A doubly reinforced concrete beam has effective cover d’ to the centre of compression reinforcement. ‘xu’ is the depth of neutral axis, and d is the effective depth to the centre of tension reinforcement. What is the maximum strain in concrete at the level of compression reinforcement?
1
0.0035 (1 – d’/d)
2
0.0035 (1 – d’/xu)
3
0.002 (1 – d’/xu)
4
0.002 (1 – d’/d)