1-D Site Response Analysis

Equivalent-linear & nonlinear ground response (OpenSees)

Soil Profile

How to prepare soil layer data

Manual entry: Click "Add Layer" and fill each row. Required fields:

FieldDescriptionExample
TypeSand, Silt, Clay, or GravelSand
Thick (m)Layer thickness in meters2.5
Unit Wt (kN/m³)Total unit weight18.0
Vs (m/s)Shear wave velocity180
SPT NSPT blow count (0 if unknown)15

CSV upload: Upload a .csv with these columns (header row required):

Type,Thickness,UnitWeight,Vs,N
Sand,2.0,17.5,150,10
Clay,3.5,16.8,120,5
Sand,4.0,18.5,220,25
Silt,2.5,17.0,160,12

Layers are ordered top → bottom. The last layer sits on elastic bedrock. Water table depth is set separately below.

0 layers · 0 m depth
# Type Thick (m) Unit Wt (kN/m³) Vs (m/s) SPT N

Water Table

Earthquake Motion

Accepted earthquake file formats

Upload a ground motion time-history file (.txt, .l, .acc, .dat). Three formats are auto-detected:

Format 1 — NPTS + DT header (recommended)
4096  0.005
0.00000  -0.00123
0.00500  -0.00256
0.01000   0.00198
...
Line 1: number_of_points   dt (seconds). Remaining lines: time (s)   acceleration (g).
Format 2 — Two-column (time, accel)
0.000  -0.00123
0.005  -0.00256
0.010   0.00198
...
dt is inferred from the first two time values. Units auto-detected: g, m/s², or cm/s².
Format 3 — Single-column acceleration
-0.00123
-0.00256
 0.00198
...
One acceleration value per line (in g). Requires constant dt = 0.01 s (default).

Files with acceleration > 50 are treated as cm/s²; > 2.0 as m/s²; otherwise as g. PGA and duration are shown after upload.

Drop time-history file or click to browse

.txt · .l · .acc · .dat
Running OpenSees analysis...

Results Summary

Figures
Interactive Charts
Shaking Simulation
0.00s / 0.00s
Sand
Silt
Clay
Water Table
Bedrock