Study into effects of inelastic behaviour over the upper regions of structural walls in a medium-rise R/C building

Student: Danreb Ramos Pablo
Supervisors: Dr. Timothy Sullivan


Recent research by Priestley & Amaris 2002 suggests that due to higher mode effects, seismic design methods included in current building codes do not provide sufficient flexural and possibly shear reinforcement to prevent inelastic behaviour over the upper storeys of medium-rise RC wall structures.

While a simple and attractive means of estimating the maximum forces in walls has been developed by Priestley & Amaris 2002, the practicing engineer is unlikely to welcome the additional reinforcement needed to sustain the larger forces. As such, it is considered that the practicing engineer needs to be shown that the development of inelasticity over the upper storeys of wall structures is, in fact, a serious risk that needs to be addressed in design.

To establish whether this is true, the following scope of works was done. A suite of simple case study wall structures in line with the Eurocode 8 seismic design provisions was designed and then subjected to non-linear time-history analyses in RUAUMOKO using 7 spectrum-compatible modified accelerograms and 7 artificial acclerograms.

Non-linear time history analyses were first run with the walls modeled elastically above the first storey. Comparisons were made between the elastic wall forces and the design forces specified by the codes. Following this, the same sets of case study structures were analyzed with varying amounts of flexural reinforcement above their base.

You may download a digital version of this MSc dissertation here.