developed formulation and analytical tool are employed to predict the loading capacity and the load-deflection response of reinforced concrete beams strengthened with FRP and the numerically simulated responses agree well with the corresponding experimental results. The major features of this frame element are its simplicity and efficiency compared with more complex FEs which makes it a suitable tool for practical use in design-oriented parametric studies. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electronic Journal of Construction Technologies / Yapı Teknolojileri Elektronik Dergisi is the property of Teknolojik Arastirmalar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study is concerned with the experimental investigation into the seismic behaviour and retrofitting of gravity-load-designed reinforced-concrete (RC) shear wall structures in Singapore. These structures are designed according to the British Standard (BS8110 1985). For this purpose, 1/5 scaled models (with and without retrofitting), representing the lower critical regions of a 25-story RC shear wall structure, were tested under cyclic loadings. Test results showed that the shear wall failed at the base due to shear and that the pushover test provides a simplified representation of the cyclic test. Retrofitting the wall with GFRP (glass fibre reinforced polymer) system resulted in improved performances of up to 20% to 30% higher ultimate load capacity and displacement. The study provides an insight into the seismic behaviour of such structures and the mechanism of the proposed retrofitting scheme for improving the structural resistance to seismic loads. [ABSTRACT FROM AUTHOR]

The intrinsic advantages of strengthening the steel-based structures by the use of fibre reinforced plastic (FRP) material have not yet been fully exploited. In this paper, a succinct overview of recent studies made to enhance the strength of steel beams using FRP laminates is presented. The results presented and discussed in this paper were obtained by closely studying the behaviour of steel beams strengthened with carbon FRP material. An attempt is made to succinctly summarise the findings for two different types of strengthening of the steel beams using carbon FRP laminates. The first type of beams focuses on enhancing the strength of steel in flexure while the second focuses on increasing the shear strength of the beams. Three beams were designed so as to cause them to fail in flexure. Of the beams studied, two were strengthened using carbon FRP strips attached to the tension flange. One of the beams was tested to facilitate comparison of their behaviour to the two beams which are strengthened in flexure. Three other beams were designed such that they failed predominantly in shear. Of these three, two were strengthened with carbon FRP strips attached to the webs while the third beam was used as a control beam for the purpose of drawing comparisons. Preliminary results revealed a noticeable increase in the strength for both the flexure strengthened beams and the beams strengthened in shear. The observed increase in shear strength of the beams was 26% while the increase in strength for the beams tested in flexure was 15%. This study convincingly shows that it is possible to strengthen steel beams using carbon FRP laminates in both flexure and in shear. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a study on the adhesion of thermoplastic films to a room temperature-hardening epoxy resin, which deals with an important question on sensor integration into fibre composites. By means of a morphological box, a test specimen is developed, which allows to test strength values for the adhesion of thermoplastic films to epoxy resin. Polyimide (PI), which is typically used as a carrier material for flexible sensors, is compared with the thermoplastics polyetherimide (PEI), polyethersulfone (PES) and polyamide 6 (PA6). To evaluate the spatial formation of the interface, images taken with a light microscope, fluorescence microscope and electron microscope and an energy-dispersive X-ray spectroscopy (EDX) analysis are presented. The images show that during the curing process of the epoxy resin the initially expected pronounced interphase does not form. In this respect, it is surprising that PEI achieves such a high adhesion strength even without extended interphase formation, that the failure of the test specimen occurs in the epoxy resin region at a tensile stress of 70 MPa and not at the interface between epoxy and PEI, as might initially be assumed. It is also surprising that PES exhibits the lowest adhesion strength of 5 MPa to room temperature-hardening epoxy resin, although in previous investigations it was often used as a soluble toughness modifier for epoxy resins. The tensile adhesion strength of PI to epoxy resin was found at 27 MPa and the tensile adhesion strength of PA6 to epoxy resin was found at 13 MPa. For sensor integration, the findings mean that flexible sensors on PEI substrates promise a low tendency to delaminate even in the room temperature-hardening epoxy resin used, while the other materials tested indicate an increased tendency to delaminate. [ABSTRACT FROM AUTHOR]

Common analytical models to predict the unidirectional compressive strength of fibre reinforced polymers are analysed in terms of their accuracy. Several tests were performed to determine parameters for the models and the compressive strength of carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP). The analytical models are validated for composites with glass and carbon fibres by using the same epoxy matrix system in order to examine whether different fibre types are taken into account. The variation in fibre diameter is smaller for CFRP. The experimental results show that CFRP has about 50% higher compressive strength than GFRP. The models exhibit significantly different results. In general, the analytical models are more precise for CFRP. Only one fibre kinking model's prediction is in good agreement with the experimental results. This is in contrast to previous findings, where a combined modes model achieves the best prediction accuracy. However, in the original form, the combined modes model is not able to predict the compressive strength for GFRP and was adapted to address this issue. The fibre volume fraction is found to determine the dominating failure mechanisms under compression and thus has a high influence on the prediction accuracy of the various models. [ABSTRACT FROM AUTHOR]