Bouncy Concrete

Mission_valley Lemme tell you a story: Here in San Diego there is a place called Mission Valley, which is where Mission San Diego ("California’s First Church") is located. (It–the church, not Mission Valley–was built over 200 years ago, before the founding in the U.S.)

I used to live right next to Mission San Diego and thus in Mission Valley.

Down the midst of Mission Vallue is the I-8 interstate.

Bisecting Mission Valley along its north-south axis is the 805 freeway.

The 805 doesn’t cross the bottom of Mission Valley, though. Instead, flung across the valley is a huge bridge, (what seems like) hundreds of feet in the air.

I get a little nervous whenever I have to cross the Mission Valley Bridge. (I once saw a too-quickly-lane-changing pickup there flip over right in front of me, killing the man and pregnant woman inside it.)

But it’s a major traffic exchange point in San Diego (photographed above by satellite), and when I lived in Mission Valley, I regularly used it.

Particularly because had friends who lived on the north side of Mission Valley, right near where the 805 bridge rejoins solid ground.

It was really convenient to go over to their house! I’d just get on the I-8, head towards the Mission Valley Bridge, and then zoom up ramp to the 805 and the point where their house was.

On the way home afterwards, I’d head down the Mission Valley Bridge, take the exit ramp curving down to the I-8, and in a few minutes I’d be home.

Now: One Friday night I was heading down the 805/Mission Valley Bridge ramp and my car (didn’t have a pickup at the time) suffered a DOUBLE BLOW-OUT. Both of my rear tires popped.

Quickly, I worked my way into the emergency lane and stopped the car. I got out to see if I could change the tires and discovered this was impossible. Not only did I not have two spares, the car consumed the entire width of the emergency lane on the bridge, meaning that my body would have to hang out into Friday night traffic if I even attempted to change the tires.

Not a good solution.

I therefore started trudging back up the incline until I reached an emergency callbox, where I could call for help. (This was in the ’90s, before I had a cell phone.)

After trudging up half a mile or so (that’s how big the bridge is), I finally reached the callbox and summoned a tow-truck. I then returned to my car to wait.

At this point in my life, I was (foolishly) suppressing the Southern elements in my speech, except that they would come out when I was either very relaxed or under stress. Needless to say, I was twangin’ up a storm by the time the tow-truck guy arrived.

Once he got there, I waited in the cab of the truck and he used it’s mechanism to slide a big metal plate under my car, which the truck then lifted up and redeposited it onto the back of the truck.

As it picked my car up off the roadway and redeposited it, the truck vibrated MIGHTILY, ROCKING BACK AND FORTH IN THE EMERGENCY LANE PRECIPITOUSLY, WITH ME IN THE CAB LOOKING DOWN INTO (WHAT SEEMED LIKE) HUNDREDS OF FEET OF DARKNESS OVER THE CONCRETE RAILING AND SAYING PRAYERS TO WHOEVER THE PATRON SAINT OF BRIDGE-BUILDING MIGHT BE (St. Patrick, among others, as I later determined).

The tow-truck guy towed me home in mere minutes, and all was well that ended well. (I bought new tires the next day.)

Now: What brings this story to mind?

When I was walking up the incline to get to the emergency phone, I noticed something very disturbing: The Mission Valley Bridge . . . BOUNCED.

As cars would zoom past me toward whatever Friday night merriments they had planned, the roadway under my feet . . . BOUNCED. It wasn’t rigid. It was made out of concrete, of course, but still it . . . BOUNCED.

In earthquake-prone California, bouncy bridges are important.

The reason is that structures that have a little "give" in them have less of a tendency to break. That’s why the wings of an airplane are designed to bounce when they encounter turbulence. If they were rigid, they’d snap off. I therefore know I’m safer if I’m sitting over the wings and see them bouncing–thought I still don’t like it. It annoys my pre-reflective sensibility that rigid structures are stronger than flexible structures.

Flexible_concrete Tonight I was thinking about this because I ran across

A STORY ABOUT EXTRA-FLEXIBLE CONCRETE.

It may not have the zing of transluent concrete, but it’s zingy (and bouncy) enough.

EXCERPTS:

By mixing fiber in concrete scientists have created a bendable material that is lightweight, resists cracking, and lasts longer.

Fiber-reinforced concrete is not new. But this variety, developed at the University of Michigan, is said to be 500 times more resistant to cracking than what your sidewalk is made of. It’s also 40 percent lighter.

The stuff is called Engineered Cement Composites (ECC).

The Michigan Department of Transportation (MDOT) will use the ECC to replace part of a bridge that crosses Interstate 94. The slab will eliminate the need for expansion joints, which are moveable steel teeth that separate sections of regular concrete. With the ECC, a longer continuous slab will be possible.

The Mihara Bridge, a new structure in Hokkaido, Japan, has a deck of ECC that is a mere 2 inches (5 centimeters) thick. It is expected to open this month.

God bless the folks who have blow-outs on the Mihara Bridge!

Hail The iPod!

Ipod_1Okay, that allusion is rather obscure, so four points (instead of the usual two) to the person who can supply the two consonants needed to complete the allusion, as well as identifying its source. (Tim J has a shot at this, I happen to know.)

That said, not only may “Hail the iPod!” be obscure, the concept of an iPod itself may be obscure for some folks.

Despite all the buzz about them on the ‘Net, an awful lot of folks aren’t sufficiently addicted to modern media trends (despite Madison Avenue’s best efforts in that regard) to have become iPod-obsessed yet.

Recently, in fact, someone asked me the very sensible question: “What is an iPod?”

I explained it by saying: “It’s like a digital Walkman.”

For anyone remotely tuned in to consumer electronics after 1980, that would do the trick, and it did.

For those even more immune to the blandishments of Madison Avenue, I’ll offer a slightly elaborated elaboration: An iPod is a hand-held device designed to do basically one thing—play audio files like a tape recorder, only without the tape.

Most of the time people play music on their iPods, but they also play spoken-word files, like audiobooks. A favorite format for these files (though not the only one) is the much-touted “.mp3” format that you may have heard of.

How it works is this:

  1. You pay for sound files that you download off the Internet and onto your computer, or your copy sound files from your CD collection (which you paid for) onto your computer. Or you make your own sound files (which you don’t need to pay for since you’re the copyright holder).
  2. Then you transfer these sound files to your iPod and then you go out in public and listen to them like a blissed out zombie through tiny electrodes attached to your braintiny earpieces. This is a process known as “capping.”
  3. You steal music and put it on the iPod and work it off in purgatory and (possibly) jail.

The thing is: iPods are really cool. Almost as cool as digital watches used to be. And they’re all the rage.

One can see why!

I bought an iPod a while back and have been using it constantly. It came in particularly useful on my recent trip. I’ve only filled up my (40 gig) iPod by 10%, but that 10% gives me 12.4 days of continuous listening without having to hear the same song twice (if I don’t want to). At this rate, I could fit four months (124 days) of solid listening onto my iPod.

As you can see, you can fit a huge amount of sound onto an iPod, and it makes packing for a long trip much easier (for me, anyway).

Of late I’ve been taking along all kinds of music CDs on trips, as well as a bunch of abridged audiobooks (since unabridged audiobooks take up too many CDs and are hard to get and expensive), as well as a lot of dead tree books that I’d rather have in electronic format.

Not anymore! (Mostly.)

This time I didn’t take any music CDs or any audiobooks on CD. I just too my iPod, which contained more music and more (unabridged!) audiobooks and downloaded radio shows than I could possibly listen to on the trip. All of the bulky audio stuff I would normally have taken to keep myself aurally entertained and informed was replaced by one tiny device not much bigger than a pack of cards.

My suitcase loved me.

The iPod even replaced dead tree books that I would have previously taken. As I mentioned, the morning I left, I downloaded Cardinal Ratzinger’s interview audiobook Salt of the Earth (from Audible.Com).

But that’s not all!

I’d also converted tons of public-domain writings by fiction authors like H. P. Lovecraft and others to .mp3 format, and these also whacked down on the number of dead tree books I would ordinarily have taken, consuming valuable space and putting additional weight load on my suitcase.

I still succumbed to the temptation of taking a few of books not yet available in electronic form (such as Cardinal Ratzinger’s Introduction to Christianity and Truth and Tolerance), but my suitcase loved me anyway. For a bibliophile such as myself, this was a real change!

To bend the old TV Land slogan, it was “Better Living—Through Technology!”