Association

SRW-TEC-004-10: Segmental Retaining Wall Design

Concrete Masonry & Hardscapes Association (CMHA, formerly NCMA and ICPI)

Cited by

CMHA recommends an engineered design above 1.2 m total height where the local code is silent.
CMHA calls for at least 300 mm of drainage stone behind the units, a drain of at least 75 mm and outlets at most 15 m apart.
CMHA sets the minimum length at the greater of 0.6 H and 1.2 m and a maximum vertical spacing between layers.
CMHA requires the wall drain to discharge at outlets.
CMHA calls for at least 300 mm of drainage stone behind the units.
CMHA spaces drain outlets no more than 15 m apart.
CMHA sets the minimum geogrid length at the greater of 0.6 H and 1.2 m.
CMHA recommends an engineered design above 1.2 m total height if the local code is silent.
Drainage, geogrid length and the 1.2 m threshold.