BCE Structural Analysis 5

Question 1

In plastic analysis, the collapse load of a fixed-fixed beam of span L carrying a central point load P is:

Accepted Answer

8M_p/L

Answer

Three plastic hinges form (two at fixed ends, one at midspan); virtual work gives P_collapse = 8M_p/L.

Question 2

The conjugate beam method converts the real M/EI diagram into an equivalent:

Accepted Answer

Load on a fictitious beam, with slopes and deflections found as shears and moments

Answer

In the conjugate beam method, the M/EI diagram becomes the load on a fictitious beam; the resulting shear and moment equal the real slope and deflection.

Question 3

Which loading condition produces the maximum positive bending moment at a section due to a moving distributed load?

Accepted Answer

Load placed only on the portions of the span where the influence line ordinate is positive

Answer

To maximize a response, load all regions where the influence line is positive for positive response and negative regions for minimum (negative) response.

Question 4

Betti's reciprocal theorem states that for a linearly elastic structure:

Accepted Answer

Deflection at A due to load at B equals deflection at B due to load at A (for identical loads)

Answer

Betti's theorem states that the work done by system 1 forces through system 2 displacements equals the work done by system 2 forces through system 1 displacements.

Question 5

In a portal frame analysis by the cantilever method (approximate), the assumption made about column axial forces is:

Accepted Answer

Column axial forces are proportional to their distances from the centroid of the column group

Answer

The cantilever method assumes the frame behaves like a vertical cantilever, so column axial forces are proportional to distance from the centroid of the column cross-sectional area group.

BCE - Bachelor of Civil Engineering Practice Test

BCE - Bachelor of Civil Engineering Practice Test

BCE Structural Analysis 5