Strip footing under a wall to SIA 262

Checks a long concrete footing under a wall, per metre of length, to SIA 262:2025 and SIA 267:2013: the soil with lift-off, the bending, shear and anchorage of the transverse bars, and in service the eccentricity, the settlement, the tilt and the bar stresses. Every step shows its formula and the clause it comes from.

What it checks

• Loads at the base, per metre: E_N,d = n_d + γ_G · (g_f + g_s) (SIA 267 §8.5.3.7), m_b = m_d + h_d · h + n_d · e_w, and the effective width B′ = B − 2 · |e|, EN 1997-1 D.1.
• Bearing, check 1: E_N,d ≤ R_N,d = q_R,d · B′, SIA 267 §8.5.3.5, equation (37).
• Overturning, check 2: |e_d| ≤ e_gr = B/3 with the favourable loads, E_N,d,inf = n_d,inf + γ_G,inf · (g_f + g_s): the joint opens at most to the axis, SIA 267 §8.5.3.6, equation (38).
• Sliding, check 3: E_T,d ≤ R_T,d = E_N,d,inf · tan δ_d/γ_R, SIA 267 §8.5.2.2, equation (31), and §8.5.3.4, equation (36), with δ_k ≤ 35° (§8.4.1.1, equation (27)) and δ_d = atan(tan δ_k/γ_φ).
• Bending at the wall face, check 4: m_d ≤ m_Rd (4.3.2.1) under the net pressure p − g_d on the cantilever, and the minimum reinforcement m_Rd ≥ m_cr = k_t · f_ctm · h²/6 (4.3.1.2), with m_cr from 4.4.1.3, equations (99) and (100).
• Detailing of the bottom bars, check 5: s_t ≤ min(1.2 · h ; 300 mm) (5.5.3.1), a_s,l ≥ 0.2 · a_s,t (5.5.3.2) and Ø ≥ Ø_min = 8 mm, EN 1992-1-1 §9.8.2.1(1).
• Shear without stirrups, check 6, at d/2 from the wall face: v_d ≤ v_Rd = k_d · τ_cd · d_v, 4.3.3.2.1, equations (35) and (36), with k_g from equation (37) and ε_v from 4.3.3.2.2, equation (39).
• Anchorage of the transverse bars, check 7: l_bd from 5.2.5.6, equation (108), for the bar stress σ_sd needed at the wall face, within the length from the face to the bar end.
• Service state: the resultant in the central third (SIA 267 §8.5.4.7), the pressure against σ_adm, the settlement and tilt, check 8, against s_adm and θ_adm (SIA 267 §8.5.4.1), and the stresses in the transverse bars of Table 17, check 9.

What you enter and what you get

You enter, per metre of length, the footing width B and thickness h, the wall thickness t_w and its offset e_w, the backfill D_s, and whether the footing is reinforced or of plain concrete. For a reinforced footing: the cover c, the outer layer, the transverse bars Ø_t at s_t, the longitudinal bars Ø_l at s_l, and any top bars. Then the materials, the weights, the resistance factors and η_t. For the ultimate state: n_d, m_d, h_d, γ_G, the pressure distribution, q_R,d, and for overturning and sliding n_d,inf, γ_G,inf, φ′_k, the base roughness, γ_φ and γ_R. Then the anchorage model and the bar ends. In service: the actions of the wall, the load case, σ_adm, up to three soil layers with t₁, M_E,1 and γ_e,1, the length L, s_adm, θ_adm and the crack requirements.

You get every check with its utilisation and clause, the soil pressures and the settlement of the rigid footing. With the Basic plan, it prints as an A4 calculation note.

Assumptions and limits

• Everything is computed for one metre of footing; the moments are taken at the faces of the wall. An offset wall gives an edge footing with a cantilever on one side only.
• With the linear distribution the footing is rigid and the base lifts off beyond the central third; the uniform option takes E_N,d/B′ on the effective width.
• Sliding counts neither c′ (SIA 267 §8.4.1.2) nor the lateral resistance of the soil. Without φ′_k, sliding is not checked.
• Plain concrete suits a lightly loaded footing whose projection beyond the wall is small compared with its thickness: the concrete takes the bending in tension.
• The settlement adds the stresses of the loaded rectangle (Boussinesq) layer by layer, EN 1997-1 F.1, down to z_lim (EN 1997-1 §6.6.2(6)); without L the strip is taken 40 · B long. It is an estimate: creep and consolidation time are not included.

Worked example

A footing 1.6 m wide and 450 mm thick under a centred 250 mm wall, with 0.6 m of backfill, Ø14 at 150 mm transverse and Ø10 at 200 mm longitudinal bars, f_ck = 30 N/mm², n_d = 380 kN/m, m_d = 20 kNm/m, h_d = 15 kN/m, q_R,d = 420 kN/m², n_d,inf = 260 kN/m, φ′_k = 30°, and in service 270 kN/m and 10 kNm/m on one soil layer with M_E,1 = 30 MN/m². These are the module's own results for its worked example, computed when this page was built.

How this module is verified

Verified clause by clause against SIA 262:2025 and against independent calculations used on real projects, before release.

Questions

Where does q_R,d for a strip footing come from?

From the geotechnical report, or from the soil bearing resistance module for a strip. It is checked as E_N,d ≤ q_R,d · B′.

When does a strip footing need top bars?

Where the weight of footing and soil exceeds the soil pressure under a cantilever, so that the base lifts off. In the worked example the whole base stays in contact.

Can I print the calculation?

The full calculation is shown on screen, free and without an account. A print-ready A4 calculation note is part of the Basic plan.

Related

• Isolated pad footing
• Soil bearing resistance
• Foundations: all modules
• SIA 262: modules and clauses

Norm: SIA 262:2025 · Page updated: 5 November 2026