INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 ISSN 2277-8616 Effect Of Batten Plates On Elastic Moment Capacity Of Standard Ipe Profiles Omar Metwally, Ihab M. El-Aghoury, Sherif M. Ibrahim Abstract : Lateral torsional buckling (LTB) failure mode controls the flexural capacity of I-beams. The main parameter that affects the (LTB) capacity of the steel I-beam is the unsupported length of the compression flange. Several configurations to increase flexural capacity include using lateral bracing, vertical stiffeners or batten plates. In this research double-sided batten plates configuration is studied on standard IPE profiles. For this aim finite element model is prepared using ANSYS v19.2. The developed finite element model is validated using experimental results previously conducted by other researchers. A parametric study is conducted using finite element model to evaluate the increase in elastic moment capacity of the IPE profiles that are strengthened with double-sided batten plates. The parameters studied in the research include the span of the steel beam, the location of batten plates relative to beam span and the batten plates dimensions. A Proposed design equations are presented to predict the elastic moment capacity of steel I-beams with various batten plates configurations. Index Terms : Lateral torsional buckling, Batten plates, simply supported beams, Finite element analysis, standard profiles, elastic moment capacity. ——————————ο΅—————————— 1 INTRODUCTION Lateral-torsional buckling (LTB) controls the flexural capacity of steel beams. When applying vertical loads to a steel I-beam that results in compression and tension in the flanges of the section. The compression flange tries to deflect laterally away from its original position, whereas the tension flange tries to keep the member straight In addition to the lateral movement of the section the forces within the flanges cause the section to twist about its longitudinal axis. Numerous experimental and numerical investigations [1 to 9] on steel I-beams strengthened with stiffeners and batten plates have been carried out to improve their behavior to lateral-torsional buckling. Lateral bracing is used also to reduce the compression flange unsupported length by preventing the lateral displacement at braced points. The previous studies showed that the batten plates have a significant effect on the elastic moment capacity of laterally unsupported simply supported I-beams. This effect is noticed for double-sided batten plates configurations. This research aims to investigate the behavior of simply supported laterally unsupported steel standard (IPE) profiles strengthened by double-sided batten plates and propose a simplified design equation to predict the increase in elastic moment capacity. 2 LITERATURE REVIEW Szewczak et al [1] numerically evaluated the behavior of steel beams stiffened with longitudinal, box-type, transversal, and cross stiffeners. They suggested that transversal stiffeners are the least effective and the boxtype stiffener was the most efficient. However, longitudinal stiffeners (i.e. batten plates) are moderately effective in increasing flexural strength. ———————————————— ο· Assistant lecturer, Department of structural engineering, Ain Shams University, Egypt. E-mail: omar.metwaly@eng.asu.edu.eg ο· Associate Professor, Department of structural engineering, Ain Shams University, Egypt. E-mail: ihab.elaghoury@eng.asu.edu.eg ο· Professor, Department of structural engineering, Ain Shams University, Egypt. E-mail: sherif.ibraim@eng.asu.edu.eg Takabatake [2]&[3] mathematically and experimentally studied the lateral buckling of the I-shaped steel beams with longitudinal and transverse stiffeners. His mathematical results for the beam with batten plates located near the support showed increasing by 260% over the unstiffened beam. Experimental results showed that the batten plates have a better enhancement on the flexural strength more than the stiffeners. Moreover, their location near the support give better enhancement in flexural strength. However, there was an disagreement between his experimental and mathematical workPlum and Svensson [4] analytically studied the resistance of lateral-torsional buckling of Ishaped steel beams with box-type stiffeners welded to web and flanges of sections to prevent warping at the beam end. Hassanien [5] numerically investigated a cantilever beam stiffened by vertical stiffeners against (LTB) and suggested that the lateral displacement would be decreased by connecting the compression flange to the tension one using these vertical stiffeners. Yang and Lui [6] numerically investigated the use of inclined stiffeners with an angle θ on the flexural capacity of steel I-beams. Their study showed that the inclined stiffeners have significant enhancement on the flexural strength of steel I-beam and its location near the beam supports give the best enhancement in flexural strength. Sorensen and Rasmussen [7] experimentally and numerically investigated a simply supported beam stiffened with vertical stiffeners and batten plates. The loading condition was point load at mid-span, the span of the beam was 5 m and the beam section was IPE 80. Their study showed that the stiffeners or batten plate does not affect increasing the warping resistance or load-carrying capacity. when it’s located at mid-span of steel beamHassan et al. [8] numerically investigated the effect of using vertical web stiffeners, single and double-sided batten plates, full-depth and partial depth T-stiffeners on the flexural strength of laterally unsupported beams. A set of steel beams simply supported and subjected to uniform moment with various spans were studied, the cross-sections used were standard hot rolled sections (HEB 260 and IPE500). The study showed that the vertical web stiffeners and partial depth Tstiffeners do not affect the flexural strength on the other side. The double and single-sided batten plates have a significant effect on the flexural strength, the best location for batten 333 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 plate is near the beam supports and have no effect at the mid-span. The increase in the number of batten plates or the batten plate dimension leads to an increase in the flexural strength of the beam Prado et al. [9] experimentally examined the behavior of I-shaped steel beams with batten plates under the action of lateral-torsional buckling. Simply supported laterally unsupported beam loaded by applying upward point loads located at one-third of the specimen length from each end. The cross-section used is a standard hot rolled section (IPE 140) with and without batten plates with a laterally unbraced length ranging from 0.69 to 6.0 m. The results of this study showed that the use of batten plates on I-shaped steel beams has a significant increase on the moment capacity in the elastic buckling zone and has a slight increase in the inelastic buckling zone. The study showed that the use of batten plates provided acceptable lateral stability on I-shaped steel beams subjected to bending stresses. Moreover, they concluded that using batten plates on I-shaped steel beams decreases the failure twist angle both in the elastic and inelastic buckling zonesThe previous literature indicates that batten plates are very efficient in increasing the elastic LTB capacity of steel I-beams in cases when it is challenging to other configurationsFrom the review of the literature, the authors were motivated to propose simplified design equations for beams strengthened with batten plates to predict the increase in elastic moment capacity of steel Ibeams with various batten plates configurations. 3 NUMERICAL MODELING 3.1 Finite Element Model A numerical finite element analysis is used to study the effect of using double-sided batten plates on the flexural strength of simply supported laterally unsupported steel Ibeams. The program used in modeling is ANSYS WORKBENCH v19.2 [10]. All beam components which are flanges, web and batten plates are modeled using solid element (SOLID 185) which is defined by eight nodes each having three degrees of freedom. The contact between beam and batten plates is modeled using (CONTACT 174) bonded type. The beam supports are defined to simulate true hinged support condition which is prevented from torsion and free to warp using remote points with deformable behavior and remote displacements prevented from lateral movement and vertical movement (Ux and Uy) and rotation (Rz). Only one of the ends of the beam was prevented from longitudinal movement (Uz) to achieve beam stability conditions. The loading condition is a uniform moment modeled as a concentrated moment at the remote points. The finite element model with the aforementioned criteria is shown in Fig.1. ISSN 2277-8616 Fig. 1. FEM support and loading conditions For all the specimens, material properties are considered. The material considered is steel grade S235 with a modulus of elasticity (E=210 GPa), yield stress (Fy=235 MPa) and Poisson’s ratio (υ=0.3). 3.2 Model Verification Bo Yang [11] experimentally and numerically investigated the behavior of simply supported laterally unsupported beam under a concentrated load. The material properties from a tensile test are (Yield stress Fy= 410 MPa, Ultimate strength Fu=570 MPa, Poisson ratio υ=0.3 and Young’s modulus E=211 GPa). In the finite element modeling, the stress-strain curve is approximated using a bilinear shape with tangent modulus Et = 0.1E. The initial geometrical imperfections are considered as span/1000. Table (1) shows the comparison between the current finite element model and Bo Yang [11] results. For specimens DTS2 and DTS3, the verification results show good agreement for both experimental and numerical work. However, for specimen DTS1, the experimental results were far from the finite element results of Yang's work and the current proposed finite element model. That’s maybe because of incorrect measurements during the experiment or an incorrect setup of the specimen and experiment procedures. TABLE 1 VERIFICATION RESULTS WITH Bo YANG’s [11] WORK Specimen ID DTS-1 DTS-2 DTS-3 Bo Yang results [13] π 52.6 179 268 π 47.3 166.5 277.2 Current finite element model π 44.5 180 270 π π 0.846 1.006 1.007 π π 0.94 1.081 0.974 Units for moments are kN.m Hassan et al. [8] studied [HEB 260 and IPE500] to determine the effect of double and single-sided batten plates on the LTB capacity. The material considered is S235 with a modulus of elasticity (E=210 GPa, yield stress Fy=235 MPa and Poisson’s ratio υ=0.3). The initial imperfections were considered as span/1000 for finite element modeling. As indicated in Tables (2 and 3) the results for HEB 260 and IPE500 specimens using double-sided batten plates show good agreement with Hassan et al. work. In these tables; L is the span of the steel beam, Np is the batten plates number and W b is the batten plate width. TABLE 2 334 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 VERIFICATION RESULTS WITH Hassan et al. [8] IPE 500 SPECIMENS πΏ π π π πΏ Hassan et al. results Current finite element model Plain Stiff. Plain Stiff. Mcr Mcr π π 122. 8 234. 5 372 115.5 184 133. 8 255 311.5 374 303 4 0.02 110 189 8 113 12 0.03 3 0.03 3 177. 6 302. 5 π π Plain DETAILED VERIFICATION RESULTS WITH Prado et al. [9] STIFFENED SPECIMENS π π Stiff. Laterally unbraced length (m) Prado et al. π 6 4.8 3.6 1.05 13.6 14.9 19.8 Current finite element model π 13.8 16.56 21 π π 1.015 1.11 1.06 Units for moments are kN.m 1.08 9 1.08 7 1.00 5 1.03 4 1.02 9 ISSN 2277-8616 Units for moments are kN.m TABLE 3 VERIFICATION RESULTS WITH Hassan et al. [8] HEB260 SPECIMENS πΏ π π π πΏ 213 4 0.02 160 8 133 12 0.03 3 0.03 3 Hassan et al. results Current finite element model Plain Stiff. Plain Stiff. Mcr Mcr π π 196. 2 230. 2 247. 8 216. 9 264. 9 276. 3 207 231 240 270 255 285 π π Plain π π Stiff 1.05 5 1.04 3 1.02 9 1.06 5 1.01 9 1.03 1 Units for moments are kN.m Prado et al. [9] investigated the behavior of I-shaped steel beams with batten plates under the action of lateraltorsional buckling. The material properties from a tensile test are (Yield stress Fy= 391 MPa, Young’s modulus E=217 GPa and Poisson ratio υ=0.3). The initial imperfections for the finite element modeling were considered as span/1000. Thirty-three IPE-140 steel beams were tested by bending. Three specimens for each sample to take the average. A comparison between Prado et al.’s [9] results and the current finite element model is shown in Tables (4 and 5). The verification results for these specimens show a good agreement for both numerical and experimental work. Fig.2. shown that there is agreement also at the deformation shape of experimental work and the finite element model. TABLE 4 VERIFICATION RESULTS WITH Nestor Prado et al. [9] PLAIN SPECIMENS Laterally unbraced length (m) 6 4.8 3.6 Prado et al. π 7.5 9.6 14.7 π 7 8.9 12.3 Current finite element model π 6.96 8.84 12.01 Units for moments are kN.m π π 0.928 0.921 0.82 π π 0.994 0.993 0.976 Fig. 2. Failure mode of the stiffened specimen. a) Prado et al experimental b) Current F.E. model 4 PARAMETRIC STUDY AND DISCUSSION Various standard IPE profiles with different spans are studied to determine the effect of using double-sided batten plates on the LTB capacity. The used steel IPE cross-section is classified as a compact sections regarding local buckling conditions. The studied spans are 6, 8, 10, 12 and 14 meters. π is the elastic critical moment from the finite element model. π is the elastic critical moment from the proposed equation and π is the elastic critical moment of unstiffened steel beam which can be determined by most design specifications such as the AISC [12] or the SSRC Guide [13]. Different parameters for the batten plate are considered. Fig.3. shows the layout for the steel beam strengthened with double-sided batten plates. The batten plate’s centerline location ( π ) varie from 0.1L to 0.45L with an increment of 0.05L. The batten plate width ( π ) is taken with several values of L/50, L/40, L/30, L/20 or L/10. The batten plate thickness ( π ) is considered to be equal to 4, 6, 8, 10 and 12 mm TABLE 5 335 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 π π πΈ πΌ πΊ π½ π πΈ πΌ πΈ πΆ =√ + (πΏ ) (πΏ ) ISSN 2277-8616 (1) The weighted average values for the warping constant and the torsional constant can be represented as : Fig.3. steel beam strengthened with double-sided batten plates. Elastic moment capacity of beam stiffened by double-sided batten plates By changing the cross-section profiles, it seems that all the cross-sections have the same behavior while using 4 batten plates per span. Fig.4. shows the relation between (π / π ) at the vertical axis and length of beam for different standard profiles at the horizontal axis. While π is the elastic critical moment from the finite element model for the stiffened beam with 4 batten plates at 0.1 L from both sides. Batten plates width is L/30 and thickness is equal to beam web thickness. 4.1 Fig. 4. different profiles of standard cross sections strengthened with double-sided batten plates. The previous studies indicated that the double-sided batten plates have a significant effect on the elastic moment capacity of simply supported laterally unsupported I-beams. This effect is noticed for double-sided batten plates configurations. The main parameters affecting elastic flexural strength are the warping constant, moment of inertia about the weak axis of the beam and torsional constant. The main concept of the proposed equation is to get the weighted average values for the warping constant and the torsional constant from the properties of IPE section and a box section consisting of IPE and batten plates. Thus, a modified torsional constant ( J* ) and a modified warping constant (πΆ ) are proposed to the elastic critical moment equation for the case of a beam simply supported subjected to a uniform moment can be written as follows: π½ = π½ πΏ +π½ πΏ πΉ πΏ πΆ = πΆ πΏ +πΆ πΏ (2) πΏ (3) From the finite element model the elastic critical moment (π ) of the stiffened beam is obtained for different cases studied in the parametric study. Then modification factor (F) is calculated using equations ( 1,2 and 3 ). Best fitting techniques are used to define Polynomial equations for this factor. πΉ = 0 1106( ) − 0 1347 + 0 0413 (4) Where: πΏ : is the total length of the steel beam πΏ : is equal to (πΏ − πΏ ) πΏ : is the total length of batten plates used at one side of the beam equal to (2π ). π½ : is the torsional constant of IPE beam π½ : is the torsional constant of the box section consisting of IPE with double-sided batten plates which according to AISC [2] equals to 2π‘ π‘ π β b π½ = ; > 10 π π‘ +β π‘ π‘ π‘ : is the thickness of flange of IPE beam π‘ : is the thickness of batten plate b : is the width of box section and equal to IPE flange width h : is the depth of box section and equals to IPE depth πΆ : is the warping constant of IPE beam πΆ : is the warping constant of the box section consisting of IPE with double-sided batten plates which is approximately equal to zero for box sections according to AISC [2] πΉ: is a factor that represents the effect of batten plate on increasing the elastic moment capacity of the beam and depends on the batten plate centerline location ( ) π : is the batten plate centerline location to the beam end Fig.5. shows the equation annotations 336 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 ISSN 2277-8616 standard deviation of 2.5 %. TABLE 6 COMPARISON BETWEEN THE PROPOSED EQUATION'S RESULTS AND THE FEM RESULTS FOR DIFFERENT STANDARD IPE PROFILES IPE 100 profile Fig. 6. the relation between the batten plate centerline location ( ) and the F factor 4.2 Accuracy of the proposed equation Table (6) shows the ratio between the finite element results and the proposed equation's results for different standard IPE profiles strengthened with double-sided batten plates under a uniform bending moment with simply supported end conditions, where π is the final elastic moment capacity obtained from the proposed design equation (2), and π is the final flexural strength obtained from finite element analysis. The used span is 10 m, the batten plate width is L/30, the number of batten plates is four batten plates per span and the batten plate thickness is equal to the web thickness of the beam. The results of the finite element results show an excellent agreement with the proposed design procedure, with an average ratio for (π / π ) equals to 0.997 and a IPE 300 IPE 400 IPE 600 IPE 500 Fig.6. shows the relation between the batten plate centerline location ( ) and the (F factor) which represents the effect of the batten plate on increasing the elastic moment capacity of the beam. The batten plate width is L/30 and the thickness is equal to beam web thickness. The beam span is 12m. It shows that for the different standard profiles, the best location for the batten plate is at 0.1L and gets reduced while moving away from the beam ends towards the mid-span of the beam. The effect of the batten plate at the mid-span position on the enhancement of the elastic moment capacity of the beam is insignificant as agreed with most of the literature such as Yang and Lui [11], Sorensen and Rasmussen [11] and Hassan et al [12]. IPE 200 Fig. 5. Beam strengthened with double-sided batten plates equation annotations π L 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 π (kN.m) 2.00 1.97 1.94 1.90 1.86 1.84 1.81 1.80 16.27 15.81 15.18 14.59 14.09 13.70 13.44 13.27 59.80 58.53 55.95 53.23 51.13 49.36 48.12 47.33 146.90 143.42 138.52 132.75 127.69 123.79 120.89 118.98 244.49 240.91 233.18 225.06 217.00 210.11 204.82 201.71 416.78 414.46 400.86 387.41 374.73 364.12 356.11 350.97 πΉ 0.0289 0.0236 0.0188 0.0145 0.0108 0.0077 0.0051 0.0031 0.0289 0.0236 0.0188 0.0145 0.0108 0.0077 0.0051 0.0031 0.0289 0.0236 0.0188 0.0145 0.0108 0.0077 0.0051 0.0031 0.0289 0.0236 0.0188 0.0145 0.0108 0.0077 0.0051 0.0031 0.0289 0.0236 0.0188 0.0145 0.0108 0.0077 0.0051 0.0031 0.0289 0.0236 0.0188 0.0145 0.0108 0.0077 0.0051 0.0031 π½ x104 (mm4) 1.48 1.41 1.35 1.30 1.25 1.22 1.18 1.16 9.90 9.27 8.71 8.21 7.78 7.42 7.11 6.88 33.14 30.48 28.09 25.98 24.15 22.59 21.30 20.29 82.49 76.05 70.28 65.18 60.73 56.96 53.85 51.40 149.26 137.06 126.13 116.46 108.05 100.89 95.00 90.37 269.62 248.23 229.06 212.09 197.33 184.78 174.44 166.31 π (kN.m) 1.99 1.94 1.90 1.87 1.83 1.80 1.78 1.76 15.58 15.09 14.65 14.24 13.87 13.55 13.28 13.07 60.46 58.20 56.09 54.15 52.41 50.88 49.59 48.55 144.30 139.28 134.62 130.37 126.55 123.20 120.38 118.11 253.37 244.60 236.46 229.01 222.33 216.49 211.56 207.60 437.89 423.80 410.76 398.87 388.23 378.95 371.12 364.85 π π 1.007 1.014 1.017 1.018 1.017 1.017 1.019 1.023 1.045 1.048 1.037 1.025 1.016 1.011 1.012 1.016 0.989 1.006 0.998 0.983 0.976 0.970 0.970 0.975 1.018 1.030 1.029 1.018 1.009 1.005 1.004 1.007 0.965 0.985 0.986 0.983 0.976 0.971 0.968 0.972 0.952 0.978 0.976 0.971 0.965 0.961 0.960 0.962 Effect of steel beam length (π) on the proposed equation for the elastic moment capacity Table (7) shows the ratio between the finite element results and the proposed equation's results for different spans under a uniform bending moment with simply supported end conditions. This study is conducted on IPE200 with four batten plates per span of a thickness (π ) and located at a distance 0.1L from both beams ends. The studied spans are (6, 8, 10 and 12m). The batten plates width is ( L/30 ). The results of the finite element results show an excellent agreement with the proposed design procedure, with an average ratio for (π / π ) equals to 1.016 and a standard deviation of 1.78 %. 4.3 337 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 TABLE 7 COMPARISON BETWEEN THE PROPOSED EQUATION'S RESULTS AND THE FEM RESULTS FOR DIFFERENT BEAM LENGTHS 10 12 π π 0.0289 9.90 26.66 1.044 27.25 0.0236 9.27 25.87 1.053 0.2 26.08 0.0188 8.71 25.15 1.037 0.25 24.88 0.0145 8.21 24.49 1.016 0.3 23.92 0.0108 7.78 23.90 1.001 0.35 23.16 0.0077 7.42 23.38 0.990 0.4 22.61 0.0051 7.11 22.95 0.985 0.45 22.28 0.0031 6.88 22.61 0.985 0.1 20.54 0.0289 9.90 19.64 1.046 0.15 20.06 0.0236 9.27 19.04 1.054 0.2 19.19 0.0188 8.71 18.48 1.038 0.25 18.36 0.0145 8.21 17.98 1.022 0.3 17.67 0.0108 7.78 17.53 1.008 0.35 17.12 0.0077 7.42 17.13 1.000 0.4 16.77 0.0051 7.11 16.80 0.998 0.45 16.55 0.0031 6.88 16.54 1.001 0.1 16.27 0.0289 9.90 15.58 1.045 0.15 15.81 0.0236 9.27 15.09 1.048 0.2 15.18 0.0188 8.71 14.65 1.037 0.1 27.83 0.15 πΉ 14 0.1 11.11 0.0289 9.90 11.04 1.006 0.15 10.82 0.0236 9.27 10.70 1.012 0.2 10.48 0.0188 8.71 10.37 1.010 0.25 10.14 0.0145 8.21 10.08 1.006 0.3 9.85 0.0108 7.78 9.81 1.004 0.35 9.62 0.0077 7.42 9.58 1.003 0.4 9.46 0.0051 7.11 9.39 1.007 0.45 9.36 0.0031 6.88 9.24 1.013 Effect of batten plate width (πΎ ) on the proposed equation for elastic moment capacity The effect of change batten plate width is studied in this section on beam stiffened with 4 batten plates. This study is conducted on different standard IPE profiles with a span of 10 meters and batten plates of a thickness (π ) located at a distance 0.1L from both beams ends. The batten plates width is defined relative to the beam span (L). The studied ratios for the width are (L/50, L/40, L/30, L/20, L/10) Table (8) shows the ratio between the finite element results and the proposed equation's results for different batten plate width. The results of the finite element results show an excellent agreement with the proposed design procedure, with an average ratio for (π / π ) equals to 1.012 and a standard deviation of 5.03 %. Moreover, we can figure out from the table that the effect of batten plate width for the same IPE profile is extremely significant on the flexural strength of laterally unsupported simply supported I-beams. 4.4 TABLE 8 COMPARISON BETWEEN THE PROPOSED EQUATION'S RESULTS AND THE FEM RESULTS FOR DIFFERENT BATTEN PLATE WIDTH 186.2 πΏ x1 0 (mm ) 200 900 186.2 100 1.62 2.08 1.2 933 186.2 66.7 1.48 1.99 1.96 1.2 950 186.2 50 1.41 1.94 1.019 1.93 1.2 960 186.2 40 1.37 1.91 12.52 1.024 20.86 6.98 800 1754.4 200 15.69 19.51 8.71 12.14 1.017 17.67 6.98 900 1754.4 100 11.34 16.64 0.0145 8.21 11.80 1.009 16.28 6.98 933 1754.4 66.7 9.88 15.57 11.54 0.0108 7.78 11.49 1.004 15.46 6.98 950 1754.4 50 9.16 15.00 0.35 11.24 0.0077 7.42 11.22 1.002 14.93 6.98 960 1754.4 40 8.72 14.65 0.4 11.03 0.0051 7.11 11.00 1.003 85.73 20.1 800 7453.2 200 59.03 79.21 0.45 10.92 0.0031 6.88 10.82 1.009 67.18 20.1 900 7453.2 100 39.56 65.62 profil e π (kN.m ) π½ x10 4 0.25 14.59 0.0145 8.21 14.24 1.025 0.3 14.09 0.0108 7.78 13.87 1.016 2.38 (mm ) 1.2 0.35 13.70 0.0077 7.42 13.55 1.011 2.09 1.2 0.4 13.44 0.0051 7.11 13.28 1.012 2.00 0.45 13.27 0.0031 6.88 13.07 1.016 0.1 13.16 0.0289 9.90 12.92 0.15 12.81 0.0236 9.27 0.2 12.35 0.0188 0.25 11.91 0.3 IPE 100 8 π (kN.m) π (kN.m) IPE 200 6 π½ x104 (mm4) π L IPE 300 L (m) ISSN 2277-8616 4 πΏ x1 0 (mm ) 800 π½ x104 (mm4) π½ x104 (mm4) π (kN.m ) 2.03 2.33 π π 1.02 1 1.00 5 1.00 8 1.00 8 1.00 7 1.06 9 1.06 2 1.04 6 1.03 0 1.01 9 1.08 2 1.02 4 338 IJSTR©2021 www.ijstr.org 66.7 33.08 60.41 55.92 20.1 950 7453.2 50 29.83 57.63 53.72 20.1 960 7453.2 40 27.89 55.90 213.4 2 164.2 1 146.9 0 138.2 3 132.9 6 359.8 9 273.1 7 244.4 9 230.8 9 224.0 3 600.5 8 462.2 8 416.7 8 394.0 5 383.6 8 51.1 800 200 51.1 900 100 144.8 3 97.97 51.1 933 66.7 82.34 51.1 950 50 74.53 51.1 960 40 69.85 89.3 800 200 89.3 900 89.3 933 89.3 950 89.3 960 165 800 165 900 165 933 165 950 165 960 18038. 8 18038. 8 18038. 8 18038. 8 18038. 8 34166. 2 34166. 2 34166. 2 34166. 2 34166. 2 59936. 4 59936. 4 59936. 4 59936. 4 59936. 4 268.3 3 178.8 1 148.9 8 134.0 6 125.1 1 477.3 9 321.1 9 269.1 3 243.1 0 227.4 8 186.0 0 155.6 9 144.1 8 138.0 7 134.2 7 326.8 8 273.4 7 253.1 7 242.3 8 235.6 8 556.4 7 470.1 2 437.5 7 420.3 5 409.6 7 100 66.7 50 40 200 100 66.7 50 40 0.99 0 0.97 0 0.96 1 1.14 7 1.05 5 1.01 9 1.00 1 0.99 0 1.10 1 0.99 9 0.96 6 0.95 3 0.95 1 1.07 9 0.98 3 0.95 2 0.93 7 0.93 7 Effect of batten plate thickness (π» ) on the proposed equation for elastic moment capacity The effect of change batten plate thickness is studied in this section on a beam stiffened with 4 batten plates. This study is conducted on different standard profiles with a span of 10 meters and stiffened with four batten plates of a width (L/30) and located at a distance 0.1L from both beams ends. The studied batten plate thicknesses are (4, 6, 8, 10 and 12 mm). Table (9) shows the ratio between the finite element results and the proposed equation's results for different batten plate thickness. The results of the finite element results show an excellent agreement with the proposed design procedure, with an average ratio for (π / π ) equals to 0.995 and a standard deviation of 4.82%. Moreover, we can figure out from the table that the flexural capacity for the same IPE profile is slightly increased with increasing the batten plate thickness of laterally unsupported simply supported Ibeams. 4.5 TABLE 9 COMPARISON BETWEEN THE PROPOSED EQUATION'S RESULTS AND THE FEM RESULTS FOR DIFFERENT BATTEN PLATE THICKNESS IPE 100 profile π (mm) π (kN.m ) 4 6 8 2.0 2.0 2.0 π½ x10 4 (mm ) 1.2 1.2 1.2 4 π½ x104 (mm4) π½ x104 (mm4) π (kN.m ) 182.5 250.5 309.1 1.47 1.60 1.71 2.0 2.1 2.1 π π 1.010 0.972 0.942 IPE 200 7453.2 IPE 300 933 IPE 400 20.1 IPE 500 59.80 IPE 600 IPE 600 IPE 500 IPE 400 INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 10 12 4 6 8 10 12 4 6 8 10 12 4 6 2.0 2.0 16.2 16.3 16.4 16.6 16.7 58.8 59.5 60.1 60.9 61.8 143.6 145.1 1.2 1.2 7.0 7.0 7.0 7.0 7.0 20.1 20.1 20.1 20.1 20.1 51.1 51.1 8 146.5 51.1 10 148.0 51.1 12 149.7 51.1 4 237.6 89.3 6 239.9 89.3 8 242.0 89.3 10 244.3 89.3 12 246.8 89.3 4 403.0 165.0 6 406.7 165.0 8 409.9 165.0 10 413.2 165.0 12 416.8 165 360.7 407.1 1319.7 1856.6 2334.6 2765.5 3157.9 4577.8 6487.0 8205.0 9764.9 11192.7 9174.2 13218. 4 16966. 3 20456. 3 23720. 7 14577. 6 21254. 5 27577. 8 33582. 1 39297. 3 21571. 0 31714. 5 41471. 8 50870. 8 59936. 4 ISSN 2277-8616 1.81 1.90 9.05 10.08 11.00 11.83 12.58 27.55 31.22 34.52 37.52 40.26 65.32 73.08 2.2 2.3 14.9 15.7 16.4 17.0 17.5 55.6 58.8 61.6 64.0 66.2 130.5 136.9 0.918 0.898 1.083 1.037 1.003 0.976 0.956 1.058 1.010 0.976 0.951 0.934 1.101 1.060 80.28 142.6 1.027 86.99 147.7 1.002 93.26 152.3 0.983 111.35 225.0 1.056 124.1 7 136.3 2 147.8 5 158.8 3 195.4 3 214.9 2 233.6 6 251.7 2 269.1 3 235.0 1.021 244.1 0.992 252.4 0.968 260.0 0.949 386.8 1.042 400.9 1.014 413.9 0.990 426.1 0.970 437.6 0.952 5 SUMMARY AND CONCLUSIONS A finite element model is performed to investigate the increase in the elastic moment capacity of steel beams strengthened with batten plates. Verification is performed to the finite element model with previous research works. The effects of using different standard IPE profiles, span of beam, batten plate centerline location ratio to the beam total length, batten plate width and thickness on the elastic moment capacity were studied. A design procedure is proposed to predict the elastic moment capacity of beams strengthened with batten plates of different configurations. The conclusions of this paper can be summarized as follows: 1- The location of batten plates has a major effect on the elastic moment capacity and it is found that the best location for batten plates is at 0.1L. On the other hand, installing batten plates at the mid-span of the beam is not effective. 2- The proposed design equations proved to be efficient and in very good agreement with the finite element results for standard IPE steel beam strengthened with batten plates taking into consideration the change of I-beam section, batten plate width and thickness. 3- The effect of batten plate width is very significant and leads to a higher increase in the flexural strength than increasing the batten plates thickness. 339 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 01, JANUARY 2021 ISSN 2277-8616 REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] Szewczak, R. M., Smith, E. A., and Dewolf, J. T. (1983), βBeams with torsional stiffenersβ, J. Struct.Engrg., ASCE, 109(7), 1635-1647. Takabatake, H. (1988), βLateral buckling of I beams with web stiffeners and batten platesβ, Int. J. of Solids. Struct., 24(10), 1003-1019. 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