Chapter 38 Exercises — Heavy Civil Construction

Work these with the chapter closed where you can. Selected answers appear in Appendix J; several calculation items carry a numeric check in a <details> block here so you can verify your arithmetic without verifying your reasoning.

Difficulty legend: ⭐ basic recall and comprehension · ⭐⭐ applied analysis · ⭐⭐⭐ judgment, multi-step calculation, or professional trade-off · ⭐⭐⭐⭐ research and extension beyond the chapter.

Part A — Conceptual Understanding ⭐

A1. In your own words, explain the difference between what a building estimator and a heavy civil estimator are actually doing when they price an item of work. Use the terms assembly and cycle.

A2. A DOT contract consists of standard specifications, standard drawings, and special provisions. Explain what each one is and describe the general relationship among them. Why does the chapter insist you verify the order of precedence in your contract rather than assuming one?

A3. Define incidental work as the term is used in a measurement and payment clause. Give four examples of activities that are commonly incidental on heavy civil contracts, and explain why an estimator who ignores them can lose money on an item that was priced "correctly."

A4. On a unit-price contract, what exactly are you bidding, and what exactly are you paid? Explain why the bid total shown at the bid opening is described in the chapter as "a comparison device."

A5. Distinguish Type I and Type II differing site conditions. For each, state what the actual condition is compared against, and say which one is generally easier to establish and why.

A6. What is a geotechnical baseline report, and how does it change the differing-site-conditions argument compared with a contract that includes only boring logs and a disclaimer?

A7. Explain the difference between a calendar-day and a working-day contract. Who bears weather risk under each, and in what currency — time, money, or both?

A8. What is a pay factor? Describe the three possible outcomes of a statistical acceptance lot (full pay, reduced pay, and removal), and explain why an agency would ever pay for material it has judged deficient rather than requiring its removal.

A9. Why does the chapter call the buffer space in a work zone "the part people give away when they are behind schedule"? What is the buffer for?

A10. State in one sentence why existing utility as-built records are frequently wrong, and in a second sentence why that is a contractual problem and not only a technical one.

Part B — Applied Analysis ⭐⭐

B1. A bid schedule contains an item reading "Item 305 — Trench Excavation, 6,400 LF." A colleague says, "Good — the trenching is a separate pay item, so we can price the pipe lean." List every question you would ask before agreeing, and describe two different measurement clauses that would make your colleague's conclusion wrong.

B2. Del's crew finds an abandoned, unmarked 12-inch clay pipe crossing the alignment at station 18+40 — it appears on no drawing, no as-built, and no locate. Analyze this as Type I and then as Type II. Which analysis do you lead with, and what does your written notice say differently in each case?

B3. Two contractors bid the same DOT project. Contractor A's structural excavation rate is $38.50/CY; Contractor B's is $22.00/CY. Give four substantively different explanations for that gap that have nothing to do with one contractor being smarter than the other. Which of them would concern you if you were the agency's engineer reviewing the bids?

B4. Look at the time-location chart in §38.5.3. The drainage crew (C) flattens between working day 48 and 66 at station 20+00. Describe three separate consequences of that flat spot: one to the schedule, one to cost, and one to safety. Then say which of the three the CPM bar chart would have revealed.

B5. An agency's contract obtains all environmental permits before letting the work, and the contractor is obligated to comply with their conditions. Your project manager says, "Good — the permits are the owner's problem." Explain, with two concrete examples, why that conclusion is dangerous.

B6. A superintendent argues that potholing utility crossings ahead of the pipe crew is "money we're spending to find problems we might not have." Construct the counter-argument using the arithmetic from §38.6.2, and then construct the strongest honest version of the superintendent's position. When might he be right?

B7. On a bridge job the agency's specification pays reinforcing steel by computed weight from the placing drawings, at $1.42/LB. Your purchasing records show you bought 11% more steel by weight than the computed quantity. Explain where that 11% went, whether any of it is recoverable, and what it means for how the item should have been priced.

B8. Your contract has an unclassified excavation item — one price regardless of material. Explain how this changes (a) your bid price, (b) your pre-bid site investigation effort, and (c) the importance of the differing site conditions clause, compared with a contract that carries separate common and rock excavation items.

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

C1 — Build a unit price from production. A 2.0 CY excavator loads 16 LCY articulated trucks in open cut. Bucket fill factor 0.92. Cycle time 26 seconds. Job efficiency 50 minutes per hour. Swell 22%. Haul 2.4 miles at 26 mph loaded, 32 mph empty. Dump and maneuver 1.8 minutes. Spot 0.5 minutes. Spread hourly cost: excavator with operator $215; each truck $124; dozer at the fill $158; grade checker $64; foreman allocated $92.

Compute: (a) LCY per pass; (b) LCY/hr at 100%; (c) LCY/hr at the stated efficiency; (d) BCY/hr; (e) truck cycle time and the number of trucks required; (f) total spread hourly cost with that truck count; (g) cost per BCY.

C2 — The measurement clause changes the answer. Take your answer to C1(g). The item is measured to a neat line and your actual excavated volume will run 1.28 times the neat-line volume. Disposal costs $1.85/BCY moved. Item fixed cost is $61,000 and the engineer's estimated quantity is 38,000 CY. Your markup is 24% on cost. What is your bid unit price?

C3 — Quantity variation. Using your C2 rate, the item finishes at 26,600 CY (30% below estimate). Compute: (a) revenue as bid vs. revenue as built; (b) actual cost; (c) actual margin vs. planned margin; (d) the stranded fixed cost; (e) assuming a ±25% threshold and that this is a major item, the adjusted unit price you would request to recover stranded fixed cost only.

C4 — Mass haul. Build a mass haul table and describe the curve for this alignment. Stations at 200-foot intervals from 40+00 to 60+00; volumes in CY, shrinkage already applied.

Compute the cumulative ordinate at every station. Then state: (a) where the peak is and what it means; (b) whether the job needs borrow, and how much; (c) whether the job produces waste, and how much; (d) which reach you would balance internally and why.

C5 — Pay factor. Using the illustrative density schedule in §38.6.5, compute the payment and the revenue loss for each lot below at a unit price of $88.60/TON, then state the total revenue lost across the four lots and express it as a percentage of full-price value.

C6 — Force account ticket. Write a complete force account daily record for this directed work: the resident engineer directs Kestrel to hand-excavate and support an unmarked 4-inch conduit discovered at station 22+60, on a Tuesday. Two laborers work 6.5 hours each; one operator works 3.0 hours; a mini-excavator operates 3.0 hours and stands by 3.5 hours; a foreman spends 2.0 hours; materials are 2 sheets of plywood, 4 timbers, and 60 LF of sand bags. Produce the ticket as you would submit it, including every field the chapter says it must contain, and write the one-sentence narrative that ties the cost to the directive. State explicitly what you do if the inspector declines to sign.

C7 — Write the notice. Draft the differing-site-conditions notice Ingrid sent at 6:52 a.m. on day nineteen. Maximum 250 words. It must: identify the location and the specific contract document the condition differs from; describe the condition factually without argument; state that work in the affected area has stopped; request inspection before the condition is disturbed; reserve rights to cost and time; and avoid asserting a dollar figure. Then write, in two sentences, why the absence of a dollar figure is deliberate.

Part D — Judgment and Ethics ⭐⭐⭐

D1. Your estimator finds, three days before bid, that the agency's plans understate the roadway excavation quantity by roughly 30% — his takeoff is solid and he is confident. Lay out at least three courses of action, including the one you believe is right. For each, identify who bears the consequence, what the agency would say if it learned what you did, and where the line between aggressive bidding and misrepresentation falls. Note where you would want an attorney's input.

D2. Your paving superintendent, facing a lot that he believes will core at 91.5%, suggests running an extra roller pass "only in the areas we think they'll test." Explain what is wrong with the proposal in three registers: contractual, ethical, and practical. Then write the two sentences you would actually say to him in the field, and describe the system change that prevents the situation from recurring.

D3. The resident engineer charges Kestrel a working day on a morning when it rained until 10 a.m. and the crew worked productively from 10:30 to 5:00. Your daily report supports the delayed start. Decide whether to contest the charge, and defend the decision. Then answer the harder question: how do you decide which day charges are worth contesting when you know that contesting all of them will damage a working relationship you need for another 140 working days?

D4. Kestrel committed a DBE firm in its bid to perform the erosion control scope. Eight weeks into the job, the DBE's superintendent has left and the firm is struggling to staff. Your operations manager suggests "we'll just run the work with our own crew and keep them on the paperwork so we stay compliant." Explain precisely what is wrong with that, what the legitimate paths are, and why this is one of the few situations in this book where the answer is not a judgment call.

D5. An agency's contract shifts all subsurface risk to the contractor through an unclassified excavation item, an aggressive disclaimer of the geotechnical data, and a differing-site-conditions clause narrowed by special provision. Is bidding this job wrong? Analyze it as a risk-pricing question and then as an industry-level question: what happens to the price the public pays when every bidder must carry an unpriceable contingency? Reference the geotechnical baseline report argument in your answer.

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

M1 — with Chapter 4 and Chapter 6. Build a one-page risk allocation comparison for the same scope of site utility work under (a) lump sum, (b) unit price, and (c) cost-plus with a GMP. For each, state who owns quantity risk, productivity risk, subsurface risk, and weather risk, and identify the single clause in each that matters most. Then add a row for "what the owner pays for risk that never happens."

M2 — with Chapter 14 and Chapter 37. Take the five crews from the time-location chart in §38.5.3 and express the same plan three ways: as a CPM activity list with logic and durations, as a time-location chart, and as a line-of-balance chart of the kind Colton Reyes would recognize from Harbor Ridge. Identify one thing each representation shows that the other two hide. Then state the general principle connecting all three.

M3 — with Chapter 21 and Chapter 28. Your Cottonwood Creek excavation item is coded and tracked weekly. Week 6 shows 2,180 CY placed at an actual cost of $52,300. Compute the actual cost per CY, compare it with the $20.00/CY variable plus $10.00/CY fixed allocation from §38.3.2, and produce a cost-to-complete forecast for the remaining quantity. Then answer the Chapter 28 question: is this item making money, and what is the earliest signal you had that it might not be?

M4 — with Chapter 26 and Chapter 33. Reconstruct the Cottonwood Creek rock event as a claim file. List every document that should exist, who creates it, and on what day. Then mark which documents are contemporaneous and which would be reconstructed if the claim were assembled four months later, and estimate — with reasoning — how much of the $201,876 recovery would survive if only the reconstructed documents existed.

M5 — with Chapter 15 and Chapter 34. Kestrel is deciding whether to bid a $24M DOT interchange in an adjacent state where it has never worked. Build the bid/no-bid analysis: what changes about the specification, the labor market, the aggregate and asphalt supply, the bonding, the prequalification, the prevailing wage determination, and the working-day season. Identify the three factors that would make you decline regardless of the margin.

M6 — with Chapter 24 and Chapter 27. Bea Salgado's finding on the scaffold near-miss was that a crew running behind carried an unwritten "make it up" pressure. Translate that finding into heavy civil: write a one-page constraint analysis of the drainage crew stuck at station 20+00, identify the pressures acting on that crew and the crew behind it, and propose two production-system changes (not rules) that reduce the hazard.

Part E — Research and Extension ⭐⭐⭐⭐

E1 — Read a real standard specification. Find the standard specifications published by the department of transportation in your state or province — they are public and generally available online. Locate the measurement and payment clause for structural excavation and for one pipe item. Write a two-page memo: what is measured, how, what is incidental, and how you would change your unit price relative to what you assumed in this chapter's exercises. Note anything that surprised you.

E2 — Read a real differing site conditions clause and a real quantity variation clause. Using the same agency's specifications, find both clauses. Answer in writing: what is the notice period? Is notice required before the condition is disturbed, in words? What is the quantity variation threshold, how is a "major item" defined, and does the clause apply to increases, decreases, or both? Then compare what you found with the hedged general descriptions in §38.3.3 and §38.4.2 and note every place the chapter's generalization does not match your agency.

E3 — Watch a paving train, or a linear schedule. If you can safely observe a paving operation from a public vantage point, time the paver's speed, count the trucks, and estimate the plant's required output to keep it moving. Where is the constraint? If observation is not practical, obtain a published linear or time-location schedule for a real infrastructure project — many transit and highway megaprojects publish them — and identify one crew convergence the schedule reveals and one it hides.