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Ties and continuity

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I have following questions reagarding the requirements in the UBC Section 1633.2.5.
 
The first paragraph states " the connections shall be capable of transmitting the seismic force induced by the parts being connected", "any smaller portion of the building shall be tied to the remainder of the building with elements having at least a strength to resist 0.5CaI times the weight of the smaller portion.". It is cleat that the "weight" is the dead load of the structure here.
 
However, the second paragraph requires a positive connection for resisting a horizontal force acting parallel to the member shall be provided for each beam, girder or truss. This forces shall not be less than 0.5CaI times the dead plus live load.
 
1.    For a one story building, I only have to provide ties between portions of building to resist the 0.5CaI times the dead load of the portion. However, when I jointing two beams (not used for drag purpose just for vertical load support)supporting the roof at the same support, we need to use the 0.5CaI times the dead load and roof(?) live load. Do I really have to include the roof live load in this case? Or is it depended on which basic load combinations(section 1612.3.1 or 1612.3.2) you use?
 
2.    Does the requirements(0.5CaI times the dead plus live load) for the beam, girder and truss apply to tie connection between the members only? How about the connection from a single beam, girder or truss to top of wall or post?
 
Thanks
 
Julian Chu
Newport Beach, CA