In large construction and fabrication spaces, overhead/bridge cranes do the heavy lifting—literally. This practical guide takes you behind the scenes of a mega-project crane install. You’ll see structural checks, safety, and QA/QC—with the same checklists pro installers use.
Bridge Crane Basics
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 system delivers three axes of motion: cross-travel along the bridge.
They’re the backbone of heavy shops and assembly lines, from beam handling to turbine assembly.
Why they matter:
Safe handling of very heavy, unwieldy loads.
Huge efficiency gains.
Lower risk during rigging, lifting, and transport inside facilities.
High throughput with fewer ground obstructions.
System Components We’re Installing
Runways & rails: runway girders with crane rail and clips.
End trucks: motorized gearboxes for long-travel.
Bridge girder(s): cambered and pre-wired.
Trolley & hoist: reeving, hook block, upper limit switches.
Electrics & controls: power supply, festoon or conductor bars.
Stops, bumpers & safety: overload protection, e-stops.
Based on design loads and bay geometry, the crane might be a single-girder 10-ton unit or a massive double-girder 100-ton system. The choreography is similar, but the scale, lift plans, and checks grow with the tonnage.
Before the First Bolt
A clean install is mostly planning. Key steps:
Drawings & submittals: Approve general arrangement (GA), electrical schematics, and loads to the structure.
Permits/JSAs: Job Safety Analysis (JSA) for each lift step.
Runway verification: Check baseplates, grout pads, and anchor torque.
Power readiness: Lockout/tagout plan for energization.
Staging & laydown: Lay out slings, shackles, spreader bars, and chokers per rigging plan.
People & roles: Appoint a lift director, rigger, signaler, and electrical lead.
Millimeters at the runway become centimeters at full span. Measure twice, lift once.
Getting the Path Right
Runway alignment is the foundation. Targets and checks:
Straightness & elevation: Laser or total station to set rail height.
Gauge (span) & squareness: Use feeler gauges on splice bars, torque rail clips.
End stops & buffers: Verify clearances for bumpers at both ends.
Conductor system: Keep dropper spacing uniform; ensure collector shoe reach.
Log final numbers on the ITP sheet. Misalignment shows up as crab angle and hot gearboxes—don’t accept it.
Girder Erection & End Trucks
Rigging plan: Choose spreader bars to keep slings clear of electricals. Dedicated signaler on radio.
Sequence:
Lift end trucks to runway level and set temporarily on blocks.
For double-girder cranes, lift both girders with a matched raise.
Use drift pins to align flange holes; torque to spec.
Measure diagonal distances to confirm squareness.
Before anyone celebrates, bump-test long-travel motors with temporary power (under permit): confirm limit switch wiring. Lock out after test.
Hoist & Trolley
Trolley installation: Mount wheels, align wheel flanges, set side-clearances.
Hoist reeving: Lubricate wire rope; verify dead-end terminations.
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.
A smooth trolley with a quiet hoist is a sign of good alignment. Don’t mask issues with higher VFD ramps.
Drive Tuning & Interlocks
Power supply: Drop leads tagged and strain-relieved.
Drive setup: Enable S-curve profiles for precise positioning.
Interlocks & safety: E-stops, limit switches, anti-collision (if multiple cranes), horn, beacon.
Cable management: Secure junction boxes; label everything for maintenance.
Future you will too. Photos of terminations help later troubleshooting.
QA/QC & Documentation
Inspection Test Plan (ITP): Hold/witness points for rail alignment, torque, electrical polarity, limit settings.
Torque logs: Re-check after 24 hours if required.
Level & gauge reports: Attach survey prints.
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.
Proving the System
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: Emergency stop shuts down all motions.
Training & handover: Operator basics, daily pre-use checks, rigging do’s & don’ts.
Only after these pass do you hand over the keys.
Where These Cranes Shine
Construction & steel erection: placing beams, trusses, and precast.
Oil & gas & power: moving heavy pumps, skids, and pipe spools.
Steel mills & foundries: hot metal handling (with the right duty class).
Warehousing & logistics: bulk material moves with minimal floor traffic.
Once teams learn the motions, cycle times drop and safety improves.
Controls that Matter
Rigging discipline: rated slings & shackles, correct angles, spreader bars for load geometry.
Lockout/Tagout: clear isolation points for electrical work.
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.
A perfect lift is the one nobody notices because nothing went wrong.
Keep It Rolling
Crab angle/drift: verify end-truck wheel diameters and gearbox mounts.
Hot gearboxes: misalignment or over-tight brakes.
Rope drum spooling: dress rope and reset lower limit.
Pendant lag or dropout: antenna placement for radio; inspect festoon collectors.
Wheel wear & rail pitting: lubrication and alignment issues.
Little noises are messages—listen early.
Quick Answers
Overhead vs. gantry? Choose per site constraints.
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.
What You’ll Take Away
Students and pros alike get a front-row seat to precision rigging, structural alignment, and commissioning. You’ll see how small alignment wins become big reliability wins.
Need a field bundle with JSA templates, rigging calculators, and commissioning sheets?
Download your pro bundle and cut hours from setup while boosting safety and ashville construction QA/QC. Save it to your site tablet for quick reference.
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