Elegant Long-Span Steel Arched Bridge per AASHTO LRFD Seismic Design

Steel arch bridge uses arch ribs as the main load-bearing components, transferring the load to the supports through compression of the arch ribs. It combines mechanical efficiency and architectural aesthetics, suitable for medium spans (30m–200m) of highways, railways, municipal, and landscape bridge projects.

1.Applicable Scenarios

2.Product Highlights

✔Large Span with Minimal Deformation: The arch structure has reasonable force distribution. With the same material, its spanning ability is 30%–50% higher than that of beam bridges, and the live load deflection is small.

✔Flexible Construction: Can use the support method, rotation method, pushing method, or cable hoisting, suitable for complex site conditions.

✔Durable and Economical: High-strength steel allows for thin coatings or weathering steel without coating, resulting in low total life-cycle costs.

✔Architectural Aesthetics: Smooth arch curves can be designed as above-deck, mid-deck, or below-deck styles, becoming a visual landmark in the area.

3.Product Materials

●Arch Rib: Q355C / Q420qD bridge structural steel, or weathering steel Q355NHD.

●Hang Rod / Tie Rod: High-strength, low-relaxation galvanized steel strands (tensile strength 1860 MPa) or parallel wire bundles.

●Bridge Deck Beam System: I-shaped or box-shaped welded steel beams, material grade Q355B or above.

●Bolts and Welds: Grade 10.9S high-strength bolts; all butt welds are full-penetration welds of level one quality.

●Anti-Corrosion Coating: Epoxy zinc-rich primer + epoxy micaceous iron oxide intermediate coat + polyurethane topcoat, total dry film thickness ≥ 240 μm.

4.Design Features

👉Selectable Structural System: Above-deck (columns on top of the arch), mid-deck (arch ribs at bridge deck mid-height), or below-deck (transfer force via hang rods) to meet different navigation/clearance requirements.

👉Optimized Arch Axis: Uses catenary or parabolic curves so that arch ribs mainly bear axial pressure with minimal bending moments.

👉Rigid Node Connections: Arch foot to arch base and arch rib to cross brace are fully welded or welded-plus-bolted combinations, ensuring good overall integrity.

👉Wind and Seismic Resistance: Equipped with lateral wind bracing or K-braces; supports use lead-core rubber bearings for seismic isolation.

👉Ease of Maintenance: Includes maintenance pathways, drainage systems, and reserved space for replacing hang rods.

5.Core Advantages

⭐Intelligent optimization of arch axis:By fitting the pressure line with an inverted catenary curve or a cubic spline curve, and optimizing using genetic algorithms, the bending moment of the arch rib can be reduced by 30%–50%, significantly saving steel usage.

⭐Excellent wind resistance stability:By installing lateral wind braces or adopting truss-type arch rib sections, the critical wind speed can be increased to over 1.5 times the design reference wind speed, enabling it to withstand typhoons and strong winds in canyons.

⭐Flexible and diverse construction methods:Various construction methods such as bracket assembly, rotation construction, cantilever buckling, or large-section integral hoisting can be employed, enabling the bridge to span existing railways, highways, and navigable rivers without disrupting their operations.

⭐Dual prevention and control of in-plane and out-of-plane buckling:By establishing lateral connections and K-shaped supports, the out-of-plane calculation length coefficient is controlled below 0.5, coupled with restrictions on the wall thickness-to-radius ratio, ensuring the overall and local stability of the arch rib.

⭐Replaceable boom system:Using parallel steel wire bundles or steel strand hanger rods, equipped with adjustable anchor heads and external vibration reduction rings, a single hanger rod can be independently replaced under bridge deck traction conditions, reducing the difficulty of maintenance throughout its entire life cycle.

⭐Digital pre-assembly technology:The full-bridge arch rib segments are scanned using three-dimensional laser scanning and assembled through simulation. The misalignment of the on-site closure joints can be controlled within 2mm, eliminating the need for temporary cutting and trimming operations.

6.Global Standard

Aspect	Global Standard Requirements
Fatigue Design	Follow ISO 13818 and Eurocode 3 Part 1-9 to regulate cyclic load impact, limit stress amplitude, and avoid structural fatigue cracks under long-term traffic and wind vibration.
Wind Resistance & Aerodynamics	Comply with Wind Load Standards EN 1991-1-4 and international bridge aerodynamic testing codes to control flutter, vortex-induced vibration and galloping for long-span steel arches.
Assembly & Tolerance Control	Adopt ISO 10721 steel structure assembly standards, strictly controlling dimensional deviation, arch rib alignment and closure precision during on-site erection.
Environmental & Sustainable Codes	Abide by ISO 14001 and international green bridge criteria, restricting harmful coating materials and requiring recyclable steel components for low-carbon construction.

7.Why Choose Our Company's Products

Full-Industry Chain Capability:​ From design, detailing, sheet cutting, pre-assembly to on-site installation, all handled by the same team, eliminating responsibility evasion.

Digital Construction Platform:​ Uses Tekla 3D modeling + CNC cutting + virtual pre-assembly; factory pass rate 100%, zero rework on site.

Track Record and Certifications:​ Completed 47 steel arch bridges, including 3 projects with spans over 150 meters; certified with EU EN1090 and US AISC.

Customized Service:​ Free preliminary proposals and cost comparisons; collaborate with landscape designers for arch rib shape and color optimization.