Single girder overhead cranes rated 1-20 tons, with spans capped near 60 feet for rolled-section girders and CMAA Class A through D service, cover the bulk of road construction lifting: rebar bundles, precast barriers, manhole rings, and small bridge girders [S1][S3][S9].
For road work specifically, the relevant envelope is 5-15 ton capacity, 20-50 ft spans, A4-A5 (CMAA Class C-D) duty, and either top-running on runway columns or under-running from existing shed steel. A double girder is normally over-specified until you cross 15-20 tons or 60 ft [S3][S5].
Capacity, Span, and Duty Class: The Three Hard Numbers
Single girder cranes on the market typically lift 0.5-20 ton stock, with custom builds to 32 ton; the 10-15 ton band is the most common production rating [S1][S3]. Span for off-the-shelf rolled sections tops out near 60 ft, and a four-sided box-girder top-running single girder can stretch to 80 ft [S1][S5]. Standard spans from Chinese OEM data run 7.5-31.5 m (about 25-103 ft) when customized, with stock keeping 25-50 ft [S3].
CMAA classification governs selection: Class A (standby), Class B (2-5 lifts/hr), Class C (5-10 lifts/hr at 50% rated load), Class D (10-20 lifts/hr, max 65% at rated), and Class E/F for severe/continuous service [S1]. For a road yard handling rebar cages or precast panels 8-12 cycles per shift, Class C-D is the right band; Class A is wrong even if the tonnage looks right, because the cycle count is what kills the hoist brake and trolley wheels [S1].
Operating envelope on a typical stock single girder: lifting height 6-30 m, bridge travel 20-30 m/min, trolley around 20 m/min, working temperature -25 to +40 C, 380 V/50 Hz three-phase, pendant or radio remote [S3]. Outdoor road sites in cold climates stay inside that thermal window without special package; foundry or hot-mix plant duty is a different spec entirely.
Top-Running vs Under-Running: Pick by Building, Not by Habit
A top-running single girder rides on rails above the end-truck columns, giving the best hook height because the hoist hangs below a single beam with full headroom above; under-running (underhung) cranes suspend from the bottom flange of the runway beams and let the hoist tuck closer to the ceiling, trading hook height for floor clearance and simpler building steel [S4][S5].
For road construction the choice usually maps to site infrastructure. A new precast yard with engineered columns takes top-running single girder up to 15 ton and 80 ft spans in box-girder configuration [S5]. A rebar storage shed with existing roof trusses, or a tent-covered staging area where the contractor cannot pour column foundations, takes under-running single girder in 2-15 ton range, often on patented track so multiple cranes can interlock and hand off a trolley between bays [S4][S5]. Under-running patented track systems often cap at 4,000 lb (about 1.8 ton) in their smallest enclosed-rail form, scaling up to 15 ton on structural I-beam track [S5].
Where headroom is the binding constraint, the under-running single girder wins because there is no second top flange eating vertical space; where hook height and future upgrade headroom matter more than ceiling clearance, top-running is the safer long-term spec [S4][S5].
Decision Criteria Compared: Single vs Double Girder on a Road Site
Single vs double girder, lined up on the four criteria that actually drive a road-construction purchase: [S1]
Capacity: single girder covers 0.5-20 ton stock (up to 32 ton custom); double girder starts where single ends, normally above 15-20 ton and into the 30-100+ ton range [S1][S3][S9]. Span: single girder is capped near 60 ft on rolled sections, 80 ft on box-girder top-running; double girder routinely runs 80-120 ft and beyond [S1][S5]. Duty: single girder maps cleanly to CMAA Class A-D; Class E/F severe continuous service is double-girder territory [S1][S5]. Building load: single girder wheel loads are lower and existing shed steel may be enough without reinforcement; double girder usually demands engineered runway columns and heavier foundations [S3][S4][S5].
Cost follows structure: less steel, fewer components, simpler trolley, and shorter install time on the single girder side; double girder is the right answer only when capacity, span, or duty pushes you out of the single-girder envelope [S3][S4]. For a typical road contractor handling barrier panels, manhole rings, and small-diameter pipe, the single girder in the 5-10 ton, 30-50 ft, Class C band is the economic choice, and going double girder burns budget without buying usable work envelope [S3][S9].
Hoist and Power Spec That Actually Matters
Most single girder cranes pair with a CD1 or MD1 electric wire-rope hoist, with electric chain hoists common on the 1-5 ton LX top-running and light under-running models [S2][S3]. For higher capacity or heavier duty, ZX-class wire-rope hoists with enclosed oil-immersed gearing and braked gearboxes extend service life and cut wheel-flange wear on the trolley [S2].
Power supply on stock units is 380-400 V three-phase at 50 Hz, with 60 Hz variants for North American sites; 220 V single-phase and 480 V three-phase are typical build options [S3]. For outdoor road work in cold or dusty conditions, the working temperature window of -25 to +40 C covers most climates without a heated cab or cold-weather package [S3].
Control: pendant and radio remote cover the standard road-construction use case; VFD (variable frequency drive) control is worth the upcharge when crews are placing precast near existing structures or swinging loads over rebar cages, because soft start/stop cuts load swing and the resulting shock loads that shorten hoist-brake life [S2][S3].
Where Single Girder Fits a Road Job, and Where It Does Not
Single girder fits: precast yard lifting barrier panels, kerb units, and small bridge beams; rebar storage sheds feeding cage fabrication; manhole and drainage component staging; asphalt plant parts shed; bridge repair mobile gantry style installs; small-diameter pipe handling [S3]. It also fits light fabrication and maintenance shops that support road crews, where the same crane moves engine blocks, gearbox housings, and small plant components [S2][S3].
Single girder is the wrong spec when the lift exceeds 20 ton (full bridge girders, large precast box culverts), when span clears 60 ft without a box-girder upgrade, when duty is genuinely continuous at rated load (Class E/F), or when the environment is explosive or highly corrosive, which a standard single girder explicitly does not cover [S3]. In those cases the answer is double girder top-running, not a stretched single girder.
Sourcing, Standards, and What to Verify on the Datasheet
For a North American road-construction buyer, the relevant standards are CMAA 70 / 74 for crane classification and ASME B30.2 for overhead and gantry cranes, with the duty class letter (A-F) printed on the nameplate; European and Asian builds reference FEM 1.001 / ISO 4301 duty groups (A3-A5 maps to light/medium, A6-A8 to heavy), and the typical Chinese datasheet quotes working class A3-A5 for the 1-20 ton single girder envelope [S1][S3]. Hoist standards on the wire-rope side usually reference FEM 9.511 / ISO 4301 for hoist duty, and DIN 15020 for older European builds [S3].
On the datasheet, verify four numbers before signing: (1) rated capacity at the hook, not at the hoist body, and confirm the duty class with a cycle count over the design life; (2) span between runway centers, plus end-truck wheelbase; (3) bridge and trolley travel speeds, and whether the hoist has VFD or contactor control; (4) power supply including phase, voltage, and frequency, plus the working temperature window [S1][S3]. For road projects in corrosive or dusty settings (lime storage, cement handling, salt barns), confirm the paint system, IP rating on the electrical panel, and whether the hoist is rated for the environment, because standard single girder builds are not specified for explosive or highly corrosive duty [S3].
Two trackable signals for road-construction buyers in 2026: Chinese OEM supply (Henan Weihua, Konecranes-affiliated builders, Street Crane UK) continues to push custom spans to 31.5 m and capacities to 32 ton on the single girder platform, while U.S. and European fabricators (Street, GH, O'Brien, Hoosier, American Crane) keep the 10-15 ton, 60 ft box-girder top-running single girder as a stocked build for fast delivery [S1][S2][S3][S4][S7]. The next node to watch is VFD-as-standard on the 5-10 ton models, which is still a costed option on most 2026 quotes rather than default.
Detailed specification references: single girder crane, road roller, and construction tools.
For related coverage, see Road Roller Types and Classifications: Spec-Driven Selection Map.