After announcements earlier this week that Caterpillar Inc. was shedding 20,000 jobs, the construction giant said Friday it was firing 2,110 additional workers at three Illinois plants. With construction projects at a national standstill, the company is looking to bring its supply in line with demand. Affected plants include the Aurora facility, which will say goodbye to 500 workers; the Decatur plant, which makes off-highway trucks and is losing 1,026 production employees; and the East Peoria location, which is cutting 584 jobs. The layoffs at the three plants will begin on April 13, the company said.