The Cathedral of Christ The Light

When the Cathedral of Francis de Sakes was rendered unusable following the 1989 Loma Prieta earthquake, the Archdiocese wanted to build a new Cathedral with a 300 year design life span. Glulam was selected as the main structural building component for its strength, durability, and aesthetic appeal.

The roof is composed of a large steel compression ring and a glass oculus. The oculus is supported by glass enclosed Glulam space frames consisting of 10-3/4” x 15” Glulam mullions that measure 103’ in length, 10-3/4” curved Glulam ribs that vary in depth from 30” to 19-1/2” and measure 97’ in length, and pre-tensioned steel rods that were manufactured in Germany.

Lathe turned Glulam compression struts connect the outer mullions to the interior ribs. Glulam louvers that vary in depth from 22-1/2” to 39” are set between each rib at seven different angles to optimize light effects.

Special attention was given to the appearance of the Glulam products. Lumber was hand selected by the manufacturers to minimize knots and voids on the exposed surfaces. Any voids were then left natural since standard fillers used to bring Glulam to Premium Appearance is often objectionable.

Western Wood prepared 67 pages of shop details from a three dimensional computer model to fully describe the Glulam components. In total, there are 26 vertical mullions, 26 curved ribs, 720 louvers, and 88 compression struts. The frames are connected with 249 unique steel assemblies and 42 unique rod assemblies.

Each Glulam member was pre-fabricated off site and many of the steel connector assemblies were plant installed to reduce jobsite costs. There were nearly 15,000 holes to pre-drill, all of which had to be accurately located. A hundegger machine was used to fabricate the louvers while the struts, ribs, and mullions were fabricated by hand. The long, curved ribs were trucked to the site from Minnesota and the rest of the Glulams were manufactured and fabricated in Oregon.

The jobsite’s proximity to busy downtown Oakland contributed to the construction challenges faced by Western Wood crews but assembly and erection of the Glulam system was achieved in just 3 months.

Wood Design & Building article.

Glulam Specifications

Specifications for Glued-Laminated Timber or “Glulams” are usually found in Division 06180 of the CSI numbering format. Specifications are written by the specifier in order to establish the standards by which the supplier or installer of the product is expected to adhere. We are providing a sample specification for those who wish to keep current as many things have changed over the years. By clicking on the link below you will be able to view and copy this sample specification.

The Ford Foundation Building

Roseburg, Oregon







Specifications of Glued-Laminated Timber Sample

Lower Burnett Road Bridge

The Foothills Rails-to Trails coalition of Buckley, Washington working in conjunction with Pierce County, had been seeking a link to connect the north and south sides of the Foothills Trail to replace the original railroad trestle that had been removed some years prior. The result is this stunning Arched Bridge that Western Wood Structures designed, fabricated, and installed.

The use of 3D modeling made possible for the bridge components to be fully fabricated prior to pressure treatment which in turn allowed Western Wood crews to complete the complex installation in less than two months. The overall length of the 3-span bridge is nearly 400 feet including approach spans and when complete the trail will measure more than 28 miles in length.

The use of pressure treated Douglas Fir Glulam as a bridge material perfectly complements the natural beauty of the wooded site.

STRUCTURE Magazine, October 2010 article

Dominion Creek Trestle

This 100 year old former Milwaukee Railroad trestle that once carried freight trains through the Montana backcountry is being retrofitted as part of a Rails to Trails project to accommodate bicycles, ATVs, and snowmobiles. This project was made possible thanks to $850,000 in Federal stimulus funding and will open miles of the Milwaukee Road passage through the dense forest toward St. Regis, Montana.

Western Wood Structures supplied the pressure treated 6.75” thick Glulam deck panels which were segmented to match the curve of the trestle. The walkway, which measures about 650 feet and rests 100-feet above Dominion Creek, is 12’ wide with 3-foot pedestrian walkways on either side. The project will be 80% complete before the snow flies this year with final completion scheduled for next spring.

The General Contractor is Dick Anderson Construction of Great Falls, Montana. Western Wood Structures met the tight shipping schedule by having the pressure treated Douglas Fir Glulams delivered in 8 to 9 weeks.

Nisqually River Estuary Boardwalk

Federal stimulus money was used to finance construction of the Nisqually River estuary boardwalk at the Nisqually River National Wildlife Refuge. The mile-long boardwalk is nearly half done and when complete it will be used to provide access out into the world of mudflats and tidal sloughs teeming with marine life and birds.

The project has reclaimed about 762 acres of the refuge, turning the delta back into the estuary and saltwater marsh it was before it was diked 100 years ago to create farmland. The goal is to restore habitat for salmon, shorebirds, and other creatures that thrive in estuaries.

The boardwalk superstructure is constructed from pressure treated Douglas fir. The preservative is ammoniacal copper zinc, or ACZA, which is approved for use by the U.S. Environmental Protection Agency. The decking is Port Orford Cedar Glulam. The boardwalk will have a life expectancy of 50 to 75 years. The U.S. Fish & Wildlife Service considered re-cycled materials for construction of this boardwalk but wood was chosen for its durability and strength.

Western Wood Structures designed this timber boardwalk and is in the midst of fabricating and shipping materials as of this writing. The General Contractor is Five Rivers Construction of Longview, Washington.

Award Winning Bridges

Western Wood Structures has been designing and selling treated timber bridges for 40 years. We have been fortunate enough to have been involved in some very interesting projects and our bridge sales have led us to nearly every state in the union plus Japan, Taiwan, and China. We are proud to show off some of our award winning bridges.

Award Winning Timber Bridges

The Anaheim Ice Arena

Engineered wood was chosen by Architect Frank Gehry for construction of the Anaheim Ice Arena for two reasons: budget and aesthetics. According to the Matt Construction, General Contractor, structural steel had originally been selected as the primary structural building product but the owner’s budget could not be met with steel. So after consulting with Western Wood Structures the switch to Glulam took place and the result was an affordable building that is aesthetically pleasing.

Eleven rows of large double-curved Glulam beams spaced at 24’ centers span two ice rinks in a saddle-shape. The main Glulams follow the curved shape of the exterior building profile and from the outside the curvature of the roof system resembles “mouse ears” a look that the owner, Disney Development, was seeking.

Moment splices were utilized to facilitate shipment of the curved Southern Yellow Pine Glulams from Albert Lea, Minnesota to downtown Anaheim.

The purlins are solid sawn Douglas fir timbers spaced at 48” centers and the roof sheathing is 1-1/8” T & G plywood. Installing the thick plywood to the 75-foot radius of the roof structure was not an easy task. The end walls are constructed of Glulam columns, sawn timber horizontal girts, and ½” fire retardant treated plywood. The arena meets the city fire codes because it is designed as Heavy Timber construction.


The dual rink facility has an NHL sized ice rink to meet the practice needs of the Anaheim Mighty Ducks and an Olympic sized rink to meet the community recreational skating needs as well as youth hockey leagues. Western Wood Structures installed this 88,000 s/f roof system in just 3 months.

Anaheim Ice Rink Case Study

Portland Bulk Terminals

Western Wood Structures was awarded a contract in 1995 to design and construct a Heavy Timber building on the banks of the Willamette River at Terminal 5 on property owned by the Port of Portland. The clear-span building measured 160’ x 1475’ and is used to store potash, a salt-like fertilizer that is mined in Eastern Canada, railed to Portland, and stored until ready for export across the Pacific.

Potash is highly corrosive to metal which makes engineered wood the perfect choice of building components. The steel connections used in this building required a special three-step epoxy coating to protect it from exposure to the potash. A metal building for an application such as this would have been cost prohibitive.

Glulam Arches are spaced typically at 32’ centers to carry the main roof loads. Glulam purlins are spaced at 4’ centers between the Arches and the roof is sheathed with 1-1/8” T & G plywood. All city fire codes were satisfied due to the Type IV Heavy Timber design employed.

Each Arch was pinned at the concrete abutments and at the top as well. This allowed for much of the roof framing to be accomplished on the ground making erection much easier as the frames were lifted and pinned in pairs.

One end wall was panelized in sections in anticipation of future expansion. It was planned that this wall would some day be dismantled and re-used when the building was added on to.

In 2006 Western Wood was awarded the contract to design and construct the anticipated addition. This addition increased the length of the existing structure by 608’ resulting in a building that now measures 160’ x 2155’. The building is now the equivalent of six football fields in length. The floor area is now 344,800 s/f and to our knowledge this building is now the largest wood framed clear-span building in Oregon. By comparison, the Tillamook Air Museum which was originally built as a blimp hangar in the 1940’s, measures 296’ x 1072’ and has a floor area of 317,312 s/f. The Chiles Center dome at the University of Portland, also a WWS project, is the largest clear-span timber building in Oregon that we know of with a diameter of 305’.

Portland Bulk Terminal Case Study

Alaska Airlines Hangar

Western Wood Structures received an inquiry from the Facilities Project Manager of Alaska Airlines in January of 2006. He contacted us because the Bowstring Trusses in their Anchorage aircraft hangar were failing. These trusses had been evaluated and “repaired” less than three years earlier and as it was presented to us “the previous structural improvements were apparently insufficient to prevent additional failures.”

The first step in meeting the needs of this client was to make a site inspection to evaluate the condition of the trusses and to map out their configuration as the original drawings were not available. Based on this initial inspection, we recommended shoring of the entire roof system be installed immediately. We then completed a structural analysis which enabled us to make the required repair recommendations and our proposal to perform these repairs was accepted.

The original hangar was built in 1954 and the hangar was added on to several years later. As a result, there were two types of Bowstring Trusses in this building – Arch Teco Trusses that were constructed from solid sawn lumber in a multiple leaf system and Tim Trusses which were constructed from Glulam. The repairs were extensive and included the following:

• All of the lower chords in the Arch Teco type trusses were replaced. The lower chords of all trusses were post tensioned using ½’ high strength cable to reduce the tension stresses in the wood members.
• All webs that exceeded an L/d ratio of 50 were stiffened by adding new structural members with screws and epoxy.
• The top chords of all trusses were strengthened by adding structural members to the sides with lag screws and epoxy.
• All web to top & bottom chord connections were strengthened using structural steel shapes.
• T-Struts were added to the lower chords of all trusses because the post tensioning cables placed the lower chords in compression.

From experience we know that Bowstring Trusses of these types have been affected by a series of changes that have rendered many of them as “dangerous members” as defined by International Existing Building Code which is further explained here. The factors described in this article contributed to the problems in this building but issues which were specific to this project added further. For instance, over framing was added which increased the dead load significantly. In addition, a drifting condition was introduced to the structure when new bay doors were added to the ends of the building. Finally, the snow load in Anchorage had been increased by code from 40 psf to 70 psf since the original building had been built.



Now that the repairs are completed, the trusses are in better condition than they day they were built and Alaska Airlines can count on the use of their hangar for many years.

Western Wood Structures was sought out for this project because of our expertise in this type of work and because we carry both an engineer’s license in Alaska as well as a contractor’s license. And it’s always rewarding to receive a nice letter from a client following the completion of a project.

The Cosumnes River Bridge

Welcome to “Working Wonders With Wood”. My goal with this is twofold: 1) to utilize this space to spotlight recent projects that Western Wood Structures has been involved in, and 2) to make an attempt to keep people abreast of recent developments and changes in our industry.

Western Wood Structures is a sales and engineering company founded in 1969. Our product lines include timber bridges, heavy timber trusses, Arches, Glulam beams, and laminated decking with our primary focus on the commercial market. Many of the projects we sell are designed in house. We also fabricate some of the projects we sell in our shop as well as install some of them with our own field crews. Sometimes we act as a material supplier and sometimes as a sub-contractor depending on factors such as project location, current work load, and customer needs. It is not uncommon for a project to start out as conceptual and pass through every department here from sales to engineering to fabrication shop to our guys in the field after it becomes an order.

Western Wood Structures offers inspection services of existing timber buildings, primarily roof systems. We are often hired to make a site inspection, run an analysis, determine the cause of any problem, and make remedial recommendations. We can then design and implement structural repairs and code upgrades to timber beams and trusses which usually involve post tensioning, shear dowel reinforcement, or other strengthening methods. There will be more on this subject another time.

This first monthly entry will focus on one of our many outstanding timber bridges: The Cosumnes River Pedestrian Bridge outside of Rancho Murieta, California. This bridge measures 410’ in length with a center span of 200’ and side spans of 105’. It is 12’ wide and was constructed primarily for pedestrian traffic, golf carts, and bicycles but it is also designed to carry a 10,000 lb. maintenance vehicle. It was required by conditional use permit when property in the Rancho Murieta South housing development near Sacramento was developed for residential use.

Western Wood Structures worked under a General Contractor, Viking Construction of Rancho Cordova, CA. Quincy Engineers of Sacramento was responsible for the civil work as well as the design of the concrete abutments.

The main carrying members are Glulam Trusses. The main span features bowstring trusses while the outer spans are parallel chords. The top chords feature a reverse continuous curve to form a flowing appearance. The curved shape of the bridge was proposed by WWS to provide a deep section in the main span as well as a smooth transition to the outside spans. The reverse in curvature begins in the side span and the point of reversal takes place in the first top chord splice in the main span. A continual graceful curve from end to end was achieved and of course splices were introduced to allow for shipment and pressure treating. The curvature gives this massive bridge a sleek appearance. Glulam floor beams support the 2-1/2” thick Glulam deck panels to form the deck and the floor beams are located at panel points so the trusses are not point loaded.

The analysis determined the radii of the truss top chords and this information was transferred to our fabrication shop where they trusses were laid out, fabricated, and match-marked. All holes were drilled in the Glulam prior to pressure treating using the steel as templates which allows for a proper treating envelope around the entire member. This extra step will help to protect the member from insect or fungal attack. Western Wood Structures believes that a treated timber bridge will easily have a life span of 75 years if it is pressure treated, fabricated before treatment, and properly maintained.

Western Wood Structures crews assembled each truss on site including much of the deck prior to erection. Viking Construction was able to build a crane pad near the river to allow the crane to set up near the main span thus minimizing the reach of the main span which weighed almost 130,000 lbs. representing the heaviest lift Western Wood Structures has ever made. Each side span was just under half this weight. Jobsite assembly and erection took a 5 person crew six weeks to complete.

This magnificent treated timber bridge is not only functional and affordable but was also able to achieve all of the aesthetic requirements of the project. It provides the access needed for the residents while allowing greater utilization and appreciation of the community’s waterway.

We are very proud of the awards this bridge has won since its completion. It earned a Merit Award of Engineering Excellence from the Consulting Engineers and Land Surveyors of California [CELSOC] in 2008. And just last month it earned a Timber Bridge Design award from the California Region of Woodworks in the non-residential category.

I hope that you will check back monthly. We welcome your questions and comments.