When Is Non-Linear Analysis, or Pushover, Required?

Non-linear analysis is an assessment approach that accounts for the cracking, permanent deformation and strength changes that occur in structural elements during an earthquake. One of these methods, pushover analysis, examines the behaviour of the structural system by applying lateral effects to the building in increments. The analysis shows which elements are stressed first, where damage may concentrate, and how far the building can displace. It can be used in determining the seismic performance of existing buildings and in examining strengthening solutions.

Whether this analysis is necessary, and to which building it can be applied, is decided by a specialist earthquake engineer in line with the relevant code conditions and engineering experience. The height of the building, the layout of the structural system, its irregularities and its vibration characteristics all influence the choice of method. Using the same analysis method for every building is not appropriate; some structures may require different non-linear calculation methods. What matters is not that a more complex calculation is performed, but that the method used is suitable for representing the behaviour of the building. The reliability of the analysis also depends on the concrete, reinforcement and structural system information being established with sufficient accuracy.