Civil Engineering Reference
In-Depth Information
a three-dimensional finite element analysis of the structure with a classical earth
pressure load. The back analysis indicated that a linear soil load with a coefficient
of lateral earth pressure,
K
, of 2 was required to reproduce the displacements
measured in the field. This large value of
K
could not be justified for the backfill,
and it became apparent that a more complex soil-structure interaction was respon-
sible for the deformations and severe structural distress in the building.
After some repairs, movement of the building was monitored, and recorded
hourly for a period of four and half years. The monitoring revealed complex
temperature-dependent soil structure interaction.
In Chapter 5, the closed form expressions derived in Chapter 3 are used to
obtain the relationship between temperature and earth pressure for the structure
monitored in Chapter 4. The data indicates that the coefficient of earth pressure
behind the monitored RFERS has a strong linear correlation with temperature.
During the cold season the building contracts, and the retained soil follows. Dur-
ing the hot season, the building is unable to overcome the earth pressure, thus it
expands away from the soil, resulting in a cumulative annual displacement. The
coefficient of lateral earth pressure changed by approximately 0.005/°C varying in
the range of 1.25 to 1.5, depending on the season. The study demonstrates that
thermal cycles, rather than lateral earth pressure, caused some of the structural
elements to fail.
1.4.3 Numerical Analysis
A numerical analysis of the instrumented structure studied in Chapter 4 was also
performed, simulating the backfill stage and subsequent temperature cycles. The
resulting deformations and stresses in the retained soil and structural elements are
presented in Chapter 6. Next, the results of parametric numerical studies on a mul-
titude of rigidly framed earth retaining structures with variable sizes and proper-
ties are presented. First, earth pressure behind RFERS at backfill stage is explored
in Chapter 7. Second, analysis of single story RFERS subject to temperature varia-
tion is investigated in Chapter 8. Finally, multi-story RFERS subject to tempera-
ture variations are analyzed in Chapter 9. Recommendations and conclusions are
presented in Chapter 10.
