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JournalofBuildingStructures31920109Vol.31No.9Sep.20100101000-6869201009-0070-08710055。Q420Q460。。。Q460。TU392.1ALimitingwidth-thicknessratioandstrengthofbeyond-limitmembersforsingleanglestrutsCHENShaofanWANGXiantieKeyLaboratoryofStructuralandAseismaticEngineeringofChinaMinistryofEducationXi’anUniversityofArchitectureandTechnologyXi’an710055ChinaAbstractInthedaysstructuralcarbonsteeliswidelyusedforsingleanglestruttheissueoflimitingwidth-thicknessratioisnotamajorone．NowadayshighstrengthsteelsQ420andQ460begintobeusedintransmissiontowersnotonlylimitingwidth-thicknessratiobutalsostrengthofbeyond-limitmembersaretobeofconcerntodesigners．Singleanglestrutsaredividedintotwocategoriesaccordingtotheforceapplicationnamelyaxialcompressionandeccentriccompression．Theirdemandofwidth-thicknessratioisnotthesamebutcurrenttechnicalprovisionsdonotdistinguishthetwocases．Basedontheoreticalanalysisandexperimentalobservationthisarticlerevealdthedifferentmeaningsoflimitingwidth-thicknessratiotoaxiallyandeccentricallycompressedanglestrutstopreventlocalbucklingandtoavoidexcessivelylowresistancetotwisting．Hencetwotypesoflimitingwidth-thicknessratioandformulaforbeyond-limitstrengthcalculationweresuggested．TheseformulascorrelatewellwithtestresultsoftwosetsofQ460singleanglestrutspecimens．Keywordssingleanglestrutlimitingwidth-thicknessratiobeyond-limitmemberlocalbucklingflexural-torsionalbuckling1919—。E-mailchensf2@yahoo.com.cn20099070。。。Q23515。GB50017—2003《》《》。。Q420Q460750kV1000kV1。。12。Q4603-4。4。。3-4。11.15。1。σcrp=0.425π2槡τE121－ν2t()b21btEνττ=Et/Eτ=1。fyτ=1b/t=18.35235/f槡y。18.3515。1wt=15235/f槡y2w=b－r－t≈b－2t3wrt。1Fig．1Flatwidthofanangleleg1b/t。α0.425π2槡τE121－ν2t()b2=απ2τEλ2bt=0.197λ槡α4槡τ4λαl/10002σ=NA1+lA1000Wy()0A=2btWy0=槡26b2tσ=NA1+8.5l1000()bλy0=120b=4.9iy0l/b=24.5σ1=1.21N/Aσ2=0.79N/AkGB50018—2002《》6k=0.567－0.213×0.79/1.21+0.071×0.79/1.212=0.458。172Fig．2Effectofinitialcrookednessonstressdistributionσ1k=0.458/1.21=0.379。αα=0.425/0.379=1.12。α1.2。4bt=0.18λ4槡τ5τ5τ=λ2n1－αp1－αpλ2nλnλn=λπfy槡E=λ93fy槡235αpαp=fy－σrc/fyσrcσrc=0.3fyσrc=0.25fy。σrc=0.27fyτ=λ2n1－0.2λ2n6λτ5λ。wbw/t=5235/f槡y+0.135λ2。wt=max15235/f槡y5235/f槡y+0.135λy0750Q345λy0＞62Q460λy0＞52235/f槡y。1.2。7fyλy0。2。λp=fy/σcr槡pσcrp1τ=1。wbλp=w/t18.35fy槡2351σcrp1.2λp=w/t16.75fy槡23588σcr=φfyfy2φ。7。9。fye=ρfy9ρρ=1λp≤0.8910aρ=1λp1－0.10λ()pλp＞0.8910bλp=0.898w/t=14.9235/f槡y2。N=φAfye11N=φAρf1211fyefy《》φfyefyλfye/槡235。1.334L125×8L125×10L160×10L160×12。Q460530MPa。413.610.514.013.315235/槡530=10。4304560803。。。。271Q460Table1ComparisonbetweensuggestedformulasandtestresultsforaxiallycompressedQ460singleanglestrutA/cm2λλpρfye/MPaλfye槡235φNc=Aφfye/kNNt/kN3Nc/Nt12508C30-120.215.01.190.7740819.80.988088450.96Q12508C30-219.915.01.200.7640319.60.987868500.92Q12508C30-320.315.11.190.7740819.90.988178250.98Q12508C45-120.022.61.200.7640329.60.967747850.99Q12508C45-219.922.51.200.7640329.50.967707601.01Q12508C45-320.022.61.210.7440329.60.967748150.95Q12508C60-120.073.41.210.7640396.10.675406100.89S12508C60-220.173.41.200.7640396.10.675437250.75S12508C60-320.073.51.200.7640396.30.675406200.87S12508C80-119.893.41.220.75398121.50.483783601.05S12508C80-219.893.41.220.75398121.50.483784100.92S12508C80-320.093.41.200.76403122.30.483875200.73S12510C30-124.115.00.950.9449821.80.98117611751.00Q12510C30-224.315.00.940.9550422.00.98120011901.01Q12510C30-324.215.00.950.9449821.80.98118111651.01Q12510C45-124.222.50.950.9449832.80.96115711451.01Q12510C45-224.222.50.950.9449832.80.96115712000.96Q12510C45-324.122.50.950.9449832.80.96115211451.01Q12510C60-124.373.30.940.95504107.30.587106701.06S12510C60-224.473.20.940.95504107.20.587137051.01S12510C60-324.473.30.940.95504107.30.587137151.00S12510C80-124.293.20.950.94498135.70.404825000.96S12510C80-224.293.10.950.94498135.50.404825400.89S12510C80-324.493.10.940.95504136.30.404925050.97S16010C30-131.215.01.250.7439219.40.98119912600.95Q16010C30-231.015.11.260.7338719.50.98117612300.96Q16010C30-331.315.11.250.7439219.50.98120212600.95Q16010C45-131.222.51.250.7439229.10.96117412400.95Q16010C45-231.122.61.240.7439229.20.96117012050.97Q16010C45-331.122.51.240.7439229.10.96117012200.96Q16010C60-131.270.61.240.7439291.20.7085311200.76S16010C60-231.370.41.250.7439290.90.7187111450.76S16010C60-331.166.01.240.7439285.20.7591410750.85D16010C80-131.286.01.240.74392111.10.556738050.84D16010C80-231.386.01.240.74392111.10.556758100.83D16010C80-331.286.01.240.74392111.10.556737400.91D16012C30-136.940.51.020.8846657.00.89153018750.82S16012C30-236.715.01.030.8846621.10.98167619200.87Q16012C30-336.815.11.020.8846621.30.98168118600.90Q16012C45-137.222.51.010.8947231.90.96168618300.92Q16012C45-236.822.61.020.8846631.80.96164518300.90Q16012C45-336.855.61.020.8846678.30.79135514500.93S16012C60-136.866.21.020.8846693.20.69118313150.90D16012C60-237.066.11.020.8846693.10.69119013500.88D16012C60-336.866.21.020.8846693.20.69118314600.81D16012C80-137.486.10.990.91482123.30.478479400.90D16012C80-237.785.11.000.90477121.20.498818950.98D16012C80-336.886.11.020.88466121.20.498409100.92D48Nc/Nt0.920.078QSD。14881011。Q460Q235。37φ《》