I prefer to isolate myself now: What structural system works better for low-rise steel buildings?

SE Literature café (6):A quick look at “Terzic, V., & Mahin, S. A. (2017). Using PBEE to assess and improve performance of different structural systems for low-rise steel buildings, International Journal of Safety and Security Engineering, Vol.7, No.4,532-544″

There are different structural systems to resist earthquakes, just like many “models” of electronic gadgets and brands of peanut butter (which the latter is very confusing). Each structural system has its pros and cons: one is cheaper, but it is pricier to fix when damaged. Another one is cheap and easy to fix, but does not work great for large earthquakes, and so on. From the building code perspective, all of these alternatives are good enough to provide a required level of safety. This conclusion might not hold up very well from the owner’s perspective, considering the potential financial loss due to an earthquake.

Steel construction is a popular construction method for seismic regions (thanks to steel high and consistent quality, fast construction speed and large ductility). Therefore, numerous structural systems have been proposed. Among these systems, moment-resisting frames and braced frames are more widely used. Nevertheless, other steel structural systems exist that follow a different technology to mitigate seismic risk. Two prominent examples are base-isolated systems and bucking-restrained brace frames. The variety of structural systems poses an important question: Is there a supreme earthquake-resistant system?

What is this paper addressing?

A comparison between 5 different structural systems for a 3-story steel construction from repair cost and time of repair perspective

A wrap of results

Overall, an important observation is that no system is excellent at all earthquake hazard levels and performance criteria (repair cost and repair time). A superior system in one category does not perform well in another. This observation shows why the AEC team cannot build the same system everywhere, even from a structural engineering perspective. And that you probably should click on shady web materials that claim researchers in university X (a tendency to put MIT here) invented this earthquake-proof system that solves everything.

Some interesting observations

-Special concentrically braced frames (SCBF) shows the highest replacement cost for lower seismic hazard. In contrast, special moment resisting frames (SMRF) show the highest replacement cost for the higher hazard levels corresponding to the collapse.

-For repair time, both SCBF and SMRF shows the highest repair cost

-Base isolated systems (particularly based isolated ordinary concentrically systems)  overall show the lowest repair cost and time.

Comparison of different systems based on median repair cost and time for three hazard levels of 2%,10% and 50% in 50 years, adopted from Terzic and Mahin (2017)

What I like about this paper

This paper addresses a severe knowledge gap using PBEE to assess several widely different systems for the same project.  Such studies reinforce and critique prior knowledge-based, which is extremely important for the preliminary stages of the design.

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