Bridge panel votes to keep rods, bolts in place on eastern span

By Jaxon Van Derbeken : sfgate – excerpt

A Bay Bridge oversight panel voted Friday to leave more than 2,000 potentially problematic rods and bolts in place on the new eastern span, rejecting a metallurgist’s attack on the $20 million testing program that vouched for their safety as unmerited.

The unanimous decision by the three-member Toll Bridge Program Oversight Committee appears to lay to rest one of the biggest uncertainties hanging over the $6.4 billion project — whether hundreds of the steel fasteners will have to be replaced at toll-payers’ expense.

After 32 high-strength, galvanized rods broke in March 2013, Caltrans created a testing program to determine whether the remaining zinc-coated fasteners on the bridge were similarly at risk.

The rods and bolts anchor the bridge’s main cable to the road deck, secure it to the top of the tower and hold down structures designed to keep the bridge from swaying excessively in an earthquake… (more)

32 cracked so far. We know the design is not approved and now we get the message that the rest of the rods that are sitting in water corroding don’t need to be replaced? Who can you trust to build and maintain our bridges these days?

Can we get the names of the the three-members on the  Toll Bridge Program Oversight Committee?

Which is more important? Keeping the decorative lights on the bridge or making the bridge safe?

RELATED:
Latest defect: Bay Bridge tower rods sitting in water

E2 Anchor Rods – on the Bay Bridge

baybridgeinfo – excerpt

BATA Presentation on Bay Bridge Delay July 2013

Overview

The eastern pier of the Self-Anchored Suspension Span contains seismic devices called bearings and shear keys. The bearings allow the road-decks to move slightly during a seismic event, while the shear keys prevent the decks from moving too much. The four bearings (two beneath each deck) and four shear keys (one beneath each deck and two beneath the cross beam connecting the decks) are bolted between the roadways and a concrete cap beam with steel anchor rods. When 96 rods were tightened to connect two shear keys to the cap beam in March 2013, 32 broke.

The rods could not be tightened until the completion of load transfer, the process of shifting the weight of the suspension span from the temporary supports to the main cable. The process was completed in late 2012.

There are a total of 288 3-inch diameter rods, which range in length from 9 to 24 feet, anchoring the bases of the seismic devices to the top of the cap beam. Each bearing has 24 rods, and each shear key has 48.

Broken rods

On March 1, workers began stressing the 96 rods fabricated in 2008 for the two shear keys; between March 8 and March 15, 32 fractured rods were discovered.

Engineers and metallurgists have determined that the bolts broke due to hydrogen embrittlement, which requires a source of excess hydrogen, susceptible material and tension. Ongoing metallurgical analysis revealed that the bolts were susceptible due to the steel being harder on the outside than in the middle, or a lack of uniformity in the steel’s microstructure. The steel also showed low toughness and marginal ductility (the ability to stretch).

The excess hydrogen caused the threaded areas to become brittle and fracture under high tension when the bolts were tightened. An ongoing investigation is looking into the source of the excess hydrogen, which may have been both internal (i.e. residual from production) and/or external… (more)

Smart Cities”/Stupid Cities—Walking is a “Technology”

By Stephen Frank : capoliticalreview – excerpt

I have three grand daughters, ages 5,2 and 1. All have learned how to walk, naturally. They lifted themselves up, and then eventually took steps, holding on to things. Finally, walking and running on their own. No computers, no fancy equipment, no high tech needed to learn to walk. But, if you live in a nutty “smart city” you will learn they you need to relearn how to walk via “technology of walking”. Someone is making a bundle out of what Jon Gruber would call “the stupid Americans”.

“In today’s auto-centric culture, the operative question for local and regional leaders as well as transportation planners is this: How do we address the growing list of public externalities ensuing from America’s perceived love affair with cars? Traffic congestion, parking demand, environmental issues, and more garner concern as today’s built environments increase in size and complexity.

Shifting this current trajectory necessitates a new mindset—one requiring city leaders to think more like engineers and behavioral psychologists and less like regulators. Amid this is a new trend that promises to accelerate the movement toward more sustainable ways of getting people from point A to point B.”

Fancy phrase for outlawing cars in dumb cities. Will we allow billions meant for roads to be spent on money losing choo choo trains, horse and walking trails and bike lanes? Apparently we are… (more)

Well put. It is good to see someone pointing out that the emperor is naked. Let’s take the money out of walking. Make walking free for all.