Overhead cranes—often called bridge cranes—are the quiet workhorses that keep heavy industry moving. This long-form walkthrough follows the journey from bare runways to a commissioned crane ready for service. You’ll see final load testing and handover—all explained in clear, real-world language.
Overhead Crane, Defined
At heart, a bridge crane is a bridge beam that spans between two runway beams, carrying a trolley-mounted hoist for precise, vertical picks. The result is smooth X-Y-Z motion: and lift via the hoist.
They’re the backbone of heavy shops and assembly lines, from beam handling to turbine assembly.
Why they matter:
Controlled moves for large, expensive equipment.
Huge efficiency gains.
Repeatable, precise positioning that reduces damage.
High throughput with fewer ground obstructions.
System Components We’re Installing
Runways & rails: runway girders with crane rail and clips.
End trucks: wheel assemblies that ride the rail.
Bridge girder(s): single- or double-girder configuration.
Trolley & hoist: reeving, hook block, upper limit switches.
Electrics & controls: VFDs, radio remote, pendant.
Stops, bumpers & safety: end stops, buffers, travel limits.
Depending on capacity and span, the crane might be a single-girder 10-ton unit or a massive double-girder 100-ton system. The choreography is similar, with heavier rigs demanding extra controls and sign-offs.
Make-Ready & Surveys
A clean install is mostly planning. Key steps:
Drawings & submittals: Approve general arrangement (GA), electrical schematics, and loads to the structure.
Permits/JSAs: Permit-to-work, hot work, working at height, rigging plans.
Runway verification: Survey columns and runway beams for straightness, elevation, and span.
Power readiness: Confirm conductor bars or festoon supports, cable trays, and isolation points.
Staging & laydown: Mark crane components with ID tags.
People & roles: Brief everyone on radio calls and stop-work authority.
Millimeters at the runway become centimeters at full span. Measure twice, lift once.
Rails & Runways
Runway alignment is the foundation. Targets and checks:
Straightness & elevation: shim packs under clips to meet tolerance.
Gauge (span) & squareness: Check centerlines at intervals; confirm end squareness and expansion joints.
End stops & buffers: Install and torque per spec.
Conductor system: Keep dropper spacing uniform; ensure collector shoe reach.
Record as-built readings. Misalignment shows up as crab angle and hot gearboxes—don’t accept it.
Girder Erection & End Trucks
Rigging plan: Softeners protect painted flanges. Taglines for swing control.
Sequence:
Install end trucks at staging height to simplify bridge pick.
For double-girder cranes, lift both girders with a matched raise.
Land the bridge on the end trucks and pin/bolt per GA.
Verify camber and bridge square.
Prior to trolley install, bump-test long-travel motors with temporary power (under permit): confirm limit switch wiring. Re-apply LOTO once checks pass.
Hoist & Trolley
Trolley installation: Mount wheels, align wheel flanges, set side-clearances.
Hoist reeving: Check rope path, sheave guards, and equalizer sheaves.
Limits & load devices: Check overload/SLI and emergency stop.
Cross-travel adjustment: Align trolley rails on a double-girder.
Pendant/remote: Install pendant festoon or pair radio receiver; function-test deadman and two-step speed controls.
Grinding noises mean something’s off—stop and inspect. Don’t mask issues with higher VFD ramps.
Drive Tuning & Interlocks
Power supply: Drop leads tagged and strain-relieved.
Drive setup: Program VFDs for soft starts, decel ramps, and brake timing.
Interlocks & safety: Zone limits near doors or mezzanines.
Cable management: Secure junction boxes; label everything for maintenance.
Future you will too. If it isn’t documented, it didn’t happen—put it in the databook.
QA/QC & Documentation
Inspection Test Plan (ITP): Hold/witness points for rail alignment, torque, electrical polarity, limit settings.
Torque logs: Record wrench serials and values.
Level & gauge reports: Note any corrective shims.
Motor rotation & phasing: Document bump tests.
Functional tests: Jog commands, inching speeds, limits, overloads, pendant/remote range.
QA/QC is not paperwork—it’s your warranty in a binder.
Ready for Work
Static load test: Apply test weights at the hook (usually 100–125% of rated capacity per spec).
Dynamic load test: Check sway, braking distances, and VFD fault logs.
Operational checks: Limit switches trigger reliably; overload trips; horn/beacon function.
Training & handover: Maintenance intervals for rope, brakes, and gearboxes.
Only after these pass do you hand over the keys.
Where These Cranes Shine
Construction & steel erection: handling long members safely.
Oil & gas & power: generator and turbine assembly.
Steel mills & foundries: hot metal handling (with the right duty class).
Warehousing & logistics: high throughput lanes.
Once teams learn the motions, cycle times drop and safety improves.
Do It Safe or Don’t Do It
Rigging discipline: dedicated signaler and stop-work authority.
Lockout/Tagout: test before touch every time.
Fall protection & edges: approved anchor points, guardrails on platforms, toe boards.
Runway integrity: regular runway inspection plan.
Duty class selection: match crane class to cycles and loads.
Safety isn’t a stage—it's the whole show.
Keep It Rolling
Crab angle/drift: re-check runway gauge and wheel alignment.
Hot gearboxes: adjust brake air gap and reduce VFD decel.
Rope drum spooling: check fleet angle and sheave alignment.
Pendant lag or dropout: shield noisy VFD cables.
Wheel wear & rail pitting: lubrication and alignment issues.
Little noises are messages—listen early.
Fast Facts
Overhead vs. gantry? Bridge cranes ride fixed runways; gantries walk on the floor.
Single vs. double girder? Span and duty class usually decide.
How long does install take? Scope, bay readiness, and tonnage rule the schedule.
What’s the duty class? FEM/ISO or CMAA classes define cycles and service—don’t guess; size it right.
Why Watch/Read This
Students and pros alike get a front-row seat to precision rigging, structural alignment, and commissioning. You’ll gain a checklist mindset that keeps cranes safe and productive.
Need a field bundle with icf walls JSA templates, rigging calculators, and commissioning sheets?
Download your pro bundle and cut hours from setup while boosting safety and QA/QC. Bookmark this guide and share it with your crew.
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