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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
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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).
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
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- concrete retaining wall Retaining wall Ground level Depth of excavation Concrete base footing
perspective view- concrete retaining wall length Buttress / piers height width
Measurement PrinciplesElement: 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