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Making A Difference
This past weekend, ETC participated in our first annual DogFest Walk’n Roll for Canine Companions. Founded in 1975, Canine Companions for Independence is a non-profit organization that enhances the lives of people with disabilities by providing highly trained assistance dogs and ongoing support to ensure quality partnerships. Canine Companions is the largest non-profit provider of assistance dogs, and is recognized worldwide for the excellence of its dogs, and the quality and longevity of the matches it makes between dogs and people. The result is a life full of increased independence and loving companionship.
ETC is proud to announce we exceeded our fund raising goal with contributions of $2,820.00 With 17 walkers and support from the entire company, we were able to have tail-waggin good time while enhancing the lives of others. We look forward to continuing our fund raising efforts for Canine Companions throughout the year. Be sure to watch our blog!
If you would like to find out more information about Canine Companions for Independence or to simply make a donation, please visit:
Changing Lives…One Dog At A Time
Most things are more fun with friends… and dogs! That’s why ETC has put together a team to participate in Canine Companions DogFest Walk ‘n Roll (9.12.15 | 10:00am | Arlington, VA). Together we’ve set a fundraising goal to help fund the work of Canine Companions for Independence. If you are up for the challenge, join our team. Or you can simply donate online and support our team (or any individual). It all goes towards the goal of giving more people with disabilities the experience of love and independence that comes with a highly trained Canine Companions assistance dog. DogFest… it’s a tail-waggin’ good time –
Time To Caulk?
Applying caulk to stop leaks is not always a good thing. Sometimes it makes matters worse by trapping water in the building façade instead of letting it drain. Here are a few areas where NOT to caulk:
*Along window or door head lintels on brick facades – leads to advanced corrosion of the steel support and either rotated/deflected steel or cracked bricks.
*Soffit (ceiling) of elevated concrete slabs (i.e. balconies, parking garage slabs) – traps water in the concrete and accelerates corrosion of the embedded steel and deterioration of the concrete
*Over/covering window weep holes – prevents windows from draining properly
Strengthening Concrete with Fibers
Fiber-reinforced polymer or FRP, is a concrete repair material that has been growing in popularity in the United States for close to 25 years now. FRP, as its name implies, is a polymer material with carbon, glass or steel wires imbedded in a polymer resin. The question is what is it good for? Often, concrete structural elements – slabs, beams, or columns, – that compose a building, will occasionally need to be strengthened due to a change in usage or loading. The typical remediation for such conditions includes the installation of structural steel frames and other elements, to provide additional strength support for the existing concrete. However, FRP is an alternative that is able to provide strengthening effects, with much lower weight. FRP can be applied to the surface of the element to provide support, via two methods. In both methods careful attention to proper surface preparation must be taken, including a primer coating to penetrate the substrate and enhance bonding ability. In some cases, an epoxy putty application is applied to create a more even bonding surface.
- FRP fabric can be applied on site by combining the fibers and liquid polymer resin, and utilizing a wet lay-up process.
- They can also be pre-manufactured off site and arrive as bars, plates, and rods and glued to a structure.
After application, the FRP becomes an integral part of the structural element providing both flexural and shear strengthening, or column confinement and ductility. The increase in structural capacity from FRP is due to the ability of the resin to transfer loads to the fibers, and the fiber’s large capacity to carry tensile loads, varying from 2-5 times the capacity of steel. So why FRP? Despite having a higher material cost than traditional strengthening methods, the reduced installation time, equipment utilization and labor can offset the higher material cost especially in areas with limited access, which would explain the increased usage of FRP over traditional methods.
Using Natural Cement to Preserve our Historical Infrastrcture
With the industrial Revolution, concrete began to be an essential piece of United States’ infrastructure. The need of large masonry buildings exploded the natural cement (a hydraulic cement made from limestone) production in the Americas. During the1890s, nearly 3 billion pounds of natural cement were produced and the demand continued to increase.
The most prolific cement production was centered on Rosendaletown, NJ, where cements became known as Rosendale cements. However, due to the high demand of cement, other options such as Portland cement, became available and overtook the market.
In 1976, natural cement became unavailable, and it remained absent for nearly 30 years. Natural cement is now being used as a restoration material of historic structures. Natural cement masonry mortar was used in the restoration of the Washington Monument and the wings of the U.S. Capitol. It also has been used for repointing the historic South Range of the American Museum of Natural History in New York.
The re-emergence of natural cement offers a variety of applications for building restoration processes preserving and protecting the authenticity of historical structures.
Epoxy Injection
Cracks are common sign that structural failure may be occurring and can lead to multiple problems such as leaks, façade deterioration, foundation instability, etc. How can we address them?
Epoxy injection is one of the most common approaches to address cracks in structures. Structural restoration using epoxy injection had been used for decades as a system for fusing a damaged element back together thus restoring the original strength, quality and load capacity of a concrete, masonry, or wood structure.
The proper selection of the epoxy injection material depends on the width of the crack and the causes of the crack. Epoxies have different viscosities which are intended to be placed in a variety of applications. Usually, thinner (less viscous) epoxies are placed in thinner cracks, while thicker (more viscous) materials are used in wider cracks.
Epoxy injection can create an impervious seal to air, water, many chemicals, debris, and other contamination that is stronger than the parent material. The injection can also help to thwart water leakage through concrete structures and prevent corrosion of reinforcing steel by protecting it against moisture.
However, a misconception we often encounter is that epoxy can be used to seal leaking foundation wall cracks. While leaking wall cracks can be injected to stop water infiltration, epoxy is the almost always the wrong material for this application. A future posting will discuss the injection of leaking cracks.
Also keep in mind that epoxy injection will not be effective, long term, if the crack is active. Before injection, the cause of the crack, i.e. over loading, corrosion, etc., must be identified and properly addressed. If the cause of the crack is not remedied, the injected element will likely crack once again, near the repair
The Ivy League
Aesthetics notwithstanding, there are potential problems associated with ivy-covered walls.
* Tenrils of ivy will find & enter cracks/breaks in masonry. As the tendrils grow, they can exert enough pressure to break or dislodge bricks & mortar. This is especially true for older masonry, which tends to be softer than the more modern materials. Ivy shoots can also intrude beneath and damage shingles, slates, copings and other roof components.
* Ivy shades building elements from sunlight and wind, which can retard evaporation of water from building surfaces. That can accelerate decay of wood elements and/or promote the growth of mold
* Covered surfaces cannot be easily inspected, maintained and repaired
* Ivy provides a safe harbor for insects and other vermin.
* Ivies of the type associated w/building adornment are invasive and opportunistic. They will overwhelm and displace other plantings if allowed to grow unchecked.
* While ivy may not be a suitable dressing for all buildings, the potential problems can be effectively managed in many instances. Conscientious maintenance will minimize the potential for damage. What’s more, removing established ivy from buildings can cause more problems than the ivy itself. Ivy’s attachment to surfaces is tenacious and remnants can remain visible decades after the plants are gone. The remnants are also resistant to “masonry-friendly” cleaning efforts. Aggresive cleaning can discolor and/or phyically damage building surfaces.
The bottom line is, if you love your ivy-covered walls, keep them. Just be prepared to expend the effort and money needed to keep the plants in check and your building protected!
Balcony & Deck Collapses
The recent deadly balcony collapse in Berkeley, California has caused some to ask if this could happen to them? Balcony and deck collapses are not typical, but it does seem like we hear about these incidents frequently. To allay your fears, first keep in mind the Building Code prescribes loads to the structural engineer that result in the design of a safe balcony. This required live load is in the 40 to as much as 100 pounds per square foot range depending on the application. So even if the lowest load rating is used, a properly design deck will support the weight of a 160 pound person occupying every two foot by two foot square area on the deck. As you can see, it would take a very crowded deck full of big people to create a danger of an overload failure. A deck with more people on it than this would likely be difficult to achieve and resemble a Guinness Book of Records attempt more than a typical party.
The deck and balcony collapses that we hear about are almost always found to be the result of either improper construction or deterioration of the structure. We rely on inspections by trained local building inspectors and third party engineers to ensure balconies are built correctly, but they are not on site watching every fastener being installed and they do not inspect every nail. So sometimes small defects are missed, but potentially tragic issues rarely get by as these inspectors keep life safety as a paramount concern.
New Trend In Interior Design
What is the hottest new trend in interior design? Concrete! There are some really interesting textures and styles being offered that go way beyond drab flower pots and utilitarian shelves made out of cinder blocks.
Check out this article on some new uses of concrete to make furniture, lamps, and even wallpaper.
http://www.housetohome.co.uk/articles/news/hot-trend-cool-concrete_533159.html
Using Water to Remove Concrete
Hydrodemolition is a method to remove concrete through the use of high-pressure water jets. This method can be used for horizontal, vertical, overhead, and underwater concrete removals.
One of the main benefits of hydrodemolition over jack hammers is the elimination of the need for a secondary process to remove microcracking related damage to the concrete that is left in place. Several other benefits are that hydrodemolition creates an irregular surface profile for better bonding of the repair material, minimal ground vibrations, and cleaning of embedded reinforcement. Environmentally, hydrodemolition is beneficial because it reduces the amount of harmful silica dust put in the air, and faster concrete removal can reduce construction time.
Although this method has its benefits, there are some negative aspects to it as well. For example, the process can consume a large amount of potable water that will later have to be treated before it can be returned to the storm drain system. Also, containing the runoff from the used water can be difficult, and in freezing temperatures, the water may create hazardous conditions.
New Research on Concrete Decay and Carbon Fiber
Recently, new research has been done in order to test the durability and strength of beams when carbon fiber strips and fabric are added to them. The experiments involved exposure to several environments such as high humidity, freezing-and-thawing cycles, and saltwater exposure.
The data recorded from the durability tests showed that in high humidity environments the bond between carbon fiber plates and concrete degraded over time, but the same conditions did not affect the bond between fabrics and concrete. This would suggest that plates would be better for indoor use rather than outside use
The freezing-and-thawing test results showed that the bond in both the plates and fabric was not affected by the fluctuations in temperature, which suggests that the carbon fiber protects the concrete from getting wet.
In the final test with saltwater exposure, carbon fiber performed well, but after 10,000 hours the concrete began to weaken, which may indicate that use in a marine environment is not recommended.
This mixed set of results will undoubtedly spawn more research and we will keep an eye on these developments.
Don’t Mess With Mother Goose
One thing we have learned over the years of inspecting properties, it’s never mess with a protective mother!
While on a recent site visit, we encountered a mother goose sitting on her nest. A loud hiss and an “I’m not moving” attitude, redirected our staff to the back entrance. What can we say….gotta respect a mother protecting her young.
Happy belated Mother’s Day from the ETC staff!