Boston, MA--The Shops at
Prudential Center is one the hubs of downtown retail, shopping, office
and convention activity. Its vast underground parking decks and
loading docks are serviced from adjacent roadways through entrances and
exits off street level. The history of expansion joint
technology is on display at various locations around this 3.2 million
square foot mixed-use development. In one location, the
breakthrough innovations of the
SYSTEM from EMSEAL is quietly, unobtrusively doing its intended
Where's the joint? In
an article featuring the performance of an expansion joint it might seem
odd to display a picture where the joint isn't obvious. Yet this
is the point. For most designers expansion joints are a necessary
evil. Evil in large part for the disruption of design aesthetic.
But expansion joints go mostly unseen by the casual pedestrian.
And when cleverly positioned, as in this case adjacent to a granite
detailing band, the joint virtually disappears.
expansion joints are design elements necessary for accommodating
movements within buildings. These movements are
caused by thermal changes, wind, dynamic loading and unloading, and
Because expansion joints
bisect or isolate structures, they are essentially a gap through every
element of the building--drive lanes, roadways, parking decks, floors, walls, foundations, roofs, bathrooms,
suites, halls, foyers, lobbies, waterproofing elements, and structural supports.
In parking decks
joints must withstand traffic from cars, trucks, vans, buses, pedestrians and all kinds of wheeled
maintenance equipment while at the same time must accommodate joint movement.
SYSTEM features an
innovative non-invasive anchoring design. This means it is the
only cover-plate-based expansion joint system on the market that is not
anchored to, or in contact with, the concrete through metal pins,
anchors, embeds, trays, or hard connections of any kind.
Instead, the stored-strain
energy of compression in its precompressed, impregnated foam sealing
assembly locks to the joint faces through a combination of inherent
backpressure, a field-applied epoxy adhesive, and injected silicone
This assembly supports a
central spline to which the cover plate is attached and centered.
Attachment of the plate
to the foam-supported spline means the system is dampened against sound
transfer. And installed over EMSEAL's resilient polyurethane nosing
material, the SJS is arguably the quietest, traffic-capable expansion
joint system available.
Oh, and did
we point out that the
SYSTEM is watertight too?
Strip seals (left),
compression seals, self-centering bar-and-gutter systems, are not
watertight, are prone to failure, and don't look that great either.
Technology has evolved beyond these systems.
After 6 years of service,
featuring aluminum coverplates (stainless steel is an option), with an
compliant coefficient of friction, this SJS SYSTEM is watertight,
quiet, traffic durable,
non-invasively anchored and aesthetically
It is of
course better to start out at new construction with EMSEAL as the basis
of design for joint systems, but retrofit is possible, practical and
lasting and can be staged for minimal disruption. Retrofit can
also be phased to suit budget constraints--allowing for gradual upgrade
of all joints over time.
expansion joint solutions in mixed-use, retail, office, sports, assembly, convention and performing
arts venues as well as in retrofit of existing structures is a central
focus of EMSEAL's.
unique approach to expansion joint treatment
combines innovative materials technologies with a fresh look at the
roles of owners, designers,
contractors, manufacturers and subcontractors, in achieving
trouble-free expansion joints.
The approach is grounded
in an integrated, collaborative process centered on joint treatment that requires all
of these parties to
detail, specify, construct, fabricate, and install