Plate Girder in Design Of Steel Structures : Practice MCQ Questions & Answers with Explanations

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Design Of Steel StructuresMediumPlate Girder

Consider the following statements with respect to plate girders and identify the correct answer.

Statement A: The intermediate transverse stiffener increases the buckling resistance of the web caused by shear.

Statement B: When the computed shear stress in the web of a plate girder is less than the critical shear stress, intermediate stiffeners are theoretically not required.

Statement B is correct and A is incorrect.

Both statements are correct.

Both statements are incorrect.

Statement A is correct and B is incorrect.

None of the above

Correct Answer:

B — Both statements are correct.

Explanation:

Explanation: Intermediate stiffeners: These are also called stability stiffeners and are provided to check the diagonal buckling of the web. Depending upon the requirements vertical (transverse) and horizontal (longitudinal) stiffeners may be provided. Theoretically, intermediate transverse stiffeners are not required when the calculated shear stress in the web is less than the critical shear stress of the web of the plate girder since the web will not buckle and failure of the web will occur due to shear yielding of the web.

Design Of Steel StructuresMediumPlate Girder

"The interconnected elements both ways behave like beams but the structure is efficient in distributing the effect of loads on an element both ways. In addition to bending, elements are also subjected to a twisting action."

The given statement is TRUE for:

Plates

rigid frames

Grids

shell structures

Correct Answer:

C — Grids

Explanation:

Explanation: The Interconnected Elements and Structural Behavior The statement describes a structural system where interconnected elements behave like beams and efficiently distribute loads in both directions. In addition to bending, these elements are subjected to twisting actions, which is a characteristic of certain structural systems. Let us analyze the options given: Plates, Rigid Frames, Grids, and Shell Structures.

Design Of Steel StructuresEasyPlate Girder

According to IS 800:1984, outstand of the stiffeners from the web should NOT exceed for sections (where â€˜tâ€™ is the thickness of the section and fy is the yield strength of steel).

$\rm \frac{125 t^{2}}{\sqrt{f_{y}}}$

12 t

$\frac{256 \mathrm{t}}{\sqrt{\mathrm{f}_{\mathrm{y}}}}$

10 t

Correct Answer:

C — $\frac{256 \mathrm{t}}{\sqrt{\mathrm{f}_{\mathrm{y}}}}$

Explanation:

Explanation: Vertical Stiffeners: Vertical stiffeners are provided to prevent buckling of the web due to diagonal compression. Some criteria regarding the design of vertical stiffness: The spacing between the vertical stiffness should be between 0.33 Ã— d and 1.5 Ã— d, d is the distance between flange angles,s, and where there is no flange angle, the distance between flanges ignoring fillets is taken. Outstand of web stiffener from the face of the web = Minimum Value = 12 tqÎµ and Maximum Value = 20 tqÎµ The greater unsupported clear dimension of the web panel should not be greater than 270 times the thickness of the web and the lesser unsupported clear dimension of the same web panel should not be greater than 180 times the thickness of the web.

Design Of Steel StructuresEasyPlate Girder

Which of the following type of connections can be used in beam to girder connections only when there is sufficient web depth in the girder to provide for the seat angle?

Direct shear connections

Seated connections (beam to beam)

Seated connections (column to beam)

Moment or eccentric connections

Correct Answer:

B — Seated connections (beam to beam)

Explanation:

Explanation: Understanding the Beam to Girder Connection Question Seated connections (beam to beam or beam to girder) are often used when there is a need to transfer loads effectively between beams or girders. In such connections, a seat angle is used to provide support to the beam, ensuring stability. However, the use of seat angles requires sufficient web depth in the girder to accommodate the angle and transfer the loads effectively.