Precast lift cores earthquake loads

[aaronPTeng]

Hi all,

For precast lift cores, besides working out joint shear at the panel connection from Earthquake and wind loads, Transferring this between the panels Via Fixings and angles,
Accounting for the moment in each panel at the bottom connection and insuring dowel bars are fully developed for the loads,

Is there other ways Precast is used to handle lateral loads?

What I typically find at around 8 or so Story's the fixings between panels start to reach there limit (1500kN joint shear). I understand the loads vary in different places around the planet, However I am more interested in the higher level conceptual strategy that people tackle this with. As the approach I typically see is ignore it all together (in a low seismic zone)

regards,


"Structural Engineering is the Art of moulding materials we do not wholly understand into shapes we cannot precisely analyse, so as to withstand forces we cannot really assess, in such a way that the community at large has no reason to suspect the extent of our ignorance." Dr. Dykes, 1976

 

[CELinOttawa]

By "Precast lift cores" I presume you're talking about tilt-panels, and specifically the elevator cores. I've seen these designed for ductility (both in the panel and in the connections).

I've also been involved in seismic upgrades where the existing panels were strapped with steel cross bracing. While that's a pretty specific application, I don't see why you couldn't adapt it to increase your connection capacity. Instead of having bars to develop in drossback ducts, you'd have a plate, angle or maybe even a tee which protrudes from the panel and connects to an adjacent panel.

Rocking foundations, isolation, soft storey bound piles or other inventive geotechnical solutions may be able to help as well. I've seen a couple of jobs in firms I've worked for where the out of the box solution was to get the loads down rather than get the strengths, stiffness, or ductilities up. Both work, so don't forget to involve our friends who play in the dirt, particularly on anything over three storeys.