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Single Span
Double Span
Triple Span
16.4 construction procedure
Two specific types of construction procedure are considered:
screed to thickness which provide optimum propping spans, but which also requires an extensive degree of supervision (refer section 14.0)
screed to Level which caters for two distinct conditions and requires a normal degree of supervision (refer section 15.0)
rigid supported tray flooring
Slabs with 0mm/0mm (primary/secondary) deflection, representing slabs which are supported on rigid supports. These slabs provide intermediate propping spans.
flexible supported tray flooring
Slabs with 10mm/20mm (primary/secondary) deflection, representing slabs which are supported on flexible supports (steel beams). These slabs require the shortest propping spans.Within each table a number of parameters are available to the specifier/ designer.
16.5 constructional live load
Depending on the project, means of laying concrete and the use of specific construction procedures, different constructional live loading may be applicable. Refer sections 9.0 and 10.0
information supplied by tables
A number of entities are given in the tables:
(a) Max span allowable, which is the maximum span permitted complying with the ‘ponded’ limitations stated in the British standard BS5950:Part 4 and which is outlined in section 11.0 (a)
(b) Visible span, which coincides with the limitations given in section 11.0 (b) and constitute reduced spans where the soffits are exposed to view and an increased aesthetic appeal is required.
(c) Soffit deflection, which gives the maximum expected deflection of the Trayfloor at the max span allowable.
(d) Prop Reaction, constitutes the full internal ultimate load reactions for double and triple spans (end spans can be taken as half the internal reaction for these spans), and the end span ultimate reactions for single span.
Propping tables have been prepared for a variety of profiles, profile thicknesses, spanning configurations, support flexibility, constructional live loading and construction procedure. Each table has the specific set of conditions which it caters for, clearly denoted in the top right hand corner of the sheet.
16.1 trayfloor profiles
The specific profiles for which tables have been prepared include:
Unifloor
Svelte Floor 60
Svelte Floor 80
16.2 trayfloor sheet thicknesses
Each profile has two possible sheet thicknesses:
.75
.95