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COMMONLY USED TIMBER BRIDGE CONSTRUCTION TERMINOLOGY AND CONSTRUCTION GLOSSARY

AASHTO

Definition: The American Association of State Highway and Transportation Officials. This nonprofit, nonpartisan agency writes the code that governs highway design. It covers all bridges from county roads to interstate bridges. Its guidelines provide important information about the load capacity and usage requirements of vehicular bridges in the 50 states, the District of Columbia, and Puerto Rico.

ACQ

Definition: (Alkaline Copper Quarternary) - a water-based wood preservative used by Bridge Builders to prevent lumber decay from fungi and insects.

Camber

Definition: the arch of a surface, sloping downward from the center toward the sides.

CCA

Definition: (Chromated Copper Arsenate) - a chemical wood preservative containing chromium, copper and arsenic. CCA is used in pressure treated wood to protect wood from rotting due to insects and microbial agents and increase the longevity of your bridge.

CuNap

Definition: (Copper Napthenate) - a historically proven, oil-based preservative treatment for wood products. It is basically the reaction product of a copper compound with napthenic acid. CuNap seals and protects against water damage, rotting, insects and many other dangers.

Dead load

Definition: the static load imposed by the weight of the materials that make up a given structure

Clearspan

Definition: a bridge that is supported only on both ends of an embankment and not in the center section with a pile.

Glulam

Definition: a stress-rated engineered wood product comprised of wood laminations, or "lams." Special bonding techniques using strong, waterproof adhesives allow individual lumber pieces to be joined end-to-end to span long distances without intermediate columns. Glulam beams are much stronger than sawn lumber. The laminating process allows timbers to be produced in a variety of shapes from straight beams to graceful, curved arches. Glulam timber is a more attractive way to span long distances compared with concrete or steel.

GVWR

Definition: (gross vehicle weight rating) - the maximum allowable total weight of a road vehicle or trailer when loaded - i.e., including the weight of the vehicle itself plus fuel, passengers, cargo, and trailer tongue weight. GVWR expresses the maximum continuous load for vehicles traversing a bridge.

HS20-44

Definition: a designation established by AASHTO. “HS” refers to the type of vehicles a bridge or highway can accommodate; “20” refers to the loading specification of the bridge; “44” indicates the year the specification was adopted. HS20-44 capacity means that the bridge or highway is able to safely accommodate 3-4 axle vehicles, such as a large semi-truck and trailer. All Bridge Builder Timber Vehicular Bridges meet these AASHTO requirements. Bridge Builders can also design HS25-44 Timber Vehicular Bridges, which are able to accommodate a much higher continuous loading capacity.

KDAT

Definition: Wood that is dried in a kiln after pressure treatment to control the rate of drying so that stresses that might otherwise result in splitting, warping, or twisting are minimized.

Live Load

Definition: a moving, variable load on a structure (e.g. a bridge) such as moving traffic or pedestrians, usually expressed in terms of pounds per square foot.

Penta

Definition: (Pentachlorophenol) - the most commonly used oil based preservative used to pressure treat and wood and guard against decay and word-boring insects. In the non-pressure process method pentachlorophenol is applied by spraying, brushing, dipping or soaking.

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Testimonial

Kevin H. Forbes
P.E., Director of Engineering
Indianapolis Motor Speedway, L.L.C.

Please accept this letter as our sincere appreciation for your recent efforts in quickly repairing one of our bridges damaged by a torrential rainstorm early in the spring of this year. Your quick response to this matter was a crucial step in opening the race track for this year's Indianapolis 500. Our appreciation and respect for your company as well as our relationship goes all the way back to 1991 when we first worked together during the reconstruction of our golf course.

Since 1991, you have completed three projects for us, the latest of which, was repairing a bridge you previously built in 2004 - a bridge damaged during a 200 - year rainstorm. However, even though the repair was, for you, a small, troublesome and complicated project, you still regarded us as though this was your first opportunity to work for a new and sought after client. The quality of your work is exacting and consistent no matter what size or complexity the project, and is exceeded only by the caliber of the people in your organization. It is that kind of unfailing attention and careful regard for a client that sets an organization apart from their competition, and it is those very same reasons that keep us returning to you.

Again, thank you for having the vision, philosophy and resources required to drive an organization that truly recognizes the regard for their clients while delivering a product with superb and consistent quality.