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.

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:

Wind-Induced Vibrations Damage Pedestrian Bridge

"The first cable-stayed bridge in Minnesota——a 686 ft dedicated bicycle and pedestrian crossing over a busy six-lane road in Minneapolis——was greeted with fanfare when it opened in 2007. But on February 19, 2012, two of the cables detached from the Martin Olav Sabo Pedestrian Bridge when the cable diaphragm plate holding them to the main pylon fractured and a portion of the plate fell to the ground... A new report has determined that wind-induced vibrations caused the failure of a cable diaphragm plate."

Framework for structural damping predictor models based on stick-slip mechanism for use in wind-resistant design of buildings

Article to be published in the June 2013 issue (Vol. 117, pp. 25-37) of the Journal of Wind Engineering and Industrial Aerodynamics. It was published online on 12 May 2013. Co-authored by yours truly and my former PhD supervisor at Tokyo Polytechnic University and current International Association for Wind Engineering president, Prof. Yukio Tamura.

Abstract:

On stick-slip phenomenon as primary mechanism behind structural damping in wind-resistant design applications

Article published in the April 2013 issue (Vol. 115, pp. 121-136) of the Journal of Wind Engineering and Industrial Aerodynamics. It was published online on 5 March 2013. Co-authored by yours truly and my former PhD supervisor at Tokyo Polytechnic University and current International Association for Wind Engineering president, Prof. Yukio Tamura.

Abstract:

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.

ICWE13 Presentation

I had the privilege to attend and present a paper at the 13th International Conference on Wind Engineering, held in Amsterdam, the Netherlands, from the 10th to 15th of July, 2011. It was a successful conference with over 600 papers, and more than 500 participants from all over the world, including a large majority from Asia.

"A journey around the edge of wind engineering"

This is a report on ‘A journey around the edge of wind engineering,’ an Intensive Course lecture by Prof. Chris Baker, that I submitted as part of the requirements in my PhD study.

What does performance-based design mean to you?

I have some background only in performance-based structural/seismic evaluation and design of buildings.  I do think in wind design performance-based design (PBD) is already being done for tall buildings particularly those which undergo wind climate studies and wind tunnel testing for structural loading, cladding design, and occupant comfort checking.  This is how I see what PBD is in general, to apply to any field (and it is just what I think).

I think...

Basic Structural Dynamics for Structural Engineers

I just delivered a basic structural dynamics lecture for structural engineers.  The audience had varying structural engineering experience from a few months to a couple of decades. 

PICE 2005 Mid-Year in Cebu

I presented a paper on "Monitoring and Mitigating Vibrations at Industrial Facilities and Construction Sites" at the Philippine Institute of Civil Engineers' (PICE) 2005 mid-year convention in Cebu. Wonderful time in Cebu. See the photos on multiply.com. Preview the paper/presentation.