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.
Table 1: Specification of Finger Expansion Joints
Movements | Thickness | Anchor bolt | Width (mm) | Height (mm) | Height of set layer |
80 | 28 | M18 × 180 | 750 | 33 | ≥ 120 |
100 | 28 | M18 × 180 | 790 | 33 | ≥ 120 |
120 | 30 | M18 × 180 | 830 | 35 | ≥ 120 |
140 | 30 | M18 × 180 | 870 | 35 | ≥ 120 |
160 | 30 | M20 × 200 | 940 | 35 | ≥ 130 |
180 | 32 | M20 × 200 | 980 | 37 | ≥ 130 |
200 | 32 | M20 × 200 | 1020 | 37 | ≥ 130 |
220 | 32 | M20 × 200 | 1040 | 37 | ≥ 130 |
240 | 34 | M20 × 200 | 1060 | 39 | ≥ 150 |
260 | 34 | M20 × 200 | 1120 | 39 | ≥ 150 |
280 | 34 | M20 × 200 | 1170 | 39 | ≥ 150 |
300 | 34 | M20 × 200 | 1270 | 39 | ≥ 150 |
320 | 36 | M24 × 240 | 1290 | 41 | ≥ 150 |
340 | 36 | M24 × 240 | 1350 | 41 | ≥ 150 |
360 | 36 | M24 × 240 | 1410 | 41 | ≥ 150 |
400 | 36 | M24 × 240 | 1470 | 41 | ≥ 150 |
Note: Other specifications also can be customized.
Cantilever expansion joint with symmetrical elements
Cantilever expansion joint with steel profiles and anchor bars
Supported finger expansion joint with anchor bar
Supported finger expansion joint with rubber sealing strip
Note: Other types also can be customized.
Our finger expansion joints are engineered for superior performance and value, offering a range of key advantages:
Robust & Simple Design: Featuring a low-profile structure with minimal complexity for exceptional durability and long-term reliability.
Enhanced User Comfort: Effectively minimizes noise and vibration transmission, ensuring a smoother and quieter ride for vehicles.
Superior Safety: The integrated anti-skidding design and highly water-resistant properties (with a dedicated waterproofing system) provide maximum traction and safety in all weather conditions.
Excellent Drainage: Effectively channels rainwater away, protecting the bridge structure and enhancing joint longevity.
Cost-Effective Solution: Combines low initial investment with minimal maintenance needs, delivering outstanding long-term value.
Proven Versatility: A widely adopted and trusted solution for various bridge and expansion joint applications.
Easy Installation & Replacement: Streamlined design significantly reduces installation time and cost, both for new projects and rehabilitation.
Finger expansion joints are a versatile solution for a wide range of infrastructure projects:
New & Existing Bridges: An ideal choice for both new construction and the maintenance or widening of existing bridges.
Large-Span Bridges: Specially designed to handle the significant movement ranges required by large-span bridge decks.
Seamless Integration: Perfectly suited for use between steel box girders, concrete beams, and at the transition between steel and concrete sections.
Highway & Expressway Use: Commonly and reliably deployed in high-traffic environments like expressways to ensure continuous, smooth travel.
Our finger expansion joint product line is designed in strict accordance with both AASHTO (U.S.) and Eurocode (E.U.) frameworks. This commitment to international standards guarantees that our products deliver exceptional performance and long-term reliability, whether in North America, Europe, or any other market that adopts these specifications. We can provide detailed calculation notes and certificates of compliance upon request for specific project requirements.
In the United States, bridge components are governed by the American Association of State Highway and Transportation Officials (AASHTO) standards.
AASHTO LRFD Bridge Design Specifications (Current Edition)
Chapter 14 - Bearings and Expansion Joints: This is the core design philosophy. Our joints are designed to meet the Load and Resistance Factor Design (LRFD) requirements for strength, serviceability, and fatigue limit states based on calculated movements from thermal changes, creep, and shrinkage.
AASHTO MP-13: Standard Specification for Steel Finger Joints
This is the key product-specific standard for steel finger joints. It provides definitive requirements for:
Materials: Specifying steel grades for finger plates, anchors, and other components.
Manufacturing: Governing tolerances, welding quality, and surface treatment (e.g., galvanizing).
Design Loads: Defining the required wheel loads and impact factors.
Movement Range: Certifying the joint's capacity to accommodate thermal expansion and contraction.
In the European Union, the harmonized Eurocode (EN) system provides the framework for structural design and component compliance.
EN 1990 (Eurocode): Basis of Structural Design
Defines the fundamental principles and load combinations (traffic, temperature, braking forces) that the joints must withstand.
EN 1991-2 (Eurocode 1): Actions on Structures - Traffic Loads on Bridges
Specifies the traffic load models (LM1, LM2, etc.) used to verify the structural adequacy of the joints under dynamic and static forces.
EN 1993-1-1 (Eurocode 3): Design of Steel Structures
As finger joints are primarily steel structures, this code provides the rules for the design and verification of steel components, ensuring structural integrity.
EN 14690: Road and airfield surface characteristics - Expansion joints for roads - Part 1: Performance characteristics
This is a critical product performance standard. It mandates requirements for:
Waterproofing: The effectiveness of the sealing system.
Durability & Fatigue Resistance: Validated through simulated long-term traffic loading tests.
Corrosion Protection: Requirements for protective systems like hot-dip galvanizing.
Skid Resistance & Ride Comfort: Ensuring safety and smooth vehicle passage.
Our finger expansion joint products strictly adhere to the current national and industry standards of the People's Republic of China, guaranteeing their safety and applicability in various bridge engineering projects within the Chinese market.
JT/T 327-2016 "Expansion and Contraction Installation for Highway Bridges"
This is the core product standard issued by the Ministry of Transport of China. It comprehensively specifies the classification, technical requirements, test methods, inspection rules, and marking, packaging, transport, and storage for expansion joints. Our products fully comply with its requirements for finger joints in the following aspects:
Movement Capacity: Capable of meeting the specified horizontal movement (X-direction) and vertical deformation (Y-direction) requirements.
Load-Bearing Performance: Verified through specified static and dynamic load tests to ensure bearing capacity.
Durability: Meets stringent requirements for fatigue performance, waterproofing, and corrosion protection (e.g., galvanizing layer thickness).
JTG D60-2015 "General Specifications for Design of Highway Bridges and Culverts"
This code is the fundamental basis for bridge design in China. It defines the various loads acting on bridge structures (e.g., vehicle loads, temperature effects, braking forces). The design of our expansion joints is based on the calculations from these loads, ensuring consistency and safety with the overall structural design philosophy.
JTG 3362-2018 "Specifications for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts"
This specification provides detailed design methods for concrete bridges and culverts, explicitly defining the structural displacements caused by concrete shrinkage, creep, and temperature changes. The selection and design of our finger expansion joints are strictly based on the calculated displacement at the beam ends according to this code, ensuring effective absorption of these movements.
For projects with stringent quality and compliance requirements, we provide an additional layer of verification through internationally recognized laboratory testing. Our finger expansion joints can be submitted to a CNAS Accredited laboratory for rigorous evaluation against relevant standards (such as JT/T, AASHTO, or EN). The resulting test report provides objective, third-party evidence of the product's performance metrics—including load capacity, fatigue life, waterproofing, and durability. This documentation is widely accepted by regulatory bodies and engineering consultants globally, serving to de-risk your project and streamline the approval process.
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.
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.
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
