Structural analysis of Félix Candela’s hexagonal hyperbolic paraboloidal umbrellas

•Geometry of hexagonal hypar umbrellas, allowing for parabolic bisectors, described.•Bisectors disrupt flow of internal forces and impede structural performance.•Performance of 6-leaved umbrellas with r/A > 0.015 m−1 not sensitive to warping.•Hexagonal hypar umbrellas more efficient than square and triangular variants.