Bay Area Structural Engineers

By Howard Cook, Founder and General Manager of Bay Area Retrofit

How do I Find a Good Engineer?

This is a difficult decision.   You want your retrofit done right and it is natural to think an engineer is the way to go.  After all, engineers design construction projects every day and will make sure your house is retrofitted correctly.

Bay Area Structural Engineers

Which engineer should I choose?

 

There is a lot to know and very few engineers or contractors take the time to learn it.  At the very least whoever you work with should follow the basic guidelines set forth in these seismic retrofit codes and guidelines.   If they are recommending something that is not in these guidelines it is probably not necessary.

When deciding who to hire these guidelines should help you.  

Real World Examples of Engineers “Making Things Up”

Below is a construction detail which tells a contractor how to build something.  In this case it is the post to beam connection.  Our first alert that something might be wrong here is that it is not recommended by any of the seismic retrofit codes and guidelines mentioned above.

 

  • The blue green arrow points to a bolt that connects the bottom of a post to a small block of cement called a pier or pier block.Bolted Block

 

  • The purple arrow points at a steel “T” strap that has zero earthquake resistance.

 

  • The red arrow points to a ST292 hardware that has zero resistance to earthquakes.

 

  • ALL of these things are deemed necessary by all seismic retrofit codes and guidelines.

 

  • Lastly, the green arrow points at a T912 hardware that does not even exist!  See what I mean about engineers making things up?

 

 

 

 

 

Here are two more examples from plans
drawn by two separate engineer. More
education is needed for the engineering
community to make retrofits more afford
able.

 

 

 

The chart below was created by a local civil engineer who, as shown by the red arrow, specifies 8-12d (12d designates the diameter and length of nail) .  This means he wants 8 12d nails to be nailed into 2 x 4 mudsill blocks.  All retrofit guidelines only recommend 4 because that is all that is necessary.  Once you watch the following video link you will know what a mudsill block is.

Another reason all retrofit codes and guidelines do not allow more than 4 of these nails is because the blocks can split as shown by the photo below

In addition, these nailed blocks are a completely untested system and the least desirable according to research engineers at the American Plywood Association.

Szumski

 

 Photo of a Split Block

Split Block

 

On your engineered drawings you will probably see something like the two drawings below.  If you do it means your engineer is using mudsill blocks.  The engineered construction detail on the left specifies TWELVE large nails in each block, far exceeding the 4 nails required by all retrofit guidelines and a certain recipe for split blocks and poor performance.

The construction detail on the right tells the contractor to look at the chart above.  In this case EIGHT nails are required.

It is not impossible to put this many nails in a block if one pre-drills the nail holes but this is so time consuming very few contractors will take the time.

 

 

 

 

 

 

 

 

The construction details below tells the contractor to install a piece of steel sometimes called a “Clip Angle” or “L90” to strengthen the connection between the floor you walk on and the boards that support your floor.   The red arrow points to the location of this hardware.  The interesting thing here is that there is not a single case in all of the earthquakes in the United States of this connection ever failing.  That is why it is never reinforced in new construction or in any national or regional seismic retrofit codes and guidelines.  This is another case of an engineer not keeping informed.

 

Typical Ineffective Construction Detail by a Bay Area Structural Engineer

 

 

 

 

Not in FEMA or other retrofit guidelines

 

 

 

 

 

 

The drawing on the left is from one of the 6 seismic retrofit guidelines.  The blue green arrows points out the fact that no steel connection is being specified here.

Angle Iron Braces

This video discusses an ineffective and untested retrofit method that your contractor or engineer may recommend.  It is always best only to use retrofit hardware and methods that are based on testing.  Otherwise, what will happen is anyone’s guess.  The information in this video was created after consultations with numerous structural engineers, especially Bay Area based Thor Matteson, and Josh Kardon Ph.D.  Both of these structural engineers told me they would be happy to tell people about them if you want to call them.   Kelly Cobeen was kind enough to do actual calculations regarding their effectiveness.  She discovered that an Angle Iron Brace has the strength of 1/4 a bolt.  In addition numerous structural engineers were kind enough to answer questions I had about their efficacy.  In addition, Buddy Showalter with the American Wood Council, the largest wood products research center in the world, was willing to give his expert opinion.  All of whom are highly distinguished structural engineers in the field of wood seismic retrofitting.

In spite of their being practically worthless they are nevertheless very expensive as shown in this 2017 estimate from a local contractor

.

 

Sample Angle Iron Braces used Extensively in San Francisco Bay Area seismic retrofits

 

Angle Iron 2

Angle Iron

 

 

Angle Iron

 

 

 

Here are some construction details drawn by a civil engineer specifying an angle iron brace.

To the left the red arrows are pointing at locations for the angle braces.  To the right is the construction detail telling the contractor how to install the Angle Iron Brace.

 

 

 

 

 

 

 

 

 

 

 

 

Screening Retrofit Professionals

In summary, find a contractor who understands the engineering, or an engineer who understands practicality.   It is important that any of them are familiar with the topics mentioned above.  The only drawback to using an engineer who understands practicality compared to a contractor who understands engineering is that you will probably need to pay the engineer $1,500 for a mediocre set of plans that will be expensive to implement, or $5000 for a good set of plans that will save on construction costs.   A specialist contractor will not need plans because he knows what to do already.

 

 

 

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Bay Area Retrofit
427 San Pablo Ave
Albany, CA 94706
With field offices in San Jose and Hayward.

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