Site investigation · Geophysics & monitoring
Building damage assessment from ground movement calculator
Bending and diagonal tensile strains in a wall from the deflection ratio and horizontal strain, the limiting tensile strain and the damage category 0–5.
Standard: Burland & Wroth (1974) deep beam · Boscardin & Cording (1989) / Burland (1995) categories
Open the live calculator → All site investigation calculators
Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Wall length in the trough | 20 | m |
| Wall height | 8 | m |
| Relative deflection Δ | 10 | mm |
| Average horizontal strain εh | 0.05 | % |
| E/G (2.6 isotropic; 12.5 framed) | 2.6 | |
| Mode | Hogging (neutral axis at base) | |
| Acceptable category | 2 slight |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Deflection ratio Δ/L | 0.001 | |
| Second moment per unit thickness | 170.7 | m³ |
| Distance to extreme fibre | 8.00 | m |
| Bending strain εb | 0.001 | |
| Diagonal strain εd | 0.000 | |
| εb + εh | 0.119 | % |
| εd,r with εh | 0.066 | % |
| Limiting tensile strain max(εb,r, εd,r) | 0.119 | % |
| Damage category | 2.00 |
- ✓ Category ≤ acceptable
Method, formulas and assumptions
- Deflection ratio Δ/L = 10/1000/20 = 5.000e-4
- Second moment per unit thickness = IF(1=1,8^3/3,8^3/12) = 170.67 m³
- Distance to extreme fibre = IF(1=1,8,8/2) = 8 m
- Bending strain εb = 5.000e-4/(20/(12*8)+3*170.67/(2*8*20*8)*2.6) = 6.865e-4
- Diagonal strain εd = 5.000e-4/(1+8*20^2/(18*170.67)/2.6) = 3.570e-4
- εb + εh = (6.865e-4+0.05/100)*100 = 0.11865 %
- εd,r with εh = (0.05/100*0.35+SQRT((0.05/100*0.65)^2+3.570e-4^2))*100 = 0.065776 %
- Limiting tensile strain max(εb,r, εd,r) = MAX(0.11865,0.065776) = 0.11865 %
- Damage category = IF(0.11865<0.05,0,IF(0.11865<0.075,1,IF(0.11865<0.15,2,IF(0.11865<0.3,3,4)))) = 2
- ν = 0.3. Category 4 here means 4 or 5 (severe to very severe). Categories 0–2 are aesthetic, 3–5 serviceability/stability (Burland 1995).
Related site investigation calculators
- Blast vibration (scaled distance) — Peak particle velocity from charge per delay and distance, and the maximum charge per delay for a PPV limit.
- Seismic refraction: two layers, forward and reverse shots — Least-squares lines for the direct and head-wave arrivals of a forward and a reverse shot give V1, the…
- Downhole seismic: interval Vs, Vs30 and site class — Corrects slant travel times to vertical, computes interval shear-wave velocities, Vs30 and the site period…
- Resistivity sounding (Wenner array) — Apparent resistivity for each electrode spacing from the measured resistance, the range and trend with…
- Inclinometer: displacement profile and rate — From initial and current deviation readings per probe interval (A-axis), the incremental and cumulative…
- Blast vibration: site law regression and charge limits — Regresses monitored peak particle velocities against scaled distance to find the site constants, then the…
For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.