Technical Drawing - Exam Papers - Ordinary - 1996 - Building

Question 4

Fig. 4 shows the outline plan of three adjoining hyperbolic paraboloid roof surfaces ABOF, BCDO and DEFO. The roof is in the form of an equilateral triangle in plan. The corners A, C and E are 12 m above ground level, corners B, D and F are 4 m above ground level, and corner 0 is 18 m above ground level.

(a) Draw the plan of the roof and project the elevation.
(b) Determine the true shape of the sections R-R and S-S through the roof surfaces.

Scale 1 : 200