Content area
Full Text
(ProQuest-CSA LLC: ... denotes formulae omitted.)
The ongoing use of Concrete Society Technical Report 43 Post-tenstoned concrete floors Design handbook (Second Edition) has highlighted certain areas where additional clarification is required. This note sets out to address this and to correct some minor errors.
JOHN CLARKE, THE CONCRETE SOCIETY
Clarifications
Allowable stresses in flat slabs without bonded reinforcement
Unlike Edition 1, Edition 2 gives only one value for the permissible stress, without bonded reinforcement, for the support and span locations of flat slabs (Tables 4 and 5). This is because the report requires bonded reinforcement in the support zone, thus the number given is only relevant to the span location.
Limitations to the use of Table 4
Table 4 has been developed assuming an equivalent frame analysis is appropriate. Therefore, it should only be used when:
* all loads are uniformly distributed
* there are no section changes that significantly affect the moment distribution, e.g. band beams.
In addition:
* the characteristic combination of loads should be used
* the stresses should not be exceeded without moving to the strip approach and therefore the limits in Table 5.
Allowable stresses in flat slabs using 'design strip'approach
Table 5 is intended to be used with finite element or grillage analysis design. It has been derived from limited current experience and...