I wrote about the FIU bridge collapse this past summer when the OSHA report came out. The more comprehensive analysis from the National Transportation Safety Board has been released, and it brought up a lot of the same issues for me. In short, regardless of the mistakes that led to the specific accident that occurred, …
It was very windy on Thursday and I wanted pizza. There’s a good shop two blocks away, and if you get two slices they use a small box rather than a bag. As I was walking back to the office, it quickly became clear that I had to use both hands to carry the box, …
Some engineering concepts are easy to explain. For example, the idea that stress and strain are related can also be expressed, crudely, as objects squash when you push on them. Everyone understands that on an intuitive level. Other concepts, like strain compatibility, are a little more difficult. The short version of strain compatibility, if I …
That odd photo is a brick pier in the cellar of an uptown brownstone. There’s some water damage at the base from rising damp, but otherwise no reason it couldn’t perform its structural role. The line of piers and girders in the cellar is below the stairhall partition on the floors above, which is an …
The defining feature of a mansard roof, a sloped facade/roof, is mildly problematic as structure. Under just the gravity load of the wall’s own weight, there is a small overturning moment, which is resisted as an inward thrust at the top and an outward thrust at the base. If the sloped wall is carrying other …
