For a building where one side can carry a runway and the other cannot. The bridge rides on the wall or column line at one end and on a floor rail at the other, so you add lifting without rebuilding the structure.
A semi-gantry crane, also called a semi-portal crane, carries one end of its bridge on a runway fixed to a building wall or column line, and the other end on a single leg that travels on a rail in the floor. It suits buildings where only one side can carry a crane runway.
Type selection
Most buildings are not symmetrical. One side is a solid column line or a load-bearing wall that a runway can be fixed to. The other side is a glazed façade, an office run, a line of machines, or open ground where no column exists at all.
Asymmetry is the usual case for a semi-gantry, but it is not the only one — a process sometimes calls for the type even where the structure could carry a full runway, because the floor-level leg keeps one side of the working area clear. On the supported side the bridge lands on the structure that already exists. On the other it lands on a leg and a floor rail, and the load goes straight into the slab.
Four conditions point to this type:
There is a condition attached, and it is structural. The elevated side transfers vertical load and moment into your columns or wall. Those loads are calculated and issued per project, so your structural engineer can verify the building before anything is fabricated.
If both sides of the building are open ground, the full gantry crane is the simpler structure. If the building can carry a runway on both sides, compare the double girder overhead crane instead. Send us a general arrangement drawing and an engineer will mark the options on it.
Our approach
A semi-gantry is calculated twice: once as a crane, and once against a structure somebody else designed, often decades ago.
So the work starts with your building. We take the column spacing, the bracket geometry and the available headroom, then set span, capacity and duty class against them. The loads the crane will put back into the structure are issued per project, in a form your structural engineer can check. Where the columns will not take what the lift demands, it is better to know that on a drawing than after manufacturing.
The floor side is the other half of the calculation. A single leg concentrates its wheel loads on one rail line, so rail type, slab condition and foundation come into the design early rather than at installation.
We manufacture the hoist unit in our own plant in İzmir, together with the steel structure, the end carriages and wheel groups, and the operator cabin. The machine and the structure are built together, so the lifting characteristic and the frame carrying it come out of one engineering office. Years later that still matters: when a wheel group needs replacing, the drawing is in the same building as the lathe.
Manufacturing
“From our plant to your building”
Technical data
Read each value with what it does for the lift — that is how the crane is sized against your building.
Our semi-gantry cranes reach 12 t on a single girder and 160 t on a double girder as a standard selection — above 160 t we engineer per project — over spans of 32 m as standard — longer spans are engineered as a special project. Every capacity-to-span pairing is calculated per project, because span, building capacity and duty class move together.
Motion runs on inverter (VFD) control for soft starts and low-sway positioning, with stepless hoisting and micro-speed positioning: 0–4 m/min as the standard speed, coming down to about 0–2.3 m/min at the top of the range. Lifting height follows your building: on the elevated side the hook works to the clearance the runway leaves, so your section drawing governs it.
| Criterion | Semi-gantry crane (this page) | Full gantry crane | Overhead travelling crane (EOT) |
|---|---|---|---|
| Where the load path goes | One end into the wall or column line, one leg to a floor rail | Down two legs to ground rails | Into the building columns and roof steel, along the whole runway |
| Building requirement | Structure strong enough on one side, verified per project | No crane runway needed on the structure | Runway and structure sized for the crane on both sides |
| Rail lines needed | One, at floor level | Two, at floor level | None at floor level |
| Floor space | One leg sweeps one corridor | Legs sweep two corridors | Floor left clear |
| Typical site | Asymmetric building, narrow workshop, yard edge, low-level second crane | Open yard, or a building that cannot carry a runway at all | Enclosed building with crane-rated steelwork |
| ABRA capacity | 12 t single girder · 160 t double girder | 12 t single girder · 160 t double girder | 250 kg – 12 t single girder · 250 kg–160 t double girder |
| ABRA span | 32 m as standard | 32 m as standard | 30 m (single) / 32 m (double) as standard |
| ABRA page | this page | gantry crane | double girder · single girder |
All ABRA figures are engineering-confirmed maxima for the type. The exact capacity-span-height combination is calculated per project against your building.
| Parameter | Value | Consequence / note |
|---|---|---|
| Lifting capacity — single girder | up to 12 t | Light and medium work; keeps the leg and the floor rail light |
| Lifting capacity — double girder | up to 160 t | Heavy and long-span work; structure sized per project |
| Span | 32 m as standard | Longer span lowers capacity and raises what the building side must carry |
| Lifting height / hook path | per project | Set from your section drawing — the runway height on the building side governs it |
| Girder type | Single or double girder | Double girder for higher capacity, longer span, cabin or special attachment |
| Building-side support | Runway on wall brackets or column brackets | Loads into your structure calculated and issued per project |
| Floor-side support | One leg on a floor rail | Rail type, slab and foundation confirmed before installation |
| Duty class | FEM 1Bm–5m (ISO M3–M8), per project | Sized to load spectrum × running hours, not to the peak load |
| Hoisting speed | Stepless, inverter-controlled — 0–4 m/min standard, 0–3.5 / 0–3.6 at 6.3 · 12 · 12.5 · 16 t, 0–2.3 … 0–3.4 from 30 t to 160 t | Standard crane speeds; micro-speed for accurate positioning |
| Trolley travel speed | 4–16 m/min to 2 t · 5–20 from 3.2 to 20 t · 5–20/25 at 25–32 t · 5–20/25/30 from 40 t | Matched to span and cycle; soft start protects the bracket and the rail |
| Bridge travel speed | 5–20 m/min to 20 t · 5–20/25/30 from 25 t | Set with the span and the cycle |
| Motion control | Inverter (VFD) | Soft start/stop, reduced load sway, gentler on structure and rail |
| Power supply | 380–415 V / 50 Hz (60 Hz for export) | Matches local and export grids |
| Protection class | IP54 / IP55 (motor and panel) | Dust and moisture protection |
| Ambient temperature | −10 … +50 °C | Standard band; site-specific duty engineered per project |
| Max wheel load / foundation loads | Calculated and issued per project | Needed before the floor rail and its foundation are designed |
| Control | Radio remote / pendant / operator cabin | Operator cabin made in-house |
| Safety | Overload switch + load cell (standard) · travel limit switches | Overload protection under EN 14492-2 |
| Standards | EN 13001 series · EN 15011 · EN 14492-2 · EN ISO 13849-1 / -2 · EN IEC 60204-32 · FEM 9.511 (complementary) · CE · ISO 9001 | Duty class stated per project |
| FEM (mechanism) | ISO M | Typical use |
|---|---|---|
| 1Bm | M3 | Light, single shift |
| 2m | M5 | Medium/heavy, 1–2 shifts |
| 4m | M7 | Very heavy, 2–3 shifts |
| 5m | M8 | Continuous / severe (process duty around the clock) |
The speeds shown are standard values; other speeds are provided on request. Where a value depends on your site, it is written “per project” and confirmed with you.
Equipment
Each option below answers a problem this structure creates:
A single girder up to 12 t suits light and medium work over shorter spans and keeps the leg light. A double girder takes the heavy end of the range and the long spans, and it is what carries a cabin or a special attachment.
Over a long span the operator needs to see the load from above instead of walking beside it. Fixed or travelling with the trolley. Radio remote and pendant push-button are the other control options; see operator cabins.
An asymmetric bridge answers hard starts unevenly. Soft acceleration keeps the load steady and takes shock out of the bracket connection and the floor rail alike.
An overload switch and a load cell are standard, so the crane refuses a lift beyond its rating.
The leg travels where people work, so travel limit switches are specified with the crane, and audible and visual warning can be added on the leg side.
Position memory, target positioning and repeat moves for a building that runs the same route all day. The operator stays in control; this is assisted automation. ABRA Crane Tracking can be added as the data layer for usage, condition and maintenance data.
Where the building is a classified area, the same crane is engineered as an explosion-protected system for gas Zone 1–2 or dust Zone 21–22, to the site's own zone map; see Explosion-protected cranes.
Applications
The common thread is a building that helps on one side and not on the other.
Type routing
Ask what already exists. A full gantry needs two rail lines and the ground to carry both, and in exchange it needs nothing from the building. A semi-gantry needs one rail line and a structure strong enough to take the other side, and it gives back the floor a second leg would have used.
Cost follows the same logic. One rail line means less civil work and less floor lost, but the saving only holds if your columns can take the load without reinforcement. That has to be calculated, which is why we ask for the general arrangement drawing before quoting.
Both types are built in the same plant and to the same duty class range. Compare the full gantry crane, or send us your load, span and column details and an engineer will tell you which structure your building supports.
Project process
Four steps, so a committee can see the whole route before committing:
Load, span, cycle, headroom, floor traffic, and what the wall or column line can carry.
We confirm the duty class, issue the building-interface and floor-rail loads for your structural and civil work, and flag any spec deviation before you sign.
Hoist unit and steel structure built in our own plant, then the runway, the rail and the crane erected and commissioned in your building.
Scheduled maintenance under an annual contract, spare parts and modernisation.
After-sales
On this type the two sides age differently. The floor rail collects whatever the building drops on it, while the elevated runway and its brackets want checking for alignment, because a building settles and a bolted connection works loose. We build the end carriages and wheel groups ourselves, so we know what to measure and when.
Maintenance is agreed under an annual contract covering 4 visits a year, with on-site response within 48 hours of a call, anywhere in Türkiye. Warranty is 2 years. Crane Contact Center 444 8 440.
We also service, supply parts for and modernise cranes we did not build, so a mixed installation stays under one contract. See after-sales service.
FAQ
A semi-gantry carries one end of the bridge on a runway fixed to a wall or column line, and the other end on a single leg running on a floor rail. A full gantry stands on two legs and two ground rails, and asks nothing of the building. Choose the semi-gantry when one side of the building can carry a runway and you want the floor on that side back.
Ours reach 12 t on a single girder and 160 t on a double girder, over spans of 32 m as standard; longer spans are engineered as a special project. What you can run at a given span also depends on what your building side will carry, so the combination is confirmed per project. Send us the load, the span and the column details.
That is the first thing we check, and it is answered with numbers. The vertical and horizontal loads and the moment the crane puts into your columns or wall are calculated and issued per project, so your structural engineer can verify the building before manufacturing starts. If the structure will not take it, a full gantry keeps the same lift and puts the load in the ground instead.
Yes, and that is a common reason to choose one. The semi-gantry runs on its own runway at a lower level and serves the floor, while the existing crane keeps the roof span for heavier work. Clearances and the travel zones of both cranes are set at design stage, and we ask for the existing crane's drawings before we quote.
Get a recommendation
Send us the load, the span, the headroom and what the wall or column line can carry. An engineer confirms the structure, the duty class and the loads your building will take — no obligation.
Or call 444 8 440
Your details are used only to answer your request
Designed and built to EN, FEM and ISO standards · CE marked · duty class defined per project (our build range: FEM 1Bm–5m / ISO M3–M8) · manufacturing in İzmir since 2004
