Having reviewed a lot of posts in this forum I have not yet seen another example similar to this.
I have attached a very simple plan view of what the Owner wants to accomplish. This is in California, Seismic design cat D, existing one story masonry house, 8" cmu partially grouted cells(all of the info I know about the cmu), wood framed roof. Due to situational requirements on their property the owner wants to demo less than 1/3rd of the existing house and in that place build a new wood framed 2 story addition.
For purposes of lateral analysis, if I consider this as one single area then I do not see any way that this could be justified by current code. If though, I consider the existing 1 story house as Area A, the the addition as Area B then I think that I might be able to justify the addition. My thoughts are as follows:
1. The addition, Area B has independent lateral resisting elements in 3 of the 4 sides.
2. The existing house, Area A also has independent lateral resisting elements in 3 sides.
3. Both areas share a common line of lateral resistance with the new wood framed interior shear wall.
My questions are as follows:
1. Due to this design method would the existing exterior masonry walls be required to be tied into the roof diaphragm for out of plane forces? This would open a Can 'O' Worms.
2. Other thoughts.
Thanks in advance.
Erik
I have attached a very simple plan view of what the Owner wants to accomplish. This is in California, Seismic design cat D, existing one story masonry house, 8" cmu partially grouted cells(all of the info I know about the cmu), wood framed roof. Due to situational requirements on their property the owner wants to demo less than 1/3rd of the existing house and in that place build a new wood framed 2 story addition.
For purposes of lateral analysis, if I consider this as one single area then I do not see any way that this could be justified by current code. If though, I consider the existing 1 story house as Area A, the the addition as Area B then I think that I might be able to justify the addition. My thoughts are as follows:
1. The addition, Area B has independent lateral resisting elements in 3 of the 4 sides.
2. The existing house, Area A also has independent lateral resisting elements in 3 sides.
3. Both areas share a common line of lateral resistance with the new wood framed interior shear wall.
My questions are as follows:
1. Due to this design method would the existing exterior masonry walls be required to be tied into the roof diaphragm for out of plane forces? This would open a Can 'O' Worms.
2. Other thoughts.
Thanks in advance.
Erik
