The science of structural response to earthquakes is about to get a massive data resource boost due to a mandate introduced in the Philippines for seismic instrumentation in buildings.
In 1992, the National Structural Code of the Philippines (NSCP) first introduced the requirement for seismic monitoring of structures for engineering design purposes. In 2010, the NSCP stated that buildings above 50 metres should have three seismic monitoring points installed, but at this time the requirement was not mandatory.
In recent years PHIVOLCS (the national earthquake authority) have warned that an earthquake of up to magnitude 7.2 is overdue for the West Valley Fault, which would be potentially devastating for Manila and surrounding populated areas. In 2015, the Department of Public Works and Highways (DPWH) issued a directive to all building officials that the seismic monitoring requirement would no longer have exemptions, and released a document titled “Guidelines and Implementing Rules on Earthquake Recording Instrumentation for Buildings”. The requirements for Earthquake Recording Instrumentation (ERI) apply to existing buildings located in Seismic Zone 4 (the entire Philippines except for Palawan and Tawi-Tawi which located in Zone 2). Only once this requirement is satisfied will a renewed Certificate of Occupancy be issued. New building permits will only be issued if plans to show a provision for a Seismic Instrumentation Room (SIR).
The engineers at ESS Earth Sciences in conjunction with the seismologists at the Seismology Research Centre have designed the Gecko Sigma strong motion accelerograph to exceed the requirements specified in the DPWH guidelines to enable detailed engineering analysis of building response due to small and large earthquakes. Taking less than an hour to install, the Gecko Sigma records ground and building vibrations continuously, with over a year of data stored in the memory buffer, ensuring no earthquake is ever missed. With its simple LCD and keypad interface, the Gecko can be set up without a computer without the need for highly trained technical staff.
We have also developed a low cost accelerograph that still meets the monitoring guidelines to enable earthquake alarms to be generated for buildings. Known as the Gecko ERI and using our LCA-5G triaxial accelerometer, the system will record any earthquake that may be felt or that may be damaging to a structure.
ESS has a number of trained local representatives in the Philippines to assist building owners in Manila with their requirement to fulfil the DPWH directive.
For information on how Gecko accelerographs comply with the DPWH guidelines, contact us today.
Download the DPWH Guidelines on Earthquake Recording Instrumentation