Concrete proposals

Re “How Risky Are Older Concrete Buildings?” Oct. 11

The article implies that retrofits would require constructing shear walls and wrapping the columns in “stronger, more resilient material than the old concrete.” Column wrapping does not necessarily mean major reconstruction of buildings.

Caltrans has used steel, carbon and glass-fiber sheets to wrap columns to increase ductility in freeway overpasses. The Navy has used similar techniques on pilings under piers. This is a proven technology that the article should have mentioned. These may not be the cheapest solution, but building owners should consider them as alternatives to conventional retrofit techniques.

BOB ODELLO

Calabasas

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The article conveys the apparent belief of some that the risk is overstated. This is not the case. Evidence confirms that in an earthquake, concrete buildings of the type described pose a high risk of collapse. Some believe the cost of retrofit will exceed the benefits. Testing this premise by leaving people potentially in harm’s way because it’s assumed that it’s “too expensive” to reduce their risk seems a bit coldhearted.

The fact is that we don’t know the costs or the benefits. An objective assessment would lead to an informed discussion between the government and building owners about what to do. Recent images from Pakistan provide a powerful incentive to deal with these buildings sooner rather than later.

RICHARD G. LITTLE

Los Angeles

The writer is the director of USC’s Keston Institute for Infrastructure.