ABSTRACT
When dealing with the real behaviour of structures, the analysis using the Laplace transform contained in the former part of this chapter is of far greater significance.
Equation (3.51) is the governing equation for the dynamic response of a structure. It is now time to 'square the circle', and look back at the conventional approach to structural design. In practice, all reference to the middle term, the one that describes damping, is omitted. There is also a tacit assumption that the response occurs only at a very low frequency. (It could not be zero frequency or there would be no motion at all.) In this 'quasi-static' approach, forces and stiffnesses are equated floor by floor.
