Explore our heavy-duty Aluminum Finger Expansion Joints for movements from 150mm to 1200mm. Offering superior corrosion resistance, lower lifecycle cost, and full compliance with AASHTO & Eurocode standards. The durable alternative to steel joints.
The Aluminum Finger Expansion Joint, also known as a comb joint, is a heavy-duty mechanical system engineered to accommodate the largest thermal expansions, contractions, and dynamic movements in bridge and structural applications. It is specifically designed for movement ranges from 150 mm to 1,200 mm.
The system operates on an intermeshing finger principle. It consists of a series of symmetrical or asymmetrical aluminum finger plates anchored on either side of the expansion gap. These robust "fingers" interlock with each other, bridging the gap. As the bridge structure moves, the fingers slide and/or lift over one another, safely absorbing multi-directional movements (longitudinal, transverse, and rotational) while maintaining a continuous deck surface for traffic.
When selecting a large-movement expansion joint, aluminum systems offer distinct lifecycle advantages over traditional steel counterparts:
Superior Corrosion Resistance:
Aluminum naturally forms a protective oxide layer, providing inherent and permanent corrosion protection. This makes it exceptionally resistant to harsh environments, such as coastal areas or where de-icing salts are used, eliminating the risk of base metal rusting that can occur if the galvanizing on steel joints is damaged.
Significant Weight Reduction:
With a density about one-third that of steel, aluminum joints are substantially lighter. This reduces transportation and installation costs and minimizes the dead load on the bridge substructure (piers, abutments, bearings), a critical factor for load-sensitive or rehabilitation projects.
Enhanced Durability & Low Maintenance:
The exceptional corrosion resistance translates to minimal lifecycle maintenance. Unlike steel, aluminum joints do not require periodic repainting for corrosion control. This results in significantly lower long-term costs, less traffic disruption, and a superior whole-life value.
Excellent Lifecycle Cost-Effectiveness:
While the initial material cost may be higher, the savings in shipping, installation effort, and decades of avoided maintenance (inspections, repainting) often make aluminum joints a more economical choice over the full lifespan of the structure.
High-Strength & Aesthetic Appeal:
Heat-treated aluminum alloys (e.g., 6082-T6) offer an excellent strength-to-weight ratio, readily meeting heavy traffic load requirements. The joint maintains a clean, modern appearance, and its neutral color blends well with concrete, without unsightly rust stains.
1. Material & Fabrication
Primary Material: High-strength, heat-treated Aluminum Alloy 6082-T6 or 6061-T6.
Surface Treatment: Standard anodized finish for hardness and corrosion resistance. Optional architectural-grade powder coating is available for extreme corrosive environments.
Manufacturing: Finger plates are precision-cut from plate stock using CNC plasma/laser cutting for accurate tolerances and smooth intermeshing.
2. Structural System & Components
Finger/Comb Plates: The main load-bearing components. Available in symmetrical (cantilever) or asymmetrical (supported) configurations to suit specific movement and load requirements.
Anchorage System: Comprises high-tensile stainless or hot-dip galvanized steel anchor bars, base plates, and bolts to create a rigid connection with the deck concrete.
Integrated Drainage System: Features a continuous drainage channel beneath the fingers to effectively collect and direct rainwater into the bridge's main drainage system.
Noise Reduction: Fingers are oriented in the direction of travel, and noise-dampening pads can be installed at the finger ends to reduce impact noise.
Movement Capacity: Designed for total movement ranges from 150 mm to 1,200 mm.
Load Rating: Engineered to support AASHTO HL-93 and Eurocode LM1 traffic loading models.
Durability: Excellent resistance to wear, fatigue, and environmental degradation.
International Standards Compliance:
U.S. (AASHTO): Designed per AASHTO LRFD Bridge Design Specifications and informed by AASHTO MP-13 (Standard Specification for Steel Finger Joints).
Europe (EN): Complies with EN 1990, EN 1991-2, and the product performance requirements of EN 1317-5.
In addition to aluminum, we offer custom expansion filler materials including:
Rubber: for vibration and noise reduction.
Silicone: ideal for high temperature resistance.
Other elastomers to meet specific project needs.
While aluminum is our specialty material, we also offer expansion joints in stainless steel (for corrosive environments), PVC (cost-effective chemical resistance), and mixed material combinations to meet your needs.
Aluminum Finger Expansion Joints are the preferred solution for:
Long-Span Bridges (cable-stayed, suspension, arch bridges).
Long Continuous Viaducts and Interchanges.
Heavy-Traffic Highways & Expressways demanding high durability and low maintenance.
Bridge Widening Joints and Rehabilitation Projects for replacing old, failed joints.
Arbridge Series Elastomeric Expansion Joints are engineered to handle a wide range of movements, from moderate ±25 mm shifts to very large ±200 mm+ displacements. Integrating elastomeric cores with reinforced metallic elements and robust anchoring, they provide exceptional durability, watertightness options, and minimal maintenance over a long service life.
Elastomeric bridge expansion joints, commonly known as rubber Bridge Expansion Joint or mat expansion joints, provide a durable and cost-effective sealing solution for bridges with low to moderate movement ranges. Their design leverages the inherent properties of elastomers to ensure smooth traffic flow and long-term performance.
Finger expansion joints are engineered to accommodate structural movements ranging from 80 mm to 1,200 mm. These joints consist of steel finger plates, CR (chloroprene) rubber sheets, anchor bolts, and other essential components. A durable rubber sheet is mounted over the retractable steel assembly, while anchor bolts secure the entire structure in place.
The fingers are oriented in the direction of vehicle travel, which helps reduce noise and enhance driving comfort. Additionally, a built-in drainage channel directs rainwater into the bridge’s drainage system, preventing water accumulation and supporting long-term durability.
Also referred to as comb expansion joints, finger expansion joints feature symmetrical or asymmetrical comb-like (saw-tooth or sinusoidal) plates. These plates are anchored on one side of the deck joint gap and interlock to span the opening. Symmetrical finger joints, often called cantilever expansion joints, are typically used for smaller movement ranges. In contrast, asymmetrical designs—known as supported finger expansion joints—are better suited for larger expansion requirements.
Available in various tooth profiles to match specific application needs.
Modular Expansion Joints are engineered systems designed to accommodate large longitudinal movements in bridge structures, typically within a range of 80 mm to 1200 mm. The core mechanism consists of a series of parallel, movement-controlled center beams, supported at predetermined intervals by a substructure of cross beams or girders. This assembly is anchored between two edge beams, which are rigidly and watertightly connected to the bridge deck. The top surfaces of all beams are precision-set flush with the road surface to ensure a continuous running plane.
Explore our high-performance Strip Seal Expansion Joints for movement ranges from 0 to 80mm. Featuring a robust steel and EPDM/Neoprene design, they deliver superior watertight sealing, noise reduction, and durability for bridge and infrastructure projects.
The Strip Seal Expansion Joint is a premier solution for effectively sealing expansion gaps in bridges and structures with movement ranges from 0 mm to 80 mm. Its intelligent design combines high-strength steel with a durable elastomeric seal to create a reliable, long-lasting barrier against the elements and dynamic traffic loads.
Westcoast New Area, Qingdao City ,Shandong Province ,China
