Connecting stick framing to Structural Masonry

[jamestkirk]

I am an engineer who was requested to look at a house renovation that is ongoing by a contractor friend. In short, nothing is working out with the design.

The owner hired an architect who hired a structural engineer to design the structure. The engineer has provided stamped drawings.

The existing house is a structural brick house (2 course brick) built in or about 1900 AD which is two stories high plus a loft. The existing masonry walls are about 20' high from ground to soffit and about 10" thick.

The existing floor joists sit on the inner course of brick, however, they are not mechanically connected to the brick wall, nor to each other. They merely sit on the inner course of brick and sit on the center beam of the house, etc.

In plan, the house is essentially a box.

The architect is specifying the entire back wall of the house to be removed to allow for unfetered acess to the addition and a timber frame addition to be butted up against the cut masonry walls. (Essentially extending the remaining masonry walls into the back yard.)

The drawings call for the timber stud walls to be lag bolted to the cut masonry.

The new floor joists do NOT run perpendicular to the walls to be braced. I.e. they run perpendicualr to the wall that is to be removed.

I know that in structural masonry, the lateral loads are resisted by the opposite walls (shear walls). Neither the architect, or the other engineer has made any design to frame the back of the house with a moment frame to replace the exsisting masonry shear wall to be removed. (I.e. fabricate a frame out of steel, weld it up, and connect it to the existing masonry.)

I have looked in the building code for any codes pertaining to connecting 2x6 stud walls to double course brick walls but can not find any details on this.

In my opinion, the remaining 2 sidewalls need to be laterally braced to resist wind loads. The other engineer has stated that these walls will be braced by the ceiling which to me is a joke because the ceiling joists run parallel to the walls that are to remain standing.

Comments???

Codes???

 

[DaveAtkins]

Usually, in a case such as yours, their is a ledger board at the floor system which is bolted to the brick. So the wall is braced at the floor level. At the roof, there may be a board laid across the top of the brick wall, bolted to the brick and fastened to the GWB ceiling. Codes do not allow a GWB ceiling to act as a diaphragm, but it will function as one. So the wall is braced at the roof. No moment frame is needed where the existing wall is to be removed IF the floor and roof diaphragms can rack their loads over to the wall at the front of the house.

DaveAtkins