טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentWilkinson Philip
SubjectModal Displacement-Based Seismic Design of Generally
Irregular RC Wall Structures
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Oren Lavan


Abstract

The seismic risk faced by societies located in earthquake prone regions, is increasing with population concentration in central business districts, as well as heavier investment into buildings and infrastructure. Developing practical robust seismic design procedures which produce economical structural systems for irregular wall structures, contributes to mitigation of earthquake hazards. Both structural and non-structural earthquake damage in buildings corresponds more directly to deformations than to forces. For irregular structures, which exhibit significantly nonlinear behavior, a deformation based design approach appears likely to produce safer designs more reliably than traditional linear force based design methods.

The goal of this research was to develop a new seismic design method for multistorey generally irregular reinforced concrete wall structures. Advantages of the proposed methodology, called Modal Displacement Based Design, include minimal-to-no iteration, as well as explicit consideration of nonlinear, torsional and dynamic higher mode effects. Furthermore, the method does not rely on empirical capacity design equations for establishing design shear and elastic moment capacities.

The core MDBD methodology was developed and applied to classes of reinforced concrete wall buildings having progressively more structural irregularity.  MDBD was first applied to single storey one way asymmetric plan wall structures subjected to a single component of ground motion. At each stage parametric studies were carried out to evaluate the utility of the design method for each level of irregularity. For all classes investigated, over 95\% of the designs generated by the MDBD methods were found to achieve peak responses between 20\% below and 15\% above the target limit responses, at the critical location.

Effective Modal Design is a Modal Displacement Based Design method which requires only Response Spectrum Analysis, not Time History or Pushover Analysis. It is a direct (non-iterative) performance-based seismic design method for generally irregular reinforced concrete wall structures, which is practical enough for use in most design offices.