V

Therefore, use the following shear values derived earlier for modal distribution:

Distribution of Base Shear. Lateral force at level x (levels 1 and 2, in our example), for mode m (modes 1 and 2,) is calculated as follows:

I Wfm where

Cvzm = the vertical distribution factor in the mth mode Vm = the total design lateral force or shear at the base in the mth mode W, Wx = the portion of the gravity load of the building at level i or x fim = the displacement amplitude at the ith level of the building when vibrating in its mth mode fxm = the desplacement amplitude at the xth level of the building when vibrating in its mth mode i=i

Figure 2.49. Distribution of modal shears: (a) first mode; (b) second mode.

Figure 2.49. Distribution of modal shears: (a) first mode; (b) second mode.

The distribution of modal base shear shown in Fig. 2.49 is calculated as follows:

Mode 1

Greener Homes for You

Greener Homes for You

Get All The Support And Guidance You Need To Be A Success At Living Green. This Book Is One Of The Most Valuable Resources In The World When It Comes To Great Tips on Buying, Designing and Building an Eco-friendly Home.

Get My Free Ebook


Post a comment