Strength and Ductility Demand A Case Study of Ethiopian Design Practice to Seismic Loads

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa University


This thesis is conducted to investigate the relationship between strength and ductility demand. The base shear and the story displacement ductility were used as parameters to establish the relationship and a five story and ten story reinforced concrete shear frames were used to this end. Eighteen shear frames with different combinations of ductility class and sub-soil class, according to the Ethiopian Building Code Standard EBCS 8, 1995, were considered. Each model was subjected to one linear static with EBCS 8, 1995 base shear distribution, two linear response spectrum EBCS 8, 1995 and EC 8, 2004, two non-linear static and one non-linear time-history analyses cases using the computer program SAP 2000 Ver.12. A range of base shear values were applied on each model to study the post-yield displacement ductility demands imposed on it. From the analyses results, different curves showing the relationship between the reduced (%) base shear yield strength and ductility demand were produced. To this effect, the non-linear static or the pushover analysis method was used as a tool. Two types of non-linear properties were considered for all the models; the first, material non-linearity following the recommendations by Federal Emergency Management Agency FEMA 356 Pre-standard and Commentary for Seismic Rehabilitation of Buildings and Applied Technology Council ATC 40 Seismic Evaluation and Retrofit of Concrete Buildings and the second Geometric non-linearity by implementing the iterative P-D analysis procedure included in SAP 2000 Ver.12. The influence of undermining the design base shear on ductility demand and the validity of permitted reductions by EBCS8, 1995 of design base shear through a behavior factor for each ductility class for the five and ten story shear frames was assessed by making use of theses curves. Finally the implementation of the relationship between these two important seismic design parameters in the current seismic design practice of Ethiopia was investigated by conducting a case study on an existing building located in Debre Birhan. Key words: Base shear yield strength; Ductility demand; Pushover analysis



Civil Engineering