Question 1
The connection of intermediate transverse stiffeners are designed for shear of
A. twbs
B. tw2/5bs
C. tw25bs
D. tw5bs
View Answer
Answer: Option B
Explanation:
Intermediate transverse stiffeners not subjected to external loading should be connected to the web so as to withstand a shear between each component of the stiffener and the web not less than tw2/5bs, where tw is thickness of web, bs is outstand width of stiffener.
Question 2
The effective length of intermediate transverse stiffener is taken as
A. 2 times the length of stiffener
B. 0.7 times the length of stiffener
C. 1.4 times the length of stiffener
D. 0.5 times the length of stiffener
View Answer
Answer: Option D
Explanation:
The effective length of intermediate transverse stiffener is taken as 0.7 times the length of stiffener. The intermediate transverse stiffener is provided mainly to improve shear buckling resistance of the web.
Question 3
The effective length of web on each side of centreline of stiffeners for interior stiffeners is limited to
A. 10 tw
B. 50 tw
C. 40 tw
D. 15 tw
View Answer
Answer: Option C
Explanation:
The effective length of web on each side of centreline of stiffeners is limited to 20 times the web thickness, i.e. 40tw for interior stiffeners and 20tw for end stiffeners . The effective section is the full area or core area of stiffener together with effective length of web on each side of centreline of stiffeners.
Question 4
The interaction expression for stiffeners subjected to external loads or moments is given by
A. [(Fq-Fs)/Fqd]+(Fs/Fsd)+(Mq/Myq) < 1
B. [(Fq-Fs)/Fqd]+(Fs/Fsd)+(Mq/Myq) > 1
C. [(Fq-Fs)/Fqd]-(Fs/Fsd)-(Mq/Myq) < 1
D. [(Fq+Fs)/Fqd]-(Fs/Fsd)-(Mq/Myq) > 1
View Answer
Answer: Option A
Explanation:
Stiffeners subjected to external loads and moments should meet the conditions of load carrying stiffeners. In addition, they should satisfy the following interaction equation: [(Fq-Fs)/Fqd]+(Fs/Fsd)+(Mq/Myq) < 1, where Fq is stiffener force, Fqd is design resistance of intermediate stiffeners corresponding to buckling about axis parallel to the web, Fs is external load or reaction at stiffener, Fsd is design resistance of load carrying stiffener corresponding to buckling about axis parallel to the web, Md is moment on the stiffener due to eccentrically applied load and transverse load, Myq is yield moment capacity of stiffener based on its elastic modulus about its centroidal axis parallel to the web.
Question 5
The second moment of area of torsional stiffeners about center line of the web is given as
A. Is ≤ αssD3
B. Is ≤ 0.34αsD3Tcf
C. Is ≥ 0.34αsD3Tcf
D. Is ≥ αsD3
View Answer
Answer: Option C
Explanation:
When bearing stiffeners are required to provide torsional restraint at the support of the beams, the second moment of area of the stiffener section about center line of the web should be such that Is ≥ 0.34αsD3Tcf , where αs = 0.006 for LLT/ry ≤50, 0.3/( LLT/ry) for 50< LLT/ry≤100, 30/( LLT/ry)2 for LLT/ry ≥100, D = overall depth of beam at the support, Tcf = maximum thickness of compression flange in the span under consideration, KL = laterally unsupported effective length of compression flange of beam, ry = radius of gyration of the beam about minor axis.
Question 6
The second moment of area of transverse web stiffeners not subjected to external loads or moments is given by
A. Is ≤ 0.75dtw2
B. Is ≥ 0.75dtw2
C. Is ≤ 1.5dtw2
D. Is ≥ 12.5dtw
View Answer
Answer: Option B
Explanation:
Transverse stiffeners not subjected to external loads or moments should have second moment of area Is about centreline of the web, if stiffeners are on both sides of the web and about face of the web, if stiffener is on only one side of the web such that Is ≥ 0.75dtw2 for c/d ≥ √2 and Is ≥ 1.5dtw2/c2 for c/d < √2.
Question 7
The function of bearing stiffener is to
A. improve buckling strength of web
B. preclude any crushing of web
C. restrain against torsional effects
D. increase buckling resistance of web
View Answer
Answer: Option B
Explanation:
The function of bearing stiffener is to preclude any crushing of web at locations of heavy concentrated loads. Thus, they transfer heavy reactions or concentrated loads to the full depth of web. They are placed in pairs on the web of plate girders at unframed girder ends and where required for concentrated loads.
Question 8
What is the stiff bearing length?
A. length which cannot deform appreciably in bending
B. length which deform appreciably in bending
C. length of outer end of flange
D. length of web
View Answer
Answer: Option A
Explanation:
The stiff bearing length of any element b1 is that length which cannot deform appreciably in bending. To determine b1, the dispersion of load through a steel bearing element should be taken as 45˚ through solid material, such as bearing plates, flange plates, etc.
Question 9
Which of the following buckling check is applied to stiffeners?
A. [(V+Vc)/γm0] ≤ Fqd
B. [(V+Vc)γm0] ≥ Fqd
C. [(V-Vc)/γm0] ≤ Fqd
D. [(V-Vc)γm0] ≥ Fqd
View Answer
Answer: Option C
Explanation:
Stiffeners not subjected to external loads or moments should be checked for buckling for a force Fd = [(V-Vc)/γm0] ≤ Fqd, where Fqd is design resistance of intermediate stiffeners, V is factored shear force adjacent to the stiffener, Vcr is shear buckling resistance of the web panel designed without using tension field action. This check is required for intermediate stiffeners only when tension field action is utilized in webs.
Question 10
Which of the following is not true regarding longitudinal stiffeners?
A. longitudinal stiffeners increase buckling resistance considerably as compared to transverse stiffeners
B. they consist of plane section for welded plate girder
C. first horizontal stiffener is provide at one-fifth of distance from compression flange
D. first horizontal stiffener is provide at neutral axis
View Answer
Answer: Option D
Explanation:
Longitudinal stiffeners are also called horizontal stiffeners. They increase buckling resistance considerably as compared to transverse stiffeners when the web is subjected to buckling. They consist of angle section for riveted/bolted plate girder and plane section for welded plate girder and are provided in the compression zone of the web. The first horizontal stiffener is provide at one-fifth of distance from compression flange to tension flange. If required another stiffener is provided at the neutral axis.