Engineering Analysis Coursework Instructions for Soil Structure Interaction Computer Lab

Aims and Objectives -

Soil structure interaction is a major challenge for engineers to design a robust structure on difficult ground conditions. In this computer lab, you will model a 2-D steel structural frame subject to a non-linear soil behaviour and investigate the influence of the soil stiffness. You will carry out a parametric study to quantify the risk of structural failure if the possible subsidence is ignored in design.

Learning Outcomes -

This coursework covers the following module learning outcomes. You will be able to

• Apply those principles to realistic engineering cases of limited complexity, incorporating sustainable and durable construction practice.
• Interpret actual or realistic data in terms of the underlying engineering principles.
• In response to a relevant engineering problem, carry out calculations that lead to a solution, at the level expected within the profession of a new graduate engineer on a career path to Incorporated Engineer.
• Present relevant information and calculations in a clear and unambiguous way.

Specifically after undertaking this coursework you will be able to:

• Model a 2 dimensional frame in a commercial software, either OASYS or Midas Civil;
• Investigate the structural behaviour as influenced by soil/foundation stiffness leading to in-service failure and possible collapse;
• Study the sensitivity of soil behaviour to the stability of a structure.

Coursework Tasks -

Part 1 - Modelling the steel frame on rigid foundation

The 2 dimensional steel frame as shown in Appendix A is for a two story office building. The quasi-permanent variable loads as indicated were considered as long term loading for serviceability analysis.

Your task is to model the steel frame in a structural analysis software without application of any safety factor. The model analysis should include the full unfactored quasi-permanent variable loads as shown in Appendix A and the unfactored self weight of the frame structural members. It is assumed that all columns are "pinned" on the foundation of which no vertical displacement will occur under load.

The following should be reported: the bending moment and the shear force diagrams for all column and beam members; the axial forces and deflections of the appropriate structural members. Indicate all significant values.

Please save the software project file with a name of "338CAB-Rigid-your last nameyour student id". Make sure you backup the file.

Part 2 - Modelling of steel frame with a foundation on soft ground

The RC pad footing, of Column A (the middle one as shown in Appendix A), has a dimension of 1.4m x 1.8m by 300mm think. The saturated clay layer underneath is 4m deep. Soil samples have been extracted for a consolidation test. The test results is given in Appendix B. Appropriate equations and evaluation guidance are also given in the appendix. You should assume that the soil condition is ONLY applicable to the foundation of column A. The foundations of the other two columns can be assumed on rigid ground (no vertical displacement) for this exercise. Keep the same variable and dead load conditions as in Part 1 above.

The following should be reported: the vertical compressive stress of the soil under column A, the vertical settlement of column A, the bending moment and the shear force diagrams for all column and beam members; the axial forces and deflections of the appropriate structural members. Indicate all significant values.

After completion of this task, save the software project file with a name of "338CABSoil-your last name and your student id". Make sure you backup the file.

Part 3 - Parametric Studies and discussion

You should assume that the given structure on the Rigid Ground condition (as in Part 1) has been designed to a "safe" standard. Compare of the results of the two models (the rigid ground model and the soft ground model) in a table format showing structural members and significant values of forces/moments. Identify the members which will be overloaded under soft ground condition. Propose and discuss the reasons for these possible failure cases (by bending or by shear or by axial tension/compression or due to excessive deflection). You should point out any limitations and assumptions of the analysis.

Part 4 - Conclusion

(i) Conclude your assessment of the soil/structure interaction problem above, (ii) comment on your experience of using structural analysis software to carry out the task and (iii) any knowledge you have learnt from the exercise.

Attachment:- Assignment File.rar