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Most stadiums leak at expansion joints. Owners
cringe at the truth and spend thousands, even millions, of dollars each year
to repair leaks. The rare exceptions – stadiums completed with watertight
joints – are characterized by a design and building process that involves a
shift in the traditional way stakeholders relate and execute their work.
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Interior Floor Joint |
This process must begin early in the stages of
design and planning, and continue until construction is complete.
How can stadium owners ensure that their facility will be leak free? There
are several steps that if followed throughout the project, will ensure the
stadium remains dry and free of the need for expensive refurbishment.
Owner Responsibilities
Less than half of one percent of a typical stadium construction budget is
spent on expansion joints. However, a majority of post-tenancy problems with
these structures relate to water ingress. Owners must be receptive to
recommendations for superior technologies presented to them by designers and
be prepared to allocate additional resources to the design contract to allow
proper detailing of joints and their relationships to other structural
elements. By spending slightly more of the construction budget on
waterproofing, stadium owners and managers can expect trouble-free, dry and
lasting joint seals.
Designer Responsibilities
Even the best waterproofing system is going to fail if there are holes in
the membrane. Structural expansion joints represent a planned hole in the
waterproofing membrane. Designing out expansion joint problems begins with
consideration of the following:
Acknowledge the Need for Expansion Joints
Structural materials have limitations. Extreme weather conditions can cause
damage over time. Cracks as a result of overstressed materials are nearly
impossible to seal and can result in dangerous structural weaknesses.
Properly designed expansion joints will prevent cracking, while carefully
chosen sealant systems will withstand weather conditions and keep the
facility dry.
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Failed Premold, typical |
Choose Expansion
Joint Location Carefully
Corners are a bad place for expansion joints. Do not cast, or use the joints
between precast corner units as the place for the structural expansion
joints. Instead, cast the corners solid, or weld these precast connections
and make them non-moving. Make the structural expansion joint in a straight
line just off the corners. Joints cut completely through the whole
structure. Therefore, think about the interior layouts in relation to
expansion joints. Considered early enough, it is even possible to hide some
joints between back-to-back interior walls thereby eliminating their
aesthetic impact as well as the need to bridge them. Finally, select and
specify all-metal, high-point-load expansion joints capable of handling
small-wheeled catering, cleaning, and other traffic that typically destroys
“rubber and rail” joint systems.
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TAKE HOME POINTS
• By spending slightly more
of the construction budget on water proofing, stadium owners and
managers can expect trouble-free, dry and lasting joint seals.
• Properly designed expansion joints will prevent cracking, while
carefully chosen sealant systems will withstand weather conditions and
keep the facility dry.
• Expansion joints must be considered a critical path item, rather than
an added piece at the end of the project. |
Select Structural
Supports Wisely
Choose split columns rather than single columns with slide bearing pads. A
single column structure results in hard-to-seal conditions around the column
caps that create shear conditions for which most watertight joint systems
are not designed. Split columns ensure that a system’s sealing integrity can
be maintained. Retrofit of failed joints around column caps in singlecolumn
construction is a specialty that we employ. However, the company’s
specialized “shear pocket” fabrication required for this type of retrofit
comes at a premium. It is better, in new construction instances, to design
out conditions requiring this expense.
Size Joints Properly
There are four main facets related to sizing joints properly: expected
movement, functional and installation temperature range, tolerance build-up,
and movement capability. Architectural teams must also take the lead for
sizing in joint design. Often, the structural team will make recommendations
without considering a material and its movement capability and other effects
on joint design. This can be avoided if the architectural team selects a
technology and takes it to the structural team with the question, “what size
joint do we need if we seal the joint with THIS specific technology?” The
resulting joint size calculation can then take into account the movement
capability of the product or technology type to be used.
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Phillies Installment |
Take Time to Find
the Right Technology
A trend in the specialty products industry is the tendency of suppliers to
commoditize products, thereby removing much of the value essential to their
proper performance. The ability and willingness of manufacturers to offer
solutions and to fabricate watertight transitions in plane and direction,
such as up and down treads and risers, remains a rare differentiator.
Features in purpose-designed joint systems include integral heat-weldable,
thermoplastic rubber flashing sheets for “sandwiching” into deck
waterproofing materials on split-slab decks. This ensures watertightness
over occupied space below, while heavyduty aluminum or steel side rails and
stainless steel retaining capping strips allow long-term maintenance access
to the sealing insert, which in turn is designed to handle cyclical
movements.
Think and Design in 3-D
Develop isometric, line-sketch schematics to show all the joints throughout
the stadium. Include all changes in plane, direction, and intersection with
other materials. This will put the design team on the same page, allowing
all participants to identify and design out many problems before
construction begins. In addition, show axonometric details of each
transition in plane and direction, especially when illustrating transitions
between different material technologies, e.g. between a concourse deck joint
and a wall joint.
Write Project-Specific Specifications
Stadiums are not the place to use a “cookie cutter” approach to expansion
joint design. The specifications for each job must match the specific
performance demands of each venue. Make sure to stick with the plan
throughout the project to ensure technology continuity and continuity of
seal.
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Premold replaced with Thermaflex |
Contract Execution
Carefully Select Contractors
Limiting work to a select group of contractors, often those
recommended by the expansion joint system manufacturer, can be a huge factor
in ensuring watertight joint seals. Because they work closely with
manufacturers, these contractors are not likely to underbid the job, keeping
change-order cost increases to a minimum, and are likely to be versed in,
and willing to remain committed to, a communication process involving the
designer, owner representative, manufacturer and general contractor.
Emphasize Expansion Joints During All
Construction Phases
Continue to place expansion joints on meeting agendas throughout the
construction process. Many subcontractors, including electrical, HVAC,
masonry, flooring, façade panel, waterproofing and caulking, work in close
proximity to expansion joint locations and they must be aware their work
cannot impede structural movement that will occur at expansion joints or
compromise the achievement of watertightness at expansion joints in any way.
Expansion joints must be considered a critical path item, rather than an
added piece at the end of the project.
Conclusion
Sky boxes that won’t heat or cool; destroyed flat screen TVs and garbage
bags over seats in high-dollar corporate boxes; infuriated, dripped on,
highly-compensated athletes; lost concession- vendor revenue; and icy slip
hazards are among the numerous complaints stadium owners and managers have
endured as a result of leaking expansion joints.
Stadium construction is a complex process. Nevertheless, with notable new
construction successes including Citizens Bank Park, and numerous retrofit
successes including FedEx Field, Fenway Park and American Airlines Arena,
EMSEAL and others, working with like-minded owners, designers, and
contractors have demonstrated that a new paradigm for expansion joint
treatment is not only possible but also practical.
Lester Hensley is president
and CEO of EMSEAL Joint Systems, Ltd. based in Westborough,
Massachusetts. |
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