Building structure element and stiffening plate elements for such an element

A floor structure element, comprising:

• a horizontally extended concrete slab;
• a plurality of discrete, parallel, horizontally separated, not mutually joined, longitudinally extended stiffening plate elements, each of such plate elements having a web with a first longitudinal edge portion embedded in said concrete slab and having a vertically extended considerable portion protruding freely, substantially perpendicularly from a first surface of said concrete slab, said first longitudinal edge portion having a wave-shaped corbelling from a plane of the web, and
• a further horizontally extended concrete element vertically separated from said concrete slab by an interspace that is arranged and adapted to receive at least one of insulation and utility piping,
• wherein a second longitudinal edge portion of said web opposite said first edge portion has a substantially continuous wave-shaped corbelling from the plane of the web,
• wherein each said second edge portion is anchored in said further concrete element and said vertically extended portion is free of both of said concrete slab and said further concrete element and defines a height of said interspace, and
• wherein the wave-shaped corbelling in the first longitudinal edge portion is continuous and a distal edge thereof follows a continuous sinuous path over plural sinusoidal cycles and projects from alternating sides of a plane of the web.