Tiebacks should form what angle with the parapet?

Tiebacks should form what angle with the parapet?

• A. 30 degrees
• B. 60 degrees
• C. 0 degrees
• D. 90 degrees

Answer: (D)

Tiebacks provide lateral restraint by pulling the wall back into the backfill. To maximize stability and minimize unwanted bending or shear on the parapet, the force from the tieback should be directed straight back from the parapet—that is, form a right angle (90 degrees) with the parapet. When the tieback is perpendicular, most of the load contributes to resisting overturning in a pure tension path into the anchor, rather than trying to slide or pry the parapet along its plane. If the angle were shallower or parallel to the parapet, the force would either cause bending and pulling on the parapet or be less effective at resisting outward movement.

Tiebacks provide lateral restraint by pulling the wall back into the backfill. To maximize stability and minimize unwanted bending or shear on the parapet, the force from the tieback should be directed straight back from the parapet—that is, form a right angle (90 degrees) with the parapet. When the tieback is perpendicular, most of the load contributes to resisting overturning in a pure tension path into the anchor, rather than trying to slide or pry the parapet along its plane. If the angle were shallower or parallel to the parapet, the force would either cause bending and pulling on the parapet or be less effective at resisting outward movement.