How do you calculate good segment handling capacity?

Multiply segments per cycle by available cycles to get gross capacity, then multiply by uptime and by first-pass yield. Here 4 × 480 = 1,920 gross, then × 0.90 × 0.97 = 1,676.16 good segments.

What is the difference between gross and good segment capacity?

Gross is everything the system physically moves — 1,920 in the example. Good capacity strips out cycles lost to feeder downtime and segments damaged on first handling, leaving the 1,676.16 that are actually ring-ready.

How much capacity do I lose to downtime versus damage?

In this example the 10% downtime costs 192 segments and the 3% first-pass loss costs 51.84 segments. Downtime is the bigger lever here, so gantry and feeder reliability deserves the most attention.

Why size segment handling above TBM advance rate?

Rings must be waiting for the erector, not the other way round. A handling capacity that only just matches theoretical advance will fall short the moment a feeder jam or a damaged segment occurs, stalling the machine.

What causes first-pass segment damage?

Chipped edges and cracked gaskets from vacuum-lifter misalignment, rough segment-car transfers, and tight clearances on a congested back-up. Improving first-pass yield often recovers capacity faster than adding cycles.

Does this include ring build time?

No — it measures how many good segments the handling system can deliver, not how fast the erector assembles them. Compare the good-capacity output against your segments-per-ring and target ring rate separately.

Tunnel Boring & Heavy Civil Equipment calculator

Segment Handling Capacity Calculator

Segment handling capacity is the number of precast tunnel lining segments a back-up gantry, erector, and feeder system can move into position ready for ringbuild over a given number of cycles, after accounting for downtime and handling damage. It is the throughput that must keep pace with the TBM's advance so the machine never waits on segments. Logistics engineers and ring-build supervisors use it to size cranes, segment cars, and the muck-versus-segment traffic on a single-track back-up. Because a damaged or chipped segment cannot be built into the ring, the metric separates gross movement from genuinely usable, damage-free delivery.

What this calculator does

Estimate segment handling capacity for tunnel boring and heavy civil equipment using production-ready inputs so teams can confirm whether capacity can cover demand before committing the schedule.
Use it when segment handling capacity in tunnel boring and heavy civil equipment is being asked to take on more work and you need to know if there is room.
It computes usable (good) segment handling capacity by multiplying per-cycle output by available cycles, then derating for feeder uptime and damage-free first-pass yield.

Formula used

Gross segment handling capacity = segment handling capacity output per cycle × available segment handling capacity cycles
Good segment handling capacity = gross capacity × expected segment handling capacity uptime × expected segment handling capacity first-pass yield

Inputs explained

Segments handled per crane cycle:
Available handling cycles per period:
Segment feeder uptime:
Damage-free (first-pass) segment yield:

How to use the result

Use it when planning segment logistics for a drive or diagnosing whether segment supply, not boring, is the constraint on advance rate.
It assumes uptime and yield are independent, steady percentages; in practice a congested back-up can couple them, and surge storage on the gantry can mask short outages.

Current U.S. benchmarks

Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate good segment handling capacity? Multiply segments per cycle by available cycles to get gross capacity, then multiply by uptime and by first-pass yield. Here 4 × 480 = 1,920 gross, then × 0.90 × 0.97 = 1,676.16 good segments.
What is the difference between gross and good segment capacity? Gross is everything the system physically moves — 1,920 in the example. Good capacity strips out cycles lost to feeder downtime and segments damaged on first handling, leaving the 1,676.16 that are actually ring-ready.
How much capacity do I lose to downtime versus damage? In this example the 10% downtime costs 192 segments and the 3% first-pass loss costs 51.84 segments. Downtime is the bigger lever here, so gantry and feeder reliability deserves the most attention.
Why size segment handling above TBM advance rate? Rings must be waiting for the erector, not the other way round. A handling capacity that only just matches theoretical advance will fall short the moment a feeder jam or a damaged segment occurs, stalling the machine.
What causes first-pass segment damage? Chipped edges and cracked gaskets from vacuum-lifter misalignment, rough segment-car transfers, and tight clearances on a congested back-up. Improving first-pass yield often recovers capacity faster than adding cycles.

Last reviewed 2026-05-12.