ロンジ土木工学　　RONJIE.COM Civil Engineering

Answer to Quora question, "What is 'spectral acceleration' in structural analysis?"

2018-02-12T01:39:00.003+08:00

Quora's bots asked me to answer the above question, and below is my response. What do you think of my response? Did it answer the question? Is there anything incorrect with what I said? How would you have answered the question? Let me know in the comments. "What is 'spectral acceleration' in structural analysis?" I would say that this is the ordinate on a response spectrum plot which gives the

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

2014-05-31T08:45:00.000+08:00

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): Another one is at the SPACE 2014 conference (Apr 2014): The above two presentations are in front of engineers and meanwhile, I made a slightly different presentation in front of non-engineers some time in Feb 2014. Unfortunately, I don't have a video of

It's risky to miscommunicate risk

2014-05-01T10:19:00.000+08:00

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

Metrology is not the same as meteorology #didyouknow

2014-03-14T07:00:00.000+08:00

I know that the word "meteorology" is difficult to pronounce and sometimes even spell. But some, whether unintentional or otherwise, pronounce it like "metrology," or its descriptive form "meteorological" as "metrological." It might be all right, because not so many people know about metrology, and even some spell checkers think it is a misspelling. But in fact, this is how it is defined:

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

2014-02-13T11:43:00.001+08:00

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

Your house is not along the faultline. What now?

2013-12-28T10:59:00.000+08:00

[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

In the eye of Super Typhoon Yolanda

2013-11-27T12:11:00.002+08:00

Well, not exactly. But pretty close -- this is a 12-minute compilation of videos taken by the folks at iCyclone.com of STY Yolanda's fury right in Tacloban City. WARNING: You are risking your life when you try to do this. Technically, the city should have been evacuated already. When authorities (e.g. PAGASA) warn of an impending storm, follow their instructions! You might say that they been "

Do we need to increase the code-required minimum design wind speed now after Yolanda?

2013-11-17T08:37:00.001+08:00

The answer to this question is NO, there is no need to provide NEW wind load code requirements for higher wind speeds. In the NSCP since its 2001 version, 250 kph is already defined as the 50-year return period gust wind speed in Zone I, which includes Bicol, Quezon, and Samar (not Leyte and other areas severely affected by Typhoon Yolanda). For Leyte and the other affected areas

Response to students' questions on NSCP 2010 wind loading provisions

2013-10-18T11:06:00.000+08:00

These are actually in the comments, but I thought I should promote them to a full post. The first asks about leeward wall pressures: Are the values for the Leeward wall pz really constant with elevation? My reply: NSCP 2010 Figure 207-6 answers your question. :) Another student asks, We are estimating wind loads on the MWFRS of the bldg. The building is a low-rise type and the calculations

Response to a reader question regarding using the NSCP for estimating wind loads on irregular shapes

2013-10-11T11:02:00.000+08:00

A reader asked: How would you evaluate the pressure coefficients for structures with irregular polygon shapes. An example would be those structures with a plan shape resembling the letters "W" or "K." Most of the pressure coefficients in the code are for uniform cross-sections such as circle, rectangle, square, and so on. I have my own approach on this (mostly based on engineering judgement),

2013-2014 1st Sem CE 197 Final Grades

2013-10-08T10:22:00.000+08:00

Another semester has gone. I feel that this class has learned things that they wouldn't have otherwise been taught, and yet there is a lot more to know. Even I am still learning! What I did was I only penalized those who did not follow instructions, such as rounding off, etc., or those who did not even try at all. That said, complaints will not be entertained. These grades are final. For one

Response to a reader question on the damping estimation formulas in NSCP 2010 Section 207

2013-10-04T10:51:00.000+08:00

A reader asked, Equations 207-38 & 207-39 equate damping to 0.016/h and 0.23/h, respectively. However, Equation 207-40 equates damping to 0.007/n, in which h = height of structure, and n = natural frequency of the structure. Are Equations 207-38 & 207-39 correct, or should h be replaced by n? Just because there are some errata in a document, that doesn't mean everything else is in error.

Another NSCP 2010 Erratum

2013-09-27T10:42:00.000+08:00

This one is actually a question asked by a former student.. from back in 2010! She says: I came across with Method 1 - Simplified Procedure, and in Equation 207-2, pnet=lambda*Kzt*w*pnet9, where pnet9, as given in the definitions, is the net design wind pressure for Exposure B at h=9m and Iw from Figure 207-3. I turn to Figure 207-3, and in the label of Figures 207-3 it states that it is "pnet (

Some NSCP 2010 Section 207 Errata

2013-09-20T10:37:00.000+08:00

If you have been using the NSCP 2010 wind loading provisions (Section 207), you have probably noticed already many typographical and other errors. I have only started to look at it more deeply recently, and here are some I noticed (and that readers have also pointed out): Section 207.7.1 points to Table 207-11, but there is no Table 207-11. Table 207-11 should actually be Table 207-5. Section

Take Home Quiz ;-)

2013-09-17T13:00:00.000+08:00

Note: This was updated on 9/17/13 at 8:00 PM. This is a take home quiz that I gave my students 10 13 days to complete on their own. To encourage independent work, I based the parameters they were going to use on their "student numbers." If you are a practicing structural engineer, go ahead and choose from the values listed below and try to answer the questions yourself. Problem 1 GEF

Presentation at the 2013 ASEP Wind and Earthquake Engineering Seminar, Cagayan de Oro City

2013-09-13T10:00:00.000+08:00

The 2013 ASEP Wind and Earthquake Engineering Seminar was held on August 16 to 17, 2013 in Cagayan de Oro City. Because of work, I took a 7:00 am flight from Manila, arrived at the CDO airport by 8:30 am, took an hour long taxi that cost P450, and arrived at the hotel venue just in time for my 9:30 am presentation! Incidentally, at around 12:30 pm, it took me about P550 of taxi to get back to

Presentation in front of ~2,000(?) Civil Engineering Undergrads at the 2013 National CE Symposium

2013-09-07T08:56:00.000+08:00

The event was held on September 6, 2013 at the University Theater, University of the Philippines, Diliman, Quezon City, and organized by the UP Association of Civil Engineering Students. I introduced the many different facets of wind engineering to these civil engineering undergrads from around the country. I think I did okay. :-)

An example problem on wind load calculation according to NSCP 2010 ;)

2013-08-08T17:00:00.001+08:00

A 20-meter-high square-plan five-storey building with flat roof and 4m-high floors, located in Makati CBD, has sides of 10 meters length each, and a large open front door on the first floor that is 2m x 2m in dimension. Assuming that G = 0.85 and that torsion is negligible, Show how this maybe is an open, partially enclosed, or enclosed building. Determine the internal

Demonstration of base-isolated versus conventional building under "earthquake" / ground motion #video

2013-07-16T03:12:00.000+08:00

Nice visualization/demonstration.

IBM to donate supercomputer to PAGASA

2013-07-11T09:56:00.000+08:00

The DOST announced that IBM will donate a supercomputer to PAGASA. The meteorological agency will purportedly use it with more advanced modelling software to account for general climate conditions in the country for the next 5 to 10 years, and to improve their weather forecasting, being able to anticipate typhoons up to 7 days before it might affect the country as opposed to the maximum 3 days

"iTyphoon" app for iOS, Android, Windows Phone, and Nokia devices

2013-07-09T06:43:00.000+08:00

From the developer's app description: "iTyphoon is a mobile application that provides typhoon updates to Filipinos and the world, free!" Download it via this iTunes link for your iPhone, iPad, or iPod touch: https://itunes.apple.com/us/app/ityphoon/id463238629?mt=8 Or visit the developer's download site to get the app on your other mobile devices: http://www.nueca.net/downloads.html

More papers on Typhoon/Wind Engineering in the Philippines

2013-07-04T04:43:00.000+08:00

These are links to papers/reports I was a co-author of, that are rather useful for typhoon/wind engineering education in the Philippines as well. Paper #1 - 2005, APEC-WW Workshop in Hong Kong, China Paper #2 - 2006, APEC-WW Workshop in New Delhi, India Paper #3 - 2007, APEC-WW Workshop in Shanghai, China Paper #4 - 2009, APEC-WW Workshop in Taipei, Taiwan Paper #5 -

Presentation at 2013 PICE National Midyear Convention

2013-07-02T06:00:00.001+08:00

On June 28, 2013, I went to Subic Bay to present a paper entitled "How to estimate 'site-specific wind loads?'" at the 2013 National Midyear Convention of the Philippine Institute of Civil Engineers. It is essentially a more formal paper version of an article I posted here on this blog earlier. The full video of the presentation is below. (Note: The slides are in English but the presentation

A report I prepared back in 2005: for #ThrowbackThursday ?

2013-06-27T14:30:00.000+08:00

Back in 2005, I was a Short-Term Fellow under what was then the 21st Century Center of Excellence Program (on Wind Effects on Buildings and Urban Environment) at Tokyo Polytechnic University, Atsugi, Japan. As part of the requirements during that two-month stint in Japan, I was asked to prepare a report that shows typhoon/wind damages and wind speed information for the Philippines. I also took it

Detroit DIYer cooks up stronger, lighter steel... shames scientists?

2013-06-25T11:01:00.000+08:00

Read this article on Engadget from back in 2011 first. The non-(civil-)engineers, of course, are in high praise for the "little guy" one-upping the "big guys" (i.e. the scientists). Because, sure, stronger and lighter steel is good. And faster production time. But hey, a DIYer discovering something is also almost effectively a scientist. An accidental one, maybe. But yeah, journalism is about

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