07-Str-A2, May 2017: worked solutions

Paper format. National Examinations, May 2017 — 07-Str-A2 Elementary Structural Design. Three hours, closed book (handbooks and textbooks permitted). Seven questions in three parts: Part A (A1–A3, structural steel to CSA S16), Part B (B1–B3, reinforced concrete to CSA A23.3) and Part C (C1, timber to CSA O86). A candidate answers two from Part A, two from Part B and the one question in Part C — five solutions of equal value, with the page-1 mark split A1 (12+8), A2 (8+12), A3 (8+12), B1 (12+8), B2 (10+8+2), B3 (12+8), C1 (8+6+6). All seven are solved here, because the set is a study resource rather than a sitting.

Reference texts.

CSA S16:19, Design of Steel Structures — Clauses 11 (section class), 13.3 (compression), 13.5 (bending), 13.8 (axial force and bending), 13.13 (welds), 14.3 (concentrated forces).
CISC, Handbook of Steel Construction — rolled-section dimensions and properties, weld tables.
CSA A23.3:19, Design of Concrete Structures — Clauses 10 (flexure and axial load), 11 (shear).
CSA O86:19, Engineering Design in Wood — Clause 6 (sawn lumber), Tables 6.3.1B and 6.4.5.
Canadian Wood Council, Wood Design Manual; National Building Code of Canada 2020 (load combinations).

Load factors. NOTE 6 on page 1 states that all loads shown are unfactored. The point loads drawn on Figures A1, B1 and B2 are occupancy loads, so they are factored by 1.5; the only dead load anywhere in this paper is the concrete self-weight of the Question B2 beam, which takes 1.25. This follows NBCC combination 2, 1.25D + 1.5L.

Check — figure page. Two figure readings are flagged where they arise: in Figure B1 the 350 kN load acts at midspan of beam BA (3.5 m from B), not at joint B; and the 80 kN horizontal load acts 4 m below B, i.e. 6 m above the pin at C.

07-Str-A2: May 2017