Oroville Dam Engineering: What Happened?

The California Department of Water Resources stopped the spillway flow on Thursday morning to allow engineers to evaluate the integrity of the structure after water had been released at 20,000 cubic feet per second through the night.

padova donna cerca uomo (Courtesy of the California Department of Water Resources).

Last week California’s Oroville Dam, the tallest dam in the United States, almost failed due to a surplus of water filling Lake Oroville. As the lake filled higher and higher, water was being released, via spillways, into the Feather River. The volume of water caused erosion of the dam’s main spillway, causing it to crater and break apart. As a result, the dam’s emergency spillway began to erode. That spillway had never been used and was unlined. The lack of concrete lining may have led to its erosion as well.

Nearly 200,000 people were evacuated from the area, many of them fleeing to higher ground cities like Sutter. As the water began to recede, residents began to travel back home.

But what went wrong? What caused the damage in the first place? Continue reading

Aerial Cranes and Properties with Poor Construction Equipment Access

Helicopter Transport in Construction and EngineeringA few days ago, I saw a report on the global crane market forecast for 2017 through 2024. It got me thinking about the different types of cranes that I have used in my career. Especially aerial cranes. Aerial cranes are great because they can be used to move large loads in areas that are hard to access and they can do so at a fraction of the price of a traditional crane. They also do not require the set up and tear down process that a traditional crane requires.

Sometimes we get asked to work on properties that are difficult to access. This could include a property that is in a remote area, on a small parcel with limited access due to surrounding properties or buildings, or in mountainous areas.    Continue reading

Avoiding Surface Water Drainage Issues

Avoid Surface Water Drainage Issues with a Gutter SystemStanding water can ruin a property and pose serious issues to a community’s health. It can be a breeding ground for bacteria and mosquitos, and can lead to structural issues for buildings on the property. There can also be issues for adjoining properties, which can in turn will draw the ire of neighbors and possibly result in increased litigation risks. If you’ve ever had a property that has issues with surface water drainage, then you know full well the damage and headache it can cause.

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Is Rotten Wood Ruining Your Property’s Structures?

Fence with Wood RotEven in drought-stricken Southern California wood rot caused by water is damaging structures on both commercial and residential property. Rotten wood caused by moisture can be easy to miss, especially when the seasons have been as dry as they have been over the last 10 years. It’s also easy to put off the repairs – for some of us the drought makes dealing with wood rot seem like a back burner project. It’s easy to ignore the problem when we aren’t expecting wet weather.

Water-caused rot develops when moisture lingers on wooden surfaces that are unprotected. The lack of protection happens when wooden structures are not repainted regularly or resealed after a period of time. The moisture will settle into unprotected cracks and crevices and that creates a fantastic environment for fungi – the real culprit of the wood rot. Wood rot only needs 20 percent moisture content to live. That means it can show up in all but the most arid temperature zones. Continue reading

Using Drones In Engineering and Construction

Done Used For Engineering SafetyDrones aren’t just for the military anymore. Drones are being used in all types of commercial industries these days, from insurance to the media to construction. Although military drones are the most familiar type of drone, they’re not very common in civilian airspace. When one does see a drone, they’re usually the kind of drone known as a hobby drone. These drones can be purchased by anyone and can be found on retail web sites like Amazon.

Drones, technically known as unmanned aerial vehicles (UAVs), have become very affordable and easier to obtain than ever. In fact, these drones are becoming so popular that according to the FAA, in 2015 alone there were over 650 drone sightings by aircraft pilots – more than double the 238 sightings in 2014. Continue reading

Combating Coastal Bluff Erosion

Coastal Bluff ErosionLiving near the ocean is a dream for many, but the reality can be anything but. Property damage or loss caused by coastal bluff erosion can destroy the reward of a lifetime of hard work. First, what is a coastal bluff and what can happen to a property when erosion occurs? Coastal bluffs consist of the entire slope that lies between a marine terrace and the sea. They are formed when there’s a rapid uplift of the shore relative to sea level. Erosion is a natural process that occurs to bluffs over time and through various mechanisms, leading to instability.

Coastal bluffs are subject to erosion via several mechanisms, including creep, sheetwash, rilling and gullying and sudden collapses. Creep refers to the slow, downslope movement of a mass of sediment. A large factor in the promotion of creep is groundwater seepage, and engineering solutions include irrigation restriction and the installation of horizontal drains, or hydroaugers, and pumping wells. Continue reading

When Do I Need A Building Permit?

When Do I need A Permit?acSeveral years ago I had a friend on the East Coast that had a problem. My friend came to me with questions after a project he was working on with a fence builder turned ugly. My friend purchased his property without a fence. Because he had several dogs on the property, he wanted a fence to keep them from wandering off the property. He called a fencing expert and began installing the fence. Everything was going well until he got a visit from his township informing him the whole fence needed to be torn down. It seems he was building without a permit. Continue reading

5 Things To Know Before A Property Renovation

5 Things To Know Before A Property RemodelAs a former guest on the popular click reference HGTV Series Flip or Flop, I had to deliver some unfortunate news to the very talented hosts of the show who rarely if ever have a flop on their hands.  This time the home that they had purchased to flip had an old fissured, crumbling concrete foundation that would require expensive replacement.  It was truly one of the worst foundations that I’d ever seen as an engineer.

The response to this episode was overwhelming with many of you asking me, hop over to this site “How do I avoid that kind of trouble?”  The simple answer to the question would be for me to say, “Buyer beware and know what you’re getting into before you sign on the dotted line.” Continue reading

Protect Yourself From Code Violations

avoid-code-violationsNothing can turn a good property investment into a nightmare faster than discovering serious code violations that require unplanned and expensive repairs.  The trouble usually starts with tenant complaints.   When tenant complaints are ignored or poorly managed with substandard repairs, these situations can quickly snowball into major code enforcement violations, fines, accidents, evacuations, loss of life, litigation and even criminal negligence.

The building codes are different in every town, city, county and state.  They are living, breathing documents that continue to change as new materials, products and construction techniques continue to evolve.  Other contributors to changes in building codes are more subtle, such as socially recognizing that people with special needs must have equitable access or the true consequences of natural disasters such as floods, tornadoes and earthquakes. Continue reading

The Importance of Constructability in Engineering Design

The Importance of Constructability in Engineering DesignWhen a property owner decides they want to repair or add on to a home or other type of structure, they often have an engineering firm design the project and then hire a construction firm to build it. All too often, however, the engineering firm fails to create a practical design that will be easy for the construction team to build. That’s where “constructability” comes into play.

Constructability is a technique in which construction processes are reviewed from start to finish during the initial engineering design phase. It all boils down to understanding and coordinating the construction process during the design and planning phases. This technique prevents problems in construction by identifying problems before the project begins construction. Don’t be surprised when your design firm wants to know early on who will build the project. As design engineers, we know the best construction firms for your particular project and want to be confident that our clients are choosing a responsible construction firm—not necessarily the lowest bidder, although competence and economy are not necessarily mutually exclusive. Continue reading