1985 Ed.]
Building (Construction) Regulations
[CAP. 123
B 101
154. Where the slab is supported by a marginal beam of depth greater than 1 times the thickness of the slabs, or by a wall-
(a) the load to be carried by the beam or wall shall be all loads carried directly on the beam or wall plus a uniformly distributed load equal to 4 of the total load on the slab;
(b) the bending moment in the column strip adjacent and shall be of the moments parallel to the beam or wall specified in regulation 155 or 156.
155. Where flat slabs are designed as continuous frames and analysed by the elastic theory-
(a) the structure shall be divided longitudinally and transversely into frames each consisting of a row of columns and a strip of slab bounded by the centre lines of the panels on each side of the row of columns, both longitudinal and transverse frames each being designed for the full load on the floor area;
(b) each frame may be analysed in its entirety, or each strip of floor or roof may be analysed separately assuming the columns to be fixed at the floor above and below;
(c) the spans used in the analysis shall be to the centre lines of supports except for a slab supported on a wall when the span shall be taken to the face of the wall plus the depth of the slab;
(d) the moment of inertia of the slab or column shall be assumed to be that of the gross cross-section of the concrete, variation of moment of inertia along the axes of columns or slabs being taken into account;
(e) the joints between column and slab shall be considered rigid and this rigidity (infinite moment of inertia) shall extend in the slab from the column centre line to the edge of the column or column head and in the column from the top of the slab to the bottom of the column head if provided;
(f) the maximum moments shall be calculated for the following arrangement of the imposed loads-
(i) where alternate spans are loaded and all other spans unloaded; and
(ii) where any 2 adjacent spans are loaded and all other spans unloaded;
(g) the slab shall be designed for the bending moments as determined in sub-paragraph (f), which shall be distributed between the column strip and middle strip in accordance with Table XXXVII;
[Subsidiary]
Panel with marginal beams or walls in flat slab construction.
Design of flat slabs as continuous frames.