Friday, January 15, 2016

Effects of the Unchartered Faults on the NSCP 2010

This paper is by Carlos Villaraza from ASEP. It was presented after the Bohol Earthquake when a new faultline is discovered. Lots of people are questioning the structural code specifically the seismic provision. However, this paper states that dividing the entire Philippines in two seismic zones rather than adopting a spectral map similar to USA, is justifiable and will take care of the uncertainties in unchartered faults.



To appreciate this paper, one must be knowledgeable with response spectra and basic earthquake engineering. Basically, every structural designer will refer to Seismic map in NSCP to get the seismic force value that a structure will be subjected into. The distance of the structure location to the nearest faultine is very important so that a specific value of seismic coefficient will be determined prior to getting seismic base shear. A problem is faced when an unidentified faultine is near the structure. However, the response spectra analysis shown by Villaraza will show that unchartered fault like in Bohol will not be much significant, by NSCP though this was not shown in the map.