The Lotterywest Walkway is a fairly recent addition to Perth’s King’s Park, featuring a spectacular arched pedestrian bridge built of weathering steel with glass parapets. My impressions are shown in the photos below. Click on any image for a slide show.
I have previously linked to a spreadsheet stored on Skydrive, but I have been disappointed that the possibilities for using live spreadsheets are greatly limited by the lack of support for VBA. It seems that Microsoft have now decided to provide programming support through Javascript. This seems like a weird business decision on their part to me, but who am I to question the mysterious ways of Microsoft.
Jan Karel Pieterse has recently added an excellent introduction to all this on his site:
Embedding Excel files on your website
Including an example of a user definable animated Lissajous Figure:
Click to visit site.
Anyone else tried this? How did you find it?
Following the last post on this topic: Continuous Beams With Cantilevers by Macaulay’s Method, and by popular demand, I have now updated the continuous beam and single span analysis functions to accept spring translational and moment restraints. Also added is a new function to find the rotational stiffness of a cantilever beam with moment fixity at the opposite end (RotnK()). The new spreadsheet can be downloaded from:
The input for the revised Conbeam function can be seen in the screenshot below:
Conbeam input (click for full size view)
The Supports input range now has two additional (optional) columns allowing the translational and rotational stiffness of each support to be specified. These have been used to model a 3 span beam with two cantilever ends, supported on 4 columns, with 4 columns above. The rotational stiffness of the columns has been found using the RotnK function (the single column stiffness is doubled at each support because there are two columns). A Strand7 frame model of the equivalent frame is shown below.
Strand7 Equivalent Frame Model
Part of the output of the Conbeam function, compared with the Strand7 results, is shown in the table below:
Conbeam output compared with Strand7 results
It can be seen there is almost exact agreement, as is also seen in the graphical results:
Conbeam output compared with Strand7 results
Newton Papers
Cambridge Digital Library
Cambridge University Library is pleased to present the first items in its Foundations of Science collection: a selection from the Papers of Sir Isaac Newton. The Library holds the most important and substantial collection of Newton’s scientific and mathematical manuscripts and over the next few months we intend to make most of our Newton papers available on this site.
This first release features some of Newton’s most important work from the 1660s, including his college notebooks and ‘Waste Book’.
Click to go to Flickr site
Edit 13 Apr 2014: See Continuous Beam Spreadsheet with Moving Load for the latest version, which is now called ConBeamU.
I have updated the Macaulay spreadsheet (described here) to allow the analysis of continuous beams with cantilevers at one or both ends. The updated spreadsheet (including full open-source code) can be downloaded from Macaulay.zip.
My first attempt was to write a Cantilever user defined function (UDF), then apply the end moment and reaction from this function to a continuous beam with simple supports at the beam ends. I ended up with a different approach, but the Cantilever UDF was completed, and is included in the download spreadsheet.
Cantilever Function Output
It turned out to be simpler to just amend the code to allow the input of the position of the end supports, with some fairly minor adjustments to the Macaulay analysis code. Input and results for a three span beam with cantilevers both ends are shown in the screenshots below (click on any image for full size view). As before, the results have been compared with an analysis in Strand7, and show near exact agreement. See earlier posts in this series for more details of the background to Macauley’s method, and details of how to use the functions.
Conbeam Input with Cantilever Ends
Conbeam output compared with Strand7 results
Conbeam and Strand7 Results Compared
