We wanted to know if PLAXIS can model a concrete diaphragm quay wall (wharf) structure. The wharf consists of concrete diaphragm wall on waterside against which the ships dock) and landside and a series of vertical concrete elements called barrettes (frame elements) embedded almost full height/depth in soil. The top of the barrettes are connected to the diaphragm walls in the transverse direction by concrete beams. There are longitudinal beams on top of waterside/ landside quay walls. The soil consists of clay and sand layers. The whole structure is known as a closed wharf structure (since you have a wall at the front and the back)
We had a few questions:
1) Is PLAXIS a plane strain based software?
2) Does PLAXIS predict hinging strains/moments and cracking in the concrete elements (across height) embedded in soil?
3) Is it possible to extract bending moments and shears of the frame elements, the wall elements, and the beams?
4) Can PLAXIS model the construction sequence of the whole structure (as against the final condition)?
5) How are seismic loads inputted into the PLAXIS model? Is it inputted as just a PGA or as a spectra?
6) Though the "structure" consists of separate elements, they are all interconnected and behave as a single mass. Does PLAXIS provide a global "performance"?
7) Can PLAXIS also indicate if there is an issues with global instability (Bishop's method) etc.?
8) How does PLAXIS model the soil structure interaction (interface between structural concrete elements) and surrounding soils?
Thanks.
Dear Jyotirmoy,
I believe that the number of questions you have on the topic may require some follow-up, therefore I would advise you to submit a service request: https://apps.bentley.com/srmanager/ProductSupport
Then, we will be able to answer in more detail based on the model you want to create. Nevertheless, you can find my answers to your questions below:
1) PLAXIS 2D can run both plane strain and axisymmetric analyses. You can check that in our Reference manual (see link at the end).
2) For modelling concreted you can use either volume elements and utilize the Concrete constitutive model we offer or use the plate elements. Each option offers different options therefore, I would advise you to check our Reference and Material Models manuals for more information (see link at the end).
3) Yes, plate elements allow for these structural forces.
4) Yes, that is what we call Staged construction and in PLAXIS it has its own mode to define all the phases according to construction planning.
5) Please check the following links for more information:https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45568/plaxis-2d-tutorial-15-free-vibration-and-earthquake-analysis-of-a-buildinghttps://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45952/plaxis-uses-smc-files-for-earthquakes-but-what-kind-of-format-is-this
6) By default, the structural elements, such as a plate, are by default rigidly connected. It is possible to add connections between plates allowing for a hinged or free connection.
7) Yes, we use a different approach, the phi/c reduction method. You can find more information in our Reference manual and in the following links:https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45939/safety-analysis-and-displacementshttps://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45960/safety-calculation-with-a-target-valueAn example can be found in our tutorials:https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/45559/plaxis-2d-tutorial-05-construction-of-a-road-embankment
8) Indeed, PLAXIS has implemented the interface elements to simulate the soil-structure interaction. You can use the Rinter parameter or assign a Custom material directly to the interface. You can check that in our Reference manual (see link at the end).
As a general comment, based on what I see in the attached pictures, you might need to consider using PLAXIS 3D for predicting the corner effects of the structure, as PLAXIS 2D performs, as you already asked, a plane strain analysis.
PLAXIS CONNECT Edition V20 Manuals:https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/46137/manuals---plaxis