GSA Raft Analysis

1
GSA Raft Analysis

• (Soil-structure interaction analysis)
• Thomas Li

2
GSA Raft Analysis

• When to use GSA Raft analysis
• What GSA raft analysis can do
• What you will get from GSA raft analysis
• Main features of GSA raft analysis
• Results from GSA raft analysis
• How to do GSA raft analysis

3
GSA Raft Analysis

• When to use GSA Raft analysis
• To consider the effects of soil settlement on top
  structures
• To evaluate soil settlements under building loads
• To predict the structure and soil responses more
  accurately

4
GSA Raft Analysis

• What GSA raft analysis can do
• Soil-structure interaction analysis of raft
  foundations

5
GSA Raft Analysis

• What GSA raft analysis can do
• Soil-structure interaction analysis of pad
  foundations

6
GSA Raft Analysis

• What GSA raft analysis can do
• Soil-structure interaction analysis of piled raft
  foundations (soil-pile friction ignored)

7
GSA Raft Analysis

• What you will get from GSA raft analysis
• Compatible vertical displacements between soil
  and structure
• More precise analysis results for both soil and
  structure
• Contact pressures between soil and structure

8
GSA Raft Analysis

• Main features of GSA raft analysis
• User defined locations and areas of
  soil-structure interaction points
• User defined elevation of the interaction points
• Maximum and minimum pressure that soil can
  support can be defined
• Two soil settlement analysis methods
• Mindlin - fast analysis
• Boussinesq - includes soil stress calculation
• Heave simulation functionality
• Non-linear soil properties (E - e curves can be
  defined)
• Flexible definition of soil strata same as
  Vdisp
• Option to create new GSA model after raft
  analysis using equivalent springs to represent
  soil

9
GSA Raft Analysis

• Results from GSA raft analysis
• Raft results - the same as other analysis
  (forces, moments and displacements etc)

Contour of Myy of the raft
10
GSA Raft Analysis

• Results from GSA raft analysis
• Soil results settlements, stresses and strains

11
GSA Raft Analysis

• Results from GSA raft analysis
• Interaction areas - contact pressures

Contour of contact pressure between soil and raft
12
GSA Raft Analysis

• How to do GSA raft analysis
• Construction of GSA model - the same as other GSA
  analysis
• Definition of soil properties - the same as Oasys
  Vdisp program

13
GSA Raft Analysis

• How to do GSA raft analysis
• Definition of soil-structure interaction points
  (area, elevation, minimum and maximum pressures)

14
GSA Raft Analysis

• How to do GSA raft analysis
• Do the analysis - through analysis wizard and it
  is similar to other GSA analyses