Fibre Reinforced Polymer or sometimes called Fibre Reinforced Plastic is a composite stuff which capable to replace conventional steel saloon for planing of structural elements. FRP is a combination of several polymers such as epoxy, polyester thermosetting plastic and venylester. Normally, fibre is normally made up from glass, C and aramid. Nowadays, use of FRP as chief stuff is really important particularly in aeronautic, military and building. There are many research workers which carried out the research based on application of FRP in building industry.
Figure 2.1: Composite Materials Usage in the Industrial Construction ( Oprisan et al. , 2010 )
For illustration in Okinawa, Japan there is a prosaic span with two uninterrupted spans was reinforced utilizing FRP ( see figure 2.2 ) . This span was constructed in 2000 with girder span lengths between 19.7 to 17.2m. The chief factor why this span constructed utilizing FRP is due to caustic environment from sea salt.
Figure 2.2: The span walker reinforeced utilizing FRP in Okinawa, Japan
Besides that, in Scandinavia, Sweden there is the first big application of FRP for beef uping of a chimney in 1997. In this chimney, about 3000m of CFRP sheet system was wrapped around the column. After 10 old ages, there is no impairment effects could be noticed on the strengthening.
Figure 2.3: CFRP strengthening of a chimney in Scandinavia, Sweden ( Taljsten B. 2007 )
2.2 Advantages of FRP
Fibre reinforced Polymer is the friendly stuff in building stuff. This stuff is truly utile and applicable for strengthened elements in structural members. The FRP have been proved as the best alternate stuff to alter from utilizing conventional steel saloon in most structural elements such as beam, column, slab, retaining wall and wharf in Bridgess building.
Once of the advantages of FRP is high corrosion opposition. Caustic job in steel saloon have effects the lastingness of strengthened structural members. In add-on, to mending this sort of job, it will do high care cost. So, FRP can be used efficaciously as reinforced stuff in chief structural elements. Harmonizing to Benjamin M. Tang, ( 2003 ) the pre and post-tension concrete will hold great workability when reinforced with FRP.
Second, the FRP can manage high tonss even this stuff is low in self-weight. FRP is lower in weigh compared to steel. But, the burden capacity of this stuff is higher based on ratio weight to denseness.
Besides that, the life period of structural members strengthened with FRP can be widening higher compared to steel saloon. This is because, the corrosion of saloon about zero compared to steel saloon. Most of construction reinforced with conventional steel saloon will has imperfect surface after some period because of corrosion consequence. Consequently, the construction ca n’t be longer used and rehabilitation procedure demands to be done instantly. Therefore, when utilizing FRP as strengthened stuff in chief structural members, it will cut down the chance of corrosion onslaught.
Cost for care besides can be reduced if the FRP be used in building. Truly, when the construction is non confronting with job such as corrosion and cleft, the care and mending plants can be reduced indirectly. Hence, the proprietor of edifice can salvage their money for disbursement with care of edifice.
2.2 Properties of Fibre Reinforced Polymer
Nowadays, most of type of FRP used for building is Glass Fibre Reinforced Polymer ( GFRP ) . But, other type that normally used is Class Fibre Reinforced Polymer ( CFRP ) . The chief mechanical belongingss to be considered in selecting of FRP are tensile emphasis, compressive emphasis, and modulus of snap. But, for this surveies merely focus more on tensile emphasis of FRP.
Tensile emphasis: The ability of a stuff to defy interrupting under tensile emphasis is one of the most of import and widely measured belongingss of stuffs used in structural applications. The force per unit country ( MPa or pounds per square inch ) required to interrupt a stuff in such a mode is the ultimate tensile strength or tensile strength at interruption. ( A.S. Singha and Vijay Kumar Thakur, 2008 )
Harmonizing to Sakurada et al. , ( 2007 ) , the stress-strain dealingss for the braided-FRP reinforcing bars in nominal diameter of 13 millimeter behaves linear elastic to failure and its ultimate tensile strength additions eventually 1354 N/mm2, 2.6 times higher than that of the distorted steel saloon with same diameter. The elongation rate at failure reaches 1.9 % whereas the mild steel in diameter of 13 mm extends at 27.4 % .
While the tensile strength of CFRP laminates did non alter significantly over 5 old ages of exposure, the in-plane shear strength showed a little lessening. Bending strength of matrix rosin decreased in early exposure phase. The consequence suggests the decrease of adhering belongingss between C fibres and rosin. ( Nishizaki et al. , 1997 )
2.3 Timber in Construction Industry
Timber beef uping with FRP is really important stuff in order to minimise the use of steel saloon. Surveies of beef uping timber beam with FRP is utile because of the belongingss of FRP can be alter and needs to be better in term of strength and lastingness. Therefore, item apprehension of lumber should go on in order to cognize the behaviour of lumber for going structural component.
Timber is an oldest stuff has been used for building industry. This sort of stuff is a alone stuff compared to common structural stuffs such as concrete and steel. Unlike other stuff, the behaviour of lumber is influenced by the being of its wet contents. Other than that, the lumber behaviour will depends besides by difference in strength when tonss are applied either parallel or perpendicular to the grain way. In fact, different species have different strength belongingss that need to be considered in selecting of lumber. Hence, to enhanced use of lumber in building industry, detail apprehension of lumber behaviour is really of import due to this stuff is more complex than those other stuffs.
2.4 Factors Affecting the Strength of Timber
Moisture Content: Once of the factor that affect the strength of lumber is moisture content. Unlike other structural stuffs, the behaviour of lumber is influenced by the being of its wet contents.
Density: Density which is expressed as mass per volume is one of the chief belongingss impacting strength of lumber. Normally, the heaviest species have thick cell wall and little pits. So, increasing of denseness will take the increasing of strength of lumber.
Slope of Grain: Angle of the grain way in a cut subdivision of lumber is non parallel to the longitudinal axis. The consequence of inclining grain have a important influence on the flexing opposition of a lumber section.If the angle of inclining grain additions, the strength of the lumber will diminish.
Temperature: The strength of lumber is besides affected by temperature, the general consequence being a additive lessening in strength with addition in temperature. This consequence is besides really dependent on wet content, dry lumber enduring much less lessening in strength per oC rise in temperature than wet lumber.
2.5 Tensile strength and compressive strength of lumber
Tensile strength of lumber will be higher if tensile forces parallel to the grain. While, the tensile strentgh of lumber perpendicular to the grain is little. But, if there is defect such as knot on lumber surface even forces applied parallel to the grain, the tensile strength of lumber may be reduced.
Compressive strength of lumber analogue to the grain is much higher compared that perpendicular to grain.
2.6 Timber Beam beef uping with FRP
Recently, there are many researches which focus on reenforcing lumber with other stuff like FRP. T. Russell Gentry ( 2011 ) stated that trials on large-scale beams with longitudinal FRP support confirm that the beef uping technique can be used to increase the flexural strength and stiffness of glulams utilizing dumbly finger-jointed low-grade wood to the degree observed in high-quality glulams constructed of highgrade lumber without longitudinal support. Harmonizing to Francesco Micelli and Antonio Nanni ( 2001 ) , different rosin showed different public presentation lastingness of FRP rebars, particularly for GFRP specimens, since glass fibre are more sensitive to external agents.
Besides that, Maurice Brunner and Marco Schnueriger ( 2005 ) showed that the usage of prestressed C laminates will take to a greater betterment of the supporting capacity of lumber beams than when the laminates are bonded in a slack province. Other than that, the prestressing force was excessively little when the grades of beef uping was instead slow. In a follow-up undertaking, surveies are being carried out to attach several beds of prestressed C laminates glued on top of each other.
In add-on, Borri et al. , ( 2001 ) stated that without asking the remotion of the overhanging portion of the construction, the usage of CFRP as a strengthening technique can be applied. The technique used proved to be easy and fast to put to death, even when on in situ parts. Other than that, Gentile et al. , ( 2000 ) concluded the strength addition of 25 to 50 per centum was obtained, depending on the support ratio and strength of the original lumber.
Thanasis C. Triantafillou ( 1997 ) , shown that a small FRP support can increase shear emphasiss in lumber constructions. This support method is really efficient in term of cost and work every bit good as can be applied with minor influence on the esthetics of wood, particularly when the FRP stuffs employed are made of glass fibres in a crystalline matrix.
The ultimate tensile strain of the lumber increased 64 per centum for the strengthened beams. The FRP stuff apprehensions crack gap, confines local rupture, and bridges local defects in the next lumber, leting the lumber to back up higher nominal emphasiss and strains before neglecting. ( Christopher J. Gentile, 2000 )
Harmonizing to A. Yusof & A ; A. L. Sale ( 2010 ) , timber beam strengthened with GFRP rods had an addition in its ultimate burden transporting capacity. The per centum of addition is between 20 to 30 per centum. In add-on, the strengthening of timber beams with GFRP besides enhanced the stiffness of the beam with a per centum of addition between 24 to 60 per centum.
James F. Brady and Annette M. Harte ( 2000 ) stated that the bonding of pre-tensioned FRP laminates in the tenseness zone of low-grade glulam beams can significantly increase their flexural strength and ductileness. This indicates that prestressed beams have a higher burden capacity but are less malleable than the non prestressed FRP reinforced glulam.
Tajnik et al. , ( 2007 ) showed if in pattern after such support ( with CFRP strip ) become decisive shear opposition of subdivision than is appropriately to utilize the C strip in place of stirrups glued on web of timber beam similar like transverse steel support in steel reinforced concrete constructions. Presented survey show an betterment of 15 % on initial and 24 % on concluding bending capacity, farther at the same clip is achieved betterment of 11 % on initial and 17.5 % on concluding bending stiffness.
Yusof Ahmad ( 2010 ) , proved the burden transporting capacity of lumber beams was increased as the per centum of GFRP used was increased. The ultimate burden and the serviceableness burden were increased between 17.0 to 25.1 % and 13.0 to 54.1 % , severally when the lumber beams were strengthened utilizing GFRP saloon for country between 0.16 to 2481.27 % . It is suggested that the per centum of GFRP between 0.6 to 0.7 % should be considered in the design to fulfill both ultimate and service burden.
Besides that, as reported by Ngu Wang Chung ( 2007 ) , the lumber beam strengthened with FRP increased between 7 to 25 % of stiffness and bending strength will depend on the type of stuff and beef uping method. In add-on, CPRP home base strengthened beam has higher flexing strength compared to the GFRP bars strengthened beam. This is because, the modulus of snap of CFRP is greater than GFRP.
2.7 Finite Element Analysis ( FEA ) in LUSAS Software
Analysis of structural members is really of import in planing phase. Appropriate analysis should be carried out to acquire the best dimension of any structural members. In structural analysis, the most popular method have been used is Finite Element Method ( FEM ) . Finite Element Method is a solution based on partial differential equation and built-in equation.
In add-on, Finite Element Analysis ( FEA ) is used to analyzed specific job by utilizing computing machine plan which to obtain approximative solution. Finite Element Analysis was proposed by R.Courant in 1943 to obtain approximative solution in quiver system. This analysis is really popular to work out structural analysis such as truss, beam and frame.
LUSAS package was developed based on Finite Element Analysis. LUSAS package can work out all types of linear and nonlinear emphasis, kineticss, composite stuff and thermic technology analysis job. For this survey, LUSAS Software is really suited to utilize due to the consequence analysis from this package about approximative with manual solution. Furthermore, this package can work out complicated and complex constructions that ease the structural applied scientist in planing a edifice.
2.8 Gap of Studies
For this research, the analysis of timber beam strengthened utilizing FRP is non much be surveies in composite stuff field. Most of researches are focus more on concrete beam strengthened utilizing FRP stuff. Furthermore, use of lumber beam as chief structural members in building is non much popular compared to concrete and steel.
BENDING BEHAVIOR OF TIMBER BEAMS STRENGTHENED USING FIBER REINFORCED POLYMER BARS AND PLATES
To find the burden transporting capacity, flexing strength or modulus of rupture, stiffness and ductileness of the lumber beams strengthened with FRP,
therefore the strength and stiffness alteration factor can be developed.
Numeric Analysis of Strengthened Timber Beam With FRP
Ngu Wang Chung
To find if strengthened beam with FRP would increase the stiffness and flexing strength of lumber
Timber Beams Strengthened with GFRP Parallel barss: Development and Applications
Chris Gentile et. Al.
To find the behaviour of sawn lumber beams reinforced with GFRP saloon
2.9 Theoretical of Background
There are several theories have been used for this survey.
Deflection at mid span ( Simply Supported ) :
Where: P = Load
E= Modulus of Elasticity
I= Second Moment of Inertia
Maximal Bending Moment ( Simply Supported ) :
Where: tungsten = point burden
L = length