The frame shown in Figure Q2 has rigid floors and can be considered as a "shear frame". The masses are lumped onto the floor slabs as shown in the Figure. Determine (i) the structure stiffness matrix (ii) the structure mass matrix and (iii) the natural periods of vibration and the associated mode shapes for this structure. The mode shapes should be plotted with respect to a vertical axis. Assume El/mL = 2. L EI El 28/08 0.8m m El 1.8EI 0.8m m 1.6EI m El 3080880