07-Str-B2 · December 2017
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format: National Exams, December 2017 — 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 answered in the answer book are marked. All six are worked below so that the paper can be used for revision whichever five a candidate chooses.
Reference texts: Hegazy, T., Computer-Based Construction Project Management (Prentice Hall) — precedence (activity-on-node) networks with lags, forward and backward passes, total and free float, earned-value progress measurement and the time–cost trade-off curve; these chapters carry Questions 1 and 3. Hendrickson, C. & Au, T., Project Management for Construction (2nd ed., Carnegie Mellon) — Chapter 5 (cost estimation and unit-cost data), Chapter 10 (fundamental scheduling procedures), Chapter 11 (advanced scheduling with lags) and Chapter 12 (cost control, monitoring and accounting), including percent-complete and earned-value reporting. Halpin, D.W. & Senior, B.A., Construction Management (4th ed., Wiley) — labour productivity, crew balance, construction contracts and bonding, and construction safety management. Peurifoy, R.L. & Schexnayder, C.J., Construction Planning, Equipment and Methods (9th ed., McGraw-Hill) — crew productivity and the physical determinants of daily output, behind Question 3. R.S. Means, Building Construction Cost Data (annual) — the structure of a unit-price line: crew, daily output, labour-hours per unit, bare material / labour / equipment, and total including overhead and profit. Sullivan, W.G., Wicks, E.M. & Koelling, C.P., Engineering Economy (17th ed., Pearson) — Chapters 5 and 6, present-worth analysis and the repeatability (common multiple of lives) assumption for alternatives with unequal lives, used in Question 4. AACE International, Recommended Practice 29R-03, Forensic Schedule Analysis, and the Society of Construction Law Delay and Disruption Protocol (2nd ed., 2017) — the delay-analysis taxonomy required by Question 2. Canadian Construction Documents Committee, CCDC 2 — Stipulated Price Contract (2020), CCDC 220 Bid Bond, CCDC 221 Performance Bond, CCDC 222 Labour and Material Payment Bond and CCDC 40 — Rules for Mediation and Arbitration, together with the BC Builders Lien Act holdback provisions — the Canadian contractual machinery behind Questions 2 and 5. Transportation Association of Canada, Manual of Uniform Traffic Control Devices for Canada (MUTCDC) and the BC Ministry of Transportation and Infrastructure Traffic Management Manual for Work on Roadways, with WorkSafeBC's Occupational Health and Safety Regulation (Part 18 Traffic Control, Part 4 lighting and workplace conditions, Part 8 personal protective clothing) — the Canadian rule set behind Question 6.
Check — what the printed R.S. Means line in Question 3 actually contains. On line 04810‑3000 the printed cells are labour-hours 0.092, bare material $3.62, bare labour $2.93, bare total $6.55 and total including O&P $8.45. The CREW, DAILY OUTPUT, UNIT and EQUIPMENT cells are blank on the paper — they are not faint, they carry no ink at all. The self-consistency of the printed row ($3.62 + $2.93 = $6.55) confirms the money columns were read correctly.
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.
A highway rehabilitation work zone is unusual among construction sites in that the principal hazard is not the construction plant but the travelling public, who pass within a metre or two of the workforce at highway speed and who have not agreed to be there. Night work compounds this: it is chosen because traffic volumes are lower and lane closures are cheaper, but it introduces reduced visibility, glare, driver fatigue, a far higher proportion of impaired drivers, and a workforce operating against its own circadian rhythm. An accident-free night work zone is therefore built on four things — a designed traffic plan, physical separation, engineered lighting and conspicuity, and management of the workforce itself — supported throughout by the internal-responsibility machinery that Canadian occupational health and safety law imposes.
Plan the work zone before anyone is exposed. Every closure begins with a written traffic management plan prepared to the Transportation Association of Canada's Manual of Uniform Traffic Control Devices for Canada and, in British Columbia, the Ministry of Transportation's Traffic Management Manual for Work on Roadways, signed by a qualified person and approved by the road authority. The plan sets out the five standard components of the zone — advance warning area, transition (taper) area, buffer space, work area and termination area — and sizes each from the posted speed. Taper lengths follow the standard relations, $L = \dfrac{W S^2}{155}$ for speeds up to 60 km/h and $L = 0.62\,W S$ above it, with $W$ the lateral shift in metres and $S$ the speed in kilometres per hour; the buffer space is a longitudinal gap that contains an errant vehicle before it reaches a worker. Sign spacing, device spacing through the taper, and the length of advance warning all come from the same tables. The plan must also address work-zone speed reduction and its enforcement, since a posted reduction that is not enforced changes nothing, and must be re-checked whenever the staging changes. Consider whether a full closure with a signed detour is safer than a live lane closure at all: on rehabilitation work the shortest exposure is often the safest exposure, and night full-closures with detours frequently beat long partial closures.
Separate workers from traffic physically. Cones and drums delineate; they do not protect. Where the exposure warrants it, use positive protection: temporary concrete barrier, water-filled or steel portable barrier with a tested crashworthy end treatment, and truck-mounted or trailer-mounted attenuators on the shadow vehicle protecting mobile and short-duration operations. All channelising devices must be crashworthy and, for night use, retro-reflectorised to the required sheeting grade. Provide a designed access and egress route for construction vehicles so that plant enters and leaves the zone without reversing into live lanes, and prohibit reversing without a spotter or a reverse-sensing system. Keep a designated escape route and a "no worker on foot" rule inside the buffer. Where a lane is opened to traffic before the next shift, verify that drop-offs, joints and temporary pavement markings meet the standard, since night drivers navigate almost entirely by markings.
Engineer the lighting, and control glare. Night work needs illumination designed as an engineering task, not as an afterthought. WorkSafeBC's Occupational Health and Safety Regulation Part 4 sets minimum illumination levels by task; typical practice is on the order of 55 lux for general work areas, 110 lux where equipment is being operated or workers are on foot near plant, and 220 lux for detail tasks such as paving-joint work or equipment maintenance. The harder problem is glare: a light tower aimed toward oncoming traffic disables approaching drivers for several seconds, and one aimed at the crew destroys their dark adaptation. Aim luminaires downward and away from the travelled lanes, use glare-shielded or balloon-type diffuse lighting near the traffic interface, mount towers high enough to lower the aiming angle, and check the finished installation from the driver's seat of a passing car before the shift starts. Provide a lighting plan that moves with the paving train, and carry portable lighting for the flagging stations at each end of the zone, which are otherwise the darkest and most exposed positions in the work.
Make workers conspicuous and control the flagging operation. High-visibility apparel to the Class 2 or 3 level required by WorkSafeBC Part 8, with retro-reflective banding on the torso, arms and legs, is the minimum for night work; retro-reflective striping on hard hats and on the back of trousers substantially improves recognition of a moving person. Flaggers must be trained and certified, must stand where they have an escape path and are visible from the full stopping-sight distance, must use illuminated wands or paddles at night, and should be rotated frequently. Where the geometry allows, replace human flaggers with automated flagger assistance devices, portable traffic signals or pilot vehicles, which removes a worker from the most dangerous position in the zone altogether. Spotters must be used for all reversing plant and around cranes and pavers.
Manage the human factors that night work creates. Fatigue is a hazard in the regulatory sense, and it must be managed like one: limit consecutive night shifts, cap shift length and consecutive hours, provide scheduled breaks and a properly lit and heated rest area, and control the commute at shift end — the drive home after a night shift is statistically one of the most dangerous parts of the job. Rotate workers between tasks to maintain alertness, run a documented fitness-for-duty and substance policy, and hold a tailboard meeting at the start of every shift covering that night's staging, the escape routes, the emergency plan and the changes from the previous night. Because a night zone is remote, dark and traversed by high-speed traffic, the emergency response plan must be specific: how an ambulance enters the closed lane, where the muster point is, who has first-aid coverage at the required attendant level, and how a serious incident triggers the reporting obligations to the provincial regulator.
Sustain the system through inspection and the internal responsibility system. Canadian OH&S law places a general duty on the employer to take every reasonable precaution and to provide a safe workplace, with parallel duties on the prime contractor, supervisors and workers, and requires a joint health-and-safety committee on larger sites. Translate that into the work zone by: a documented hazard assessment and safe-work procedure for each activity; a daily drive-through inspection of the whole zone at the start and end of each shift with the devices checked against the approved plan and the check recorded; competent-person supervision on every shift; a near-miss and incident reporting system with real follow-up; and a stop-work authority that every worker knows they may exercise without consequence. Record device counts, lighting checks, flagger certifications and tailboard attendance, because on a highway job the paperwork is also the defence when an incident is investigated. The measure of the system is simple: no worker should ever be on foot in a live lane, and no motorist should ever be surprised by the work zone.
