Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format. 07-Str-A5 Advanced Structural Design, National Exams December 2014. Three hours, open-book (handbooks and textbooks permitted, no notes). Seven questions of equal value; any five constitute a complete paper, and only the first five presented are marked. All solutions below answer all seven, because the set is a study resource rather than an exam script. All loads shown on the figures are unfactored.
Design data supplied on the paper (SI). Concrete \(f'_c = 30\ \text{MPa}\); structural steel \(F_y = 350\ \text{MPa}\); rebar \(f_y = 400\ \text{MPa}\). Prestressed concrete: \(f_{ci} = 35\ \text{MPa}\) at transfer, \(f'_c = 50\ \text{MPa}\), \(n = 6\), \(f_{ult} = 1750\ \text{MPa}\), \(f_{y} = 1450\ \text{MPa}\), \(f_{initial} = 1200\ \text{MPa}\), losses \(= 240\ \text{MPa}\), hence \(f_{pe} = 960\ \text{MPa}\).
Reference texts.
Check: load classification. The paper prints the loads as unfactored but does not split them between dead and live. Throughout this solution every printed load is treated as a specified live load and factored at 1.5, while member self-weight is treated as dead and factored at 1.25 (NBCC 2020 combination 2, \(1.25D + 1.5L\)). If a different split is stated on exam day, re-run the same arithmetic with the stated factors — the method is unchanged.
Check: Figure 4 geometry. Read from the drawing on page 4, the beam \(AC\) is \(4 + 8 + 4 = 16\ \text{m}\) long with the rigid joint \(C\) at its right-hand end, directly over the column; the 400 kN acts at \(C\), and the 200 kN loads act at 4 m and 12 m from \(A\). Support \(A\) is drawn with the same circle-on-hatching symbol used for the rollers in Figures 1 and 2, so it is taken as a roller (vertical reaction only); base \(E\) is fixed. The frame is therefore indeterminate to the first degree.
