A maintenance report has limited value if it only says that a tower was "checked" or "normal." The next inspector needs something measurable to compare. That might be a verticality reading, a note about one bolt group, a photograph of a repaired galvanized area or the exact location of a bent member.
Reference maintenance data used by Hebei Yifeng Steel Structure Co., Ltd. includes vertical deviation of no more than 1/1500 of measured height, overall member bending of no more than 1/1000 of member length and local bending of no more than 1/750. Those figures are useful because they turn a visual impression into a repeatable observation. They are not a substitute for the project design, but they give inspection teams a consistent way to record change.
The location of a defect matters as much as its size. Corrosion around a main connection, for example, deserves different attention from light surface staining on an isolated secondary member. Areas near platforms, ladders and antenna supports also see more human contact, so worn coatings or loose hardware may appear there first.
A six-month general inspection can be used as a reference interval, with extra checks after strong wind, ice loading or seismic events. The important point is continuity. If each visit records the same measurement positions, photographs and repair actions, trends become visible before they turn into larger problems.
Tower inspection involves height and structural risk, so qualified personnel and suitable access procedures are essential. A clear record should show not only what was found, but also what was tightened, repaired or left for engineering review.
