Liquid Retaining Structure Design to British Standards

[Ussuri]

I have a design query with regards to water retaining structure design to BS 8110 and BS 8007.

Clause 2.2.1 to BS 8007 states "the design of the whole structure and and individual members should be in accordance with the recommendations of BS8110..."


Then Clause 2.7.3 to BS8007 defines the exposure condition to BS8110art 1:1985 (the superseded code) as severe. Clause 2.7.4 states that the durability requirements correspond to the recommendations of BS8110art 1:1985.


This 1985 version of BS8110 was replaced by the 1997 version, and in the new code in Table 3.3 the lowest grade of concrete for a severe exposure condition is C40.


Back to BS8007, Clause 6.3 states that "the 28 day characteristic cube strength shall not be less that 35N/mm2, and the concrete shall be classed as C35A."


Does this mean that the concrete shall be classed as grade C35A with a 28 day characteristic strength of 40N/mm2? It has been suggested that the requirements of 8110 Table 3.3 can be ignored and that you should not use anything stronger than 35N/mm2 in a water retaining structure.


Can anyone tell me if the durability requirements have changed from BS8110:1985 to BS8110:1997, and has anyone come across this before?

 

[letrab]

Hi Ussuri,

The durability requrements of 8110 is primarily based on c:w ratio and strength requirements can be adjusted as described in sub-clauses 3.3.5.1 to 3.3.5.3.
However, using the codes as stated, BS 8007 requires class C35 or higher and your exposure conditions requires class C40 or higher.
Consequently Class C40 is the lowest grade of concrete you should use to ensure compliance with the codes.