However the minimum required lap length l 0,min should be provided in accordance with EN §8.7.3(1). If a smaller percentage of bars is lapped in one section then required lap length may be multiplied by the factor α 6 / 1.5, where α 6 = ( ρ l / 25) 0.5 and ρ l is the percentage of the bars lapped in one section. The lap lengths presented in the tables assume that >50% of the bars are lapped in one section (i.e.For ULS verifications when the provided tensile reinforcement A s,prov is more than than the required reinforcement A s,req then the required anchorage and lap lengths may be reduced by the ratio A s,req / A s,prov, however the minimum required anchorage length l b,min the minimum required lap length l 0,min should be provided in accordance with EN §8.4.4(1) and §8.7.3(1). the stress of the bar is assumed equal to the design yield stress f yd = f yk / γ s.
'Good' bond conditions are applicable when any of the following conditions is fulfilled: a) Vertical bars or almost vertical bars inclined at an angle 45° ≤ α ≤ 90° from the horizontal, b) bars that are located up to 250 mm from the bottom of the formwork for elements with height h ≤ 600 mm, or c) bars that are located at least 300 mm from the free surface during concreting for elements with height h > 600 mm.When adequate cover is not present the anchorage and lap lengths for other-than-straight bars in compression should be used instead. The condition of adequate cover c d > 3 Φ for other-than-straight bars in tension is defined in EN Figure 8.3.
The detailing rules and the equivalent anchorage length for each of these standard shapes are defined in EN Figure 8.1.