-Elaborate on the spring-mass model and sketch it for single- and double-storey buildings. -What are three types of Earthquake Response Analysis? -Figure shows the typical structural planes (above view) of two buildings. All joints of the frames are pin-joint. The mass distribution in the floors is uniform and the stiffness (k) of all the braces is equal. The two planes are the same from every aspect, except for the brace arrangement as shown. The number of floors in the two buildings is the same. Display the centre of mass and centre of rigidity of the floors and elaborate on how you find them. Compare the torsional potential of the two buildings under the same earthquake load. -A structural plane (above view) of a four-storey building having similar storeys, is shown. The plane consists of six squares, each having 6m x 6m dimensions. The stiffness of braces are k, 2k and 3k as shown. All the joints in the frames are pin-joints. Only the braces resist the lateral loads in this building. Determine the coordinates of the centre of rigidity of storeys. 2k k k 3k 2k k