Lazy Navel Gazing

This blog has two starts: November 2009 when I experimented with blogging software and almost exactly a year ago, when I let B^4 talk me into this. Here’s the index:

  • Total posts: 228
  • Posts since I started for real: 226
  • Posts since January 1, 2011, when I decided to try to post every day: 100
  • Days missed since then: 2, with more likely to come
  • Comments: 2002
  • Spam comments I’ve deleted: 189
  • Maximum views in a day: 213
  • Views as of this writing: 12,563
  • Blogwhoring episodes at Sadly, No!: about a dozen.
  • Posts worth reading: five or six.

Landmarking

This is horseshit for any number of reasons, starting with the fact that the suit is motivated solely by bigotry and ending with the fact that these stupid motherfuckers, if they won, would undermine New York’s landmarks law. People don’t realize how weak historic preservation is in this country: building on the national register have no particular protection from alteration or demolition, and most local landmarking laws are weak. NYC’s is the strongest in the country, partly because development pressure is so strong here and partly because of the memory of our great martyr, Penn Station.

I doubt this lawsuit will get far, but if it were successful it would allow anyone to challenge landmarking decisions – which in the end are subjective assessments of historical and cultural value – and thereby greatly reduce the ability of the Landmarks Commission to do its job of protecting actually historic sites.

Bad Luck Strikes The Inanimate

One of the most beautiful (IMO) bridges in New York is barely known. t was well-regarded when built, but had the misfortune of (1) losing its name to a much bigger bridge half a mile away and (2) being blocked from view on one side by new construction. I am speaking of the Washington Bridge connecting streets in upper Manhattan to streets in the Bronx over the Harlem River. (All pix, click to embiggen.)

The bridge actually has two identical arch spans, one over the river and the other over the low land on the Manhattan side adjacent to the river.

What makes the Washington so good looking is that the spandrels – the curved triangles between the road deck and the arches – are filled with some of the laciest steel latticework you’ll ever see. It’s best appreciated when looking slightly obliquely:

It opened in 1888, more than 40 years before that Georgey-come-lately on the other side of Manhattan. The real loss came later, when the “Trans-Manhattan Expressway” (also known as the stub end of the Cross-Bronx Expressway that connects to the GWB*) and the Alexander Hamilton Bridge were built just north of the Washington, obscuring the view from that direction and degrading the view from the south.

*Initials that to any New Yorker mean George Washington Bridge, regardless of what odious meanings they may have acquired since 2000.

Failure

Preface: I know no more about nuclear power plants than any other outsider.

“Failure” is yet another word that has a technical meaning among engineers that is similar but not identical to its common meaning. When an engineer discusses failure, he or she means something along the lines of “performance that does meet a specified set of criteria.” A program crashing on your laptop is a form of failure that has few adverse consequences (other than your blood pressure) and is therefore considered acceptable. A building collapse under ordinary loading – whatever that means – is a catastrophic collapse that will have, at the least, legal repercussions.

Another terms of art: “safety factor.” It means the capacity of a designed system divided by its actual load. (That system can be the electrical power grid, your town’s sewer system, or a building frame.) Modern building codes have design safety factors in the range of 1.2 to 1.8, depending on circumstances and based on the heaviest expected loading: the 100-year storm wind or snow, the 500-year earthquake, and so on. Airplanes have high safety factors or their mechanical and electronic systems, but as low as 1.1 on their structure for the simple reason that making a plane stronger makes it heavier. Elevators have very high safety factors, which is why you pretty much never hear of an elevator failing by having its cables snap.

How does failure in the engineers sense occur? The capacity was less than expected (from wear, weathering, man-made damage, mis-design, or poor construction) or the loads were higher than expected. The loads got to be higher than the capacity (SF < 1) and something gave way. Some failures are local and therefore not horribly serious, some are systemic, and the worst begin locally and trigger systemic failure. There’s a lot more to say on this topic, so I’ll return to it in the future.

A common belief among engineers is that no failure has a single cause. This is not provable and in my opinion not really true, but it’s a good rule of thumb because it’s true most of the time. Most building failures that I’ve seen first-hand had multiple causes. The explosive Ford Pintos were a good example of one bad design flaw that could cause failure when combined with a common accident type, so each exploded car had two causes for its failure. The nuclear power plants in northeast Japan have multiple and redundant safety systems, many of which failed simultaneously or nearly so and have led to the possibility of catastrophic failure. I’m sure that the reasons for that will be examined in depth in the coming months. I’m also sure some of the reasons found will be of the “we didn’t think that we would get earthquakes or tsunamis this big” variety.

The picture shows the result of failure of cast-iron columns. The building had been 9 stories high the previous day, under construction.

Japan: Comparative Damage

The really striking thing about the pictures I’m seeing is how large a percentage of the damage is tsunami related. Japan has some of the strictest building codes in the world, and a good rate of code compliance, so even the wood houses tend to survive even as large an earthquake (now estimated at 9.0) as this. But few buildings are strong enough to withstand the pressure of a tsunami, and those few tend to be damaged by floating debris consisting of other buildings, ships, trees…

The continental U.S. has not suffered from a major tsunami since formal records have been kept. Perhaps the closest equivalent was the Johnstown flood, which wiped a large portion of the town off the map.

PS: A good way to visualize the issue.

No Surprise

Anyone who’s ever driven the Cross-Bronx could have told you this.

Why is it so bad? Heavy traffic, heavy truck traffic, narrower-than-modern-standard lanes, retaining walls on both sides, narrow or no shoulders, steep grades, mediocre comic book.

PS: I forgot to mention: most of the exit and entrance ramps are too steep and have too-short deceleration and acceleration lanes; the remainder have no deceleration and acceleration lanes.

A Reminder

The Richter and Momement-Magnitude scales are logarithmic. A magnitude 7.0 earthquake releases ten times as much energy as a magnitude 6.0 quake. In recent quake terms: Haiti was at 7.1, Christchurch was at 6.3, and yesterday’s quake off the Japanese coast was at 8.9 or so. The Japanese quake was roughly 400 times as powerful as the New Zealand quake.

Destructiveness is related to more than magnitude: local ground conditions; the direction, frequency, and type of movement; and the local building types all play large parts. For example, Christchurch was entirely filed with new buildings that meet the current N.Z. codes, there would have been far fewer deaths. On the other hand, it is hard to overstate the amount of energy it takes to create a tsunami that threatens both the east and west coasts of the Pacific Ocean.

 

Update: Idiots.

The Second Worst Idea…Or Not

An artist has decided to draw every building in New York. I find this doubtful. First, there are roughly 1,000,000 buildings in the city, so at a pace of ten per day it will take him just under 274 years. (Obviously he could do more than ten per day, but I’m assuming he needs to eat, sleep, shit, and work.) Second, his style is nice but is not exactly photographic. His illustration of one tenement is not going to be all that different than his illustration of another. Finally, and maybe I’m being naive here, but who is the audience?

I’m not saying he should stop. I’m just boggled.

Hat tip to Willy.