nxstructural

Project

Identification printed on the report and drawings.

Project name

Client

Location

Designed by

Checked by

Wall geometry

Heights are measured from the finished ground in front of the wall.

Wall type

Retained height above the front ground (m) Top of wall = top of backfill

Depth of the base underside below the front ground (m) Foundation depth

Stem thickness at the top (m)

Stem thickness at the base (m)

Batter on Face of the stem that is inclined

Base width B (m)

Toe length (m) Ignored for an L-shaped wall

Base slab thickness (m)

Front ground level (RL m) For levels on the drawings

Length of wall (m) For the bar bending schedule and quantities

Shear key

Increases the sliding resistance by passive pressure in front of the key.

Provide a shear key

Key depth below the base (m)

Key width (m)

Key position

Soil, backfill and water

Unit weight of soil γ (kN/m³)

Angle of internal friction φ (deg)

Backfill slope θ (deg) 0 = level backfill; must be less than φ

Surcharge on the backfill q (kPa) e.g. 10 kPa traffic / construction

Surcharge is permanent (counts as resisting)

Coefficient of friction μ (base on soil)

Safe bearing capacity (kPa)

Rely on the soil above the toe

Rely on passive resistance in front of the base

Passive resistance factor Fraction of the passive force relied upon

Water table behind the wall (no drainage)

Water table above the base underside (m)

Saturated unit weight γsat (kN/m³)

Unit weight of water (kN/m³)

Seismic (IS 1893)

Mononobe-Okabe earth pressure; dynamic increment at mid-height.

Consider seismic forces

Design horizontal seismic coefficient αh Z/2 · I/R · Sa/g

Vertical coefficient αv / αh 2/3 usually

Increase of SBC with seismic loads (%)

Safety and load factors

IS 456 cl 20 and Table 18.

Factor of safety - overturning 0.9 Mr / Mo ≥ 1.4 (cl 20.1)

Factor of safety - sliding ≥ 1.4 (cl 20.2)

Factor of safety - seismic case

No tension under the base (e ≤ B/6)

Load factor γf (static) 1.5 (DL + LL)

Load factor γf (seismic) 1.2 (DL + LL + EL)

New retaining wall design