MOMENT DISTRIBUTION w/SIDESWAY

[hst22]

Hello, so we are designing for a 2-story house on which we are only going to analyze 1 frame. I am going to use MDM for the structural analysis. I have some questions to ask.

1. Is my roof level symmetrical in terms of its loadings and lengths? I am pretty confused since I thought it was symmetrical but someone told me it was not.
2. So if it is symmetrical, does it still incur sideways since the lower part of my structure has sideways?

3. 1st-floor columns are RC, while 2nd-floor columns are Timber. Given that they were pinned rather than fixed, how am I supposed to do my analysis by using MDM? I was wondering if I should consider the pin supports as another set of exterior columns resting on the fixed RC frame so that DF will be 1 as well.

Your help will greatly contribute to my understanding of structural analysis. THANK YOU & GOD BLESS!

 

[BAretired]

1. The roof is symmetrical with the loads shown, but loads can be unsymmetrical. Snow does not necessarily maintain a symmetrical configuration; and wind load acts perpendicular to the walls, causing sidesway at all levels.

2. Sidesway exists at roof level if gravity load is not symmetrical or if lateral forces exist.

3. The upper tier can be assessed separately from the lower tier. With pin connections at second floor, the only forces which need to be applied at second floor will be wind forces and column loads.

In analyzing the lower tier, the assumption you make regarding the fixity at the base of the concrete columns will be important. The concrete columns are neither fixed nor hinged at the base. If shear walls could be used, it makes life much simpler.

BA