Structures placed on hillsides often present a number of challenges and
a limited number of economical choices for site design. An option
sometimes employed is to use the building frame as a retaining element,
comprising a Rigidly Framed Earth Retaining Structure (RFERS). The
relationship between temperature and earth pressure acting on RFERS, is
explored in this monograph through a 4.5 year monitoring program of a
heavily instrumented in service structure. The data indicated that the
coefficient of earth pressure behind the monitored RFERS had a strong
linear correlation with temperature. The study also revealed that
thermal cycles, rather than lateral earth pressure, were the cause of
failure in many structural elements.
The book demonstrates that depending on the relative stiffness of the
retained soil mass and that of the structural frame, the developed
lateral earth pressure, during thermal expansion, can reach magnitudes
several times larger than those determined using classical earth
pressure theories. Additionally, a nearly perpetual lateral displacement
away from the retained soil mass may occur at the free end of the RFERS
leading to unacceptable serviceability problems. These results suggest
that reinforced concrete structures designed for the flexural stresses
imposed by the backfill soil will be inadequately reinforced to resist
stresses produced during the expansion cycles.
Parametric studies of single and multi-story RFERS with varying
geometries and properties are also presented to investigate the effects
of structural stiffness on the displacement of RFERS and the lateral
earth pressure developed in the soil mass. These studies can aid the
reader in selecting appropriate values of lateral earth pressure for the
design of RFERS. Finally, simplified closed form equations that can be
used to predict the lateral drift of RFERS are presented.
KEY WORDS: Earth Pressure; Soil-Structure Interaction; Mechanics;
Failure; Distress; Temperature; Thermal Effects; Concrete; Coefficient
of Thermal Expansion; Segmental Bridges; Jointless Bridges; Integral
Bridges; Geotechnical Instrumentation; Finite Element Modeling; FEM;
Numerical Modeling.
