Laminated Concepts Inc.

economy • strength • durability • beauty

For over 30 years being a proud supplier of quality engineered glued laminated  timber products for the transportation industry.

BRIDGE CONSTRUCTION - LIVE !!!

   One of Laminated Concepts' latest projects is the supply of a 50' x 30' glued laminated timber stringer bridge structure to Buchanan County, Iowa. The County will be using their own crews to demolish, and construct the new bridge on GRS abutments. The interesting thing about this project is that it is being partially funded with the assistance of the Federal Highway and the National Center for Wood Transportation Structures.  (http://www.woodcenter.org)

   The folks in Iowa will be installing sensors in both the abutments and bridge superstructure to record several performance parameters used to evaluate and understand the behavior of all the parts of the GRS-IBS abutments and bridge superstructure.

   AND, they invite you to watch. The complete construction process is being monitored and is available to watch on the NCWTS's website (http://www.woodcenter.org/bec_cam/).

   We would like for you to watch the process and as always, if you have any questions or comments, feel free to contact us.

 

  

 

Timber...the material of the future??

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

To many, the idea of a 30-story skyscraper made of wood is ludicrous. Such a building would be a match strike away from becoming a towering inferno and about as struc‐ turally sound as a Jenga tower, right? If you are envisioning a massive tower construct‐ ed of two-by-four framing like many stick-built homes, you’d probably be right. These wooden skyscrapers, or woodscrapers, are being built using mass timber, a material stronger and more technologically advanced than your standard two-by-fours. Mass timber is a term used to describe a number of large engineered wood products that typically involve the lamination and compression of multiple layers to create solid pan‐ els of wood. Examples of mass timber include cross laminated timber (CLT), laminated strand lumber, laminated veneer lumber and glue-laminated timber.
Advocates of mass timber claim a number of benefits of its use over traditional steel and concrete for constructing tall buildings. If the timber is sourced responsibly, it pro‐ vides a completely sustainable and renewable building material. Carbon emissions from manufacturing mass timber products are a fraction of those created by the pro‐ duction of steel and concrete. The production of steel and concrete materials account for about 8 – 15% of global greenhouse gas emissions annually. The CO2 absorbed dur‐ ing the tree’s life remains trapped in the building product when using mass timber.

Mass timber has a natural tendency to char in a fire which slows the burning process and helps maintain structural integrity. Its resistance to fire can be further improved by encapsulating mass timber in gypsum board. Tests have shown that cross laminated timber can achieve a fire rating of three hours. Mass timber products have been proven to be as strong as, or stronger, than both steel and concrete and are consider‐ ably lighter than concrete. The thermal performance of mass timber is far superior to its steel and concrete counterparts which means lower heating and cooling costs.
Wooden skyscrapers are still in their infancy. Wooden skyscrapers are currently at the same developmental stage that steel skyscrapers were back at the turn of the 20th cen‐ tury. Current wooden skyscrapers are topping out at around 10 stories like the 10-story Forte Building in Melbourne and the 9-story Stadthaus in London. And much in the same way that steel skyscrapers got progressively taller and taller, there are already plans for taller and taller wooden skyscrapers.
Architect Michael Green has proposed and designed a 30-story wooden tower for Van‐ couver, a 35-story project called Baobab for a design competition in Paris as well as designing the 96 ft. tall Wood Innovation Design Centre which completed construction last year. C.F. Møller designed a 34-story wooden skyscraper that could get built in Sweden and the HoHo project, a 24-story, 276 ft. project could be built in Vienna next year. In Bergen, Norway, a 14-story building is currently going up constructed of CLT and glulam.
The USDA launched the U.S. Tall Wood Building Prize Competition last year with a prize purse of $3 million to demonstrate the architectural and commercial viability of using sustainable wood productions in high-rise construction.
The architectural firm of Skidmore, Owings & Merrill (SOM) has explored the possibili‐ ty of tall wood buildings as a sustainable alternative to building with steel and con‐ crete. SOM are tall building experts, having designed iconic skyscrapers such as the Willis (Sears) Tower and One World Trade Center. SOM published a research paper in 2013 to demonstrate that a 42-story building could be built using cross laminated tim‐ ber for the floors, central core and shear walls and glue laminated lumber, or glulam, for the building columns. Concrete beams would be used along perimeter of each floor. The design was based on the SOM-designed Dewitt-Chestnut Apartments.
Wooden skyscrapers could command a large market in the future, provided they can prove to be a viable alternative at 40 stories or more. Wooden skyscrapers and mass timber skyscrapers could be the ultimate eco-friendly alternative to their concrete and steel counterparts.

Solutions......

  • BRIDGE PROBLEM & CRITERIA:
  • 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.

Wood and Water (Part 2)

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.

Copyright  2017 LCI.