Vilabar Where test evidence is available, it might be possible to reduce the protection to the bolts of the connection. Except as permitted under the Copyright, Designs and Patents Act no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means? These tests should be carried out at an approved testing station and the recommendations derived from them should be prepared by a suitably qualified person. Design using structural fire standards — Minimum thickness of concrete for trapezoidal profiled steel sheets see Figure 8 Concrete type Minimum thickness of concrete for a fire resistance period of: The strength retention factors for bolts and welds are given in Table 4.
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For other loading arrangements, including partial distributed loads and asymmetrical point load systems, the shear span Lv should be determined on the basis of appropriate tests or by approximate calculations similar to the following. Lv Pa 6. The deflection of the profiled steel sheeting due to its own weight and the weight of wet concrete calculated as in 5. These limits should be increased only where it can be shown that greater deflections will not impair the strength or efficiency of the slab, lead to damage to the finishes or be unsightly.
The factor 1. The effective width of slab resisting bending moments and shear forces due to a concentrated load should be determined as follows. In Table 2, the depth should be taken as the overall depth of the composite slab Ds and the span as the effective span of the profiled steel sheets Lp. Table 2 — Span-to-depth ratios Type of concrete Single spans Condition End spans Internal spans 2 For resisting shear forces: where a Ls is the distance from the load to the nearer support; and is the effective span of the slab.
Normal weight Lightweight 35 30 38 33 A line load running parallel to the span should be treated as a series of concentrated loads. Where there are discrete concentrated loads or line loads, transverse reinforcement should be placed on or above the profiled steel sheets.
It should have a cross-sectional area of not less than 0. This transverse reinforcement, which may include reinforcement provided for other purposes, should be ductile see 3. NOTE The values in this table apply to slabs with nominal continuity reinforcement over intermediate supports. For slabs designed as continuous with full continuity over intermediate supports, reference should be made to BS For mild exposure conditions in accordance with BS , the cross-sectional area of reinforcement in a longitudinal direction should be not less than 0.
For propped construction consideration should be given to increasing the area of steel reinforcement over supports as appropriate, depending on the span and the crack widths that can be tolerated.
For other conditions of exposure reference should be made to BS Where such nominal reinforcement also provides fire resistance, see also 3.
BS 5950-8 PDF