Houston has his 18-foot Geometric Mouse; Yale University, the giant Lipstick (Ascending); Philadelphia a 45-foot-high Clothespin. Now it is Chicago's turn to inaugurate one of Claes Oldenburg's whimsical pop art extravagances. This one is a 40,000-pound, 101-foot, latticed gray baseball bat entitled Batcolumn.

Oldenburg's latest work was commissioned for the new Social Security Administration Building located on Chicago's skid row. But the sculptor, who grew up in Chicago where his father was Swedish consul, means to salute America's national pastime. "Chicago is a baseball town," he affirms, "and Chicago is vertical."

When Oldenburg conceived of a bat 10 years ago, he imagined it would sit on a Chicago street corner and spin. When the actual commission came through in 1975, Oldenburg bought six toy bats as models instead. "I collect toys the way other sculptors collect pieces of anatomy," he explains. "With toys you get simplified forms." But not too simple. Batcolumn consists of 1,608 pieces of steel welded together.

There was some grumbling about spending $100,000 of the taxpayers' money on a baseball bat (Oldenburg, 48, says it all went into the work itself). Could the big stick with all those holes in it symbolize Chicago's less-than-successful baseball teams? Maybe, conceded White Sox owner Bill Veeck, who added, "I wish I had a guy who could swing it."