Thanks for consideration of the adoption of our
SJS SYSTEM for
use on your project.
will find that the
SJS SYSTEM is
an evolution of proven existing technologies applied innovatively to large
joints. While innovative SJS already has an impressive
record of performance and adoption.
It is a system that so effectively employs the performance
characteristics of its components as to appear disarmingly uncomplicated.
Yet, it is a system that was launched following a methodical, iterative, and
thorough development, testing, prototyping, and field testing process.
performance was modeled using Finite Element Analysis (FEA) and subsequent
customization such as plate specification for extraordinary loading on
specific projects have been modeled again using FEA to prove to the
specifier and owner the suitability of the system. We have even gone so far
for one owner to provide independent lab certification of the stainless
steel grade supplied in order to confirm the mill certifications provided by
are pleased to demonstrate to you the type of evidence you are requesting is
available in abundance from EMSEAL. We would challenge you to compile a
similarly complete validation of performance claims for the manufacturers
of the self-centering bar systems, their components, or any other technology type you are
Innovation is the basis of our entrepreneurial spirit and our economy.
Without embracing evolving technologies from the standpoint of good, sound
engineering common sense, thorough vetting through testing, modeling and
field trials, and with a modicum of risk, we would not be flying through the
sky, walking on the moon, or even improving the lifespan of our parking
decks by tensioning cables through curing concrete to increase the final
density of the deck.
15 years since 1990 our sales team pleaded for a comparative 'seismic joint'.
"Just give us what
everybody else has--a self-centering bar, plate and gutter system--so we can
have a shot at this work." Our response was consistently the same:
because everyone else has one, when what they have does not adequately
address the purpose, doesn't mean we should copy it.
imitate," is the slogan that drives our product development philosophy and
we are arguably the only expansion joint manufacturer that is consistently
challenging existing paradigms, including our own, to bring improvements and
innovations to the field.
invention of a breakthrough microsphere-modified acrylic impregnation in
2005 provided the platform for the development and release of evolutions of
our previous technologies in subsequent years that include:
DSM SYSTEM for
seismic and large deck joints;
ever trafficable, watertight, 2-hour fire-rated all-in-one deck joint;
ever watertight, 2-hour rated, STC 56+, all-in-one joint system for concrete
and gypsum walls;
chemical resistant applications;
fabrication of terminations and transitions.
These innovations join our long list of
other industry-standard products:
MIGUTRANS, in establishing EMSEAL as the leader
expansion joint innovation.
Need for a Better Seismic Expansion Joint
Our research, observation, and conversations with owners who have failed and
leaking joints including cover
plates or self-centering bar systems installed and were pleading for a
better replacement, were:
“They are so noisy we can't rent the retail space
below these joints in our garage” (Providence Place Mall);
“They leak onto
the lower levels of the garage forming ice sheets in the winter” (Morris
Crossroads Corporate Center and U of Tennessee);
“The screws keep backing out and the plates
clatter drawing complaints from the library, preschool and hotel adjacent to
the deck” (U of Tennessee);
“The "gutter" leaks at all joins, has become
clogged with dirt, grit, food, and syrup, and has become a tunnel and
haven for rodents” (Oakland Raiders);
“The plates are cupping under wheel
loads, the screws have come loose and the joint leaks” (U of Georgia);
plates have come loose, are a trip hazard, and the joint leaks into the
concession area below” (Philadelphia Eagles);
“We don’t care if it leaks at
this point please get rid of the noise, it sounds like someone firing a gun”
(Home Depot World HQ Parking Deck, Atlanta, GA);
The R&D project goals for the SJS SYSTEM were:
- Traffic Load Durable
- Non-Invasive Anchoring
- No Hard Connections to Concrete (between the system or the coverplate)
this link to see and hear the difference in this video)
- For use in movement joints larger than 4-inches (100mm)
These goals were based on the shortcomings of the self-centering bar and
cover plate systems. All of these criteria were met, are embodied in the
SJS SYSTEM, validated by independent testing, and have been proved in nearly
4-years of in-field service.
Fundamentally, as it relates to the sealing of large joints in any concrete
deck and particularly in post-tensioned concrete the
Non-invasive anchoring and the fact that our cover plate is not in any way
attached into the concrete should be the driver of performance criteria on
which a specification is based.
essential differentiators of the
over any other are:
- no metal embedments
- no hard connections to the concrete whatsoever
Our evolutionary based innovations eliminate the shortcomings that come with
self-centering bar systems and cover plates, in post-tensioned or any other
concrete for that matter, and further eliminate the need to lower yours and your clients
performance expectations on this critical element of the structure.
We offer the following
documentation in support of our claims and in addition answers to the
sometimes-asked questions below:
SCOF Tests (Standard Coefficient of
UL 2079 Cycling Videos
Embracing a new or evolved technology does not equate to an admission that
previously employed technology didn't perform within it's limitations.
On the contrary it is the consultant's responsibility to inform and advise
owner/clients of the latest treatment options.
With going on four years
of experience and over 22,800 feet of material installed on more than 45
projects, in 18 states, and four countries, the SJS SYSTEM has been widely
adopted and is functioning well.
What testing has been done to verify the adhesion of the foam to the
concrete during a seismic event?
UL 2079 contains a
cycling component that puts joints through an aggressive rapid-cycling
cycle. UL 2079 has been the basis of cycling certification of our other
breakthrough innovations in fire-rated expansion joint sealants for decks
early vetting of these product concepts ran in parallel with the development
of the SJS SYSTEM. We contracted with UL to perform the cycling test as
part of our "proof of concept" stage of the R&D process. The favorable
cycling result caused us to continue to pursue development of both the SJS
SYSTEM and the fire-rated products. EMSEAL foam, bonded to concrete with
epoxy in the standard manner prescribed by our installation instructions has subsequently repeatedly passed this testing as part of the UL Certification
process, proving the bond and the ability of the foam to follow rapid joint
cycling. Please watch the UL 2079 video and observe the foam product being
cycled and while you’re there take a look a the SJS SYSTEM installation at
UL 2079 Cycling Videos.
How sensitive is
the adhesive to foam bond to variations in tolerance of the sides of the
Within reason not at
all. Because the non-sag epoxy paste is applied to the face of the formed
joint, as long as the face has been cleaned well, the epoxy can be used to
fill voids that inevitably exist. In addition the flexibility of the foam
under its own 2.2 lbs/sq.in of backpressure will press into the voids to
form a secure bond. If there are massive deficiencies such as voids left by
poor concrete consolidation, or protrusions left by poorly aligned formwork,
etc., these of course must be rectified before installation.
What testing and/or analysis has been
done on the plate for vertical and lateral traffic loading? What loads used?
independent-lab-run Finite Element Analysis (FEA ) was employed in proving
the SJS SYSTEM concept and has been subsequently conducted to simulate some
extremely severe conditions of both vertical and lateral loading. The first
FEA simulated a 4000 lb SUV, brakes locked, skidding across the joint. The
subsequent stresses are enormous and safety factors are very impressive
(more typical of life-safety factory for elevators for example) than for
deck joints. The total lateral displacement of the plates under these
conditions was less than 3/4 of an inch (19mm). Do you have similar studies
of the self-centering bar systems--I would be curious to know how they
compare? The FEA and other tests done by independent engineering firms in
validating the SJS SYSTEM performance claims contain all of the load and
assumption data used for your perusal and can be accessed at the previously
analysis or testing?
The next independent FEA
we conducted was to simulate fork-lift loads over various plates for some
isolated conditions on Atlanta's CONRAC deck. All of our recommendations
for coverplate thickness are based on what FEA terms "infinite life".
Please see above list of FEA and other testing.
an acceptable deflection criteria for the plate at design maximum opening?
We specify plate
thickness based on material type (aluminum or stainless) based on the
vehicle type, loading and joint gap widths expected and communicated to us
by the designer of the project. Deflection of the plates of our system vs.
any another system will be roughly equivalent for similar cover plate
materials and thickness if similar calculations are done.
The SJS SYSTEM cover
plates are designed to achieve “infinite life” under design loading
conditions. Under this loading, the deflection of the system is minimal, and
the safety factors on yield are quite large. For example, our FEA analysis
shows, on a typical deflection scenario for a fully loaded
SJS SYSTEM for
normal automobile traffic over even a 15-inch wide gap (10-inch wide nominal
joint at max (+50%) opening) and using a 3/8” Type 304 stainless steel
coverplate, is less than 1/32”.
In addition to designing
the system to achieve "infinite life" under design loads, a further FEA was
conducted to simulate 3 times normal design loading. This simulation
resulted in no permanent yielding of the cover plate, and no permanent
Other manufacturers whose systems are not designed around
“infinite life” may reduce cover plate thickness in an effort to reduce
overall cost. While simple calculations will show that the design is safe
under static loading, they do not take into account the dynamic, and
repetitive nature of the actual situation. Long term repetitive cycling will
induce stress concentrations, localized yielding, cracking, and cupping of
materials with reduced safety factors. These behaviors can lead to rapid
failure of the system itself, and potentially of the deck materials as well.
Is Emseal truly watertight? Is there a testing criteria?
In the case of a bus
drive lane at a major airport where the joint is located at a turning lane
and where bus loads as well as substantial tire torque on the plates is
occurring, we ran a further independent FEA to simulate a 45,000 lb bus,
torqueing its tires at a dead stop. From the results we designed,
increased spline and foam assembly depth, a
coverplate thickness and bolt-hole spacing to provide "infinite life"
according to the FEA under this heavy-duty scenario.
Yes. The criteria is
that no water passes through the joint and that no water is evident from the
underside leaking through the joint, and that no water presents itself on
the decks below. This can be observed as the result of observation after
rain storms over time or as the result of deliberate water testing by
damming an inch of water over the joint. The reason this can be observed is
that the system is watertight at the deck surface and does not employ
gutters either as a component of the system or attached below the joint as a
Gutters attached below expansion joint systems hide the symptoms
of leaking joints and are, in our opinion, not a good idea. De-icing salt or
low-pH water that leaks through non-watertight joints into gutters must
first contaminate the joint system components and the concrete over which it
flows. This precipitates corrosion and structural damage of concrete in
beams, columns, and decks.
The University of Tennessee Knoxville, Millers
Crossroads Executive Park, the owners of the new stadiums for the New York
Yankees, Mets, Jets/Giants, and Twins and Atlanta CONRAC; Providence Place
Mall, Green Bay Packers; U of Georgia; and dozens of other parking and
stadium owners have all entrusted watertightness of their buildings to
EMSEAL and the SJS SYSTEM either in new or retrofit conditions. If they
leak--we hear about it. Where we have had problems they have been minor,
traceable to installation oversight and immediately rectified.
years of experience and over 23,000 feet of material on more than 50
projects, in 18 states, and four countries, is a more than adequate a sample
from which to gauge our claim that the
SJS SYSTEM is watertight.
using SJS SYSTEM?)
It must be made clear
that EMSEAL endeavors to provide WATERTIGHT expansion joints and not
weather tight products. The distinction here, is as stated above.
Keep the water at the surface or exterior of a structure. Do not allow the
water to enter the building. Once the water is in the building, the owner
has been given a water management system. If a manufacturer submits a
gutter as a component of their solution, they have admitted that the primary
system will leak. The gutter will trap moisture in the joint gap and will
rapidly contribute to concrete damage. The gutter approach negates inspection for
the building owner leaving deterioration most likely unobserved for an
extended period of time.
criteria is used to define noise mitigation/dampening?
When you want a loud
noise to accentuate an orchestral piece, you bang two pieces of metal
together. Or you strike pieces of loosely attached metal laid across an
opening in a frame with rubber mallets. A cover plate with any play under
it riding over a hard surface or another piece of metal is the same idea.
Make the plate's riding surface a hollow box of metal and you've added a
resonance chamber to further amplify the sound. Bolt down, or embed a
metal box to high PSI concrete with metal pins or anchors, cantilever it
even slightly off a beam into air and then strike it hard, and repeatedly,
with the enormous force of air-filled rubber mallets and you've designed
pretty much a perfect noise making machine.
Remove any one of the
elements above and you will make less noise. The criteria to define the SJS
SYSTEM's noise mitigation/dampening claim is ultimately the absence of
cacophony unpleasant to the human ear
this link to see and hear the difference in this video). Here are the elements
that go into the
SJS SYSTEM being arguably the quietest coverplate system available:
A) The reason coverplates
bang is they either don't lie flat as the result of camber or undulations in
the concrete, cups in the plates, or loosened fastenings. If you can level
the concrete you can eliminate undulations. By using our self-leveling,
flexible, low-aggregate, resin nosing material in a blockout as a leveling
medium--we level the plates and in addition, the medium on which the plate
rides becomes a sound attenuating material that is softer than metal or
concrete or metal boxes.
B) By eliminating any
metal anchors or embeds into the concrete deck we sever a hard, resonance
inducing connection to the concrete. We replace this with two highly
resilient foam springs. The foam has been independently tested to have a
STC of 54. It is an exceptional sound noise reducing medium. Consequently
the vibrations of any noise induced at the plate is further absorbed and
dissipated into the foam. Self-centering bar systems would be essentially
transparent to noise. An STC of 20 is not unreasonable to suppose for a
cover plate and gutter system. With each 10 db increase, a normal person
perceives a “doubling” of the subjective amount of noise. This means that
the self-centering bar systems could be perceived to be 8X louder (3 doublings). And,
that's not even taking into account the fact that these systems can actually
generate noise, in addition to not damping it.
C) The coverplate screws
are self-tapped into the spline which is flanked by the foam. This means
vibration that normally works to loosen screws is virtually eliminated.
Screws that stay tight, keep the plates down snug and they do not bang.
The bottom line, is when
you drive over
SJS SYSTEM installed as recommended over our
resin-rich nosing material you
might hear a gentle, low-frequency, thud but not a harsh, penetrating,
high-frequency, metallic clang.
this link to see and hear the difference in this video)
are the benefits to the owner?
No metal embedments, no
drilling, no cutting and no hard connections to the post-tensioned concrete
whatsoever are the essential differentiators of our system over any other.
Add watertightness and sound dampening and it is clear why this technology
is in the best interest of owner/clients. Eliminate screws loosening,
eliminate gutters and eliminate water management to downspouts, and it is
clear why the use of SJS SYSTEM is in the owner’s long-term maintenance and
total cost of ownership interests. With the elimination of the gutter
system and the decrease in labor costs to install the SJS system relative to
the self centering technology, we would additionally submit that the
installed cost is LESS expensive at NEW CONSTRUCTION as well.
At the end of the day,
the self-centering bar technology was a beefing up of an interior joint
design in the hopes it would be suitable to parking deck and other open-air
uses. It has worked adequately in some cases where meticulous
installation has been assured but the basis of its design
for the application demands into which it has been marketed is flawed. The
"gutter" component in the predecessor interior joints was referred to as a
"moisture barrier" and was intended to catch the few drips of cleaning water
that got through the joint. This water would evaporate in the "moisture
barrier" The fundamental roots of these systems in interiors puts their
principle of operation in contradiction with the requirements of a parking
By contrast, the SJS
SYSTEM was developed to meet the rigorous requirements of performance of
open air structures free of the constraints of the interior joint paradigm.
Trafficable, watertight, sound attenuated, durable under vehicle loads.
Engineered, independent lab tested, field proven.
In 1990 EMSEAL
received a letter from a major national design and engineering firm. In
every one of the thousands of
luncheon seminars since,
our specification development engineering
team have opened our presentations with a paraphrase from that letter:
“[We have come to realize
that our] projects show more problems with expansion joint seals than all
other product categories combined. Yet, expansion joint seals are a
miniscule part of most of our projects in terms of construction costs. …How
can we work together to produce trouble-free expansion joint seals?”
Working with engineers,
architects, general contractors and subcontractors in the shared goal of
providing owners with trouble free joint seals, EMSEAL has made the
realities and wisdom of this quote the de-facto mission of the entire
Through espousing an
approach based on:
ownership of responsibility for our respective aspects of the work;
- communicating early, often and in 3-D;
- development of 3-dimensional joint layouts that have been adopted as a new
page in the bid documents by numerous firms nationally;
on continuity of seal and
thinking, designing, detailing, bidding,
constructing, manufacturing, and installing in three dimensions;
- working with designers to have the courage to advocate for better
technologies and to justify to owners these recommendations as in their
the invention of shear pockets to handle
perpendicular movement in extruded glands;
warranting transitions in
similar and dissimilar technologies to be watertight;
and through the R&D
process previously described, EMSEAL is working together with like-minded
firms all over the world to produce projects with trouble-free joint seals.
Thanks again for your
consideration. The evolution of the building sciences is inevitable and
evident all around us. EMSEAL is working continuously to bring evolution to
the tiny portion of building science that is structural movement joints.
20+ year mission to elevate structural expansion joint technology and
practice has been deliberate, conservative, and dogged in its single-minded
pursuit and ask that you will acknowledge this effort through the adoption of
our joint systems in your base spec and on future projects. Please
click here for a guide specification
for use in making the SJS SYSTEM the basis of design for your seismic and
joints. And, cross reference your spec in the drawings with details
SJS SYSTEM CAD library.