Category: Dr. Cerato’s Blog (Page 3 of 4)

The three week test sequence is finally complete.  We pulled the skids off yesterday afternoon and are un-installing the piles today (Wednesday, February 24, 2016).  I will take lots of pictures of the piles as they come out of the sand box – I want to check out what exactly happened to some of the strain gages – we have to be able to gage piles and there really isn’t a standard, proven method.  One of the great pieces of information from this test is how to gage piles in very dense sands (N=35)… or how to better gage piles in a dense sand. It isn’t a trivial matter. I am looking forward to helping our industry get a better handle on that.

We stayed on schedule the entire time thanks to careful planning and preparation, the generous cash and in-kind donations of my DFI sponsors and my on-site contractor, Torcsill Foundations, who worked seamlessly with the site staff to support the project. These guys are the best and the site staff praised them everyday for their professionalism, work ethic and fantastic attitudes.  They got the job done!

The local news media came out yesterday to shoot the last big skid shake.

http://www.10news.com/news/engineers-test-new-technology-to-protect-buildings-from-earthquakes

http://www.kpbs.org/news/2016/feb/23/san-diego-earthquake-simulator-rocks-metal-pilings/

Discovery Canada was onsite for about 8 hours yesterday and their Daily Planet show will air in about 3 weeks. I’ll keep everyone posted on the additional news coverage and data management.

We are tentatively scheduled to present preliminary findings at Super Pile ’16 in Chicago in June, the HPTC specialty seminar in LA in July and the DFI International Conference in NYC in October.  I’ll hopefully be able to thank each of you in person for your help with this project when I see you.

We spent a LONG day Friday taking off the concrete donut weights, measuring and drilling lots of pile cap holes and we managed to place one skid around 5:30 pm. Early Saturday morning we placed the second skid and filled them both with sand. Each skid weighs about 3,000 lbs and we filled the 5.5″ pile skid with around 13,000 lbs of sand for a total weight of about 16,000 lb, or 4,000 lbs per pile. On the 3.5″ pile skid we loaded it with about 4,000 lbs of sand plus the skid for a total of roughly 7,000 lbs or 1,750 lbs per pile. During the inertial weight tests we took the 3.5″ piles to 95% of their ultimate bending moment with about 1,600 lbs on the pile, so I did not feel adding much more load was prudent. We’ll see what happens during the Takatori 100% shake!

We should be shaking the skids tomorrow (Monday) in the “fixed” connection condition and then the “pinned” condition Tuesday morning. In the “pinned” condition we take out one bolt from each pile cap and leave one in place. Hopefully we are on tear down mode Tuesday afternoon.

If you aren’t here, you are missing it! Pilot light is on….woohooo!!!!!!! 

Greetings from the 2016 GeoStructures conference in Phoenix. Don’t worry- I fly back to San Diego tonight to keep the test sequence moving ever forward. We are planning on having all the cables hooked to the data acquisition by the end of the day Tuesday and do the first shake on just the piles Wednesday the 17th. Once we are done with that shake we will load the concrete weights on the piles and then hopefully do the inertial weight shake sequence on Thursday the 18th. There are hard hats available onsite and bring a pair of safety sunglasses.  Let’s shake (and hope the piles behave as they were modeled)! Exciting! See you there.  

In an amazing feat of teamwork, we were able to finish splicing, dropping and bundling 125 strain gauge cables.  We also worked on getting the seismic skids modified and pile caps marked for installation.

We will spend Thursday and Friday hooking up the strain gauge and accelerometer cables into the data acquisition system and hopefully get to the “checking” stage before the long weekend for an anticipated Tuesday shake of just the piles with no weights.

We had a great two days out in sunny and hot San Diego installing piles.  The team did a great job with all the instrumentation and we only lost 27 gages (out of 152) due to sand abrasion, mostly at the helix level, and some crunched wires.  The amount of data we’ll collect should be outstanding.  We will spend Wednesday and Thursday hooking up the instrumentation and hopefully we will be ready to shake by Friday morning – if not Friday, then we’ll shake first thing Tuesday and then start putting on the pile caps and concrete donut weights for a shake either Wednesday (17th) afternoon or Thursday (18th).

Here is another recent news story about our seismic research project!

http://www.koco.com/news/ou-researcher-studying-building-techniques-for-earthquakes/37878158