Question

2. Short answer questions (5 scores for each question, 20 scores in total) (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?

Answer 1

The local stability checking tormulla of solia web axial compression member are : Ls It is charaderized by the Hexural debormation of a plate with out movement of the intersection lines between adjacent plates as shown in figure below. to The EN 1993-1-5 uses an effective width concept shown in figur below to design thin wall CFS Cross-sections for local buckling. K belfy fy Kbe/ P=0219 02 19 i teft TE K b be K.be Local buckling with cij effective wiath concept (i) Effective width of outstana compression element

Хр where According to EN 1993-1-5 the effective wiath of internal and outstand compression element are given by :- p=bea a (1-0.055(3+4)) + fostinternal tis Compression b element (1-0-188 ap Đ for outstand АР Compression element tips Where fp = fy b= Gross wiath of plate be effective wiath of plate & Reduction factor of plate wiath 4-stress ratio For= Elastic local buckling stress. Xp= material yeila stess If the maximum compression takes place at the free longitudinal edge as shown in tigure (ii). Then, the effective wiath (be) and effective thickness (text) is written as in be = 0.426 teff = (1.758-0.75+ Where, to thickness of plate teft effective thickness of plate

* When the local stability of column web does not meet the following measures should be taken :- requirements 9 con be ci It prevented by controlling the wiath-thickness ratio. (11) It can be done by adopting higher thickness of the plate. (ii) Higher thickness of plate is adopted in rolled steel sections. (iv) In In case Case of built up sectionsana cola toumea sections longitudinal stiffeners are provided which divide the total wiath into a smaller wiatha