by Don Friedman on January 21, 2018

So far we haven’t found a project use for Mola, but that doesn’t mean we’re not using it to make models.

Analyzing Sisyphus

January 7, 2018

You can’t really see it, but I took that picture during the snowstorm on Thursday. The somewhat hyper maintenance staff in Battery Park City had already plowed this section of park walkway once, as you can see, and were plowing elsewhere at the time. They were obviously on some kind of schedule to rotate through […]

Read the full article →

Extreme Events

January 4, 2018

Today’s storm gives a good context for the loads that are code-mandated for use in building design and analysis. I’m going to make a point now, at the beginning, and again at the end because it’s so important: I’m not arguing against the loads defined in building codes, I’m simply comparing extreme events with ordinary […]

Read the full article →

A Different Take

December 17, 2017

Here’s a good interview with John Ochsendorf, a professor at MIT and the director of the American Academy in Rome. (I see John on average once a year at a conference, so I know a bit more about his work than Wikipedia.) His research, for years, has focussed on structural analysis of old-fashioned masonry structures. […]

Read the full article →

Theory Imposed on Reality

December 15, 2017

That’s a fine, very-short-span bridge in the Ramble in Central Park. Honestly, it feel ridiculous to call it a bridge when the space below it resembles, more than anything else, a door, but what else could it be? One pedestrian path crosses over another, and a wall of large ashlar blocks has a hole in […]

Read the full article →

When Is An Arch Not An Arch?

November 15, 2017

That’s the F/G subway, paralleling 9th Street in Brooklyn, where the tracks cross over Fourth Avenue. The train is elevated here because it crosses over the Gowanus Canal a little to the west at the Smith/9th Street station. As the tracks head east, to the left, they stay at roughly the same elevation as the […]

Read the full article →

Arching Action Index

October 31, 2017

I’ve been caught up in writing about arching action recently, and I thought it might make sense to collect all of the posts on this topic in one place. So: What Is Arching Action? Arching Action, Too Not Amenable To Easy Analysis Arching Action Visible Jack Arches Are Arching Action If I post again on […]

Read the full article →

Physically Impossible

October 31, 2017

That’s the north facade of 390 Fifth Avenue, the Gorham Building, at its east end where it meets the Fifth Avenue facade. It was built in 1906 and the avenue storefronts were modified in the late 1960s or early 70s. Where the newer glass curtain wall ends, just to the left of the truck, you’ve […]

Read the full article →

Inverted Arch Foundations Are Upside-Down Fun

October 5, 2017

Every once in a while during design, I remind myself of what various types of structural member do, as a way of thinking about what I need done. For example, the simplest definition of a “beam” that I can come up with is “a linear structure that carries load at right angles to its long […]

Read the full article →

Blatant and Odd Fakery

October 4, 2017

The entrance to a garage in a late-1980s, maybe early 1990s apartment house is dead center in that photo. I can’t stop staring at the “flat arch” above the opening. Someone went to a lot of trouble to make the stone veneer (which is most likely in front of concrete block back-up) look like this […]

Read the full article →