Expansion Joints and Pre-Compressed Sealants

SJS-Seismic Joint System                                             US Patent: 6,532,708

Watertight, Sound-Dampened Seismic and Large-Gap Joint System For Parking Decks, Car Parks, Stadiums, Floors

Tech Data

Install Data


Guide Spec





SJS en español


Traffic durable

Sound dampened
Non-invasive anchoring
• No concrete-embedded cover plate anchors
hard connections to concrete
• Minimal components
• Self-locating plate anchors

• No gutters

• Rapid installation--new or retrofit
Eliminates leaks at large structural expansion joints
Reduces maintenance costs
• Built-in fire rating with EMSHIELD SJS-FR

parking decks/car parks
• mall bridge connectors
• airports

Standard Sizes
4" to 18" (100 - 450mm)

Product Depth
4" to 8"(100 - 200mm) wide = 4"(100mm) deep
9" to 18" (225 - 450mm) wide = 5" (125mm) deep

Movement Capability
Up to 100% Total (+50% and -50% of nominal supplied size.)

• Standard cover plate is aluminum with ADA-compliant, flint-
  blasted finish. Stainless steel also available.
• Other finishes by request
(contact EMSEAL)

Product Description

The SJS SYSTEM by EMSEAL is comprised of silicone-and-impregnated-foam hybrid components that ensure watertightness, absorb sound, dampen vibration and offer uncomplicated installation.

Created from the latest evolution in the field-proven technology used by EMSEAL for over 30 years of sealing horizontal plane joints with impregnated foam sealants, the SJS is constructed from two horizontal joints pre-assembled in parallel adjacent to a heavy-duty extruded aluminum spline.

The spline acts as a receptor for attaching the surface-mounted traffic plates that bear vehicle and other loads.

The result is a system that offers features and benefits not found in alternative products intended for large, horizontal structural joint gaps.


Who's using SJS SYSTEM?

Features Explained

Watertight – The tensionless silicone bellows are installed flush to the mounting height of the system and just below the cover plate ensuring watertightness at the traffic surface.

This eliminates the need for ineffective moisture barriers and secondary gutter systems.

SJS SYSTEM is also available specifically for watertight integration with split-slab buried waterproofing systems--see SJS-FP.

Sound Dampened
– The flanking impregnated foam and silicone hybrid dampens sound and shock effectively. When installed over EMSEAL-supplied elastomeric nosing material (EMCRETE), the result is arguably the quietest watertight cover plate system available.
(Click to see and hear the SJS difference.)

Installs Rapidly – Using non-invasive anchoring the SJS SYSTEM eliminates drilling associated with hard metal-to-concrete connections as well as intrusive pins, anchors, screws, bolts or tracks, trays or rails. The system is locked to the joint faces by the backpressure of the foam and an epoxy adhesive, and by the weight of the assembly.
(Watch the video of installation in a parking deck or a stadium).

Self-Locating Cover Plate Screws – The center spline is a continuous receptor for the cover plate screws that are self-tapped into the anchor channel. This dramatically reduces the installation-related problems of locating self-centering, sliding ball devices and pantographs. The probability of screws being left out is eliminated ensuring proper anchoring.

Self-Locking, Vibration-Dampened Screws – Vibration in systems that rely on metal-to-metal connections and contact points is the main cause of screw loosening. SJS by EMSEAL minimizes vibration through the dampening action of the massive and continuous springs of impregnated foam along the entire length of the joint. In addition, 30 pounds of force is required to loosen the screws offering excellent screw tightness without the need for thread-lock compounds.

Field-Adjustable Plate Support – Concrete in new and retrofit applications is inevitably uneven across and along the joint. The SJS SYSTEM is installed over a leveling-bed of EMSEAL-supplied elastomeric nosing material providing the ability to fine-tune the support of cover plate sections.  This eliminates plate rocking and noise caused by unleveled plates. Systems that attach or utilize intrusive extruded rails to receive sliding ball and socket devices cannot be adjusted to eliminate unevenness across and down the length of the joint.

Continuity of Seal – All EMSEAL expansion joint systems feature continuity of seal through changes in plane and direction –– an essential performance differentiator. Interlocking or continuous fabricated transitions for curbs, sidewalks, treads and risers, and parapets for example, are available with the SJS SYSTEM.

Finite Element Analysis (FEA) Compiled Safety Factors – Prior to field trials, the SJS SYSTEM was modeled using FEA to determine the suitability of design to worst case possible parking deck loads.

Under the scenario of a 4,000 lb vehicle skidding across the joint system to full stop once past the cover plate, FEA modeling predicted lateral displacement of the cover plate of less than 3/4-inches (19mm) and safety factors in key components as follows:

FEA Safety Factors:
Traffic Plate - 5; Screws - 11; Spline Pins - 10; Center Spline - 7

Extreme Conditions--SJS Seismic Joint System is designed to handle the vast majority of heavy traffic and load applications. For high-torque, extremely heavy load applications in traffic decks see SJS-HD and contact EMSEAL.
Installation Video

(NOTE: This video demonstrates the ease of installation of the SJS SYSTEM using Custom-90-degree transitions pre-manufactured to field measurements provided by the installing contractor. This video does not cover in detail all of the installation steps for the system. Please consult your EMSEAL field technician and the complete installation instructions).

The EMSEAL video library has additional SJS videos.


SJS-SYSTEM in Stadiums--Watertight system for large concourse and tread and riser joints.  Shown here replacing rubber-encased cover plate.

(click images to enlarge)

Link to Watertight Stadium Joint Selection Guide

Seismic Joint System: Patent No. 6,532,708


EMSEAL JOINT SYSTEMS LTD. 25 Bridle Lane, Westborough, MA 01581
EMSEAL LLC. 120 Carrier Drive, Toronto, ON M9W 5R1



1-800-526-8365 -- 508-836-0280 --  techinfo@emseal.com -- Fax: 508-836-0281

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