Chapter 18 — Exercises

Work these with a pencil and a calculator, not in your head. Several of them are the exact arithmetic you will do in a trailer at 3:00 in the afternoon while three people wait for an answer.

Difficulty legend: ⭐ basic · ⭐⭐ applied · ⭐⭐⭐ advanced judgment · ⭐⭐⭐⭐ research and extension

Rates to use throughout unless a problem says otherwise (fully burdened, Rivermont market):

Northgate canonical figures you will need: 210 peak craft workers · $5,150/CD extended general conditions · $5,500/CD liquidated damages · $10,650/CD total daily exposure · 412,000 SF gypsum board · 38,500 SF curtain wall · 99,000 SF floor deck · dried-in March 28, Year 2.

Part A — Conceptual Understanding ⭐

A1. State the superintendent's product in one sentence, as a condition rather than an activity. Then give two examples of work a superintendent does that produces that condition but that an outsider would not recognize as "supervising."

A2. List the six categories the paid craft hour divides into, per §18.1. Which one is usually the largest non-productive category, and why is that category mostly the general contractor's responsibility rather than the subcontractor's?

A3. Explain the difference between a control monument, a benchmark, and an offset line. Why can a control point never sit on a column grid line?

A4. Why do dimensional tolerances accumulate rather than average out? Give a two-step example from a building you have seen.

A5. Name the two fields on a delivery request form that do most of the work, and explain what conflict each one reveals.

A6. Define double handling in one sentence. Why does it never appear as a line item in an estimate?

A7. What is the difference between an excusable delay and a compensable delay? Which does a typical weather clause grant, and what does that mean for your general conditions?

A8. Explain, mechanically, why housekeeping is a leading indicator of planning rather than a cause of productivity.

A9. In your own words, what does an ICRA precaution class actually require of a construction manager, and who performs the assessment?

A10. Why is a backcharge without written notice usually worth nothing?

Part B — Applied Analysis ⭐⭐

B1. A subcontractor submits this delivery request: "Friday, 1 truck, ceiling tile, unload with forklift." Write the three follow-up questions you send back, and state what specific downstream cost each question prevents.

B2. Your superintendent tells you the site "feels slow" but cannot say why. Design a one-week, low-cost observation you could run — with no special software and no consultant — that would tell you where the craft hour is going on your job. Say what you would record, how often, and what you would do with the result.

B3. A crew of eight glaziers is standing at 7:20 a.m. because the curtain-wall bundles they need are at the bottom of a stack in the laydown yard. Walk backward through the chain of decisions that produced that moment and name the four distinct decisions that could each have prevented it. For each, say who made it and when.

B4. Your job is a five-story renovation of an occupied office building. The owner's tenants use the two passenger elevators. You have no crane and no hoist. List the vertical-transportation options actually available to you, and rank them by cost per pound moved, explaining your reasoning.

B5. Compare just-in-time delivery and stockpiling for each of the following, and state which you would choose and why: (a) hollow-metal door frames on a congested urban site with a reliable local supplier; (b) imported porcelain tile with a 16-week lead time on a suburban site with three acres of laydown; (c) ready-mix concrete, anywhere.

B6. Margo's rule is that Saturday picks are single-trade days. Explain the safety reasoning, and connect it explicitly to the canonical scaffold near-miss in week 34.

B7. A neighbor calls three times in two weeks about dust. You are within your permitted work hours and you are running a water truck. Write your actual response plan — what you do, what you write down, and what you tell the neighbor — and explain what you are protecting yourself against.

B8. Your project is pursuing LEED and the waste-diversion credit. Your gypsum container is 200 feet from the interior work areas and the mixed-waste container is 40 feet away. Predict what will happen and state the fix in one sentence.

Part C — Calculations and Deliverables ⭐⭐–⭐⭐⭐

C1 — The cost of standing still. Your job peaks at 164 workers at a site-wide blended rate of $71.00/MH. Your extended general conditions run $4,400/CD and your liquidated damages are $3,000/CD. (a) What does one hour of site-wide idleness cost? (b) How does that compare to one calendar day of being late? (c) Your temp power goes down for 3.5 hours on a Tuesday, affecting 62% of the workforce. Price it. (d) What fraction of (c) does your company actually write a check for, if you self-perform 20% of craft hours?

C2 — Double handling, your own quantity. A project has 268,000 SF of gypsum board. Sheets are 4 ft × 12 ft. A two-laborer team moves 48 sheets per crew-hour in a second handling. The laborer rate is $52.00/MH. (a) How many sheets? (b) How many man-hours does one extra handling cost? (c) What is the dollar cost? (d) If 40% of that second handling crosses floors at 40 sheets per hoist load and a 9-minute cycle, how many hoist-hours does it consume, and how many 540-minute days is that?

C3 — Does the hoist fit? One hoist, 540 productive minutes per day, five-day week. Next week's demand:

(a) Compute demand in minutes and compare to capacity at 100% utilization. (b) Recompute the real shortfall at 75% realistic utilization. (c) Propose three demand-side fixes (reduce loads or cycle time) and estimate the minutes each saves. (d) Price one supply-side fix: a second operator for 2 extra hours/day, 5 days, at $52.00/MH.

C4 — The pour-or-don't-pour decision. You have a 240 CY elevated topping pour scheduled for tomorrow at $206/CY. Crew is 14. Pump at $295/hour for 6 hours. Overnight low is forecast below the threshold in your cold-weather protection plan, and your blankets are on another job. (a) Price the cancellation: pump cancelled inside 24 hours at 30% of the day's charge; ready-mix short-notice cancellation $1,150; crew redeployed with an estimated 5 hours of inefficiency across the 14 people at $58/MH. (b) Price the failure case: assume plastic shrinkage and cold-weather damage across 30% of the 22,000 SF placement, evaluated by the structural engineer and repaired at $6.80/SF, plus 4 days of delay to floor covering. (c) State your decision and the one condition that would change it.

C5 — Build a crane pick schedule. You have one crane, one pad, 8.5 productive hours (6:30 a.m.–3:30 p.m. less a 30-minute lunch and a 30-minute end-of-day securing). Requests:

(a) Total the requested time against available time. (b) Build the schedule, including a held-open contingency block of at least 30 minutes. (c) State what you cut and the exact sentence you say to that foreman.

C6 — Temporary heat and the enclosure milestone. Six indirect-fired heaters, 14 hours/day, 4 gal/hr each, diesel at $4.35/gal. Rental $58/unit/day. Monitoring labor 4 MH/day at $52.00/MH. (a) Daily cost. (b) Cost of a 92-day protection period. (c) What is one week of earlier enclosure worth? (d) Your enclosure subcontractor wants $9,000 to add a crew for two weeks and pull dry-in forward by 9 days. Is it worth it? Show the arithmetic and name one non-monetary factor.

C7 — The sanitation arithmetic. Your job peaks at 148 workers on a four-story building. Currently all portable toilets are at grade at the east end. (a) At a planning ratio of one unit per 10 workers, how many units do you need? (b) If the average round trip from the work face is 11 minutes instead of 4, and each worker makes one trip per day, what is the daily man-hour cost at a blended $66.00/MH? (c) Over a 120-day peak period, what does that total? (d) Four floor-mounted units and their servicing cost $18,400 for that period. Argue the decision.

Part D — Judgment and Ethics ⭐⭐⭐

D1. Your cleanup subcontract language lets you clean and backcharge at cost plus 15% after one written notice and 24 hours. A subcontractor you like is behind and messy; a subcontractor you dislike is behind and messy. Describe the policy you would set in advance so that your enforcement is defensible, and explain what happens to your leverage if you enforce selectively.

D2. A trade foreman asks you to authorize a crane pick at a measured wind speed slightly above what the load chart allows for that configuration, arguing the load is heavy and low-profile and "it's fine." He is probably right about the physics. Write your answer and explain what you are actually protecting.

D3. Your project is behind. Your superintendent proposes cutting the composite cleanup crew from three laborers to one for eight weeks, saving roughly $50,000, and "letting the trades pick up their own." Evaluate the proposal on productivity, safety, and contract grounds. What would you need to be true before you would agree?

D4. You discover that a subcontractor's crew has been staging 34 pallets of tile mid-bay on an elevated deck for three days without any structural review. Nothing has failed. Describe exactly what you do in the next hour, the next day, and the next week — and say what you write down and to whom.

D5. A neighbor's complaint log shows eleven entries over four months, all closed with "within permitted hours." Your project attorney later tells you this log is the best evidence against you in a nuisance claim. Explain how a record intended to protect you became a liability, and rewrite the entry format so it does not.

Part M — Mixed and Interleaved Practice ⭐⭐–⭐⭐⭐

M1 — with Chapter 14 (scheduling). An activity reads "Hang drywall, Level 3 — 12 work days, crew of 12." Show the duration arithmetic that produced 12 days at 11.5 MH per 1,000 SF for 94,000 SF. Then recompute the duration at the unstaged rate of 14.6 MH per 1,000 SF. State the schedule impact and whether it consumes float or the critical path — and explain how you would know which.

M2 — with Chapter 16 (buyout) and Chapter 19 (subcontractors). Write the cleanup and material-handling paragraph for a drywall subcontract scope sheet. It must define scope of cleanup, sweeping, container and stream, delivery notice, staging responsibility, floor-loading limits, the backcharge rate, and the notice procedure — in under 200 words, in language a foreman can act on.

M3 — with Chapter 13 (estimating) and Chapter 21 (equipment). Your Division 01 estimate carried $220,000 for a material/personnel hoist over 10 months. In month three the schedule slips 6 weeks. Compute the general-conditions impact, then evaluate the alternative of demobilizing the hoist for 4 weeks and re-erecting it. State the three costs of that alternative that are not rental.

M4 — with Chapter 8 (structure) and Chapter 33 (claims). It rains 14 days beyond your weather allowance. Nine of those days you could not place concrete. On five of them your dried-in interior work continued at full staffing. Using the entitlement / causation / damages framework, state how many days you can defend, and list the six daily-report fields that decide it.

M5 — with Chapter 1 (the CM role) and Chapter 27 (lean). Take the five items from Margo's 6:15 a.m. walk in the chapter hook. For each, (a) name which of the six craft-hour loss categories it attacks, (b) state whether it is a constraint that should have been removed in the six-week look-ahead, and (c) write the one-line entry it would generate on a constraint log.

M6 — with Chapter 24 (safety) and Chapter 20 (labor). Argue, with specific mechanisms rather than slogans, that a material-handling plan is a safety plan. Use at least three distinct injury mechanisms and connect each to a specific logistics decision from this chapter.

Part E — Research and Extension ⭐⭐⭐⭐

E1. Find a real construction project near you and observe it from a public sidewalk for 30 minutes on a weekday morning. Record: how many trucks arrive, how long each occupies the gate, whether anyone directs them, where material is set down, and whether you can see a posted delivery or pick schedule. Write one page on what you can infer about how that job is run, and be explicit about what you cannot know from the sidewalk.

E2. Look up your own jurisdiction's actual requirements for: permitted construction work hours, construction noise limits, street occupancy and right-of-way permits, and fugitive dust or track-out control. Write a one-page site-operations compliance summary for a hypothetical project at a specific address, citing the actual ordinance or agency — not a summary you found on a contractor's blog. Note where the requirements are ambiguous, because they usually are.

E3. Obtain the publicly available guidance on Infection Control Risk Assessment from a health-care engineering body or a state health department, and write a two-page summary aimed at a project engineer who has never worked in a hospital. Cover who performs the assessment, how activity class and patient risk group combine, what the precaution levels physically require, what documentation is generated daily, and what Interim Life Safety Measures are. Be careful to describe what the guidance actually says rather than what you assume it says.