Dynamic Stiffness Matrices for Linear Members with Distributed Mass

The analytical determination of dynamic stiffness matrices in the frequency domain for linear structural members with distributed mass provides an efficient and accurate procedure for the dynamic analysis of frames. This formulation allows to account not only for the distributed masses but also for wave propagation effects within each member. It provides therefore a more economical solution and a more accurate one than the use of lumped or even consistent mass matrices, which would require dividing the member into various elements to reproduce these effects, particularly for high frequencies. This problem has been discussed recently in relation to the seismic analysis of structures (bridge piers in particular) subjected to vertical ground accelerations. It had always been a major consideration in the interpretation of dynamic non-destructive tests based on impact loads and wave propagation. In this paper the dynamic stiffness matrices for linear members with different formulations are presented together