New for the 2013.n version is the option to introduce one and two-pile pile caps with an eccentric column with respect to the axis defined by the piles. Similarly, the program can also analyse pile caps with three or more piles, with a column that lies outside the area defined by the centres of the piles.
Strap beams are required for both cases, to absorb the bending moments that are generated due to the eccentricity of the column. The main reinforcement of the pile cap is designed assuming it is exposed to centred compression loads.
In the case of one and two-pile pile caps, the strap beam is required so to guarantee the equilibrium of the foundation if, as usually occurs, the piles supposedly only resist axial forces.
In all cases, the fact the column is situated outside the area defined by the piles implies the load transmission mechanism from the support to the piles is similar to that of a corbel. The program assumes that the top reinforcement provided in the strap beam is capable of resisting the tensile forces as would the main reinforcement of the corbel, hence the transmission mechanism is guaranteed. This is true as long as the reinforcement of the strap beam has been designed correctly to resist the centring forces and is anchored below the column.
