We were sent an email today (containing an article posted below) about the use of timber as a building material for large commercial buildings . The article was originally posted in the Fall 2015 issue of Construction Data Quarterly. Although this idea has been in the works for a few years now, I was impressed reading it. Then and now.
The advancements in timber or should I say the advancements in engineered timber design and manufacturing, are securing a spot for this construction material in the Country’s infrastructure. It's also one of the few products that can truly boast entirely made in the USA. With its low carbon footprint, renewable, managed supply chains and competitive pricing, timber will shine as its introduction into the larger commercial building structures. Something that those of us involved with engineered timber highway structures….bridges….have known all along.
Towering Timber: Will Future Skyscrapers Be Made Of Wood?
Posted on March 18, 2016 by Kendall Jones+ in Construction News
1 week maximum road closure from demolition to opening for traffic
2 day maximum bridge superstructure construction schedule
LRFD HL93 loadings, Crash Tested Guide Railings and meeting the hydraulics of the existing superstructure.
SOLUTION:
Pre fabricated, Stress Laminated Glu Lam Deck.
For a County in New Jersey that is exactly what was chosen for this 42'-0 bridge span. The bridge utilizes treated glued laminated beams placed side by side with field installed transverse stressing rods, stressed to a predetermined level. Using stressed beams instead of systems like a stringer bridge with transverse deck, allow the depth of structure to be kept to a minimum, matching the previous structures depth.
The bridge is designed with a 10° skew to align with the stream profile. Stress laminated decks require that the stressing rods are placed perpendicular to the bridge structure. Each beam had to have different fabrication performed due to them being offset from the adjacent beams.
All the holes were predrilled at the plant prior to pressure treatment.
Within the first day, all beams were set and aligned. The high strength rods were installed then stressed.
The second day was left to assemble the Crash Tested guide railing and anchor the bridge to the concrete abutments.
A 36’ long x 10’ wide Pedestrian/Vehicular bridge structure is loaded out of Laminated Concepts Inc.’s facility in Big Flats, heading to Port Byron, NY as part of the Port Byron Old Erie Canal Heritage Park Project through the New York State Thruway Authority.
The all wood structure was manufactured and assembled at our yard facility in Big Flats for general contractor, Cold Spring Construction of Akron NY
To continue the conversation of water protection of wood, I would like to discuss Glu Lam transverse decking. Transverse decking is used on structures with steel stringers as well as timber stringer bridges making it probably the most common type of timber bridge component used. Due to the nature of the timber deck orientation, the deck ends (which contain all end grain) are exposed to the elements, rain, snow & ice as well as water runoff from the roadway surface.
Protection of this face of the panel is important to the longevity of the material itself. You always have to look for ways to keep the material dry and stable.
The following are some pictures of a recent deck project where pre bent metal drip edges were manufactured and placed on alternating panels where scupper opening will occur. Our hope is that the panel end grain will be protected from any water run off. This detail can be used on decks that do not have alternating panels as well. Note that installation is required prior to rail placement.
Just a quick note for this construction season. It doesn't require a lot of time or money to help protect your timber structure from water. A simple drip edge, placed at the scupper openings prior to membrane and paving, will help protect the deck face from water runoff.