record scaling

02-Analytical capabilities
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Posts: 11
Joined: 13 May 2021, 21:26

record scaling

Post by aliisaberiiii »

Hi everybody
I downloaded the record from Peer. Each Time Series Records has two horizontal components(H1,H2).There are two maximum accelerations for each component(PGA1,PGA2). To scale it, it is necessary to divide the components of each into the maximum acceleration (max(PGA1,PGA2)). I want to analyze the structure under shock and aftershock. There are also two maximum accelerations for aftershock (PGA3,PGA4). Now my question is, to scale, should horizontal aftershock components be divided by their maximum acceleration (max(PGA3,PGA4)) or maximum total acceleration (max(PGA1,PGA2,PGA3,PGA4))?
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Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA

Re: record scaling

Post by huffte »

There are various definitions of scaling parameters in modern design codes and specifications. Some rely upon a geometric mean response spectrum of the two horizontal components. Others rely upon a maximum direction response spectrum of the two components rotated through all possible angles. Yet others are not explicit in defining the target spectrum basis. So, it seems that the answer to your question depends upon what you wish to accomplish with your analysis and may be best answered by your supervisor. Certainly, SeismoSelect has multiple options for the target spectrum basis.

On the surface, it seems that you would want to maintain the relative differences between a main shock and an aftershock. In other words, if the main shock PGA were 1.0 g and the aftershock PGA were 0.7 g, then it would seem to make sense the make the scaled aftershock 70% of the scaled main shock. That said, I reiterate that this is likely a decision you and your supervisor should make, based on the goals you hope to achieve.
Tim Huff
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