1、2011-9-27同济大学 吴冲 Tongji University, Wu Chong02011-9-27同济大学 吴冲 Tongji University, Wu Chong12011-9-27同济大学 吴冲 Tongji University, Wu Chong22011-9-27同济大学 吴冲 Tongji University, Wu Chong32011-9-27同济大学 吴冲 Tongji University, Wu Chong42011-9-27同济大学 吴冲 Tongji University, Wu Chong50min;8effLbb2011-9-27同济大学 吴冲 T
2、ongji University, Wu Chong6slAslAslA(outstand element)0b0b(internal element)(internal element)0bFig. 2.5: Definition of notations (b0, Asl)2011-9-27同济大学 吴冲 Tongji University, Wu Chong72011-9-27同济大学 吴冲 Tongji University, Wu Chong82011-9-27同济大学 吴冲 Tongji University, Wu Chong9Fig. 2.8: Influence of the
3、 flange stiffening ratio on the elastic effectives width2011-9-27同济大学 吴冲 Tongji University, Wu Chong10Fig. 2.8: Influence of the flange stiffening ratio on the elastic effectives width2011-9-27同济大学 吴冲 Tongji University, Wu Chong112011-9-27同济大学 吴冲 Tongji University, Wu Chong122011-9-27同济大学 吴冲 Tongji
4、University, Wu Chong13Fig. 2.10: Influence of the considered limit state and of the bending zoneon the effectives width (for the case 0 = 1)2011-9-27同济大学 吴冲 Tongji University, Wu Chong142011-9-27同济大学 吴冲 Tongji University, Wu Chong152011-9-27同济大学 吴冲 Tongji University, Wu Chong16Fig. 2.12: Post-critic
5、al response of slender plates in compression 2011-9-27同济大学 吴冲 Tongji University, Wu Chong17Fig. 2.19: Plate-like and column-like behaviour of plates in compression2011-9-27同济大学 吴冲 Tongji University, Wu Chong182011-9-27同济大学 吴冲 Tongji University, Wu Chong19Fig. 2.13: Basic ideas of reduced cross-secti
6、on method and reduced stress methodlim0bultacteffyyPdxbfbb flimeffybbf2011-9-27同济大学 吴冲 Tongji University, Wu Chong202011-9-27同济大学 吴冲 Tongji University, Wu Chong212011-9-27同济大学 吴冲 Tongji University, Wu Chong22Fig. 2.14: Effective cross-section2011-9-27同济大学 吴冲 Tongji University, Wu Chong23Fig. 2.15: C
7、lass 4 cross-sections in pure compression2011-9-27同济大学 吴冲 Tongji University, Wu Chong24Fig. 2.16: Class 4 cross-section in pure bending2011-9-27同济大学 吴冲 Tongji University, Wu Chong252011-9-27同济大学 吴冲 Tongji University, Wu Chong26Fig. 2.17: Determination of effectivep area by iterative procedure2011-9-
8、27同济大学 吴冲 Tongji University, Wu Chong272011-9-27同济大学 吴冲 Tongji University, Wu Chong282011-9-27同济大学 吴冲 Tongji University, Wu Chong292011-9-27同济大学 吴冲 Tongji University, Wu Chong30Fig. 2.18: Assumed stress distribution in a hybrid girder with h = 460 N/mm2 / 235 N/mm2 = 1.962011-9-27同济大学 吴冲 Tongji Univ
9、ersity, Wu Chong31/2.0hyfywff2011-9-27同济大学 吴冲 Tongji University, Wu Chong32efflocbb, c efflocAA2011-9-27同济大学 吴冲 Tongji University, Wu Chong33Fig. 2.20: Examples of internal and outstand plate elements of cross sectionsinternal compression plate elements: 2011-9-27同济大学 吴冲 Tongji University, Wu Chong3
10、421.0for0.50.0850.0550.055 31.0 for0.50.0850.055locpplocppwhere is the ratio of stresses at both edges of the plate withthe maximum compression stress in the denominator21.0for0.7480.1881.0 for0.748locpplocpp2011-9-27同济大学 吴冲 Tongji University, Wu Chong35,ypcr pf22,212 1cr pEtkb21k b is the appropria
11、te plate width t is the plate thicknessE is elastic modulus of steel (E = 210000 N/mm2) is the Poisson coefficient of steel ( = 0.3)k is the plate buckling coefficient, dependant on the stress ratio and boundary conditions (for plates with = a/b 1.0 k is given in Table 2.2 and Table 2.3). For plates
12、 with 1.0 and subjected to uniform compression, k is given as 128.4pbtk2235/yfN mm2011-9-27同济大学 吴冲 Tongji University, Wu Chong36Effectivep width and plate buckling coefficient2011-9-27同济大学 吴冲 Tongji University, Wu Chong37Effectivep width and plate buckling coefficient2011-9-27同济大学 吴冲 Tongji Universi
13、ty, Wu Chong38,10.055 3/0.18, but1.00.6pp redp redp redp,10.188/0.18, but1.00.6pp redp redp redp,0/com Edp redpyMf2011-9-27同济大学 吴冲 Tongji University, Wu Chong39Fig. 2.21: Plate-like buckling of a stiffened plate2011-9-27同济大学 吴冲 Tongji University, Wu Chong40,yc eff locyA cypcrccr pcr pNAffNAFig. 2.22
14、: Stiffened plate under uniform compression ,c eff locsl effloc iloc iiAAbt2011-9-27同济大学 吴冲 Tongji University, Wu Chong41Fig. 2.23: Stiffened web plate in bending 2011-9-27同济大学 吴冲 Tongji University, Wu Chong42 Width for gross area Width for effectivep area Condition for i 1,edgeb 1125b 1,125effb ,11
15、,0cr slcr p 1,infb 11135b 11,135effb 10 2,supb 2225b 2,225effb 22,10cr sl 2,infb 22235b 22,235effb 20 3,supb 30.4cb 3 ,0.4c effb 3320 3,edgeb 30.6cb 3 ,0.6c effb 30 2011-9-27同济大学 吴冲 Tongji University, Wu Chong4322,212 1cr ppEtkb224,24,2 11if1 14 1if1 1ppkk;0,5slslppIAaIAbIsl is the second moment of
16、area of the whole stiffened plate Ip = bt3/(12 (1-p2) = bt3/10.92 is the second moment area of the plate itselfAsl is the sum of the gross areas of individual longitudinal stiffenersAp is the gross area of the plate. 2011-9-27同济大学 吴冲 Tongji University, Wu Chong44Fig. 2.24: Web plate with a single st
17、iffener in compression3,1,112232,1,22222,1,11222,1 12431.05ifif414,33slcr slcslslcr slcslslslcIt bEAb bEIEt baAaAb bIb bat b,2ccr pcr slcbb2011-9-27同济大学 吴冲 Tongji University, Wu Chong45 Stiffener I Stiffener II Lumped stiffener Location (b1,b2,b) 12,IIIb b b 12,IIIIIIbbb 12,IIIIIIIIIbbb Cross-sectio
18、n area ,1slA ,2slA ,1,2slslAA Second moment of area ,1slI ,2slI ,1,2slslII Fig. 2.25: Model with two longitudinal stiffeners in compression zone 2011-9-27同济大学 吴冲 Tongji University, Wu Chong46,2,2121,1,1,2,2slcIIIIIslcslcAbbbbAbAb2011-9-27同济大学 吴冲 Tongji University, Wu Chong4722,2212 1cr cEta,yccr cf2
19、011-9-27同济大学 吴冲 Tongji University, Wu Chong48,1,1A cyccr csleffA cslfAAAsl,1 is the gross cross-sectional area of the stiffener and adjacent parts of the plateAsl,1,eff is the effectivep cross-sectional area of the stiffener and adjacent parts of the plate with due allowance for plate buckling of su
20、b-panels2011-9-27同济大学 吴冲 Tongji University, Wu Chong492,1,2,1slcr slslEIAa2011-9-27同济大学 吴冲 Tongji University, Wu Chong500.09/ei e,1,1slslIiA = 0.34 (buckling curve b) for closed stiffeners = 0.49 (buckling curve c) for open stiffenerse = max (e1, e2)e1 for single-sided stiffeners is the distance bet
21、ween the centres of gravity of the stiffener alone Gst and the stiffener with the contributing plating Gsl (see Fig. 2.26a) ande2 is the distance between the centres of gravity of the contributing plating alone Gp and the stiffener with the contributing plating Gsl. For double-sided symmetrical stif
22、feners e1 = e2 (see Fig. 2.26b). Fig. 2.26: Definition of distances e1 and e22011-9-27同济大学 吴冲 Tongji University, Wu Chong51 2ccc,1, but 01cr pcr c and care plate buckling reduction factor and column buckling reduction factor of unstiffened or stiffened platescr,p and cr,c are elastic critical stress
23、es for plate-like and column-like buckling of unstiffened or stiffened platesFig. 2.28: Interpolation between plate-like and column-like behaviour2011-9-27同济大学 吴冲 Tongji University, Wu Chong52, c effceffAb,c effcc eff loci edge effiAAbt,1,1cyslc eff loccom EdMf AAIf cfy/ M1 is smaller than the average stress com,Ed in the column (stiffener), the effectivep area of that column should be reduced accordingly:2011-9-27精品课件精品课件！2011-9-27精品课件精品课件！2011-9-27同济大学 吴冲 Tongji University, Wu Chong55
