Page 13 - LWFC Catalog

5PM - MSE Walls Using Lightweight Fills – State of the Practice and Case Histories Slopes,
5:50PM embankments, and retaining wall structures for infrastructure projects are frequently
constructed on sites with less than ideal soil conditions. When unsuitable soils are encountered
the goal of the geotechnical engineer is to provide cost-effective solutions to remedy issues
related to settlement, stability, and bearing capacity. When these concerns are present,
it can be desirable to use fill materials with low densities in order to reduce the magnitude
of the applied loads. Otherwise, the use of conventional or quarried select fill materials
may require more costly ground modification techniques to achieve a suitable factor of
safety. This presentation will explore the use of expanded shale, clay, and slate lightweight
aggregates as a cost effective solution on sites with challenging soil conditions. The content of
the presentation will include a general overview of common ground improvement methods
and where lightweight aggregate fill options fit. Specific applications will be reviewed along
with select project case histories.

5PM - Using Geofoam Block Technology to Construct Staircases on Compressible
5:50PM Foundation Construction of tier seatings, staircases, landscape terraces and terrains,
undulating form of fills and access ramps using geofoam blocks in the structures without
imposing additional stresses to the structural frame is an attractive application not only in
the new construction but also in the renovation projects. In addition to the load reduction
function which prevents possible structural rehabilitation if conventional fills are selected,
geofoam blocks are also preferred since they provide an economical solution and ease
of installation. Two rows of adjacent industrial structures were constructed with elevation
differences of 7.5 m between their foundations. CPTU testing program was performed to
estimate consolidation and shear strength properties of the local subsurface conditions. Firm
to stiff clay with high compressibility extends to a depth of approximately 10.5 m. A layer of
hard clay extends from 10.5 m below the ground surface to the refusal cone tip stress at the
depth of 12.2 m. Therefore, the mat foundations of these structures were designed as deep
foundation using drilled shaft piles. A 7.5 m high staircase with two space landings needed
to be constructed in a constricted access area of 6.6 m wide for pedestrian access. During
the construction of the drilled shaft pile foundations no subsurface improvement has been
considered in the area where the staircase will be constructed. The allowable consolidation
settlement criterion was not met if the staircase was selected to construct as a reinforced
concrete structure. Mobilization of the equipment to construct the pile foundation of this
staircase structure in this constricted area after the completion of industrial structures was a
main challenge. Therefore, geofoam technology was selected to construct this staircase to
prevent the total consolidation settlement. Custom cut geofoam blocks with a height of 17
cm to accommodate the ease of installation of the risers were used in the block placement
plans. Backslope where the geofoam block staircase constructed was not stable. Therefore,
to prevent lateral earth movement of the 7.5 m high adjacent soil slope and increase
the stability of the back slope to prevent a possible long-term slope failure, a total of four
embedded type cantilever bored piles were constructed. This application is also considered
as a side-hill fill where geofoam blocks are placed adjacent to a stable back-slope. Selecting
geofoam block technology was a key for the construction of a high staircase structure in a
constricted area without the need for a soil improvement. Using geofoam blocks were not
only prevented soil improvement but also reduced the project completion time significantly.

5PM - Case Studies: Long Term Performance of Cellular Concrete Fill in Geotechnical
5:50PM Applications Cellular Concrete Fill has been used in Geotechnical projects in the United
States since the mid 1970s. The early applications included Bridge approaches, Roadways,
and replacement of poor soils. This presentation will examine a number of these early
projects, first exploring why cellular concrete fill was required. It will then discuss cellular
concrete fill production and installation and the physical properties of the installed fill. It will
also analyze the overall performance of cellular concrete fill in real world conditions over a
period of 40+ years.