Boundary elements in structural walls: why the ends of a wall need special treatment

1The wall ends work hardest

In an earthquake, a structural wall carries large in-plane bending moments, with its two ends carrying the largest tension and compression. If the concrete at the wall ends lacks confinement, it can crush before the expected deformation is reached.

2What boundary elements do

Boundary elements concentrate longitudinal bars at the wall ends and confine them with stirrups, raising the compressive capacity and deformation capacity of the wall ends. Whether they are required and how far they extend is determined according to the code.

3Strong axis and weak axis

The moment capacity of a wall along its length (strong axis) is far greater than across its thickness (weak axis). Real loads often act in both directions, so a structural wall also needs a biaxial check.

4Entering a structural wall in StructFlow

The structural wall tool describes the section by wall length, thickness, two boundary elements, and web bar spacing, generates all bar positions automatically, and completes the biaxial interaction surface and load checks.

Further reading