DEBATE EMERGES OVER WHETHER MODERN PROTECTIONS COULD HAVE SAVED BALTIMORE BRIDGE

When a 900-foot container ship struck the San Francisco-Oakland Bay Bridge in 2007, the span stood firm and no one died, either on the ship or the highway above.

The bridge's supports were protected by a fendering system of concrete and other materials that was installed to absorb such strikes. And it's now prompting the question: Could such a system - or others like it-have saved Baltimore's Francis Scott Key Bridge? Some experts are saying yes.

Sherif El-Tawil, a University of Michigan engineering professor, said there are several safety measures that "would have made a huge difference" had they been in place Tuesday morning when a cargo ship plowed into the bridge and caused its collapse.

El-Tawil said a fendering system may have softened the 985-foot-long ship's blow. Pilings anchored to the river bottom, known as dolphins, are another measure that could have helped to deflect the container ship Dali. And yet another potential protection would have been islands of rocks or concrete around the bridge's supports.

"It may seem like a very large force," El-Tawil said of the massive cargo ship. "But I think you can design around it, either through a protective system or by designing the bridge itself to have massive towers." Such protections have become a focal point in the wake of the tragedy, which claimed the lives of six construction workers. Experts say the 47-year-old Key Bridge did not appear to have the protections that are common among newer spans.