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 Member Update
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reinforcing bars of steel, or rebar, and are generally positioned near your existing round support columns and existing concrete pads. To start with, your new steel H columns go through these grade beams. When this system is filled with concrete, bolted, welded, and connected to the wooden structure of your building with metal clips, once again it forms what is called a moment frame. This frame, along with your shear walls and reinforcing carpentry, add the rigidity necessary to keep your building stable during an earthquake.
Shear walls that you see on your plans are used to augment the moment frames, and in some cases, are a less expensive way of doing the job of a steel and concrete moment frame. And here is just one of the many areas where having an on-the-ball, experienced engineer who is working to give you a seismically retrofitted building really pays off. Putting plywood over existing 2x walls and / or building new “2 x 4” or “2 x 6” walls in the right areas can save you a bundle of money. These walls are generally indicated on your floor plans with hatch marks and / or symbols. Their length is also normally indicated on your plans. If you cannot find them, do not be afraid to ask your engineer.
Metal flat straps like you will find in a Simpson Strong Tie catalogue are used to hold wooden elements together. As an example, where wood members abutt up against each other, your engineer will need to keep them from separating in a seismic event, so they may use a strap to tie them together. This same
solution may also apply to a line of blocks between floor joists.
The “LTP” is a flat metal plate and the A35 is a bent (90 degree) metal clip made to connect wooden members that abut each other in corners at a 90 degree angle, while the LTP flat plate can be used in any situation where parallel wood members abut each other.
In conclusion, what I have attempted to do in writing this article is to put in plain words the potential pitfalls of your project and structural elements that go into your soft story, earthquake retrofitting project. Yes, it is just a warning to owners, but do not just find the lowest bid and sign it. It is not what is included in the contract, it is what is not (e.g., the “exclusions”) that count and can always cost you money. Get involved and stay involved in the process. Many owners, when confronted with the complexity of the soft story program just give up and sell what may otherwise be a valuable income earning building. I am not saying this is necessarily the wrong thing to do, but before you take that step, educate yourself.
As I began this article, it is true that yes, I am a contractor, and my company does soft-story seismic retrofitting. We also work as consultants on soft-story projects.
(800) 931-6666
Robert Gross is the Owner of Crown Hill Construction & Design, an Interior Design and General Contracting company based in Los Angeles. You can reach Mr. Gross at weatherail66@gmail. com or via telephone at (323) 465-5082.

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