Question

(1) Write down the local stability checking formula of solid web axial compression member. When the local stability of column web does not meet the requirements, what measures should be taken? (2) When calculating the global stability of lattice axial compression members suffering from bending about the imaginary axis, why is the equivalent slenderness ratio used? (3) Briefly describe the cross-sectional selection principle of axially loaded members: axially loaded members.

Answer 1

Local stability Checking formula for Solid Wes auxial Composers member a A) O The akume that colourn buckling AISC Specifications for column Strength linit However, if the colours section is made of thin (clender) plate Elements, then failule can occur due to local buckatiel is the governing slate. of the webs. ay if then the not be of franges local buckling of the individual plate Elements occurs, column may able to develop its buckling Strength By Thee fore local limit Chate must be prevented from buckling Column Strength чу Controlling the Local buckling depende on the Slendermers (widterton b ratio of the plate Element of the yield stress thickness t (fy) of the material, the & Each plate Element myt be stocky enough lie, have a beer from ratio that prevents local buckling governing colums Strength 67 The Aise specification B5 provides the slenderney, bu dints that the individual plate Elements must saticky local buckling does not control. So that

) Als specification provides two slendeenes limits Cup of E) for the local buckling of plate Elements. Compact force 'non-compact slender t Axial shortening, A figi1 local buckling behawar of plate Elemt. T² EI local burkeling F = (KL) 2 FF maxinum con ceitical Coad modules of Elasticity. 1 = Smallest moment of Inertia of cross section L = Un supported lenger of colum colum effective length factor K -

End Home PgDn PgUp 2 8 Glabal Stability of Lattice Axeal Compression members on The angle of inclination of the lacing after the longitudinal axis of the column should be between 45 to 700 dy Slendeeness ratio na te shoud not exceed of the lacing bars r TUS 0 Effective length le of lacing bars Type of lacing le lengter between inner end rivets on single lacing riveted ends lacing Double lacing, niveted at ends 0.7 x length betwen endriers on har tacing bars. 0-7x distance blo inner ends or (9 Welded tring effective length of welds at ends. L Þ5o Com o for suited can weld Catrice remin 0.7x maxinem sendones ratio of comprenon mantel d minm thinnes t & To single lacing t 4. Double lecting 60

End Home PgDn Cross-sectional selection principle of Axially loaded members the for such members. Cross section checks, buckling resistence will also be checked This is offers the critical case as member is influenced by of factors including type & the Unbraced length a number buckling Strength of the the section of the member.