KVPT’s Patan Darbar Earthquake Response Campaign - Work to Date - September 2016

Plan drawing of Manimandapas
showing the proximity to the
adjacent Manga Hiti public well.
The north end of the South Manimandapa
is highlighted, showing
how it is bearing directly onto the
wall of the well’s staircase. This
is one of several unique boundary
conditions to consider in this
project.
Base drawing from Becker-Ritterspach,
1994
Reinforced concrete is the main example of a highly homogeneous
material, and that is one of the major factors
resulting in its widespread use as the main foundation
material in new structures and for rebuilding of historic
structures. The application of a poured liquid medium
that assumes its final shape and cures into a solid mass,
when properly proportioned and mixed, can provide an
extremely homogeneous mix of strong foundation material.
Foundation development at South Manimandapa
Foundation development took the forefront in the discussions
for this project, more so than usual, because
approval was needed before construction could begin,
and this proved to be difficult to obtain. Schedules and
funding deadlines, largely based on assumptions that
the project should be straightforward due to the size of
the structure, quickly began to fall behind due to development
of several iterations of foundation options in
search for a responsible solution that would be acceptable
to the Deparment of Archaeology. Up to this point,
the foundations have proven to be the most involved
aspect of design and discussion for the structure. This
was somewhat surprising as this structure is one of the
smallest in Patan Darbar.
The main technical boundary conditions on foundation
design includes the limited footprint around the site due
to the adjacent public well, limited materials and construction
techniques available in Nepal, and the limited
depth allowed for foundations due to the presence of
water supply pipes running to the adjacent well.
The main concept behind the foundations is that we
need to tie together the building elements, such as base
stones that were not properly tied back to the plinth
structure. In addition to the typical idea of having a
small concrete ring beam behind the base stones to allow
for anchoring the base stones back to continuous structure
(via stainless steel dowels), multiple concepts were
developed for the foundations during the design process.
One early concept was to implement a steel grillage
beam foundation. Grillage foundations are steel wide
flange sections assembled in grids and embedded into
the ground. These are used in areas of weak soils and
also to utilize a building’s self weight to combat the
overturning forces of top-heavy structures such as the
Manimandapa. This system would be best utilized if the
structural system above included a stiff central core, as
central steel columns could be run directly down to the
grillage beams and provide a solid load path. Features of
this solution include that it avoids extensive use of reinforced
concrete, can be assembled and constructed more
quickly, can provide substantial lever arm to combat
overturning lateral forces, and if stainless steel beams are
encased in concrete or cementitious mortar, the lifespan
can be much higher than other foundation types. To obtain
the proper counterbalance force against overturning
in the case of the Manimandapas, however, the grillage
beams need to be at least 4 feet below grade. This pre-
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