Complex sentence: Archeologist Mary Metcalf estimates the project required more than 500,000 person-hours, and 26,000 wood beams to support Chetro Ketl's walls and ceilings.
Split into simpler sentences: Archeologist Mary Metcalf estimates the project required more than 500,000 person-hours. She notes that 26,000 wood beams were used to help support Chetro Ketl's walls and ceilings.