Measurement for Civil Engineering works -Retaining Wall-

Overview A retaining wall is generally defined as a vertical wall that holds back earth. However a retaining wall has many uses such as: A retaining wall for roadside embankments A retaining wall can separate older roads from highways A house retaining wall for the garage A retaining wall helps keep river banks from eroding A retaining wall to keep earth from stairwells and driveways

Common materials used for retaining walls Wood sheets; Steel and plastic interlocking sheets; Reinforced concrete sheets; Pre cast concrete elements (crib walls and block walls); Closely spaced in-situ soil-cement piles; Wire-mesh boxes (gabions); Anchors into the soil or rock mass (soil nailing).

Earth-retaining structures

Gravity wall

Crib wall

Gabion wall

Cantilever wall

Common types of retaining wall (sides of highway / expressway) block retaining wall Vegetative retaining wall

Common types of retaining wall (hill side building development) Segmental block retaining wall system Concrete retaining wall

Drainage system in retaining walls

Section view- concrete retaining wall Temporary formwork is a MUST to form the shape of retaining wall before in-situ concreting works coming in concreting works and concrete hardening to form the final product of retaining wall structure

Section view- Segmental blocks retaining wall

Section view- Vegetative retaining wall

Section view- concrete retaining wall Ground level Depth of excavation Concrete base footing

perspective view- concrete retaining wall length Buttress / piers height width

Measurement Principles Element: mass concrete retaining wall ***Refer to drawing given; Main components: Concrete foundation / bases for retaining wall Concrete retaining wall Concrete piers Weep holes (drainage ) Pocket of granular fill Total measured length for retaining wall = 30.00 m

Taking-off lists (lists of items to be measured) Excavation works E.1.5.1 – excavation, foundation, earth -starting from commencing level – m3 Concreting works F.1.3.2 – In situ concrete designed mix, Grade 25, in bases – m3 F.1.4.4 – In situ concrete designed mixed, Grade 30, in retaining wall – m3 F.1.4.5 – In situ concrete designed mixed , Grade 30, in piers – m3

Taking-off lists (lists of items to be measured) Formwork F.4.1.1 – Formwork, to sides, of bases – m2 F.4.1.3 – formwork, to back sides. of retaining wall – m2 F.4.1.3 – Formwork, to end sides / faces, of retaining wall – m2 F.4.4.3 – Formwork, to sloping faces of retaining wall – m2 F.4.1.4 – Formwork, to sides, of piers. – m2

Taking-off lists (lists of items to be measured) Drainage H.5.1.1 – outlet structures, 100mm diameter weep holes @ 1.8m centre, inside the retaining wall – nos. Filling E.3.4.3 – Filling, to structures -between piers, pocket of granular material, continuously. – m3

Techniques to take-off into dimension paper

Billing paper