Section 6: Non-Contact Lap Splices

General

Where a traditional lap splice is not possible, such as where columns are stepped or drilled shafts frame into to dissimilarly shaped or sized columns, use a non-contact lap splice. Depending on the geometry of the two connected elements, non-contact lap splices will need to be provided in either the lower element, the upper element, or both elements.

Detailing

When calculating the required lap length,

l_{s}

, use reinforcement confinement factor,

λ_{r c}

λrc, of 1.0.

Provide a total splice length:

l_{n s} = l_{s} + S_{s p}

, where

S_{s p}

equals the maximum lateral spacing between longitudinal reinforcement transferring the force.

Provide transverse reinforcement along the provided splice length that satisfies the following requirements:

For laps confined by spiral reinforcing, provide transverse reinforcement that satisfies Equation 5.10.8.4.2a-1.

For laps confined by stirrups, provide transverse reinforcement spaced no wider than the maximum allowed spacing of transverse reinforcement, smax

S_{s m a x}

, for each face of the column. Observe minimum spacing requirements for concrete consolidation as outlined in AASHTO LRFD Bridge Design Specifications
. Use the following equation to determine the maximum allowed spacing of transverse reinforcement for each face:

S_{s m a x}

\frac{n_{t r} A_{t r} f_{y t r} l_{s}}{A_{T l} f_{u l}}

where:

n_{t r}

= number of legs of column transverse reinforcement, perpendicular to face of the column

A_{t r}

= area of column transverse reinforcement (in2 )

f_{y t r}

= specified minimum yield strength of column transverse reinforcement (ksi)

l_{s}

= standard required splice length (in)

A_{T l}

= Total area of longitudinal reinforcement in tension at face of the column (in2 )

f_{u l}

= = ultimate strength of longitudinal reinforcement (ksi)