Esz

yd A

s,prov

Maximum bar size is 25 > 16 mm OK

Maximum bar spacing is 250 (pure flexure) > 165 mm OK

Note that only one of these conditions needs to be met.

In CIRIA Guide 2, the bars must be anchored to develop 80% of the maximum ultimate force beyond the face of the support and 20% of the maximum ultimate force at or beyond a point 0.2/o from the face of the support, or at or beyond the far face of the support, whichever is less. The main reinforcement must be anchored so that the concrete within the area of support relied upon for bearing is adequately confined.

EC2 for deep beams requires that the reinforcement, corresponding to the ties considered in the design model, should be fully anchored beyond the nodes by bending up the bars, by using U-hoops or by anchorage devices, unless a sufficient length is available between the node and the end of the beam permitting an anchorage length of Zb .

The EC2 requirements are clearly more onerous.

Support A anchorage

Table 4.11 Table 4.12

CIRIA Guide 2 CI.2.4.1

b,net a LA

where bd

= 0.7 for curved bars with side cover > 30 = 2.7 N/mm2 for good bond in bottom half of pour

Table 5.3 Eqn 5.3

s,req

s,prov

Therefore b,net

0 0

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