Case Study 18-2 — The Week of Eight Crane Moves

Everything and everyone here is a Tier-3 illustrative composite. The numbers behave like real numbers.

Setup

Project: Northgate Outpatient Pavilion. Topping out was November 12, Year 1. The building must be dried in by March 28, Year 2 — the milestone that lets the interior finish trades start in earnest and that turns off roughly $1,950 a day of temporary heat.

The lifting equipment. After the steel crawler demobilized, Kestrel kept one 90-ton hydraulic truck crane on the job with an operator and an oiler, all-in at about $310 per hour. It works from three pads:

              MERIDIAN CLINIC  (open, ambulance route)
    ══════════════ clinic drive — KEEP CLEAR ══════════════
    ───────────────── north property line ─────────────────
    │  [PAD A]  ████████████████████████████████████  │
    │  north     █                                  █  │
    │  precast   █   NORTHGATE PAVILION — 4 STORIES █  │   KIRKBRIDE
    │            █                                  █  │   AVENUE
    │  [HOIST]═══█                                  █  │   (single
    │  west      ████████████████████████████████████  │    gate)
    │                                                  │
    │  [PAD C]                    [PAD B] ── east drive │
    │  west/south CW + roof        east — blocks drive  │
    │                                                  │
    │        L A Y D O W N  —  W E S T                 │
    └──────────────────────────────────────────────────┘
    ────────── south property line — FIRE LANE ────────
                    ALDER STREET

Moving the crane from one pad to another — retract outriggers, pick up mats, travel, set mats, deploy and level outriggers, re-verify the load chart configuration — takes about 90 minutes.

The three trades competing for it, in the eleven-week enclosure push:

The cast: Margo Deacon (general superintendent), Ray Alvarez (project manager, narrating), Nadia Haddad (VP of Operations), Dani Okonkwo (field engineer).

What happened

In the first week of December, Year 1, Dani pulled the crane logs and counted something nobody had counted before.

Eight crane moves in five days.

Cordova's erection sequence, drawn by their detailer months earlier, worked panel by panel around the perimeter in the order the panels were cast — which meant the crane bounced between Pad A and Pad B every time the sequence turned a corner. Crossline and Summit both needed Pad C, and each time either got it, the crane had to come back.

Eight moves × 90 minutes = 12 hours of crane time that lifted nothing.

And the two-day slip was not a one-time event. It repeated. At that burn rate the enclosure sequence would arrive at March 28 roughly three weeks late, and three weeks late on dry-in is three weeks of temporary heat at $1,950 a day, three weeks of finish trades that cannot start, and a substantial completion date with $5,500 a day of liquidated damages standing behind it.

The meeting

Thursday afternoon, in the trailer. Nadia Haddad on the phone from the office.

Nadia: "Bring a second crane. We've got eleven weeks of enclosure and we're bleeding two days a week. Just buy the capacity."

Margo: "We don't have a capacity problem."

Nadia: "We're two days behind."

Margo: "We're two days behind because the crane spends a quarter of its life driving in a circle. It's got plenty of hook. It just keeps ending up in the wrong place. Adding a second one gives me two cranes with the same problem and a lift plan I have to pay somebody to write."

Ray: "Where would the second one even go?"

Margo: "Pad B. Which is on the east drive. Which is where the pump truck sets up for two more topping pours. So now I've got a crane, a pump, and a gate on the same forty feet of pavement, and Ruthie is out there with a radio trying to sort out which one of them gets to exist."

Nadia: "Then what's your answer?"

Margo: "Stop moving the crane."

The two options, priced

Ray and Dani put both on paper over the weekend. Eleven weeks of enclosure work.

Option 1 — Add a second crane

Plus what it costs that is not on the invoice:

• Pad B occupies the east drive. Two level-topping pours must be resequenced or moved to Saturdays.
• Two cranes with overlapping swing radii is a materially different risk picture. It requires a written plan, continuous supervision, and a discipline that a job under schedule pressure is exactly the wrong environment for.
• The gate throat is already half-consumed by the pump. Adding a second crane's support traffic to a single-gate site does not solve congestion; it imports more of it.

Option 2 — Change the sequence

The comparison

Kestrel resequenced.

What actually happened

Over the following eleven weeks, crane moves dropped from eight per week to two — one midweek and one to set up for the Saturday pick day. Weekly waste fell from $14,048 to roughly $4,170, an additional avoided cost of about $9,878 per week, or $108,658 across the push, on top of the $163,898 saved by not renting a second crane.

The enclosure caught up. The building dried in on March 28, Year 2, and because the south elevation closed early under the enclosure-by-area resequencing, temporary heat ran 77 days against a budget of 84 and came in $13,650 under.

Analysis

The constraint was position, not capacity. This is the whole case study in one line, and it generalizes far beyond cranes.

Nadia's instinct — "we're behind, buy more capacity" — is the most common wrong answer in construction management, and it is wrong for a specific, diagnosable reason. Before you buy capacity, you have to know what the resource is actually spending its time on. A crane at 28% travel is not short of hook. It is short of stability of position. A hoist that is 30% oversubscribed is not short of lift; it may be short of a schedule. A crew that is behind may not be short of people; it may be short of material at the work face — which is Case Study 18-1.

The diagnostic question is always the same: where does the resource's hour actually go? That is the same question §18.1 asks about the craft hour, applied to a machine.

Why the sequence change worked — the mechanism. Cordova's original erection sequence was optimized for the precast yard, not for the site. Panels were cast in the order the forms became available and shipped in casting order, and the erection drawing followed the shipping order around the building. That is a completely reasonable way to run a precast plant. It just happened to impose 90 minutes of crane travel on Kestrel every time the sequence turned a corner, and nobody had ever put a dollar figure on that because the cost landed on a different company than the decision.

This is a scope-and-coordination failure, not a technical one. The fix cost Cordova $2,200 of detailing and a brace rental. Nobody had asked, because nobody had counted.

The Saturday-work honesty check. Option 2 buys part of its savings with premium time, and premium time is not free of non-monetary cost. You saw this in the canonical steel acceleration: Kestrel spent $168,000 to recover 17 of 23 days, and the bill included trade stacking, a rework event on deck-edge detailing, and a spike in near-misses in weeks 34 through 36. Six Saturdays is a much smaller dose than that, but it is the same drug. Margo's rule on Saturday picks was that they were single-trade days — one crew, one crane, no stacking — precisely because a Saturday with three trades and reduced supervision is how the scaffold in week 34 got modified overnight by a trade that had not erected it.

⚠️ Safety note. Two cranes working within each other's operating radius is not simply "two cranes." It requires a written plan addressing swing paths, blind lifts, communication protocol, and a designated lift director with the authority to stop both machines. Struck-by hazards — including loads, load-handling equipment, and the crane itself — are one of OSHA's Focus Four. The cheapest lift plan is the one where the two machines never share airspace, and the second cheapest is the one you actually pay somebody to write and enforce. There is no third option.

What Margo did that was hard. She told her VP no, in front of her PM, with a number. That is the part of this case study that is not about cranes. Nadia was not being foolish; buying capacity under schedule pressure is a defensible executive instinct and it is right often enough to be a habit. What beat it was not seniority and not volume. It was twelve hours, eight moves, and 28.2% — three numbers Dani produced from a crane log that already existed and that nobody had ever added up.

Discussion questions

1. Nadia's instinct was to buy capacity. Name two other situations in construction where "buy more capacity" is the reflexive answer, and describe the diagnostic you would run first in each.
2. Cordova's erection sequence was optimized for their precast plant. Whose job was it to notice the conflict, and at what point in the project should it have been caught? Be specific about the meeting and the document.
3. Option 2 costs $88,632, including $32,520 of Saturday work. Build the argument that the Saturday premium is the most expensive part of Option 2 even though it is not the largest line item.
4. The crane log had been kept all along. Why do you think nobody added up the moves until week 41? What routine would surface this automatically on your next job?
5. Suppose the resequence had not worked and the enclosure had continued to slip. At what point — measured how — should Kestrel have reversed course and brought the second crane? Write the trigger as a one-sentence if-then statement.

Your turn

You are the superintendent on a different job: a six-story building with one tower crane — so no pads and no moves, but a hard limit of roughly 50 productive picks per day.

Four trades submit next week's pick requests:

Your task:

1. Compute the week's capacity and the shortfall.
2. Allocate the picks using the conflict-resolution priority order from §18.3.4, and state what you are cutting and what you are telling that trade.
3. Identify two non-crane options that would reduce demand rather than ration it, and estimate what each would save in picks.
4. Write the one-paragraph email you send Friday afternoon to all four foremen.