Una estructura de pórtico de un solo vano de dos plantas está sometida a una carga sísmica. The modulus of elasticity and cross‑section of the frame beams are much larger than those of the columns, so the beams can be considered rigid. The elastic response spectrum is given by the standard SIA 261/1:2003. Neglecting self-weight and assuming the lumped masses are at the floor levels, determine the natural frequencies of the structure. For each frequency obtained, specify the standardized displacements of the floors as well as equivalent forces generated using the elastic response spectrum according to the standard SIA 261/1.2003.
A cantilever beam with an I-beam cross-section of length L is defined. The beam has five mass points with masses m acting in the X-direction. Se omite el peso propio. The frequencies, mode shapes, and equivalent loads of this 5-DOF system are analytically calculated and compared with the results from RSTAB and RFEM.