As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GYR - DURING C11 CHECK DISCOVERED THE AFT CABIN FLOOR STRUCTURE INTERCOSTAL WEB FROM BS 1620 TO BS 1640 AT BL 0 CRACKED, .5 INCHES, ON THE UPPER AFT CORNER. MAINTENANCE REMOVED AND INSTALLED NEW WEB FROM BS 1620 TO BS 1640 AT BL 0 IAW BOEING 757-200 SRM 51-40-05-0G FIG 2.