Annie and I had a lovely trip to Santa Barbara and then over to Yosemite for some snowshoeing. One the way down we camped at Pismo Beach near a wintering spot for monarch butterflies. Yosemite Valley is uncrowded this time of year which was nice. We visited Hetch Hetchy Valley for the first time. Hetch Hetchy is north of Yosemite Valley and reached from Hwy120. We had an enjoyable hike to Wapama Falls and didn’t see another person for several hours. Recommended.
I’ve been thinking about how tower cranes are disassembled from the top of skyscrapers.
I searched the Web and the most common answer is that a mobile crane is used to disassemble the tower crane. This obviously works for short tower cranes. If the tower crane is erected on the outside of a skyscraper it can lower itself down with a climbing unit until it is low enough to be disassembled by a mobile crane. (example photo)
However, I did not find a good description of what is done when the tower crane is built inside an elevator shaft and is too tall for mobile cranes.
As luck would have it, a tower crane was being assembled in Berkeley last week and I went over to ask the workers how they disassemble tower cranes from skyscrapers. The company doing the assembly Sheedy Drayage out of San Francisco. They said that sometimes they need to erect a roof-mounted derrick to disassemble the tower crane. These pages on their web-site have some photos and descriptions of using a hand-assembled derrick to hoist a larger roof-mounted crane to the roof.
http://sheedycrane.com/project_345_california_st.html
http://sheedycrane.com/company_history.html
Some other tower crane disassembly info:
Here is a description of disassembling the tower crane from the top of the Stratosphere in Las Vegas.
The history channel has an episode on tower cranes.
History Channel, Mega Movers: Tower Crane
Aired on June 13, 2006
http://store.aetv.com/html/product/index.jhtml?id=76199
This site has good photos and a description of disassembling a tower crane with a climbing unit.
http://frank.itlab.us/bridge/wrapper.php?apr_08_2005_east_crane.html
I had the pleasure of visiting the Oakland Zoo with 80 first graders yesterday. Highlights were a young giraffe and the new Children’s Zoo area with alligators.
I recently had a need to concatenate a bunch of PDF files into one PDF file so the contents would be easier to browse and search. I looked on the web for pointers to free Linux-supported tools and found this helpful post: http://ansuz.sooke.bc.ca/software/pdf-append.php
I first tried pdftk and it failed with a message that the owner password was required. I checked the security settings of the PDFs in question and ‘document assembly’ was restricted so I’m guessing that is what caused pdftk to fail.
http://www.accesspdf.com/pdftk/
Next I tried the iText tools. This required downloading the iText jar file (libitext-java Debian package) and compiling the concat_pdf class for command line concatenation operation as described in the iText tutorial.
http://www.lowagie.com/iText/
http://www.lowagie.com/iText/tutorial/ch13.html (concat_pdf)
This solution worked well for me but it was a hassle to install the Sun JDK to compile concat_pdf.java.
While doing some aptitude searching I found the pdfjam package is a set of scripts interfacing to the pdfpages tools. The pdfjoin script worked great on my PDFs.
http://www.warwick.ac.uk/go/pdfjam
If you are running Debian I recommend you try pdfjoin in the pdfjam package first.
Memorial Day weekend backpacking trip along the northern 25 miles of the Lost Coast. Beautiful weather, good company, wildflowers, and miles of beach!
Larry and I took a nice 12 day road trip to the Northwest to visit friends near Port Orford, Oregon and in Seattle, Washington. The photos start in Seattle, cover our day trip to Vancouver, BC, and then head down the coast.