Bending of Beams - Structural and Stress Analysis - page 248

1m

0.15 m

0.75 m

A

0.3 m

F IGURE P.9.11

P.9.12 A precast concrete beam has the cross section shown in Fig. P.9.12 and carries
a vertically downward uniformly distributed load of 100 kN/m over a simply supported
span of 4m. Calculate the maximum direct stress in the cross section of the beam,
indicating clearly the point at which it acts.

27 . 6N/mm 2 (compression) at B.

Ans. −

A 50 mm

B

40 mm 40 mm

500 mm

C

50 mm

F D

300 mm 100 mm

F IGURE P.9.12

P.9.13 A thin-walled, cantilever beam of unsymmetrical cross section supports shear
loads at its free end as shown in Fig. P.9.13. Calculate the value of direct stress at the
extremity of the lower flange (point A) at a section half-way along the beam if the
position of the shear loads is such that no twisting of the beam occurs.

Ans . 194.7N/mm 2 (tension).

40 mm

800 N

2.0 mm

100 mm 2.0 mm

400 N

1.0 mm
A

80 mm

2000 kN

F IGURE P.9.13

P.9.14 A thin-walled cantilever with walls of constant thickness t has the cross section
shown in Fig. P.9.14. The cantilever is loaded by a vertical force P at the tip and a