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.
Movement Capacity & Load Rating: Certified to accommodate specified longitudinal movements (e.g., 160, 240, 320, 400mm) under standard traffic loads such as AASHTO HL-93 or EUROCODE LM1. The integrated displacement control system manages these movements while maintaining structural integrity.
Multi-Directional Performance: Beyond primary longitudinal shift, the system is designed to accommodate specified transverse movements (e.g., ±10 mm) and rotations about all three axes (pitch, roll, yaw), ensuring full compatibility with complex bridge dynamics.
Structural Beams: Fabricated from high-grade steel (e.g., Grade 345 MPa / S355), with corrosion protection via hot-dip galvanizing to a minimum thickness of 85 μm.
Sealing System: Utilizes continuous, pre-compressed elastomeric seals (e.g., Chloroprene) to create a watertight barrier, effectively preventing water and de-icing agents from penetrating the bridge substructure.
Anchoring & Support: Features a high-strength reinforcement cage anchoring system and, where applicable, integrated bridge bearings to ensure stable load transfer and long-term durability.
Modular expansion joints are composed by boundary beams, middle beams, cross girders, displacement control systems, bridge bearings, anchoring components and rubber sealing belts.
Table 1: Types and Sizes of Modular Expansion Joints
Type | B1(mm) | B2(mm) | H(mm) | F(Min.)(mm) | F60(mm) | F70(mm) | F80(mm) | G(WT)(kg/m) |
MEJ-140 | 400 | 400 | 400 | 140 | 260 | 280 | 300 | 150 |
MEJ-220 | 480 | 300 | 400 | 220 | 400 | 430 | 460 | 210 |
MEJ-300 | 560 | 300 | 400 | 300 | 540 | 580 | 620 | 250 |
MEJ-380 | 640 | 300 | 400 | 380 | 680 | 730 | 780 | 290 |
MEJ-460 | 720 | 300 | 400 | 460 | 820 | 880 | 940 | 410 |
MEJ-540 | 800 | 300 | 420 | 540 | 960 | 1030 | 1100 | 500 |
MEJ-620 | 880 | 300 | 440 | 620 | 1100 | 1180 | 1260 | 596 |
MEJ-700 | 960 | 300 | 450 | 700 | 1240 | 1330 | 1420 | 745 |
MEJ-780 | 1040 | 300 | 460 | 780 | 1380 | 1480 | 1580 | 1060 |
MEJ-940 | 1200 | 300 | 500 | 940 | 1660 | 1780 | 1900 | 1340 |
Table 2: Specification of Modular Expansion Joints
Type | Displacement | Width (mm) | Interval | Height of Support Beam |
MZL-80 | 80 | 80–160 | 50–130 | 700 |
MZL-160 | 160 | 160–320 | 80–240 | 700 |
MZL-240 | 240 | 240–480 | 160–400 | 800 |
MZL-320 | 320 | 320–640 | 220–540 | 800 |
MZL-400 | 400 | 400–800 | 310–710 | 800 |
MZL-480 | 480 | 480–960 | 400–880 | 800 |
MZL-560 | 560 | 560–1120 | 490–1050 | 800 |
MZL-640 | 640 | 640–1280 | 550–1190 | 800 |
MZL-720 | 720 | 720–1440 | 590–1310 | 800 |
MZL-800 | 800 | 800–1600 | 620–1420 | 900 |
MZL-880 | 880 | 880–1760 | 700–1580 | 900 |
MZL-960 | 960 | 960–1920 | 780–1740 | 900 |
MZL-1040 | 1040 | 1040–2080 | 810–1850 | 900 |
MZL-1120 | 1120 | 1120–2240 | 890–2010 | 900 |
MZL-1200 | 1200 | 1200–2400 | 970–2170 | 900 |
In general, modular expansion joints include the following components:
Center Beam
The centre beam carries the vertical and horizontal traffic loads with sufficient evenness and skid resistance. The traffic loads are transferred to the crossbeams. Further, it supports the seals between the centre beams and between the centre beams and the edge beams.
Edge beam
The edge beam carries the vertical and horizontal traffic loads and transfers the loads into the main structures such as abutment and bridge. Further, it supports the seal.
Support beam(cross beam)
The support beam transfers the loads from the centre beams to the main structures. In addition to the load bearing function, it can slide or rotate in order to allow movements of the main structures without the locking solid of the main structures and the centre beams.
Pantograph (crossbeam)
The pantograph support acts as a crossbeam with a variable length by rotation of its parts. Further it acts as a control element for the centre beams.
Crossbeam box (joist box)
The crossbeam box supports the crossbeams and ensures by its stiffness that the forces applied by the prestress elements are not susceptible to variation due to moving end supports surfaces.
· Seal
A seal functions as a barrier for the surface water to ensure the watertightness, it is flexible in all directions and does not carry the traffic loads.
· Fixed and/or sliding bearing
The bearing transfers the (traffic) loads from the centre beam to the crossbeam and/or to the main structure. The bearing can be fixed or sliding, in all cases it enables rotations. Rotations can cause reaction moments from deformation or friction in curved sliding surfaces.
· Prestress element
A prestress element prevents uplift of the centre beam to crossbeam connection and/or uplift in the crossbeam to main structure connection. A prestress element can be fixed or sliding and always has to allow rotations. Rotations can cause reaction moments from deformation or friction in curved sliding surfaces.
prestress element |
pretress element |
· Control elements
Control elements ensure that the centre beams are at approximately equal distances at the various opening positions of the modular joints.
· Anchor
Anchors ensure the connection of the expansion joint to the main structures.
· Additional surface elements (e.g. noise reducing)
Surface elements reducing the noise of traffic on the joint.
Independent Load & Movement Control: The system features a distinct separation between the load-bearing structure (center beams, cross girders) and the displacement control mechanism. This clear division of labor ensures that traffic loads are efficiently transferred to the bridge structure without interfering with the joint's ability to accommodate thermal expansion, contraction, and other movements, guaranteeing long-term reliability and safety.
Precision-Guided Synchronous Movement: Manufactured to high precision tolerances, the system ensures that all center beams displace uniformly and simultaneously. This synchronized movement, guided by individual control units, prevents binding or uneven gaps, which is critical for maintaining structural integrity and a smooth riding surface under repeated cycling.
Multi-Axial Movement Accommodation: Each support point within the joint often incorporates a combination of sliding and rotational bearing elements. This design allows the joint to adapt not only to longitudinal movement but also to minor rotations in all three axes (pitch, roll, yaw), providing exceptional compatibility with complex bridge behaviors, including those in curved, skewed, or sloping decks.
Optimized Material Efficiency: The design employs a shared cross girder to support multiple center beams within a single control box. This efficient configuration significantly reduces the total number of structural components and the overall size of the substructure required for large movement ranges, leading to a more compact and material-efficient solution without compromising performance.
Modular expansion joints are the preferred solution for a wide range of bridge structures requiring a longitudinal movement capacity of 80 mm to 1200 mm. Their robust and adaptable design makes them suitable for:
Complex Bridge Geometries: Ideal for application on sloped, widened, curved, and skewed bridges where multi-directional movements are present.
Highway & Expressway Decks: Used at expansion points on main bridge decks, at bridge approaches, and in elevated interchange sections to prevent damage from thermal stresses.
Critical Structural Protection: They effectively protect the bridge substructure (piers, bearings) from damage caused by restraint of movements, thereby preventing uncontrolled cracking and ensuring the long-term service life of the structure.
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.
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.
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
