Sign Structures

Overhead sign structures are among the most visible pieces of highway infrastructure — and among the most structurally demanding. A full-span sign bridge over an interstate carries sign panels weighing thousands of pounds at heights of 18 to 22 feet, exposed to sustained wind loads, vibration-induced fatigue, and the corrosive effects of road salt spray. Ideal Fencing Corp installs overhead sign structures across Colorado, Washington, Oregon, Idaho, Montana, Utah, New Mexico, Kansas, Wyoming, Kentucky, Tennessee, Ohio, and Nebraska, bringing the structural rigging capability, crane operations expertise, and DOT documentation discipline that these high-profile installations require.

Sign Structure Types

**Full-Span Overhead Structures**: Truss or monotube sign bridges that span the entire roadway, supported on columns at each shoulder. Used for multi-lane guide signs, electronic variable message signs, and toll gantries. Span lengths range from 60 to 160 feet depending on roadway width and shoulder configuration.

**Cantilever Sign Structures**: Single-column structures with a horizontal arm extending over one or more travel lanes. Used where a full-span structure is not required or where median width prevents column placement on both sides. Cantilever arm lengths range from 18 to 50 feet. We install both monotube and truss-type cantilever structures.

**Butterfly Sign Structures**: Back-to-back cantilever structures sharing a single center column in the median. Each arm extends over the adjacent travel lanes, providing sign mounting for both directions of travel from one foundation. Space-efficient for median-mounted installations.

**Span-Wire Systems**: Steel cables spanning the roadway between two poles, supporting signs suspended from the cables. A lighter and more economical alternative to rigid overhead structures for locations where vibration and wind loads are manageable. Used for smaller sign panels and lower-speed roadways.

Structural Engineering and Fabrication

Every overhead sign structure begins with structural engineering. Our design process follows AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals (LTS-6) and the applicable state DOT structural design manual. We produce sealed engineering drawings, foundation designs, and connection details. Structures are fabricated at AISC-certified fabrication shops to AASHTO and AWS welding standards, with galvanized or weathering steel finishes per specification.

Foundation and Erection

Foundations for overhead sign structures are typically drilled shafts (caissons) ranging from 3 to 8 feet in diameter and 15 to 40 feet deep, reinforced with steel cages and anchor bolt assemblies. We self-perform drilled shaft installation with our own equipment and subcontract geotechnical drilling when project scale warrants.

Structure erection requires crane operations with detailed lift plans — pick weights, boom lengths, outrigger loads, and clearance envelopes are calculated for every lift. Our rigging crews hold NCCCO crane operator certifications and follow OSHA 1926 Subpart CC crane safety standards. Lane closures and traffic control are coordinated with the DOT to minimize impact on travel lanes during erection.

Inspection and Rehabilitation

Existing overhead sign structures require periodic inspection per FHWA guidelines (23 CFR 650) and National Bridge Inspection Standards when applicable. We perform structural inspections, connection bolt torque verification, anchor bolt condition assessment, and fatigue crack detection. For structures requiring rehabilitation, we provide re-galvanizing, bolt replacement, anchor bolt repair, and structural strengthening services.

Investment

Overhead sign structures represent significant capital investment. Full-span overhead truss structures typically cost $80,000 to $250,000 per installation including foundation, fabrication, and erection. Cantilever structures range from $40,000 to $120,000. Butterfly structures run $60,000 to $150,000. Span-wire systems cost $15,000 to $40,000. All pricing is project-specific based on span, height, wind zone, and sign panel loading.