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

tural and climatic considerations but not earthquake activity.
The iconic multi-tiered temple type, with its very
wide overhanging roofs and timber structure but little
or no positive connections of inside to outside, or of the
main edifice to the base, is a classic example.
Erratic maintenance has long been an issue, especially
since the end of the monarchy in the 1950’s and the subsequent
decline of land trusts charged with maintaining
temples and shrines. Traditional structures have heavy
clay tile roofs set in mud; horizontal timbers embedded
in rubble walls with mud mortar; and bases unprotected
from the cyclical rising damp of ground water and
monsoons. Together with significant declines in quality
of replacement wood, these issues leave structures vulnerable
to plant growth on roofs, rotting timber ends,
top loading, and poor connections that—without proper
maintenance and reinforcement—can easily lead to
earthquake damage. The probability of poor future
maintenance, the certainty of future earthquakes, and
life safety concerns support the case for more durable
interventions today than in the past.
We have identified several seismic model projects in
Patan Darbar. In the course of design and restoration or
rebuilding of these projects, we will continue to develop
a range of seismic strengthening strategies and techniques,
which can then serve as models for addressing
common types of structural earthquake damage in other
traditional structures. For key model projects, we have
1) rebuilding schemes for collapsed multi-tiered temple
type structures (Char Narayana, Hari Shankara); 2) in-situ
repairs of the multi-tiered temple type (Vishveshvara);
and 3) rebuilding of the open arcade type—mandapa/
sattal structures (Manimandapas),—which is inherently
challenging given their timber column structure without
ground floor walls for bracing and connection.
The two general kinds of structural challenges we face
are 1) rebuilding collapsed structures—where modeling
will be possible, but implementation quality is difficult
to predict; and 2) reinforcement of existing buildings,
some of which are significantly weakened. Structural
design for rebuilding is more straightforward, mainly
because new structural characteristics can theoretically
be specified/quantified. Goals are to develop a range of
solutions which vary with each building’s importance,
specific construction, and risk of collapse; to develop a
safety assessment guide for our team’s field use, also collaborating
with local engineers; and to refine our range
of strengthening techniques.
The biggest challenge for these cases will be in the tradeoffs
between new and old methods: To what extent
should structurally inadequate historical building details
be retained? Which details are so inherently weak that
alternatives must be sought? Which characteristics are so
key to the buildings’ history or aesthetics that new ways
to maintain them must be sought? What determines the
choice between a safer modern—say—steel—structure
inserted (whether visible or not) within an exterior of
historical details, versus a less safe rebuilding of the historical
building with less intrusive reinforcement measures?
Another significant challenge will be to develop a methodology
to analyse historic buildings which survived the
2015 earthquake with or without damage, to determine
appropriate strengthening interventions. For these, alternative
methods of structural modeling need to be developed
to allow quantitative analysis; and many of the
same questions will apply.
Past KVPT projects illustrate many points along the
continuum from minimal intervention to maximum
sensitive seismic strengthening. Structural solutions of
interest includes Patukva Agamchhen (1994, no damage
in 2015), Jagannath Temple (2003, moderate cracks at
upper level), Ayaguthi Sattal (1999, no damage), Vabaha
(1994, very minor damage), and Radha Krishna
(1991, collapsed). We have already analyzed some of our
other projects fairly extensively in the past (e.g., Sundari
Cok). It will be instructive to better analyze how and
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