A steel erection schedule should be the operation expressed over time.
Typically, the superintendent develops the first pass at the sequence durations using the drawings, model and experience. The production model helps make the assumptions behind those durations visible so they can be tested, resource-loaded and eventually compared with actual performance.
- Model pieces
- Planned picks by work class
- Production rates
- Crew-days
- Sequence durations
- Schedule
Once those durations are time-phased by sequence, the schedule provides the basis for the weekly manpower and crane-loading plans.
Classify the planned picks.
For this example, the crane-installed work is classified as bent or preassembled, extra-heavy, heavy, standard, light and extra-light. Each crane work class is assigned an expected rate in picks per raising-gang day:
| Work class | Planned rate |
|---|---|
| Bent or preassembled | 8 picks/crew-day |
| Extra-heavy | 8 picks/crew-day |
| Heavy | 12 picks/crew-day |
| Standard | 25 picks/crew-day |
| Light | 35 picks/crew-day |
| Extra-light | 45 picks/crew-day |
| Hand iron | 20 pieces/detail crew-day |
These are illustrative starting assumptions, not universal standards. They should be developed with the superintendent and adjusted using historical production.
Start by grouping the pieces into planned crane picks. A Christmas-tree pick can erect several pieces, but it remains one pick. The rate should reflect the expected mix and the time required to rig, land and connect that steel.
For example, 30 single-piece picks and 15 two-piece Christmas-tree picks would erect 60 pieces in 45 picks. That is 1.33 pieces per pick, not a threefold increase in daily production. This illustrates the relationship; the workbook uses each sequence’s own grouping.
In this simplified workbook, all Christmas-tree pieces are assigned to the extra-light class. The class pick counts reconcile to the total planned picks. Grouping is already reflected in those counts, so no additional Christmas-tree multiplier is applied to duration.
Hand iron remains separate because it does not pass through the crane-pick cycle in the same way.
Add the crew-days from all work classes to get the total.
Example revision: The worked figures below retain the earlier teaching example. The current erection plan and production examples now share the revised 1,505-ton, 3,087-piece example with 2,642 crane picks and updated production rates.
Apply the method to the eight-sequence project.
The sample project contains 1,740 tons, 2,320 model pieces, 2,073 crane-installed pieces, 1,875 planned crane picks and 247 pieces of hand iron.
Applying the work-class rates produces the following durations:
| Seq. | Tons | Installed pieces | Crane picks | Erection days | Days at 200 t/wk |
|---|---|---|---|---|---|
| 1 | 320 | 180 | 164 | 7.8 | 8.0 |
| 2 | 295 | 193 | 181 | 7.3 | 7.4 |
| 3 | 270 | 210 | 202 | 6.8 | 6.8 |
| 4 | 240 | 230 | 218 | 6.2 | 6.0 |
| 5 | 210 | 255 | 235 | 5.6 | 5.3 |
| 6 | 175 | 285 | 255 | 5.9 | 4.4 |
| 7 | 135 | 330 | 290 | 6.6 | 3.4 |
| 8 | 95 | 390 | 330 | 7.3 | 2.4 |
The lower sequences agree closely. The methods separate as the steel gets lighter and the piece count rises.
Sequence 1 contains eight bent picks, eight extra-heavy picks, twelve heavy picks, eighty standard picks and fifty-six light picks. The eight bents contain 24 model pieces, so 180 crane-installed pieces become 164 planned picks.
At 200 tons per week, 320 tons implies eight days. The two methods agree closely.
Sequence 8 contains 300 individual extra-light pieces and 90 extra-light pieces grouped into 30 Christmas-tree picks. That gives us 390 crane-installed pieces and 330 planned picks. At 45 extra-light picks per crew-day:
The same duration implies approximately 53 pieces erected per day: 390 ÷ (330 ÷ 45). Picks/day describes the crane production rate; pieces/day describes the resulting erection throughput. The sequence also contains 80 pieces of hand iron and 95 tons.
At 200 tons per week, the tonnage implies only 2.4 days. The classified picks produce 7.3 days.
That is the point of classifying the work. The sequence is light by weight, but it still contains a large number of pieces that must be handled, landed, connected and bolted.
Use tonnage as the back-check.
The 200-ton target still matters. It gives us an operating and logistics check.
For this example, assume a truck payload of 24 short tons (48,000 pounds). Eight truckloads provide 192 tons per week. Receiving two loads per day during the five-day setup week creates a 240-ton opening buffer. After that, eight loads per week support the production plan until the remaining steel is delivered. Actual payloads depend on the truck, trailer, steel geometry and route limits.
The difference is that 200 tons is not being used to manufacture the duration. It is being compared with the duration produced by the work.
The lower sequences track closely with the tonnage target. As the work shifts toward lighter pieces, the calculations separate.
In Week 2, the raising gang erects approximately 205 tons using 105 crane picks. Across five planned crane days, that requires about 21 picks and 41 tons per crane-day.
By Week 11, the raising gang is making approximately 224 crane picks and erecting 262 pieces, but those pieces represent only 74 tons. The five-day crane window requires about 45 picks and 15 tons per crane-day.
The operation has not necessarily slowed down. The work mix has changed.
Each row uses its own scale. Tons, picks and installed pieces describe production demand. Crane days show the finite operating window available to deliver it.
Picks and tons tell us what the crane must produce. Crane days tell us how much operating time the plan gives it. Reading all three together makes the required daily throughput visible instead of hiding it inside a weekly total.
Build the schedule from the crew-days.
The work-class model produces 53.6 erection crew-days. In this one-crane, one-raising-gang setup, those same 53.6 days are also 53.6 planned erection-crane days. With a five-day workweek, that becomes approximately 10.7 production weeks.
Weeks 2 through 11 each consume five crane days. The remaining 3.6 crane days fall in Week 12.
After one week of setup and receiving, the sequences can be scheduled continuously. A sequence does not need to begin or finish at a week boundary. It can consume part of one week and continue into the next.
That gives us a time-phased production schedule based on the calculated work instead of assigning each sequence to an arbitrary weekly block.
The handoff between sequences occurs wherever the calculated crew-days place it—not necessarily at the end of a week.
Use the schedule to build the resource loads.
Once the erection schedule is established, the supporting crews can be loaded around it:
- Raising gang
- Plumb and bolt
- Welding
- Decking
- Detail, punch and closeout
- Supervision
In this example, the raising gang contains six people working five tens. The calculated erection duration produces approximately 3,217 raising-gang man-hours.
Dividing those hours by 1,740 tons gives approximately 1.85 raising-gang MH/ton. Dividing the same hours by 1,875 picks gives 1.72 MH/pick. Using unrounded values, MH/pick × picks/ton returns the same MH/ton. This anchors the crane-based plan to the labor estimate; follow-up and support labor must be added separately for total-project MH/ton.
The follow-up crew headcounts remain separate weekly planning assumptions in this example. Review their timing against the revised erection handoffs rather than assuming they shorten automatically. A two-person detail crew remains through Week 16 for hand iron, punching and closeout. The combined manpower plan peaks at approximately 1,200 man-hours per week, or an average equivalent of 24 people working five tens.
Will the crane be available?
Five ten-hour shifts convert the time-phased crew plan into weekly labor demand.
Week →
The same time-phased schedule produces the weekly crane-loading plan. Instead of an undefined utilization percentage, it shows observable production demand in tons, crane picks and installed pieces, along with the crane days available to deliver it.
When I review the resource-loaded plan, I start with deliveries. Can we get the steel there when we need it, and does that delivery plan fit with what the crane is scheduled to erect? From there, I work through the follow-up crews to see whether plumb and bolt, welding, decking and detail can keep pace.
I’m looking closely at manpower spikes because crew availability is a known constraint. I also look for sequences with unusually long durations. They may need that time, but I want to understand what is driving it. The review gives us a chance to investigate those anomalies and check whether the plan reflects the conditions we expect in the field.