Seismic Accelerographs are very expensive. A single unit will easily cost you an average of well over
and about a million pesos (Philippine Currency) more or less, certainly much more than the
price of some quality brand-new cars. Prices range from a little less than a
million pesos to around 2 million pesos for a single unit depending on the
brand and supplier that you will be dealing with. But why so expensive? Is it
worth the usefulness of the device? Only the suppliers can answer these most
commonly asked questions and the best that buyers can do is to thoroughly
require them to provide you with more than satisfactory answers.
With so much cost involved in purchasing seismic
accelerographs, one must be fully equipped with utmost care and purchasing
knowledge as this equipment will be installed in the very structures that you
will be spending a lot of your working time in, supposedly, with your safety
and the structural health in mind. Diligence in the entire procurement process
is a must. Mistakes can be very costly in the long run. Hands-on supervision in the entire procurement process is
irreplaceable to ensure everything falls rightly into place. In my honest opinion, if you prefer to be on the safe side, this is not something to be passed on to subordinates as the nature and
purpose of the purchase truly requires top-level decision making and
monitoring.
This was specifically written primarily to properly
guide, inform and protect the buying entities into making wise and logical
decisions and have their money’s full worth in whatever brand of seismic
accelerograph that they will prefer to buy. The decision will and always rest solely on the buyer.
The truth is, very few people are aware of what Seismic
Accelerographs are. It is not some common commodity that we can regularly see
in malls, hardware and even online shopping sites, thus can easily be inspected
and inquired upon. It is as strange an equipment as anything can be that even
some of the most experienced engineers have not had the first-hand experience
of physically seeing one or are at least close to being familiar with the
technical aspects, specifications and functions of the equipment.
What Are Seismic Accelerographs?
The Department of Public Works and Highways and Seismic
Accelerograph suppliers often refer to their products as earthquake recording
instruments (ERI). Their specific and main function supposedly revolves around
Structural Health Monitoring according to most product suppliers. It is along
this line that their marketing campaign has been directed to and is the usual
description that they are passing on to their clients.
However, one can have a good insight to the nature of
seismic accelerographs looking at the manner it is aptly described and defined
according to the DEFINITION OF TERMS AND ACRONYMS of the GUIDELINES AND
IMPLEMENTING RULES ON EARTHQUAKE RECORDING INSTRUMENTATION FOR BUILDINGSissued
by the Department of Public Works and Highways (DPWH):
“SEISMIC
ACCELEROGRAPH. Accelerograph that
records the acceleration of particles on the surface of the earth as a function
of time, which is called an accelerogram. The accelerograph generally records
three (3) mutually perpendicular components of motion in the vertical and two
(2) orthogonal horizontal directions.”
“ACCELERATION. The
rate at which the velocity of a particle with time as recorded by seismic
accelerograph (expressed in Gal or cm/sec squared).”
“TRI-AXIAL. The characteristics of an accelerometer to
provide ground shaking sensing in three (3) dimensions commonly known as x, y,
z (i.e., transverse, longitudinal, and vertical).”
Readers are presumed to be aware of the DPWH requirement on
the installation of Earthquake Recording Instruments (ERI) as it will not be
separately discussed on this blog.
All upcoming and future posts will strictly be based on the
“contents” of the GUIDELINES AND IMPLEMENTING RULES ON EARTHQUAKE RECORDING
INSTRUMENTATION FOR BUILDINGS issued by the Department of Public Works and
Highways (DPWH).
You may drop an email at seismicphils@gmail.com for a free full copy of the DPWH IRR and will gladly send it to you
in PDF format. Please include your questions or inquiries regarding seismic accelerograph procurement process if any with your name, designation,and company so can be addressed properly.