SOIL-STRUCTURE INTERACTION. CAPITOL HILL RELIEF SEWER (ELLIPTICAL SECTION)

In order to develop methods of analysis and design of reinforced concrete buried structures constructed in open cut, soil structure interaction as applied to buried structures under static loads was researched. The work was performed on the Capitol Hill Relief Sewer Section II (Washington, D.C.) which is a vertical, semi-elliptical, non-prismatic, buried, reinforced concrete arch constructed in an open cut. The study included a review and appraisal of the analysis and design procedure and an evaluation of the method of analysis to predict the pressure distribution on the buried structure. A field measurement program was conducted for acquiring data describing lateral movements of the bracing and soil (by inclinometers), and earth loads on the buried structure by Gloetz pressure cells. Field and laboratory tests were performed to evaluate the engineering properties of the soils surrounding the structure. A finite element incremental nonlinear program (FEECON) using the hyperbolic stress-strain formulation for the constitutive model was utilized to make predictions consistent with observed measurements and produce an economical design. Proper account of the soil and concrete properties, the sequential construction procedures, and boundary conditions in the analysis resulted in good correlation between the predicted and the field measured stresses. It was found that the finite element analysis gave lower stress values beneath the slab and appeared to give higher values at the barrel (attributed to the different installation methods used for the base and barrel cells). The anlaysis, using a fixed excavation wall, closely simulated the field conditions and produced the best correlation between computed and normal stresses. It was also found that large changes in the concrete stiffness do not apprecialbe affect the interface pressure provided the relative stiffness between the concrete and the surrounding soil remains high. The change in water table elevation can significantly affect the stress distribution on a buried structure. The study revealed that stiff foundation soils produce a relatively uniform contact pressure of lower magnitude than soft foundation soils, but has negligible effect on the barrel pressure distribution. Relatively stiff backfill soils tend to decrease the crown pressure but increase the pressure in the region of the quarter point on the arch.

  • Corporate Authors:

    Howard University

    Department of Civil Engineering
    Washington, DC  United States  20059
  • Authors:
    • Mensah-Dwumah, F K
  • Publication Date: 1975-7

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 145 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00126844
  • Record Type: Publication
  • Report/Paper Numbers: MS Thesis
  • Files: TRIS
  • Created Date: Nov 5 1975 12:00AM