07-Str-B2 · May 2018
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format: National Exams, May 2018 — 07-Str-B2 Management of Construction. Three hours, closed book, one approved Casio or Sharp calculator permitted. Six questions of equal value (20 marks each); any five constitute a complete paper and only the first five that appear in the answer book are marked. All six are worked below so the paper serves as a complete revision set whichever five a candidate elects.
Reference texts: Hegazy, T., Computer-Based Construction Project Management (Prentice Hall) — precedence (activity-on-node) networks with start-to-start lags, forward and backward passes, total and free float, the late bar chart, and contractor cash-flow and overdraft analysis; these chapters carry Questions 1 and 5. Hendrickson, C. & Au, T., Project Management for Construction (2nd ed., Carnegie Mellon) — Chapter 5 (cost estimation and unit-cost data), Chapter 8 (bidding and contract award), Chapter 10 (fundamental scheduling procedures), Chapter 11 (advanced scheduling with lags) and Chapter 12 (cost control and financing of constructed facilities). Halpin, D.W. & Senior, B.A., Construction Management (4th ed., Wiley) — quantity take-off, crew productivity, bidding strategy, bonding and construction safety management. Peurifoy, R.L. & Schexnayder, C.J., Construction Planning, Equipment and Methods (9th ed., McGraw-Hill) — excavation production and the physical determinants of backhoe daily output, behind Question 2. R.S. Means, Building Construction Cost Data (annual) — the anatomy of a unit-price line: crew, daily output, unit, and bare material / labour / equipment / total columns. Sullivan, W.G., Wicks, E.M. & Koelling, C.P., Engineering Economy (17th ed., Pearson) — Chapters 5 and 6, present-worth analysis and the repeatability (least common multiple of lives) assumption for alternatives with unequal lives, used in Question 4. Canadian Construction Documents Committee, CCDC 2 — Stipulated Price Contract (2020), CCDC 220 Bid Bond, CCDC 221 Performance Bond and CCDC 222 Labour and Material Payment Bond, with the BC Builders Lien Act holdback provisions and the Master Municipal Construction Documents (MMCD) — the Canadian tendering and payment machinery behind Questions 3 and 5. WorkSafeBC Occupational Health and Safety Regulation (Parts 8, 11, 12, 13, 18 and 33), CSA Z259 fall-protection and CSA Z94.4 respirator series, and the Transportation Association of Canada Manual of Uniform Traffic Control Devices for Canada — the Canadian rule set behind Question 6.
Check — how the two printed figures on page 2 were read. Network (Question 1): nine activity boxes with seven links — A → D carrying the printed SS = 3 lag (the line leaves A's top-left corner, runs across the top of the sheet and drops into D's top-left corner), then D → H, B → E, B → F, C → G, F → I and G → I, all finish-to-start with zero lag. No further arrows are drawn; A, B and C are the only start activities and E, H and I the only finish activities. Foundation plan (Question 2): an 80 m × 70 m rectangle with a rectangular notch 25 m deep cut into the top edge, one internal trench running the full width 20 m up from the bottom (the 50 m and 20 m dimensions meet on it), and one internal trench dropping from the bottom of the notch to that line. The notch width is not dimensioned on the paper, and Step 1 below shows the total trench length does not depend on it, so nothing is assumed. All plan dimensions are taken as trench centrelines; reading them instead to the outside face of the trench would shorten the total by about 1.6 per cent and change no conclusion.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
The eight measures below are discussed against the Canadian regulatory frame — in British Columbia the WorkSafeBC Occupational Health and Safety Regulation, with the applicable CSA standards and, for roadway work, the Transportation Association of Canada's Manual of Uniform Traffic Control Devices for Canada. The general principle running through all of them is the hierarchy of controls: eliminate the hazard, then engineer it out, then control it administratively, and only then rely on personal protective equipment. Several of the items below sit at the bottom of that hierarchy and are therefore last resorts, not first choices.
1. Fall protection. Required whenever a worker may fall three metres or more, or a lesser distance where there is an unusual risk of injury, and delivered by guardrails, travel restraint, a fall-arrest system to CSA Z259, or a control zone with a written safe-work procedure. A fall-protection plan is required in writing above 7.5 m. This is predominantly a building-project measure, because the exposure is created by working at height on structure, formwork, roofs and leading edges. It is not exclusive to buildings, however: highway work generates falls from bridge decks, retaining walls, abutments, falsework and the tops of large culverts, and those exposures are governed by exactly the same rules. Falls are consistently the leading cause of serious injury and death in Canadian construction, which is why the measure heads the list.
2. Scaffolding. A designed, inspected temporary work platform, erected on adequate sills, plumb and braced, with guardrails and toe boards, complete planking, safe access, and a tag system recording inspection before each shift and after any alteration; systems over the height threshold in the regulation require professional engineer design drawings on site. Scaffolding is essentially a building measure: it exists to give trades a stable working surface against a vertical face, which is what building envelopes, masonry, cladding and interior finishing demand. On a highway project scaffolding appears only in the structural pockets of the work — bridge pier and abutment forming, soffit access, sign gantries, tunnel linings — and even there suspended platforms or under-bridge inspection units are often preferred.
3. Ladder safety. Ladders must be CSA-graded for construction, secured at the top or held, extended a metre above the landing, set at roughly a 4:1 pitch, kept clear of electrical conductors, and used for access rather than as a work platform for anything but light, short-duration work with three points of contact maintained. Ladder safety is relevant to both project types, and it is the most universally applicable item on the list: every site has an access requirement somewhere. Its risk profile differs, though — on a building it is mostly floor-to-floor and scaffold access, while on a highway project it is access into excavations, manholes, catch basins and formwork, where confined-space and traffic hazards may compound the fall risk.
4. Personal protective equipment. The baseline set is a CSA-approved hard hat, CSA-grade 1 safety footwear, eye protection and high-visibility apparel, with hearing protection, gloves and respirators added by hazard assessment. PPE applies to both project types without exception, but the specification differs in one important respect: on a highway project high-visibility apparel is the primary control against being struck by traffic or plant and the regulation requires the higher classes of garment with retroreflective striping, night-rated where work is after dark, whereas on a building site it is largely a plant-and-crane visibility measure. PPE is the last line of defence and never substitutes for an engineering control.
5. Safety net. A net rigged below a work surface to arrest a fall where guardrails are impracticable and personal fall arrest cannot be anchored — classically under structural steel erection, wide-span roof work or bridge deck construction. Nets must be designed and installed to a recognised standard, hung with adequate clearance below and sufficient extension beyond the work edge, and inspected after any impact. Nets are used on building projects mainly for steel erection and roof work, and on highway projects for bridge deck and superstructure work over water, traffic or a railway, where debris containment matters as much as personnel arrest. So the honest answer is both, but only in the narrow situations where the higher-order controls are genuinely unavailable.
6. Respiratory equipment. Selected by written hazard assessment, fit-tested to CSA Z94.4, with the right cartridge or supplied-air arrangement for the contaminant and a written respiratory-protection programme covering training, cleaning and storage. Applicable to both, again with different drivers. Building work generates silica dust from concrete cutting and grinding, welding fume, spray-applied coatings and adhesives, asbestos and lead in renovation, and confined-space atmospheres in tanks and shafts. Highway work generates silica from rock drilling and concrete sawing, asphalt fume, diesel particulate in tunnels and trenches, and blasting residues. Substitution and local exhaust or water suppression must be considered before respirators are issued.
7. First aid. Every workplace requires a first-aid assessment that fixes the level of attendant, the equipment and the transportation arrangements from the number of workers, the hazard rating and the travel time to hospital, together with a written procedure for summoning aid and an emergency transportation plan. This applies to both project types, and it is the item where the highway case is materially harder: a linear, remote or nightshift roadway project may be far from a hospital and spread over many kilometres, so a higher-level attendant, a dedicated transport vehicle and mobile first-aid stations that move with the work front are commonly required, while a building site can rely on one fixed, well-signed station.
8. Welding safety. Requires hot-work permits and fire watch, screening against arc flash for passers-by, local exhaust ventilation or respirators for fume — particularly with galvanised, stainless or coated steel — compressed-gas cylinder securing and separation, competent operator qualification to CSA W47.1 fabrication certification, and inspection of leads and grounding. Welding occurs on both project types: structural steel erection, reinforcing, mechanical piping and handrails on buildings; bridge girders, splices, guardrail and sign structures, and pipeline or utility work on highways. The distinguishing factor is the surrounding environment — combustible finishes and confined interior spaces make fire and ventilation the dominant concerns on a building, while live traffic, exposure to weather and the structural criticality of field welds dominate on a highway.
Summarising the pattern: fall protection and scaffolding are driven by building work but appear on the structural elements of highway projects; safety nets are a narrow, specialised control on both; and ladder safety, PPE, respiratory protection, first aid and welding safety apply universally, with the highway versions differing chiefly in the addition of a traffic hazard, greater remoteness and more night work. The one measure with no direct counterpart in the list — traffic control by qualified persons under the MUTCDC and Part 18 of the regulation — is the defining highway safety measure, and a complete answer notes its absence.
| Measure | Highway | Building | Governing rule (British Columbia) |
|---|---|---|---|
| 1. Fall protection | limited — bridges, walls, falsework | primary | OHSR Part 11; CSA Z259 series |
| 2. Scaffolding | limited — piers, abutments, soffits | primary | OHSR Part 13 |
| 3. Ladder safety | yes | yes | OHSR Part 13; CSA Z11 |
| 4. PPE | yes — high-visibility class critical | yes | OHSR Part 8; CSA Z96, Z94.1, Z195 |
| 5. Safety net | bridge decks over traffic or water | steel erection, roof work | OHSR Part 11 |
| 6. Respiratory equipment | yes — silica, asphalt fume, diesel | yes — silica, welding fume, asbestos | OHSR Parts 5 and 8; CSA Z94.4 |
| 7. First aid | yes — remoteness governs the level | yes | OHSR Part 3 and Schedule 3-A |
| 8. Welding safety | yes — field welds, weather, traffic | yes — fire and ventilation | OHSR Part 12; CSA W117.2, W47.1 |
