FRENCH CODE 1) NF P 11-212 - DTU 13.2 (1978 & additional modifications 1991) II ) Fascicule 62 titre V III) Euro Code 7 : Geotechnical Design

DTU 13.2 Micropiles : - Drilled - Diameter < 250 mm Classification based on the method of grouting

Design : - Structural bearing capacity - Geotechnical bearing capacity - Control tests

Structural bearing capacity : Micropiles (II, III, IV) - Steel is only considered in the design - Admissible stress - Service loads (ELS) : sa = 0.5 se - Ultimate loads (ELU) : sa = 0.75 se - Reduction of the section for corrosion - Buckling verfication (Mandel Method)

Geotechnical bearing capacity Friction forces only Qs = 2pDs L qs Design Diameter (Ds)  : Ds = a Dd (Dd = Drilled diameter) Values of a

Determination of friction qs Cohesive soils (laboratory tests) Without results from in-situ tests Cone penetration tests Pressuremeter test of Menard

b = 1 (low injection pressure) (Type I, II) Cohesive soils qs = b Cu b = 1 (low injection pressure) (Type I,  II) b = 1.5 (high injection pressure) (III et IV) Without results from in-situ tests

Cone penetration test qs = qc /a

Pressuremeter test of Menard Classification (soil, type of micropile)

Reduction factor for qs Service loads (ELS) : 0.5 Ultimate loads (ELU) : 0.75

Control tests - Compression : 1 test / 200 micropiles - Tension : 1 / 50 - N < 25, without test, reduction of the bearing capacity by 1.5