20/04/2026
ROLE OF OPEN LOOP STIRRUPS IN COLUMN LAP SPLICE ZONES
When OPEN LOOP STIRRUPS (crossties) are provided in column reinforcement, they are used to supplement closed ties by ensuring full lateral support of all longitudinal bars, especially in critical regions such as lap splice zones.
In lap zones where bars overlap and rely on CONCRETE BOND rather than direct continuity, the reinforcement becomes more susceptible to buckling, slipping or concrete splitting and to control these risks, the spacing of stirrups is reduced (typically around 100 mm or less, depending on your applicable design code) and additional crossties or open loop stirrups are introduced. The spacing at this zone should be lesser in the rest of stirrups.
They are arranged such that no longitudinal bar remains unsupported to ensure that both outer and inner bars are adequately restrained to improves confinement of the CONCRETE CORE and enhances the overall stability and bond performance of the column.
