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Re: Traditional Timber Frame House

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>
>Brandon Erickson wrote:
>>
>> I am working on a traditional timber frame home on ocean front property
in New
>> England.  The post-and-beam construction uses large timbers to construct
a
>> series of bents which define the cross-section of the house.  The timbers
are
>> combined with mortise and tenon type connections.  There are no nails,
light
>> metal hangers, etc. used.  1" diameter oak pegs are used instead.
>>
>> My question is with regard to the lateral system of such a building.  The
>> building faces open ocean and will get some pretty heavy wind storms.
Does any
>> one have experience or suggestions as to how to approach the lateral
design of
>> such a building?  The little bit of literature I've found indicates that
walls
>> are not used for rigidity.  Are the bents to be considered as some type
of
>> moment frame?  What about in the direction perpendicular to the bents?
>>
>> Thank you in advance for your responses.


This poses an interesting problem related to the sucess of old structures
built in the tradition ways before metal spikes and connectors were
available. Does anyone have any information as to how well the Gamble
residence (Proctor & Gamble) performed in the Northridge or other nearby
earthquakes. If you recall, the Gamble residence was built around the turn
of the century (1900's) by Green and Green Architects. The home is a two
story heavy timber structure where all of the connections are made with
wood - including locking spikes and pressure wedges (for lack of a better
word).
I don't recall any published reports of damage to the home from severe wind
or seismic activities. The workmanship is magnificent (you can tour the home
in Pasadena California) and the wood to wood connections follow oriental
methods of notched and keyed as well as mortised and tendoned joints. In
some cases, tendones were secured into mortises with wood spikes.

John Bryan's response came closest to what I would do, however, Knee Braces
have not done all that well over the years in seismic country. It is
generally believed that you can not gain fixity in a wood connection unless
the wood is embedded into a foundation or buried in a wall deep enough to
resist rotation. Knee braces add strength to the joint, but do not create
fixity. I would consider a Knee braced structure as a simple truss to see
what forces you arrive at in each member. You should then be able to
calculate if the net area of the mortise is sufficient for the stress
applied.
Another reason to be thankful over the holidays for Simpson, Harlen, Silver
and KC Metal Products.

Dennis