Fiber Reinforced Polymer Composite Systems

Question: Discuss about the Fiber Reinforced Polymer Composite Systems. Answer: Introduction: There are different types of applications of the segmental bridge piers and these applications are seen in the high earth quake risk zone, as a result of this, the researchers and the designers are very concern with the seismic performances of these designs (Fenget al. 2012) ( https://www.iitk.ac.in/nicee/wcee/article/WCEE2012_1870.pdf ). Different types of investigations such as pseudo static tests are performed by the investigators in order to understand the seismic performance of the segmental columns. According to the research, the traditional or conventional reinforced bridges have suffered lots of damage at the time of earth quake and also after earth quake. The deformations that were caused by the earth quakes sometimes found to be permanent deformations. In order to improve the seismic performance and also to reduce the impact of the earth quake unbounded post tensioning is to be used at the centre of the precast segmental columns. It can also be done in order to reduce the residual displacement to a minimal level. The research shows that it has been proved that if these implementations can be made then the structure will definitely experience less damage due to earth quake than the traditional structures has experienced, though the seismic performance of the structure will depend on the design details. According to the research, in recent years, in order to overcome the problems related to earth quake, an innovative segmental system was developed in the Washington State University. It contains fiber reinforced polymer tubes that are filled with segmental concrete. These are known as SPPT CFFT. The polymers are super imposed on each other. There are some ducts that are situated in the pre cast segments through which the tendons are passed through. These tendons are designed in such a way that they remained anchored within the foundation. There are several structural benefits of this innovative design. The loads that are post tensioning are capable o f keeping the entire system as a single unit (Haitham, 2010) ( https://www.dissertations.wsu.edu/Thesis/Summer2010/H_Dawood_062510.pdf ). If the stress reaches zero even for only once, an increase in the lateral load can be seen and this increase creates an opening between that particular segment and the segment which is situated beneath that particular segment. This opening propagates with the load, if the load increases, the propagation also continues. At this time the post tensioning steel bar is elongated and as a result of this, the stress on the tendons increases. As the propagation increases, the stiffness of the entire system reduces. It results into the reduction of the absorption of the seismic impacts and damages to the structure. The unbounded tendons are the only tendons that are chosen for this purpose as the strain and stress do not remain concentrated in these types of tendons. It also has the capability of transferring the shear forces throughout the interface of t he surface. The friction related to shear depends on the clamping force. It is provided by a pre stressing tendon. The self-centering capability is also known as restoring force and this force is given to each and every pier in order to ensure that no deformation can take place at the time of earth quake or after earth quake. It has found from the research the SPPT CFFT bents and piers have some certain behaviours under the loads of seismic pressure and these behaviours are found to be very encouraging. Here, the drift of the residual pier are taken as negligible. The damage is also reduced to the minimal level; in this case the damage is represented as a form of concrete spelling. It remains only limited to the region of compression. The longitudinal bars are yield in this area. Generally, in this case, the typical R. C. Pliers are used. As a result of this the structure can remain stronger at the time of seismic events, and it can also retain its strength immediately after the s eismic event has taken place (Yu-Chen, 2007) (ftp://mceer.buffalo.edu/OConnor/ftp/S-ABC/ABC-MAIN.Data/PDF/Dissertation_Ou-2820423199/Dissertation_Ou.pdf ). As a result of this, the structure will require minimal amount or repair even after a devastating seismic event. The cost of the repair can also be reduced significantly. The construction schedule can also be shortened as a result of this type of structure design and it is included in the agenda of benefits that are provided by this type of design. It is also very helpful in managing the environment. The research shows that the use of this type of structure is being used widely in United States of America and the main purposes of using such design are to shorten the duration of the construction work, innovative designs and less environmental impact (Haitham, 2010) (https://www.dissertations.wsu.edu/Thesis/Summer2010/H_Dawood_062510.pdf ). Figure 1: Schematic drawing of the SPPT-CFFT System Fibre reinforced polymer wrapping It has been found the research that if reinforced polymer wrapping is done or if fibre reinforced polymer ( FRP ) is used then the structure will have more strength and the life span of the structure can be increased significantly. As it is a very light weight element, it is capable of providing a lot of advantages (Pannirselvam et al. 2009) ( https://www.arpnjournals.com/jeas/research_papers/rp_2009/jeas_1109_262.pdf ). In this type of design, the labour cost can be reduced to the minimal level. All the constraints that are related to the site can be removed. The as the weight is very lower, the ration between the strength and weight is very high i.e. The strength of this type of design in the foundation makes the foundation strong or provides strength to the foundation significantly. The durability of the structure as well as the life cycle can be enhanced significantly also with the help of the use of the reinforced polymer wrapping. With the help of such polymers, the structural behaviour of the entire structure can be understood. ERP are used for rehabilitating the current structure. This type of polymer is capable of changing the entire work pattern and design pattern. If any structure is repaired with FRP and if FRP are used at the outside of the structure, then it will add huge strength to the structure (Pannirselvam et al. 2009) ( https://www.arpnjournals.com/jeas/research_papers/rp_2009/jeas_1109_262.pdf ).The FRP plating is known to be a versatile method. It can be applied for the new beams as well as for the beams that already exist and the pattern of applying in the both case is same. FRP is known to be a composite material and it mainly contains carbon, glass fibre and aramid. A matrix of resin is also available in this material. There are some other ingredients that are added while applying the polymers in the construction. The main component of this type of polymer is found to be resin. Resin controls the mechanical property and the characterist ics of the polymers. There are different types of FRP , among them some are used in most of the cases, these are very common in the construction work and these common FRP are known as ( i) Carbon Fibre Reinforced Polymer ( CFRP ), ( ii)Aramid Fibre Reinforced Polymer ( AFRP ) and ( iii ) Glass Fibre Reinforced Polymer ( GFRP ) (Pannirselvamet al. 2009) ( https://www.arpnjournals.com/jeas/research_papers/rp_2009/jeas_1109_262.pdf ). There are different systems by which the FRP can be applied and among these systems the most two common systems are prefab system and lay up system. In case of the traditional; system that was applied in previous times, dry and unidirectional fibre sheets were used. The fabric that was used was also dry and multidimensional. The capacity of FRP can be enhanced if the design and the system can be modified and if it is chosen properly with the requirement. It also helps in distributing the non uniform stress and the shear crack can be determined with the help of this. With the help of FRP, a structure can be modified and a new structure can obtain the required strength as well as ductility. FRP is applied in providing strength to the beams, slabs, columns and even the masonry walls. It also helps in achieving the shear strengths of the components of the structure. Excellent compression strength and tensile strength can also be added to the structure with the help of this polymers i.e . FRP. If plating is done of the FRP laminates, then it may result into the enhancement of the composite moment of the inertia of that particular section. Beams are the components that take a major part in transferring of loads and the entire mechanism of this transfer depends on these (Fiber-Reinforced Polymer (FRP) Composite Systems, 2014) (https://www.mapei.com/public/CA/linedocument/FRP_Brochure.pdf ). Against all types of failure ( Almost ) beams are the only components that create the first line of defense. Beams provide proper strength to the foundation. The cost of FRP is high but if it is compared to the advantages of FRP then it can be said the cost is very low as so much benefits can be obtained from only this amount of money. Generally pre manufactured cured laminates are used in the system and it is used through applying adhesive (Ã…Â ¢Ãƒâ€žÃ¢â‚¬Å¡RANU et al. 2008) ( https://www.bipcons.ce.tuiasi.ro/Archive/105.pdf ). 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