Numerical Simulation of Soil Structure Interaction in Pile-supported Integral Bridges

June 11, 2020
BLOG PROJECT TUTORIAL

Example #1. Integral bridge on piled bank seats 

 

Limit equilibrium methods- Depth of soil affected by abutment movement can be identified without soil-structure  interaction analysis
- Thermal movement ≤ 40 mm;
- Skew ≤ 30°

 

PD 6694-1:2011 9.4.4 Horizontal soil pressures on end screen and abutments that accommodate thermal movements by translation without rotation

 

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3 Methods to consider soil properties in midas Civil

 

(1) Pile springs – user-defined p-y curves 

 

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(2) Pile springs – built-in p-y curves

 

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(3) Pile springs – Method of subgrade reaction (used in this example)

 

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Applying Temperature Loads and Results

 

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Apply Earth Pressure based on PB6694-1

 

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Envelope Results by Load Combination

 

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Example #2. Integral bridge with full height abutments supported on a single row of piles

 

Soil–structure interaction- Depth of soil affected by abutment movement cannot be easily identified unless a soil-structure interaction analysis is performed
- Thermal movement > 40 mm;
- Skew > 30°
- Over-consolidated back-fill material
- Layered soils

 

PD 6694-1:2011 9.4.5 Horizontal earth pressures on full height frame abutments on piles and embedded wall abutments (soil– structure interaction analysis)

 

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Soil structure interaction model can be generated with midas GTS NX. In order to consider the variable elastic modulus, we can imply import the materiel properties from Excel into GTS NX and assign them to each soil layers.

 

 

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Construction stage analysis with 5 stages considering structure and back-fill soil construction with temperature loads has been performed. The stress profile from soil is obtained and compared with earth pressure applied to abutment to obtain H'(depth of soil influenced by the abutment movement) and d'(the moment of the structure at a depth H'/2 due to an expansion or contraction of the end of deck). Update Soil Shear Modulus, R_FG, and young's modulus in GTS NX model file and update the results again. By doing this iterative analysis again, we can obtain the converged results.

 

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About the Author
Pere Alfaras | Principal Bridge Engineer | Arcadis UK

Alfaras has more than 12 years of experience in bridge and structural design. He has also been a renowned lecturer at UPC/Barcelona Tech for 5 years and his main focus was on Finite Element Methods.

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midas Civil project tutorial of the Numerical Simulation of
Soil Structure Interaction in Pile-supported Integral Bridges

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