Spending on most categories of nonresidential and multifamily construction declined from February to March as contractors struggled to find enough workers and get timely deliveries of materials, according to an analysis the Associated General Contractors of America. “Contractors continue to report strong demand for most types of structures, with few owners canceling or postponing planned projects,” said Ken Simonson, the association’s chief economist. “But worker shortages and supply-chain problems, from lockdowns in China to the war in Ukraine, are slowing project completions.”