884 Materials and Structures(2008)41: 879-890 Fig 3 Tension test prefabricated FRP composite [31 in Table 3, and in Fig 3. The exact dimensions of the recommendation by ASTM [3] of specimens length, straps widths that were recommended by standard of 250 mm, was difficult to adopt due to the yere difficult to meet. If one would wish to cut apparatus jaws length, and that was the reason why 15.0 mm wide straps out of fabrics, as recommended the total length of l=450 mm was used (see Fig. 5) by ASTM standard [3], it should be done along the Though, the specimen length between the jaws was fibers bundle, which would cause cutting of fibers. 150 mm, i.e., the required value by standards [3]. All For that reason each specimen consisted of exact specimens in this testing were dry interwoven fibers number of fiber bundles. The each bundle was i.e., without coating of epoxy glue, not strengthened 2.63 mm wide. Thus six bundles were 15.8 mm wide at their ends or anywhere else. Extensometer, type that was close to 15.0 mm. Tensile strength values in Multisens B066608, was used for deformation mea this research were determined by testing series of five surement. The extensometer was placed in the middle different specimen types of various widths (see of the strap, at the length of 50 mm. Specimens were Fig 5a). The specimen,'s type widths were:(1) stretched at the speed of 2 mm/min. At the grip area 2.63 mm or one fibers bundle, (2) 15.8 mm(6 rubber jaws with wider clamps were used, thus there bundles),(3)50 mm(19 bundles),(4)100 mm(38 was neither tearing, nor slipping of the specimen bundles), and(5)200 mm(76 bundles). The cutting straps. The tensile strengths of the specimens were of straps out of fabric is shown in Fig 4. Each represented both in MPa fab as in [3)) and in kN/m series type consisted of five specimens. The max as in [5). The tensile strength and the modulus of elasticity are determined by adopting the measured value of the glass fabric thickness of 0.636 mm. The defining tensile strength in MPa is not always practical because it is difficult to determine the average thickness of the fabric. The fabric is inter- woven with thin threads. and even the smallest error in such determination could influence the thickness value of tensile strength. The specimens of 50 mm width show the highest tensile strength and strain at failure. In specimens some of the fibers were at beginning stretched more than others and thus they broke earlier during the testing. When the most stretched fibers in narrower straps break, they cause proportionally more cross section damage than breaking of most stretched fibers in wider straps. It Fig. 4 Straps cutting out from fabric has happened because all the fibers could not bein Table 3, and in Fig. 3. The exact dimensions of the straps widths that were recommended by standards were difficult to meet. If one would wish to cut 15.0 mm wide straps out of fabrics, as recommended by ASTM standard [3], it should be done along the fibers bundle, which would cause cutting of fibers. For that reason each specimen consisted of exact number of fiber bundles. The each bundle was 2.63 mm wide. Thus six bundles were 15.8 mm wide that was close to 15.0 mm. Tensile strength values in this research were determined by testing series of five different specimen types of various widths (see Fig. 5a). The specimen’s type widths were: (1) 2.63 mm or one fibers bundle, (2) 15.8 mm (6 bundles), (3) 50 mm (19 bundles), (4) 100 mm (38 bundles), and (5) 200 mm (76 bundles). The cutting of straps out of fabric is shown in Fig. 4. Each series type consisted of five specimens. The recommendation by ASTM [3] of specimens length, of 250 mm, was difficult to adopt due to the apparatus jaws length, and that was the reason why the total length of l = 450 mm was used (see Fig. 5). Though, the specimen length between the jaws was 150 mm, i.e., the required value by standards [3]. All specimens in this testing were dry interwoven fibers i.e., without coating of epoxy glue, not strengthened at their ends or anywhere else. Extensometer, type Multisens B066608, was used for deformation mea￾surement. The extensometer was placed in the middle of the strap, at the length of 50 mm. Specimens were stretched at the speed of 2 mm/min. At the grip area rubber jaws with wider clamps were used, thus there was neither tearing, nor slipping of the specimen straps. The tensile strengths of the specimens were represented both in MPa (ffab as in [3]) and in kN/m (fmax as in [5]). The tensile strength and the modulus of elasticity are determined by adopting the measured value of the glass fabric thickness of 0.636 mm. The defining tensile strength in MPa is not always practical because it is difficult to determine the average thickness of the fabric. The fabric is inter￾woven with thin threads, and even the smallest error in such determination could influence the thickness value of tensile strength. The specimens of 50 mm width show the highest tensile strength and strain at failure. In specimens some of the fibers were at beginning stretched more than others and thus they broke earlier during the testing. When the most stretched fibers in narrower straps break, they cause proportionally more cross section damage than breaking of most stretched fibers in wider straps. It has happened because all the fibers could not be b c a d α l a d b a Fig. 3 Tension test specimen drawings of prefabricated FRP composite [3] Fig. 4 Straps cutting out from fabric 884 Materials and Structures (2008) 41:879–890