Structure Engineering notes for GATE, PSUs -part 4

Hello there,

Here is another list of one liners which are useful for your preparation of GATE and PSUs exams.

• A simply supported beam of circular cross-section with diameter d and length l carries a concentrated load W at the center of the beam. The strength of the beam is proportioned to 1/d^3.
• A cantilever beam carries a uniformly distributed load from fixed end to the center of the beam in the first case and a uniformly distributed load of same intensity from center of the beam to the free end in the second case. The ratio of deflections in the two cases is 7/41
• If the length of a simply supported beam carrying a concentrated load at the centre is doubled, the deflection at the center will become eight times.
• A simply supported beam with rectangular cross- section is subjected to a central concentrated load. If the width and depth of the beam are doubled, then the deflection at the center of the beam will be reduced to 6.25%.
• A laminated spring is given initial curvature because spring becomes flat when it is subjected to design load.
• A laminated spring is supported at center and loaded at ends.
• Laminated springs are subjected to bending stresses.
• Deflection in a leaf spring is more if its stiffness is less.
• Buckling load for a given column depends upon both length and least lateral dimension.
• When both ends of a column are fixed, the crippling load is P. If one end of the column is made free, the value of crippling load will be changed to P/16.
• Euler's formula for a mild steel long column hinged at both ends is not valid for slenderness ratio less than 80.
• A long column has maximum crippling load when its both ends are fixed.
• Effective length of a chimney of 20 m height is taken as 40 m.
• Rankine's formula for column is valid when slenderness ratio has any value.
• Slenderness ratio of a 5m long column hinged  at both ends and having a circular cross-section with diameter 160 mm is 125.
• The effect of arching a beam is to reduce bending moment throughout.
• Internal forces at every cross section in a arch are normal thrust, shear force and bending moment.
• According to Eddy's theorem, the vertical intercept between the linear arch and the center line of actual arch at any point represents to some scale bending moment in real arch.
• In a three hinged arch, the linear and actual arch meet at least three points.
• If a three hinged parabolic arch carries a uniformly distributed load over the entire span, then any section of the arch is subjected to normal thrust only.

Thanks for visiting!

Reference: Civil Engineering Objectives - by S P Gupta and S P Gupta