A self-erecting tower crane's maximum free-standing height as per the manufacturer's charts is 35 m. During erection, at what height above the crane's base must the first tie-in connection be made if the crane is operating in an exposed, high-wind zone?

Question: A self-erecting tower crane's maximum free-standing height as per the manufacturer's charts is 35 m. During erection, at what height above the crane's base must the first tie-in connection be made if the crane is operating in an exposed, high-wind zone?

Answer options: ✅ Typically between 2/3 and 3/4 of the maximum free-standing height, or as per the manufacturer's specific wind zone charts.

• Exactly 35 m, as this is the maximum allowable without ties.
• At 1/2 of the planned operational height, regardless of free-standing limit.
• Below 15 m to ensure stability during initial stages.

Correct answer: Typically between 2/3 and 3/4 of the maximum free-standing height, or as per the manufacturer's specific wind zone charts.

Explanation: CSA Z248 requires that tower crane tie-ins begin when the crane approaches its free-standing height limit, often specified by manufacturer's charts for particular wind zones. This is typically done at 2/3 to 3/4 of the maximum free-standing height to maintain structural integrity and account for dynamic loads and wind forces before reaching the absolute limit.