Robert Silman, a structural engineer who rescued Frank Lloyd Wright’s cantilevered Fallingwater in Pennsylvania from the edge of collapse, and preserved dozens of other landmarks besides, died on July 31 at his home in Great Barrington, Mass. He was 83.

He had multiple myeloma, a form of cancer, his wife, Roberta Silman, said.

Mr. Silman was the president emeritus of the engineering firm Silman, headquartered in Manhattan, which he founded in 1966.

Though he came of age when engineers were expected to perform feats of awe-inducing bravura, Mr. Silman largely contented himself with the invisible, ingenious stitchery that protected the work of other engineers and architects.

“Any time we faced any intractable problem in trying to save a building, we called Bob,” Peg Breen, the president of the New York Landmarks Conservancy, said on Friday.