CONCRETE EUROCODE EN1992 fails to properly tackle early age thermal crack control and could lead to 'insufciently robust design solutions', industry research body CIRIA warned this week.
Fears that the new Eurocodes could result in designers specifying half the steel required to properly control cracks prompted CIRIA to this week publish a new design guide to accompany the code 'The approach [to earlyage thermal cracking] is fragmented, ' explained consultant Phil Bamforth who drafted the guide for CIRIA.
'The effect of these changes is to reduce signicantly the reinforcement requirements for crack control, ' he added.
'Observations of early-age cracking indicate that these reductions may lead to insufciently robust designs.' The new CIRIA guide, C660:
Early-age thermal crack control in concrete is complementary to EN1992, the new structural design Eurocodes for concrete.
EN1992 is due to replace the current British Standard for concrete design by 2010.
CIRIA C660 provides a design process based on the combined requirements of EN1992-3 for water retaining structures and EN1992-1-1, which is the general design code.
It gives alternative values for some Eurocode design coefficients for early age thermal cracking, and explains the background to their development.
'The need to provide additional guidance on early age thermal cracking to accompany the Eurocodes has been known for some time, ' said Steve Denton, Parsons Brinckerhoff director of bridge and structural engineering who led the CIRIA C660 drafting panel.
'I expect that it will become the industry standard, recognised as non-contradictory complementation information (NCCI) to accompany the Eurocodes, ' said Denton.
But Denton defended the quality of the EN1992 code overall and said it was unsurprising that some issues are not comprehensively treated.
'This has always been the case in Standards, ' he said. 'If anything, the Eurocode coverage is generally broader than existing Standards.' Antony Oliver