Archive for the ‘Other topics’ Category

Oakland builders, what are you thinking?

12 June 2017

Californians have always known we’re prone to earthquakes. The first Californians didn’t have our worries about it, though, because their structures were small and limber, no larger than a temescal sweathouse. Things changed when the missionaries of New Spain came into the country starting in the late 1700s. When the earthquake of 8 December 1812 took down the six-year-old stone church at San Juan Capistrano during the day’s first service, the forty natives who died were probably the first Californians ever, in thousands of years, to be killed by a structural collapse from an earthquake.

To the Americans who succeeded the Spanish and Mexicans in the Bay area, earthquakes were well known. By my count, after Oakland incorporated in 1852 its inhabitants experienced thirteen notable earthquakes in the 54 years before 1906. As the American cities grew up around the Bay, builders sought to guard against quakes with thick walls of ever-stronger materials, culminating in concrete and steel. In the century since the 1906 San Francisco quake, engineers and architects have repeatedly improved the building codes.

Today, buildings of almost any shape and size can be designed to withstand the largest earthquakes. That doesn’t mean we’ll trust them. Just as some of us get vertigo looking at photos of confident rock climbers, appearances can outweigh reason.

In recent months, two large buildings have been proposed in downtown Oakland that actually included overhangs. The one originally submitted for 325 22nd Street, facing the Ordway Building, looked like this, with a cantilevered soffit (as seen on SocketSite).

The Planning Department didn’t like its bulkiness and awkward fit with its neighboring buildings, so that design was replaced with a more traditional set of boxes.

The other building site is at 1100 Broadway, the lot next to the old Key System Building, both of which have been vacant since the 1989 earthquake. The latest project, from new owners Ellis Partners, is supposed to renovate and integrate with the Key Building, and this overbearing design is what they came up with last month.

After getting feedback from planners and the Oakland Heritage Alliance, they submitted a revised design last week. They just love that looming cantilever — in fact they added more on other sides.

Builders and planners are pros, so the overhangs are designed to hold. I understand that very well in my head. But how many of us will feel secure beneath — or inside — a cantilevered structure?

The National Earthquake Hazard Reduction Program (NEHRP) has funded and published research into building standards since the 1970s. Its publication Earthquake-Resistant Design Concepts spells out seven characteristics that are necessary for buildings in areas prone to large earthquakes. Two of those are especially pertinent for cantilevered designs: continuous load paths and regularity. The first means that the forces a quake imposes on a structure need to be guided down to the ground. The second means that irregular buildings must be extra strong, as “the damage can be concentrated in one or a few locations, resulting in extreme local damage and a loss of the structure’s ability to survive the shaking.”

I think these are obvious to most people, and that’s why, say, the new Kaiser hospital is reassuring in its continuity and regularity. The Transamerica Pyramid, even the new Salesforce Tower — reassuring.

The design for 1100 Broadway is a textbook example of discontinuous and irregular, especially in its integration with the hundred-year-old, damaged Key System Building. The NEHRP Concepts classify downtown Oakland office buildings in Seismic Design Category E, just short of the most stringent category used for hospitals, police and fire stations and other critical structures.

After the East Bay’s next big earthquake, our perceptions will change. It’s important to think about that. Old-timers who were here for the Loma Prieta quake in 1989 can tell you. For years afterward, this fine old town will feel like Doctor Caligari’s city, angular and foreboding.

When large quakes strike, buildings can sustain damage in an earthquake and then collapse in aftershocks, of which we will have plenty after a magnitude 6.7 event. I use that magnitude because the official odds are based on it, and they give the Hayward fault a one-in-three chance of producing one before the year 2043, within the useful life of these proposed buildings.

No one alive has experienced such a quake in Oakland. Once we do, buildings with overhangs, even if they perform superbly, will no longer look vibrant or stylish — they’ll look deadly to our newly cautious eyes. And with that they’ll be effectively worthless, except maybe for low-income housing (which would be a good thing). And the city that thought such a building was a cool statement will be judged for that statement.

I submit that builders and the city should be very conservative in not just their designs, but the appearance of their designs.

Adeline rise

5 June 2017

Down at the foot of Adeline Street, past Green Valley Food, past J. K’s Brickhouse, past Magnolia Oakland at 3rd Street, the road ends at the old shoreline. Where the Amtraks roll by was once coastal marsh.

The geologic map uses an old pre-earthquake topographic base, so ignore the freeway and find Adeline, running through the “m” in Qms. The Qms refers to the Merritt Sand, the field of ancient sand dunes, once covered with oak forest, where the city of Oakland first took root.

If you stand at 3rd Street and look north past the 5th Street Lofts, the BART tracks and the 880 freeway, you’ll see the land lift as the road leads into West Oakland.

A benchmark on this spot has an elevation of 9 feet above sea level. Between here and 5th Street was once a small arm of the Bay, long since filled in. Another benchmark on 7th Street is at 16 feet, and just north the ground goes above 20 feet.

The Merritt Sand dunefield is very level. Its highest point is roughly under City Hall, at an elevation a little over 40 feet.

What I marched for

24 April 2017

Saturday was Earth Day, an occasion that usually leaves me lukewarm at best. But this year it was also the day of the worldwide March for Science. A few news stories have quoted environmentalists who resented that the march happened on “their” day. But from my viewpoint, that’s the best day of the year for a science march. The Earth Day community needs the help, and the organizers are upping their game.

We should have a science march, or at least a rally, every year. This year’s inaugural march had a militant edge. So did the original Earth Day. And for centuries before that, scientific advances have shaken up establishments of all kinds. This sign, quoting Galileo’s legendary comment after the Church forced him to renounce his discoveries, was a shout-out to that long history.

The authorities can threaten people for their beliefs, but they can’t force facts to be untrue. And when Galileo muttered “Nevertheless it moves,” he was talking about the Earth.

Other signs were more contemporary, more pointed . . .

. . . and funnier.

One of my favorite geeky jokes was on Twitter: “The numbers for the Science March seem high but we won’t know until we compare it to the numbers at the placebo march that’s also happening.”

I could have marched with the group from the American Geophysical Union, which endorsed the event. I’ve been an AGU member and rabid fan since the mid-1980s. But I chose to walk with the Northern California Science Writers Association, because they represent my practice. Our little group took a side route to the march along Drumm Street, and when we got there Market Street was packed.

It took us an hour to stroll to the Civic Center. People lined the route, holding their signs and admiring ours. There was a learning fair at the other end, what we used to call a teach-in.

As I prepared to return to Oakland, incoming marchers still filled Market Street to the limits of my sight. This was not a small occasion.

There were thousands of signs. This one reminded me of an important truth.

It means that the scientific method is simply a more rigorous version of something we all do. When we face a question of any size, whether it’s choosing fruit at the market or investing our life’s savings, we make our best estimate of what to do, check the results against our expectation, and then make adjustments in how to proceed. Science is common sense weaponized, and the better we are at common sense the more we are like scientists.

One thing that stood out to me at the San Francisco March for Science was that science has more than practitioners — it has fans. When the speakers at the rally made shout-outs to NASA, they drew widespread cheers. The same for stem-cell researchers at the California Institute for Regenerative Medicine or NIH — cheers. These things deserve their applause, and I cheered them as a fan.

Although there were geologists and geology fans in the crowd, we didn’t get a chance to make or hear a cheer of our own on Earth Day. I know, we’re grownups and don’t need the adulation, but what about the kids who are into minerals and fossils? Do they sense there’s a pivotal role for them in extrasolar planetology? In evolution studies? In global sustainability, in climate studies, in remediation of polluted places, in ecology? Are geology’s strengths in earthquakes, volcanoes, floods and landslides unworthy of comment in a march for science? Does plate tectonics, with its elegance and grandeur and promise, have no fans among the rally planners?

Geologists do tend to keep their heads down. Because Earth science is too wonderful to neglect, I plan to push ahead. You are fans, and I have hundreds more stories for you.