The Republic of the Philippines is vulnerable to different disasters including earthquakes due to its geographical location. The risk exposure that the country is facing put the safety of existing structures in line especially those in the Metropolitan Region. The most common type of building in the Philippines is a reinforced concrete framing with masonry walls as partitions and exterior walls. Concrete hollow block is frequently used material in building construction. However, these walls are not considered in practical design since it is a non-load bearing element in the structure.
In this study, a seismic evaluation on a two-story RC structure was conducted considering the effects of secondary walls in terms of strength, ductility and failure mechanism of the structural members. Since there were no available guidelines in seismic evaluation in the Philippines, the JBDPA Standard were adapted. The main frame had 21MPa compressive strength while the walls had 6.9MPa. The capacities of bare frame and frame considering walls were investigated using the JBDPA Method and analyzed by Response 2000 Software. As a result, the seismic index on the first floor of the structure had some inadequacy with respect to the Japanese Code. The walls did not have much effect on the seismic index of the structure.
On the other hand, the secondary walls had the effect of increasing the strength index of the columns but reducing its ductility. The same goes for the failure mechanism of the frames. For frames neglecting the walls, there were no column failure in the 1st and 2nd level of the building. Whereas, if the secondary walls were considered, some of the beam-column joints presented a column failure in the 1st and 2nd level. This type of failure may be due to the reduction on deformation capacity of the frames.
Keywords: seismic evaluation, non-structural walls, ductility