We erected fewer tons today. Did the crew slow down, or did the work change? Before drawing a conclusion, let’s look at what the numbers can tell us.
Steel erection productivity is commonly estimated and tracked in man-hours per ton. MH/ton connects the labor we spend to the weight we install, which makes it useful for building labor budgets, forecasting cost and measuring field performance.
But MH/ton is still an outcome. It tells us how many man-hours were consumed for each ton of steel without necessarily telling us why.
The same operation can produce a different MH/ton.
Suppose a six-person raising gang works a ten-hour day and completes 35 picks. The raising gang consumes 60 man-hours.
On one day, those picks produce 100 tons. On another, they produce only 70:
Looking only at MH/ton, the second day appears less productive. But the crew worked the same hours and completed the same number of picks. The operation did not slow down. The picks became lighter, so it took more picks to produce a ton.
Break apart the outcome.
We can separate the work mix from the operation by breaking MH/ton into two parts:
Picks/ton describes the work mix. It tells us how many installation events are required to produce a ton. MH/pick describes the operation. It tells us how much crew labor is consumed to complete each pick. MH/ton is the combined result.
Picks/ton is partly a planning choice. How we group pieces into picks, plan shakeouts, or use multiples and tandems affects the pick plan. It reflects both the work mix and how we intend to erect it. Define what counts as a pick and use that basis consistently.
In the example, MH/pick stays constant while picks/ton increases:
The higher MH/ton was caused by a change in the work mix, not a change in the rate of the operation.
Two work packages can both produce 12 MH/ton in very different ways:
The result is identical, but the work mix and operation are different. That does not automatically mean one crew performed better. The packages may involve different framing, connections, access, crane movements or repetition. MH/ton alone cannot show us that.
What is inside your MH/ton?
Compare the two 12 MH/ton packages, then change picks per ton or man-hours per pick independently. Tonnage and raising-gang staffing stay fixed.
Did the work change, or did the operation change?
In my experience, the picks often get lighter as we move up a building, but the effort does not disappear. We still have to rig, fly, connect and bolt every stick. That can bite a plan in the ass if we overclaim tonnage in the lower levels without considering what the lighter, more fragmented roof steel will do to production later. The crew can keep making picks while the tons fall off.
The sample production model carries that change through an eight-sequence building. Tons fall from 278 in Sequence 1 to 89 in Sequence 8 while model pieces rise from 297 to 631. After those pieces are grouped into planned picks, picks/ton rises from 0.97 to 5.52.
The chart below isolates the tonnage and model-piece shift from that dataset. The workbook carries the next step by converting the model pieces into planned picks.
Each level is treated as one sequence. The lines show each sequence’s share of total project tonnage and total project pieces.
Sequence 8 contains only 5.9% of the project tonnage but 20.4% of its pieces. The work mix rises from 1.07 to 7.09 pc/ton, more than six times as many pieces for every ton. If the labor budget follows tonnage alone, the lightest and most fragmented sequence receives the smallest share of the hours.
Piece count is not the same as planned pick count, but it is an early warning that the work mix is changing.
View illustrative sequence data
| Sequence | Tons | Pieces | pc/ton | Tonnage share | Piece share |
|---|---|---|---|---|---|
| 1 | 278 | 297 | 1.07 | 18.5% | 9.6% |
| 2 | 251 | 287 | 1.14 | 16.7% | 9.3% |
| 3 | 224 | 306 | 1.37 | 14.9% | 9.9% |
| 4 | 207 | 339 | 1.64 | 13.8% | 11.0% |
| 5 | 181 | 364 | 2.01 | 12.0% | 11.8% |
| 6 | 154 | 402 | 2.61 | 10.2% | 13.0% |
| 7 | 121 | 461 | 3.81 | 8.0% | 14.9% |
| 8 | 89 | 631 | 7.09 | 5.9% | 20.4% |
A rising MH/ton may instead mean that each pick is consuming more labor. The crane may be waiting on material, access may be worse or connections may be more difficult. Heavy picks can distort the picture in the opposite direction, making tonnage look strong while the operation moves through picks slowly.
Picks/ton describes what the crew is being asked to build. MH/pick describes how labor is being converted into completed work.
Here, the labor measures cover the raising gang. Strong tons or picks per day can still leave a package unfinished if the detail crews cannot keep pace.
Compare the work at the work-package level.
A useful comparison needs context: the members included, planned picks, crane arrangement and conditions affecting the operation. A repetitive beam pick is not the same as a tandem pick.
For each work package, we can capture installed tonnage, completed picks and crew man-hours, then calculate picks/ton, MH/pick and MH/ton. That gives us a way to explain why productivity changed and decide if the same assumptions belong in the next package.
The point is not to replace MH/ton. It is to understand what is inside it.
Once we understand the work mix and the operating rate separately, we can do more than explain what already happened. We can begin using planned picks, expected MH/pick and available crew hours to calculate duration and build the schedule from the operation.