North­eastern civil and envi­ron­mental engi­neering pro­fessor Mishac Yegian recently com­pleted a com­pre­hen­sive seismic eval­u­a­tion of the Brooklyn Bridge. The grand dame of bridges, he found, is made of sturdy stuff.

In fact, Yegian and grad­uate stu­dent Bryan Stroham, working with the New York City Depart­ment of Trans­porta­tion and the Par­sons Cor­po­ra­tion, an engi­neering com­pany, cal­cu­late that the foun­da­tion of the East River span could with­stand an earth­quake reg­is­tering 6.5 on the Richter Scale without sliding or sep­a­rating from the soils and bedrock that sup­port it.

We imple­mented some of the most advanced field-​​testing tech­niques to eval­uate the con­di­tion of the Brooklyn Bridge mate­rials, which include Southern pine, mortar, con­crete, granite and marble,” says the long­time pro­fessor and former depart­ment chair. “After inten­sive study, we deter­mined that the bridge’s struc­ture is safe, pri­marily because of the mas­sive size of its foundation.”

In Feb­ruary, the results of Yegian’s study were fea­tured in a cover story in Civil Engi­neering, the mag­a­zine of the Amer­ican Society of Civil Engineers.

Although sci­en­tists can’t be sure when or if a seismic event of this mag­ni­tude might occur in New York City, Yegian points out that the area has expe­ri­enced earth­quakes in the past, and undoubt­edly will again in the future.

Using sophis­ti­cated mod­eling tech­niques, the researchers focused their seismic testing on the Brooklyn Bridge’s foun­da­tion, main tower and cable anchor­ages on both the Man­hattan and the Brooklyn sides. The bridge does not require rein­force­ments to sur­vive a major seismic event, they believe.

Most of the struc­ture is its foun­da­tion, which is below the water line, in what we call the mud line,” says Yegian. “It is embedded in the soils at the bottom of the river.”

The sus­pen­sion bridge, which boasts a 1,595-foot center span, was the largest of its kind when it opened in 1883. It is, Yegian says, among the most his­toric struc­tures he has ever studied.

This National Sci­ence Foundation–funded expert has made a career of assessing the seismic vul­ner­a­bility of the built envi­ron­ment. “I study dams, build­ings and other struc­tures,” he explains. “Overall, my research deter­mines whether mit­i­ga­tion is needed to pro­tect a struc­ture, and, if yes, what the most cre­ative, cost-​​effective ways of doing so might be.

My focus has been on large his­toric bridges,” he adds, “and New York City has been one of the most impor­tant places for sat­is­fying my curiosity.”

Not long ago, how­ever, Yegian brought his pro­fes­sional exper­tise to a problem of a dif­ferent scale. Before a col­lec­tion of small Greek and Roman sculp­tures owned by the Museum of Fine Arts, Boston, went on loan to a gallery in earthquake-​​prone Japan, Yegian was asked to deter­mine the art’s vulnerability.

He placed crude replicas of the statues on a “shaking table” in his lab to test the risks the ancient objects might encounter, and sug­gest ways of pro­tecting them.

Whether he’s exam­ining objects large or small, Yegian’s life­long interest in seismic mit­i­ga­tion has remained unshaken.

Since receiving his doc­toral degree from MIT in 1976, he has held many honors and dis­tinc­tions. He is a fellow in the Amer­ican Society of Civil Engi­neers and a Dis­tin­guished Col­lege of Engi­neering Pro­fessor at North­eastern. He earned the university’s Excel­lence in Teaching Award in 1995, and the Robert D. Klein Dis­tin­guished Scholar Award in 1992.