A long-term deflection test is performed for 470 days on two simply supported prestressed concrete box beams under sustained uniform load. The deflection growth rules of the box beams under both cracked and uncracked states are studied. The measured longterm deflection of the cracked beam is 18.4% larger than that of the uncracked beam, whereas the deflection growth coefficient of the cracked beam is 65.3% that of the uncracked beam. The larger long-term deflection of the cracked beam is mainly attributed to the huge value of the instantaneous deflection caused by the crack. Then, the cracks l...
