Place the roast in a Dutch oven; add broth, onion and celery. Bring to a boil. Reduce heat; cover and simmer for 2-1/2 to 3 hours or until the meat is tender.
Remove roast and cool slightly; shred meat with two forks. Strain vegetables and set aside. Skim fat from cooking liquid and reserve 1-1/2 cups. Return the meat, vegetables and reserved cooking liquid to the pan.
Stir in the ketchup, brown sugar, vinegar, salt, mustard, Worcestershire sauce, garlic, bay leaf, garlic powder, paprika and hot pepper sauce. Bring to a boil. Reduce heat; cover and simmer for 30 minutes or until heated through. Discard bay leaf. Serve beef on buns. Yield: 12-15 servings.