RC Shear Keys in Building Structures
RC Shear Keys in Building Structures
(OP)
All,
I'm currently reviewing structural drawings for a code compliance check and the RC details indicate a 'Shear Key' at the interfaces between floor slabs, walls and columns etc. I understand that this is a standard way of detailing concrete pour breaks by North American practice. And for the purpose of design the joint is considered continuous for moment and shear transfer. This is a method in the UK that we are not familiar with. Am I correct in understanding that the joint is effectively a smooth finish and effectively forms a separation joint with no aggregate interlock across the joint? If so does the joint not effectively become a hinge since the only thing continuous across the joint is the rebar.
Any comments would be appreciated.
Many thanks
Hannis
I'm currently reviewing structural drawings for a code compliance check and the RC details indicate a 'Shear Key' at the interfaces between floor slabs, walls and columns etc. I understand that this is a standard way of detailing concrete pour breaks by North American practice. And for the purpose of design the joint is considered continuous for moment and shear transfer. This is a method in the UK that we are not familiar with. Am I correct in understanding that the joint is effectively a smooth finish and effectively forms a separation joint with no aggregate interlock across the joint? If so does the joint not effectively become a hinge since the only thing continuous across the joint is the rebar.
Any comments would be appreciated.
Many thanks
Hannis






RE: RC Shear Keys in Building Structures
RE: RC Shear Keys in Building Structures
RE: RC Shear Keys in Building Structures
RE: RC Shear Keys in Building Structures
Not being Structural in expertise, I have seen it done two ways in pits within the confines of a plant where the floor was poured then the walls later. One with the 2 x 4 key and bent bars from the floor and with bent bars only without the key. Is the method without the key acceptable practice? There is no soil swelling or anything against the walls.
RE: RC Shear Keys in Building Structures
RE: RC Shear Keys in Building Structures
Additional dowels crossing the joint may also be used to transfer the shear using the shear friction concept defined by ACI.
ACI 318-02, 6.4.4 requires construction joints in structural floors to be located in the middle third of the span. The commentary states that "when shear due to gravity load is not significant, as is usually the case in the middle of the span for flexural members, a simple vertical joint may be adequate. Lateral force design may require special design treatment of construction joints. Shear keys, intermittent shear keys, diagonal dowels or shear transfer method of 11.7 may be used whenever a force transfer is required."
RE: RC Shear Keys in Building Structures
Zambo