This paper describes the development of a space truss structure using Glass Fiber Reinforced Plastic (GFRP) pipe that decreases life cycle cost and enhances construction efficiency. Material tests, structural experiments and FEM analysis verify the practicality of this structural system

Hagio, Hiroya

Itohiya, Go

Kimura, Kohzo

Takahashi, Koichiro

Tazawa, Hitoshi

Utsumi, Yoshikazu

English

Engineering Conferences International

ProceedingsAdvanced Materials for Construction ofBridges, Buildings, and Other Structures IIIEngineering Conferences International Year 2003Development of Space Truss StructureUsing Glass Fiber Reinforced PlasticsHiroya Hagio∗ Yoshikazu Utsumi† Kohzo Kimura‡Koichiro Takahashi∗∗ Go Itohiya†† Hitoshi Tazawa‡‡∗Obayashi Corporation, hagio.hiroya@obayashi.co.jp†Obayashi Corporation, utsumi.yoshikazu@obayashi.co.jp‡Obayashi Corporation, kimura.kohzo@obayashi.co.jp∗∗Obayashi Corporation, takahashi.koichiro@obayashi.co.jp††Asahi Glass Matex Co., Ltd., itohiya@agm.co.jp‡‡Asahi Glass Matex Co., Ltd., tazawa@agm.co.jpThis paper is posted at ECI Digital Archives.http://dc.engconfintl.org/advanced materials/11Development of Space Truss StructureUsing Glass Fiber Reinforced PlasticsHiroya HAGIO1, Yoshikazu UTSUMI2, Kohzo KIMURA3, Koichiro TAKAHASHI4Go Itohiya5, Hitoshi TAZAWA6KEY WORDS: Space Truss Structure, Buckling, Fire Protecting Performance, GFRPABSTRACTThis paper describes the development of a space truss structure using Glass Fiber Reinforced Plastic (GFRP) pipe that decreases life cycle cost and enhances construction efficiency. Material tests, structural experiments and FEM analysis verify the practicality of this structural system.1. INTRODUCTIONThere has been increasing social demand to extend the life of buildings and to decrease their life cycle cost to reduce carbon monoxide emissions. Because of its durability, GFRP pipes are applied to space truss structures to reduce maintenance costs. Maintenance costs are expected to be reduced even in severe environments such as indoor pools, seashores and hot springs. Furthermore, GFRP’s light weight is expected to result in shorter construction time. Fig.1 is a conceptual diagram of a space truss structure showing the name of each member.1 Deputy Chief Research Engineer, Project Promotion Department, Technical Research Institute, OBAYASHI Corporation, 4-640 shimokiyoto,Kiyose-shi,Tokyo 204-0011 Japan, T: 81-424-95-1019, hagio.hiroya@obayashi.co.jp2 Research Engineer, Construction System Engineering Department, Technical Research Institute, OBAYASHI Corporation, 4-640 shimokiyoto,Kiyose-shi,Tokyo 204-0011 Japan, T: 81-424-95-1135, utsumi.yoshikazu@obayashi.co.jp3 Dr.Eng., General Manager-In Charge, Project Promotion Department, Technical Research Institute, OBAYASHI Corporation, 4-640 shimokiyoto,Kiyose-shi,Tokyo 204-0011 Japan, T: 81-424-95-1120, kimura.kohzo@obayashi.co.jp4 Deputy Chief Research Engineer, Project Promotion Department,  Technical Research Institute, OBAYASHI Corporation, 4-640 shimokiyoto,Kiyose-shi,Tokyo 204-0011 Japan, T: 81-424-95-1120, takahashi.koichiro@obayashi.co.jp5 Technical Group New Business Dept., ASAHI GLASS MATEX CO.,LTD. 1-2-27, Miyashimo, Sagamihara, Kanagawa 229-1112, Japan, T: 81-42-772-1174, itohiya@agm.co.jp6 General Manager C&A DEPARTMENT, ASAHI GLASS MATEX CO.,LTD. 1-2-27, Miyashimo, Sagamihara, Kanagawa 229-1112, Japan, T: 81-42-772-1174, tazawa@agm.co.jp1Hagio et al.: Development of Space Truss Structure Using Glass Fiber ReinforcedPublished by ECI Digital Archives, 2003GFRP PipeNodeJointFig.1 Conceptual Diagram of Space Truss Structure2. MATERIAL PROPERTIES OF GFRP PIPESGFRP pipe is made of E glass and modified acrylic resin (FR resin). The pipes are formed by the pultruded method. FR resin’s characteristics include weather resistance, chemical resistance and incombustibility. The pipe used in these tests had an external diameter of 145mm and a wall thickness of 7.5mm. This cross section is determined by trial design. Sections 2.1 and 2.2 describe the material properties under room-temperature and high-temperature environments. Section 2.3 describes the material’s fire protection performance.2.1 Material Properties of GFRP at Room TemperatureTensile and compressive tests were performed in accordance with JIS K 7054 shown in Fig.2 and JIS K 7056 shown in Fig.3. In addition, pipes 200mm long, as shown in Fig.4,were not cut in the longitudinal direction but the actual section was directly compressed. The results of tensile and compressive tests are shown in table 1. The compressive elastic modulus obtained by the JIS K 7054 tests is equivalent to that of direct compressive tests. However, the JIS K 7054 compressive strength is higher than that of compressive tests on the actual section. The compressive strength of the former is unreliable in comparison with the results of later-described buckling tests. It is likely that the supporting jig constrained the radial deformation. Accordingly, the compressive strength obtained from the direct compressive tests is adopted as the compressive strength in consideration of the dispersion.2Advanced Materials for Construction of Bridges, Buildings, and Other Structures III, Art. 11 [2003]http://dc.engconfintl.org/advanced_materials/11252501206565145200elevation viewplan20 P1377supporting jigshapeFig.2 JIS K 7054 Fig.3 JIS K 7056 Fig.4 Method of suggestingTable 1 Material Strength Test Results (*: 200mm, **: 290mm)t Et c Ec c Ec c EcN/mm2 kN/mm2 N/mm2 kN/mm2 N/mm2 kN/mm2 N/mm2 kN/mm21 294 19.9 212 24.4 195 25.6 190 25.72 388 22.7 230 25.7 211 25.9 210 25.43 301 17.6 217 29.2 173 25.9 172 25.44 286 21.1 217 25.3 - - 190 26.25 337 20.2 233 22.5 - - 179 26.2with actual section**JIS K 7054 JIS K 7056 with actual section*2.2 Material Properties of GFRP at High TemperatureHigh-temperature strength tests were performed on GFRP at a preset temperature in a furnace. The results of high-temperature strength tests are shown in Fig. 5. The tensile strength at 250 degrees was approximately 80% of that at room temperature. The compressive strength at 175 degrees was about 70% of that at room temperature. It therefore appears that the inflection point, where the strength drops rapidly, is beyond the scope of these tests.02004006000 100 200 300tensile strengthcompresseve strengthstrength(N/mm2 )temperature (degree)Fig.5 Strength of GFRP at High Temperatures3Hagio et al.: Development of Space Truss Structure Using Glass Fiber ReinforcedPublished by ECI Digital Archives, 20032.3 Fire Protection Performance of GFRPThe fireproof performance of FR resin is compared with that of phenol resin (PR resin).The test samples were 100mm square and 12.5mm thick. The tests were performed in accordance with ISO 5660. Table 2 shows the results, and Fig.6 and 7 illustrate the relationships between the heat release rate and time and the relationships between the smoke extinction coefficient and time. According to Fig.6, PR resin corresponded to a flame retardant material. However, the ignition time and the quench time of the FR resin were equal to those of the PR resin. But the maximum heat release rate of the FR resin was one fifth that of the PR resin. Furthermore, the gross calorific value of the FR resin was much smaller than that of the PR resin. Thus, the FR resin is suitable as a quasi-noncombustible material. Furthermore, we see from Table 2 that the amount of smoke for the FR resin was less than that of the PR resin. Consequently, it is clear that the FR resin is superior to the PR resin in respect of fireproof performance.0204060801000 400 800 1,200FR resinPR resinHeat Release Rate(kW/m2 )Time (sec)0.00.10.20.30.40.50.60.70 400 800 1,200FR resinPR resinSmoke Extinction Coefficient (1/s)Time (sec)Fig.6 Relationships between Fig.7 Relationships betweenHeat Release Rate and Time Smoke Extinction Coefficient and TimeTable 2 Results of Cone-Calorimetersec kW/m2 secFR resin 389 16.7 1000 0.1 3.2 9.0 quasi-noncombustiblePR resin 323 87.3 1120 0.0 18.3 44.9 flame retardantjudgementgross calorific value @MJ/m2ignitiontimemaximum heatrelease ratetime atextinction offlamename 5min 10min 20min3. STRUCTURAL PERFORMANCE OF EACH MEMBERIn order to clarify the structural performance of a truss member, a joint member and a node member, experiments were performed on each.4Advanced Materials for Construction of Bridges, Buildings, and Other Structures III, Art. 11 [2003]http://dc.engconfintl.org/advanced_materials/113.1 Structural Performance of Truss MemberCompressive tests were carried out on GFRP pipes to determine crushing failure for a small slenderness ratio and buckling failure for a large slenderness ratio. The parameter was length. Test pieces were 1000mm to 3000mm long in 500mm steps. Three pieces of each length were tested. Both ends were pin supported. Four strain gauges were joined with an adhesive at the central part as shown in Fig.3. The relationships between axial stress and axial strains for the pipe length 2500mm are shown in Fig.8. This graph shows that the specimen crushes after elastic buckling. The results of compression test on the pipes are plotted up to failure in Fig.9. The slenderness ratio is calculated as the distance from pin support to the other support. Fig.9 shows Euler’s equation calculated from material tests and the results of the compressive tests with the actual section. The experimental values are similar to those given by Euler’s equation. Furthermore, the fluctuation of the tests is small. Thus, the buckling stress is demonstrated by Euler’s equation calculated from material tests. The compressive stress was evaluated not by JIS K 7056 compression test results, but rather by compressive tests on the actual section to take dispersion into account.-10,000-8,000-6,000-4,000-2,00002,0000 20 40 60 80 100BCL25-5S_CA-AS_CC-AS_CE-AS_CG-Astrain (10-6 )axial stress (N/mm2)0501001502002500 10 20 30 40 50 60 70 80CrushingBucklingcompressive strength(N/mm2 )slenderness ratioStandard strengthvalues of suggesting methodBuckling curveFig.8 Relationships between Axial Stress Fig.9 Results of Compressionand Axial Strains of Pipe length 2500mm Tests on Pipes3.2 Structural Performance of Joint MemberCompressive and tensile tests were performed to clarify the structural performance of a joint. Fig.10 illustrates its suggested structure. The inner pipe and the GFRP pipe are connected with rivets as well as adhesive. The load/displacement relationships are shown in Fig.11.5Hagio et al.: Development of Space Truss Structure Using Glass Fiber ReinforcedPublished by ECI Digital Archives, 2003insertGFRP pipe inner pipeboltrivet   -400-300-200-1000100200300400-50 -25 0 25 50T1T2T3C1C2C3P[kN]displacement[mm]tensile testscompressive tests      Fig.10 Joint Structure                      Fig.11 Load/Displacement Relationships  3.3 Structural Performance of Node Member  Compressive and tensile tests were carried out to clarify the structural performance of the stainless steel node. Due to space limitations, discussion on the results of the tensile tests is limited here. The load/displacement relationships are shown in Fig.12. The heavy line in Fig.12 is the calculated value assuming symmetry. It is discovered that the rigidity obtained from the test is close to calculated one.  0 5 10 15 200100200300400500Experim ent sAn alysisDisplacement (mm)Load (kN) Fig.12 Load/Displacement Relationships   4. EXPERIMENT ON SPACE TRUSS STRUCTURAL FRAME  This chapter describes the structural performance of a space truss structural frame combining each member.  4.1 Specimen  The size of the specimen was based on the trial design of the 10m×20m span. The specimen comprises three quadrilaterals connected at two upper chords. From the design axial force of the truss member of 150kN, the GFRP pipe has an external 6Advanced Materials for Construction of Bridges, Buildings, and Other Structures III, Art. 11 [2003]http://dc.engconfintl.org/advanced_materials/11diameter of 145mm and a wall thickness of 7.5mm. The bolts are made of SUS630. The nodes are made of SUS304A.  4.2 Experimental Method  Photo.1 shows a view of the test. The test load was applied at the center of the four pin supports. The load, displacements and strains of the pipes were measured.   Photo.1 View of Test  4.3 Results of the Experiment  Fig.13 shows the load/displacement relationships of points V10 and V11. The displacements are commensurate with the load. The maximum strength is determined by the buckling of the upper chord. Fig.14 show the upper chord load/strain relationships. Buckling is observed at 315kN. The maximum strength is 350kN. After that, the load drastically decreased. The buckling mode is antisymmetric, protruding from the vertical plane.   7Hagio et al.: Development of Space Truss Structure Using Glass Fiber ReinforcedPublished by ECI Digital Archives, 20030 10 20 30 40 500100200300400V10V11V10(analysis)V11(analysis)Displacement (mm)Load (kN)V11 V10     -5000 -4000 -3000 -2000 -1000 00100200300400pipe51-upipe51-lpipe51-dpipe51-rStrain (10-6)Load (kN)upside downsideleftsiderightside Fig.13 Load/Displacement Relationship     Fig.14 Upper Chord Load/Strain Relationship  4.4 FEM analysis  Fig.15 shows the nodal numbers and the element numbers used for the FEM analysis. In Fig.15 the parentheses indicate the nodal point number. The equivalent rigidity of the component was calculated by linking the node, the bolt, the disk and the pipe as the serial spring. As a result, the compressive rigidity of the component is 31.2kN/mm2. The tensile rigidity is 29.4kN/mm2. The difference is due to the difference of the stress transmission path. Although the tensile elastic modulus is a little different from the compressive elastic modulus, the tensile elastic modulus is adopted for the FEM analysis on the ground so that the displacement calculated from the tensile elastic modulus is on the safe side. The deformation and the axial force when the load is 200kN in the analysis are shown in Fig.16. Then the vertical displacement at the center of the upper chord is 22mm. A glance at Fig.13 will reveal that the load/displacement relationship is equivalent to the experimental value of until the load reaches 280kN. Table 3 compares the axial force at a load of 200kN. Except where the axial force is small, the analytical values are similar to the experimental ones.  Table 3 Comparison of the Axial Force at Load 200kN Analysis AnalysisAxial force Strain Axial force Axial force Strain Axial force1 35.6 441 35.3 1.01 23 -70.3 -892 -72.8 0.972 105.7 1,443 115.5 0.92 24 69.7 922 73.8 0.943 35.6 448 35.9 0.99 31 -70.8 -903 -73.7 0.964 35.6 432 34.6 1.03 32 -70.8 -863 -70.5 1.005 105.7 1,399 112.0 0.94 33 -70.8 -906 -74.0 0.966 35.6 440 35.2 1.01 34 -70.8 -872 -71.2 0.997 0.0 62 5.0 0.00 41 -70.3 -847 -69.2 1.028 0.5 4 0.3 1.67 42 69.7 907 72.6 0.969 0.5 5 0.4 1.25 43 69.7 923 73.9 0.9410 0.0 170 13.6 0.00 44 -70.3 -894 -73.0 0.9621 69.7 893 71.5 0.97 51 -140.5 -1,797 146.7 -0.9622 -70.3 -866 -70.7 0.99 52 -140.5 -1,767 -144.3 0.97ExperimentratioExperiment ratioNumber Number8Advanced Materials for Construction of Bridges, Buildings, and Other Structures III, Art. 11 [2003]http://dc.engconfintl.org/advanced_materials/11(1) (2) (3) (4)(5) (6) (7) (8)(9) (10) (11)1 2 34 5 67 8 9 10212223 24313233 34414243 4451 522800 2800 280084002800Laod1979.951 52(9) (10) (11)    Fig.15 Nodal Numbers and                  Fig.16 Displacement and Axial Force     Element Numbers               at Load 200kN  5.CONCLUSIONS  The conclusions of this paper are as follows: 1. The tensile strength and elastic modulus of the GFRP pipe are demonstrated by the method with JIS K 7054. The compressive strength and elastic modulus of the GFRP pipe are evaluated not by JIS K 7056 but rather by compressive tests with an actual section in consideration into the dispersion. 2. The modified acrylic resin is superior to the phenol resin in respect of fireproof performance. 3. An experiment was carried out on a space truss structural frame combining each member. As a result, the load/displacement relationship is linear until buckling occurs. Furthermore, the analytical values are similar to the experimental ones.  REFERENCES  Yoshikazu Utsumi, Hiroya Hagio, Kohzo Kimura, Koichiro Takahashi, “Development of Space Truss Structure using Glass Fiber Reinforced Plastics (Part 1) -Studies on Structural Properties-”, Report of Obayashi Corporation Technical Institute, No.65, 2002, pp11-16 (in Japanese)  Hiroya Hagio, Yoshikazu Utsumi, et al, “Development of Long Span Structure using Glass Fiber Reinforced Plastics (Part 1 and Part 2)”, Summaries of Technical papers of Annual Meeting Architectural Institute of Japan, pp.963-966, 2000.9 (in Japanese)  Yoshikazu Utsumi, Hiroya Hagio, et al, “Development of Long Span Structure using Glass Fiber Reinforced Plastics (Part 3 and Part 4)”, Summaries of Technical papers of Annual Meeting Architectural Institute of Japan, pp.871-874, 2001.9 (in Japanese)   9Hagio et al.: Development of Space Truss Structure Using Glass Fiber ReinforcedPublished by ECI Digital Archives, 2003

Development of Space Truss Structure Using Glass Fiber Reinforced Plastics

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Development of Space Truss Structure Using Glass Fiber Reinforced Plastics

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