Engineers from FPL and the VA Inspect 134-Year-Old Milwaukee Medical Center Building

The first building in what is now the Clement J. Zablocki Veterans Administration Medical Center (VAMC) in Milwaukee, Wisconsin, was originally approved for construction by President Abraham Lincoln just one month before the end of the Civil War, for the care of disabled soldiers. That structure was completed in 1869.

Originally called the National Home for Disabled Volunteer Soldiers and nicknamed the “Old Main,” the Zablocki VAMC now consists of 20 buildings.

Adam Senalik, FPL Engineer, visually inspecting the studs of a wall on the top floor of Building 7 at the Zablocki VAMC.

Last week, it was time for an inspection of Building 7 – the Soldiers’ Home. Like Buildings 2 and 5, it was built as a barracks for soldiers receiving care at the Milwaukee Soldiers Home. Consisting of three stories and a large basement foundation, the Soldier’s Home, designed by celebrated architect Henry Koch, was ready for business in 1888. Building 7 now supports the offices of the Compensated Work Therapy Department. New IT requirements require the VAMC to update the structural integrity of some of the older buildings.

Bob Ross, FPL Engineer, investigating the structural members in the wall system on the top floor of building 7. Note that the outer layers of the wall have been removed to expose the structural members.

To that end, Forest Products Laboratory Research General Engineers Bob Ross and Adam Senalik took the 90-minute drive to Milwaukee to join Erik Billstrom, on-site engineer for the VA, to carry out the necessary structural analyses.

Erik Billstrom, VA engineer, examines a large white pine timber in the high ceiling of the basement maintenance room and finds he is easily able to remove wood samples by hand.

According to Bob and Adam, FPL regularly receives requests for structural condition assessments, mostly dealing with historic wood structures, structural assessment, inspection, and assignment of allowable design values.

“We usually try to provide direct assistance to other Federal agencies and Departments,” said Bob. “This is especially true for the DoD and Veterans’ Administration.

“What matters most here,” added Bob, “is that this campus does good things for veterans.” The Zablocki VAMC serves more than 64,000 U.S. veterans every year.

Bob added that the book he coauthored, Wood and Timber Condition Assessment Manual, now in its second edition, summarizes structural condition assessment research currently used for wood and timber structures. The publication can be found at:  https://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr234.pdf.  A previous FPL LabNotes article provides a summary of the manual here:  https://www.fpl.fs.fed.us/labnotes/?p=4599.

Bob Ross reveals a deteriorated nail from the basement ceiling

Starting on the third floor of building 7, the three engineers began to examine the condition of the walls and ceiling.

“It’s in pretty bad shape,” said Adam. “But about what we expected.” Previous engineering analyses had found that the structural beams were not designed for heavy weight. 

The group then climbed up into the dark attic above the third floor and removed a few samples of wood. The blackened strips of wood appeared as if they had been in a fire.

“Maybe they were at one time,” observed Bob. “Further analysis will tell us.”

Satisfied with their inspection and the samples they had acquired, the analysts moved down to the utility room on the basement level. Here, the late 19th-century origins of the building were even more apparent, with period arches and a brick wall that had survived more than a century of water damage. The wall appeared not unlike a medieval dungeon in its heavily “blurred” condition.

Erik set up and climbed a tall step ladder to examine a large white pine timber across the ceiling of the basement. He reached in and was able to effortlessly lift spacers out of the surrounding structure. Finally, the three engineers placed all their gathered samples into large, labeled plastic bags.

“It was a good inspection,” Adam concluded. “I only hope that this building can be saved.”

Reducing Wildfires through Better Utility Pole Inspections

They can pop up almost anywhere.

“They” are wildfires, which can result in loss of human life and lead to billions of dollars of property damage every year in the United States.

Hundreds of failures in electrical utility poles across the nation are one of the leading causes of these disasters. In Idaho alone, nearly 300 wildfires have been caused by utility pole failures in the past 15 years – an average of 20 wildfires every year.

Electrical utility pole failure is one of the leading causes of wildfires nationwide. The sheer number of poles involved makes regular inspections challenging – but the Forest Products Lab is finding new ways to carry out pole inspections quickly and easily. (Forest Service photo)
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Investigating CLT’s Ability to Fight Fungus

The growing reputation of cross-laminated timber (CLT) as a sustainable, cost-effective, and innovative building material has prompted researchers at the Forest Products Laboratory (FPL) to build upon past research and investigate the material’s ability to fight against fungus.

Intact cross-laminated timber panel section (left); 4-in. cube cut from panel section for scaled-up decay testing.

(A) Intact cross-laminated timber panel section; (B) 4-in. cube cut from panel section for scaled-up decay testing.

Praised for its many benefits, including speed of construction, cost, sustainability, excellent thermal and sound insulation, and fire restriction qualities, the pre-fabricated building material has made a name for itself in the construction and worldwide mass timber market. CLT has already made an appearance in a variety of high-rise apartment buildings in the Pacific Northwest and Southeast United States, urging scientists in the Lab’s Durability and Wood Protection Unit to further examine how the timber fairs against a rainy, humid climate.

The study builds upon past conclusions that untreated CLT is susceptible to mold and a variety of fungi. While decay can be reduced with preservatives such as boron, researchers are using more methods to investigate resistance treatments.

Scientists have implemented soil block assay tests on numerous random samples of CLT, and also plan to conduct mass loss and x-ray density profiling to assess decay in CLT.It is hoped that this exploration will help researchers develop more targeted fungal reduction methods for CLT.

The project will conclude in early 2017.  For more information on CLT and fungal resistance, read the full Research in Progress report.

Blog post by Francesca Yracheta

Decayed Wood Does Not Hold Paint: Contractor Tips From FPL

The following was adapted from the Forest Products Laboratory’s Wood Handbook, Wood as an Engineering Material.

Decayed wood does not hold paint. Although this may be self-evident to some, it is one of the main tips researchers at the Forest Products Laboratory (FPL) have for contractors across the nation. Even in new construction, where new wood is expected to be free of decay, contractors can do several things to keep it that way.

If possible, paint all end grain surfaces with an oil-alkyd primer, such as the ends of siding and trim, brick molding, railings, balustrade, posts, beams, and edges of panel products.

When repainting, inspect wood for decay. Problematic areas include end grain of balustrade, brick molding, siding that butts against a roof, and the bottoms of posts on porches. Decay often occurs in the center of the wood, so the surface can appear sound; probe several areas with an ice pick to ensure the wood is sound. Replace boards having decay.

Decay and paint failure in a wood railing. Decayed wood does not hold paint.

Siding intersecting a sloping roof should have a gap (50mm) between the end grain of the siding and the roof shingles. Check for a finish on the end grain; if there is no finish, treat the end grain with a water-repellent preservative (WRP), prime, and top-coat. If there is already a coating on the end grain, keep it painted.

End grain of siding that butts directly against roof shingles (not a recommended construction practice) is not accessible for painting, however you can try to wick WRP into the end grain from a wet brush.

Insects seldom cause problems with finishes. However, when repainting a structure, it’s a good idea to inspect it for termite tunnels and carpenter ants. A termite tunnel is a sure sign of infestation.

Presence of carpenter ants may indicate decay in the structure. Carpenter ants do not eat wood, but they often tunnel out decayed areas to build their nests. Note that woodpecker holes often indicate insect infestation, as woodpeckers will destroy the wood to get to the insects beneath.

For more information, please see chapter 16 of FPL’s Wood Handbook, Wood as an Engineering Material.

Wood vs. Water: Who Will Win - the Cabin or the Creek?

One thing we know for sure at the Forest Products Laboratory (FPL) is that wood and water don’t mix, and keeping wood dry is essential to long service life. So really, 80 years seems like a good, long life for a log cabin built with untreated logs, situated just 10 meters from a river in an area with high snowfall, and subjected to the subsequent spring melting that follows each winter. For this cabin, maintained by Michigan Technological University’s School of Forest Resources and Environmental Science, staying dry has been nearly impossible.

Otter River cabin, 2013.

Otter River cabin, 2013.

Situated on the north branch of the Otter River in the Portage Township of Upper Michigan, the cabin was built in 1934-1935 by the Civilian Conservation Corps and housed workers who used the site as a trout hatchery. In 1955, it was transferred to Michigan Tech with promise that public rights of hunting, fishing, and trapping would be maintained. Over the years, continuous maintenance was needed due to periodic flooding and the resulting log deterioration.

Since 1998, Michigan Tech and FPL have cooperated to conduct periodic inspections of the cabin. The latest inspection, completed in 2013, utilized various techniques to analyze the condition of the log cabin.

Some decay was obvious with visual inspection alone.

Some decay was obvious with visual inspection alone.

Visual inspection is the simplest method for locating deterioration. Here, researchers look specifically for evidence of water intrusion and damage, especially near the foundation, and evidence of structural failure of the timbers. Many of the logs showed signs of severe deterioration, with the ends of several having been entirely destroyed.

Sound transmission measures the time it takes for stress waves to travel between sensors placed on opposite sides of a timber. Significantly longer transmission times, relative to the base times known for several species, indicate the presence of deteriorated wood. Nearly half of the tested logs produced results in the ‘deteriorated’ or ‘severely deteriorated’ range.

Micro-drilling resistance test of wall timber.

Micro-drilling resistance test of wall timber.

Micro-drilling resistance is a commercially developed technique based on the underlying premise that degraded wood is relatively soft and will have low resistance to drill penetration. Researchers conducted micro-drilling resistance tests in areas of the timbers they believed contained decayed wood based on results from the visual assessments and stress-wave testing. Test results showed that many logs were deteriorated, with most having an outer shell of solid material but a severely degraded core.

In the end, these test results showed that water had finally won the war over wood. Researchers recommended the cabin be dismantled, salvaging any possible historic materials (hardware and any sound timber), and suggested a smaller structure be built on the site using the salvaged materials where appropriate.

For more information on the project, see this FPL Research Note.