Question

Classify the flange and web of I-section shown below in terms of compression resistance. It has had stiffeners welded to the web and flanges. fy=355Mpa.

2. Classify the flange and the web of I-section shown below in terms of compression resistance. It has had stiffeners welded to the web and flanges. fy=355 MPa (3) (A) Flange-Class 3. Web-Class 3 (B) Flange - Class 3. Web - Class 4 (C) Flange -Class 4. Web - Class 3 (D) Flange -Class 4. Web-Class 4 150 Figure 1. Cross-section of the profile.

Answer 1

Title - Classification of Cross-section

Solution: 0 Given: I-section Yield Strengths Nominal value, fy= 355mpa a for the Web to belong to Class 3 there is condition as follows: d = 124.E tw where, d= web depth tw web thickness € Nominal value of factor and if the above condition is not satisfied, then the Web will belong to Class 4. Lets check by substituting values, d {124. tw 0.5 < 12 4 X 190 4 (335) 47:5 < 100.88 : As the condition is satisfied, therefore the web belongs Class 3. to

2 For the compression Flange to belong to class 3 there is a follows condition as с $14.€ tf where, ca flange outstand width tf flange thickness E (235,000 Nominal value of factor fy and if the above condition is not s satisfied, then the flange will belong to class 4. Lets check by substituting values, с < 14. E tf .. 73 2351005 14:X VI 5 355 14.6 11.39 As the above condition is not satisfied, hence it can be said that flange belongs to class 4 Answer. (C) Flange - Class 4 , Web - Class 3

Summary - Class 3 are the one which reach the yielding but doesnt allow for local yielding while Class 4 are the sections that allow for local yielding beyond the yield limit. The conditions stated above determine whether Class 3 or Class 4 exists for the cross section.