David Cushman Coyle (1887–1969) was an American structural engineer, economist, and writer.
Coyle was the structural engineer of the Washington State Capitol and a prominent economic thinker during the New Deal.
[2] He also wrote several books on economic theory and policy, including Brass Tacks (1935) and Uncommon Sense (1945).
He engineered the concrete dome that spans the building's rotunda using a cantilevered truss system.
At 287 feet in diameter, it remains the largest free-standing masonry dome in North America.