BEJS SYSTEM -- Bridge Expansion Joint System

RESIZE, REBUILD, RESEAL --The EMSEAL Approach to Bridge Expansion Joint Retrofit.

RESIZE:
The fundamental issues that affects joint sealing in any structure are sizing of the joint in relation to both:

1) the movement expectations of the structure as a product of its length and the temperature range for its geographical location, and...

2) the movement capability of the joint material being chosen to seal the joint. 

Too often these calculations are not done in unison resulting in joint failure.

REBUILD:
As the result of years of vehicular punishment combined with freeze-thaw cycles, and rebar corrosion, concrete or asphalt at joint edges is usually badly cracked or deteriorated.  By removing the cracked concrete and replacing it with EMSEAL's impact-resistant, fast curing, nosing material, the joint edge can be repaired while at the same time reforming the joint gap to a dimension suited to handling the movement expected at the joint and within the capability of the BEJS SYSTEM.

RESEAL:
Installation of the BEJS SYSTEM is fast, can be staged while preserving partial traffic flow, can be done day or night, and can be installed in a wide temperature range.

Continuity of seal is critical.  This refers to ensuring that not only the joint in traffic surface is watertight but that the joint through all changes in plane and direction up, over, and down all adjacent sidewalks and/or parapets is also watertight.  To achieve this, the joints in the parapets and sidewalks must be sized the same as the roadway joint and the system sealing the roadway must transition through all the elevation changes.  The goal is to have the joint watertight from outside of parapet to outside of parapet across the whole bridge.

Expansion joints are not drains.  One of the major, if not the major cause of structural deterioration of piers, columns and beams on bridges is attributable to leaking joints or joints that are used as drains.  Water laced with de-icing salts and atmospheric contaminants directed through expansion joints sheds directly onto the most critical structural elements of bridges.  Corrosion and expansion of rebar and subsequent spalling result. This requires the reconstruction of the beams, piers, columns and wing walls at considerable expense.  Unless the joint above these structural elements is made watertight throughout its length (from outside of parapet to outside of parapet), and unless the pitch of the bridge drains water away from the joints to a less critical discharge point or to purposed-designed drains, this cycle of deterioration will recur at an accelerated pace. Universal-90's are EMSEAL's unique, factory-fabricated transitions and termination units that ensure watertightness at changes is plane and at terminations. See Factory Fabricated Terminations and Transitions below.

Uses
Ideal for new construction and retrofit of old or failed bridge expansion joint systems in:
• concrete-to-concrete substrates;
• rebuilt joint faces;
• where demolition and removal of existing embedded metal angles is not feasible or affordable and where joint size and expected movement are within the BEJS SYSTEM movement capability;
• as a lasting replacement for all failed liquid-sealant joints in parapets, sidewalks, jersey-barriers, etc.

Movement Capability
+30% and -25% (Total 55%) of nominal material size (see "Performance").

FIRE RATING Expansion Joints in BRIDGE Design:
With notable events such as Oakland California's tanker-fire fed structural collapse of the MacArthur Maze Freeway interchange roadway spans, fire-rating of bridge structures is being increasingly considered.  Extension of fire rated design across expansion joints can be achieved with EMSEAL's breakthrough fire-rated, traffic durable, high movement and watertight joint seal.  EMSHIELD DFR2 provides all of these functions in a single product installation.  Movement cycled and 2-hour fire tested to UL 2079, EMSHIELD DFR2 is the first of its kind expansion joint system to satisfy all performance demands in a single installation process.  For more information see EMSHIELD DFR2.

Product Description
The BEJS SYSTEM builds on a track record of over 30 years of sealing bridge joints with impregnated foam sealants and is an evolution of EMSEAL's 20H SYSTEM and DSH SYSTEM.

The system is comprised of:
1) Precompressed, silicone-and-impregnated-foam hybrid installed into...
2) field-applied epoxy adhesive on the joint faces; with the Pecora 301 silicone bellows locked to the joint faces with...
3) a silicone sealant band (see Figure 1).

The BEJS SYSTEM features an innovation in sealant technology in the form of a patent-pending acrylic adhesive infused into the cellular foam base material. This new chemistry incorporates a hydrophobic microsphere component never before available in a sealant formulation.

The material features sealing performance significantly greater than any acrylic impregnated predecessor. In addition, it is odorless, clean handling, UV stable, non-staining, and features low temperature flexibility not previously available in asphalt, wax, or isobutylene-based predecessors.

The result is extension of the usability of the product to applications where asphalt and wax-based predecessors did not work well under conditions of thermal shock (rapid opening and closing of joints during large temperature swings). These applications include joint-face adhered installations on top decks as well as intermediate decks.

Suitability is further extended to horizontal-plane joint applications in colder geographical regions to which asphalt and wax-based predecessors have not previously been recommended.

Features
Watertight—the tensionless silicone bellows is installed just below the deck surface. This ensures watertightness is achieved at the deck surface. Unlike liquid-applied sealants, compression seals, and inflated seals, the BEJS SYSTEM does not rely in adhesion in tension.  Instead the material is precompressed in the factory ensuring that the spring energy of compression is always pushing back on the substrate.

Non-Invasive Anchoring—there are no hard metal-to-concrete connections in the system. This includes embedded pins, anchors, screws, bolts or tracks, trays or rails. The system is locked to the joint faces by means of the 1) backpressure of the foam; 2) the epoxy adhesive, and 3) the injected silicone sealant band at the joint face to foam and silicone bellows interface.

Continuity of Seal—as in all EMSEAL expansion joint systems, continuity of seal through changes in plane and direction is an essential performance differentiator. Details for watertight, field-fabricated transitions from deck to wall, at curbs, sidewalks, parapets, tees, and crosses are available with the BEJS SYSTEM.

Aesthetics & Versatility—Standard bellows color is black with grey also readily available (other custom colors are also available), uniform bellows appearance, double sealing, fuel resistance, and an enhanced ability to handle variations in joint size are among other system features.

Performance
• Capable of movements of +30%, -25% (55% total) of nominal material size.

• Substrates must be parallel, plumb and capable of resisting approx. 2.5 psi backpressure from the foam.

• Standard sizes from 1/2" (12mm) to 4" (100mm). Other sizes available subject to review of application: consult EMSEAL.

• Fuel Resistance: Silicone sealant is not degraded by contact with fuel. Some swelling of the material will normally occur, but it will return to its original shape upon evaporation of the fuel.

Composition
• BEJS is produced by coating an impregnated cellular foam with Pecora 301 highway-grade silicone.
• The expanding foam is cellular polyurethane foam impregnated with a water-based acrylic containing a high performance micro-cellular additive.
• The silicone external facing is factory applied to the foam at a width greater than maximum joint extension and is cured before final compression.
• Silicone application and curing takes place in a factory-controlled environment. In contrast to field applied liquid sealant and backer rod installations, no movement takes place during curing that can cause deformation or stresses in the material.
• When compressed, a bellows is created in the coating. As joint movement occurs the bellows simply folds and unfolds free of tension on the bond line, and virtually free of tensile stresses in the silicone material.
• The foam provides a resilient backing to the silicone coating, making the system capable of resisting reasonable transient point loads.
• BEJS SYSTEM is supplied in 6.56 LF (2m) shrink-wrapped lengths (sticks). It is precompressed to less than the joint size for easy insertion. After removal from the shrink-wrap and hard board restraining packaging, it expands gradually.


UNIVERSAL 90's
(Expanded Universal-90's information)

Factory-Fabricated Terminations and Transitions—in all EMSEAL expansion joint systems, continuity of seal through changes in plane and direction is an essential performance differentiator.

BEJS is manufactured in straight-run sticks which can be joined in the field to EMSEAL’s patent-pending "Universal-90" Transitions and Terminations.

Universal-90 Upturn Termination	Universal-90 Flipped-Over as Downturn Termination
Universal-90 Upturn Transition	Universal-90 Flipped-Over as Downturn Transition

100% free of wax or asphalt compounds (Why does this matter?)

(Need help with Bridge and Road Expansion Joints and Joints Sealants? Fax Us This Checklist)