Na

where n = perpendicular distance from B to the N.A. = 44 mm and Mn.a. = 10000 cos 47°41' x 1.2 = 8079 Nm

1.23 xlO"6

This confirms the result obtained with the alternative procedure of Example 1.2.

Problems

1.1 (B). A rectangular-sectioned beam of 75 mm x 50 mm cross-section is used as a simply supported beam and carries a uniformly distributed load of 500 N/m over a span of 3 m. The beam is supported in such a way that its long edges are inclined at 20° to the vertical. Determine:

(a) the maximum stress set up in the cross-section;

(b) the vertical deflection at mid-span.

12 (B). An I-section girder 1.3 m long is rigidly built in at one end and loaded at the other with a load of 1.5 kN inclined at 30° to the web. If the load passes through the centroid of the section and the girder dimensions are: flanges 100 mm x 20 mm. web 200 mm x 12 mm, determine the maximum stress set up in the cross-section. How does this compare with the maximum stress set up if the load is vertical?

13 (B). A 75 mm x 75 mm x 12 mm angle is used as a cantilever with the face AB horizontal, as shown in Fig. 1.19. A vertical load of 3 kN is applied at the tip of the cantilever which is 1 m long. Determine the stress at A. B and C. [196.37, -207 MN/m2.]

75 mm

0 0

Post a comment