Presentation(s) on observed wind damages due to Typhoon Yolanda

I have made about three presentations now on the same topic above. One is at the UPD-ICE* Forum on Earthquakes and Typhoons (Jan 2014):

It's risky to miscommunicate risk

In a previous post, I asked that we take caution how we communicate a certain risk. That example talked about the location of the "Valley Fault System," previously called the Marikina Fault, which obviously presents a certain disaster risk. One problem was that risk wasn't quantified then -- how close should one be to the fault lines to be at risk? It wasn't very clear, but people could readily assume that if they are clearly not along the fault lines, they should be safe. If they're not sure, they should consult PHIVOLCS (not PHILVOLCS, by the way), who can provide information on distance of a certain property from the nearest fault line.

Damping in buildings for wind-resistant design based on a stick-slip model

I am posting a download link to a copy of my dissertation here for those of you who are interested.

Title:

DAMPING IN BUILDINGS FOR WIND-RESISTANT DESIGN BASED ON A STICK-SLIP MODEL

Abstract:

Damping is said to be one of the most important parameters in the wind-resistant structural design of buildings. But, damping is also known to have high uncertainty, which leads to low reliability in the design. Current estimation formulas and early research on structural damping, particularly, are associated with stick-slip mechanism. But these current models have only shown this qualitatively. In the end, these models fitted formulas to databases of full-scale experimental data. This dissertation therefore aims to quantitatively study the stick-slip mechanism itself to derive a theoretical expression, and finally, to apply the derivation to actual physical structure data to illustrate that stick-slip damping is indeed a valid model. The study starts from a very simple one-degree-of-freedom (1DOF) system with one stick-slip component (1SSC), to a more complicated 1DOF system with a large number of SSC (NSSC). The study also briefly touches on the damping of SSC inside MDOF systems. The study of MDOF with NSSC systems is necessary because actual physical structures are such.

Your house is not along the faultline. What now?

[Image from tulisanes.wordpress.com]

A friend linked to this blog article:

http://tulisanes.wordpress.com/2012/04/03/is-your-house-standing-on-an-earthquake-faultline

Obviously, the author has good intentions, although he is seemingly not an engineer (or maybe still a young engineer?). The impression I'm getting though is that the article is suggesting to check whether your house/property is along one of the published faultlines. If it is, you're obviously in danger. But it might also give the impression that if you are a good distance away, you probably shouldn't worry.

Response to a Reader Question... from 2007! About Billboards.

The e-mailer asked:

I was wondering if we could discuss billboards of the flexible type? I am a BS Geography student finishing my thesis right now and trying to find resource persons or key informants.

My thesis is about the hazards the billboards pose to human life and property. In line with my recommendations part, I wanted to seek alternatives on billboards, if not alternatives for the laws for it. Since I see that billboards can not really be wiped out, due to its economic contributions to the LGU or National government, your concepts are deemed vital.

The initial plan I have in mind is to interview you RE solutions we could make if and when billboards can not be banned totally.

Billboards proved to be something that can affect adversely the lives and properties of people. As a social scientist, I saw it very interesting to tackle but not really focus on the technical aspects of it. Flexibility is understood as a solution to the social problem.  

I replied:

How do we get "Site-Specific Wind Loads" in the Philippines?

I was asked this question, and here is how I would answer it.

In the structural engineering community especially in my home country, the interest and knowledge in earthquake engineering and earthquake-resistant design has grown rapidly over the past two decades especially after the 1990 Luzon Earthquake. Some of the recent "buzz words," if I may use that term, in the community are "site-specific seismic hazard assessment," and "performance-based seismic design."

Amplitude-dependent model of structural damping in buildings based on stick-slip mechanism for use in wind-resistant design

On February 9, 2013, I successfully "publicly" defended my PhD dissertation on the topic mentioned above. I will soon be posting the full dissertation manuscript once it is final. I requested my friend to take a video of the whole presentation, including the question-and-answer portion at the end, as well as closing remarks by my PhD supervisor. The video is shown below.

A tragic event due to faulty construction?

Check out the video on this link: http://www.facebook.com/photo.php?v=1817415148842. (Thanks to my friend VIR for sharing the link.) The tragedy is not even due to an earthquake, other natural disasters, nor even a terrorist attack.

My friend ponders, is it the designer's or the contractor's fault?

An engineer's dilemma. Any thoughts?

A contact on Facebook posts photos of his "dream home," located in earthquake-prone Philippines. Problem is, it's all concrete hollow block (CHB / CMU / concrete masonry unit) walls. Filled and reinforced, I'm sure. But, no reinforced concrete columns? Based on what I know, this kind of construction is not safe at all, specially in earthquake-prone countries. Or even if it had (and it didn't) have reinforced concrete columns, they still require proper seismic design. These all-masonry wall systems are just bound to collapse when the next big one happens. What do I do? Do I become the bearer of bad news? Do I give unsolicited advice? The problem also is that who knows when the next big one will happen, right? If nothing big occurs during our lifetime, then, well it would seem I am wrong, after all, no? What to do, what to do.

Please share your thoughts in the comments.

"High-rise" and "tall" buildings, and the 10 worst collapses in history

Image from Wikipedia

What makes medical practice better? The fact that doctors have made a ton of fatal mistakes that has cost lives. And they learned from those mistakes. That's pretty much how it is for civil engineers, and particularly in this case, for structural engineers. If you think doctors and engineers know everything and can't make mistakes, you're thinking wrong. Doctors and engineers and other professionals are researching, discovering, and learning new things everyday.

Anyway, check out this list on bestonlineengineeringdegree.com of the 10 worst high-rise building collapses in history. If in case the link stops working, you can try this Google-cached copy of the webpage:

Japan, tsunamis, Katrina, and other natural hazards

I haven't blogged in a long time, and yes, although we were probably 300 km away from the earthquake, tsunami, and nuclear triple disaster this past March, that event was one reason.  But the truth is I mostly got really busy with my work.  Now I just wanted to share second-hand information from a Japanese, about Japan and its battle against earthquakes and tsunamis, and to talk about the similarities with New Orleans and Hurricane Katrina.

What is Engineering? + New Engg.RONJIE.COM Look

If this isn't your first time here (http://ronjie-engg.blogspot.com/), you would have noticed the new look of this website that is all about engineering, from the RONJIE.COM perspective.  What is Engineering?

Appropriate "retrofit" designs save lives from earthquakes, typhoons, and floods

This download <http://www.unesco-ipred.org/gtfbc/DWf_10_key_points_Hurricane_resistant_construction.pdf> provides a pretty simple enough starting point on what things owners could do to protect life and property.  It appears to have been prepared by Development Workshop France.

Multi-Tiered Evaluation of Existing Structures

If you are familiar with FEMA publications related to seismic evaluation of existing buildings, you may have heard of the terms "Rapid Visual Assessment," "Tier 1 Screening Procedure," "Tier 2 Evaluation Procedure," and "Tier 3 Detailed Evaluation Procedure," and even "Seismic Rehabilitation."

Looking at these different types of "assessment" procedures together, I would consider them to be a 6-step overall process of seismic evaluation and rehabilitation design for existing buildings: