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

to make it available to other agencies coming to the
Kathmandu Valley to help with rebuilding heritage who
might be interested.
• Ideology vs science (politicization of technical issues)
The local campaigns to avoid modern materials are worrisome
and counterproductive-- essentially as they preclude
doing seismic strengthening methods/technology
in the foundations - where steel and reinforced concrete
have been shown around the world to be the only feasible
and durable solutions. These can have lifespans well
in excess of 75 years if properly detailed and maintained,
and these materials are used all over the world, including
heritage sites.
• Agreement on fundamentals
Still, we are in agreement with most of what the local
campaigners are saying and we share their ultimate goals
of preserving. The difference is where a technical matter
becomes an ideological sticking point.
• Connections
Newar Architecture has long been known for weak connections
between building elements. Wood joints that
have room to move, timber columns with tenons only
1 inch long, chukul pegs at rafters that are meant to be
tightened periodically but aren’t, struts that rely on roof
loads to hold them in place with no direct connection,
- the list goes on. The materials and the heavy use of
strong timber should typically yield better seismic stability,
but the weak point lies in the connections that
easily pull apart during seismic motion. Meanwhile, the
ends of timber elements rot in poorly maintained Newar
structures. Reinforcing of connections between sound
existing building elements with direct structural connections
using stainless steel dowels and plates can go a long
way to making these buildings safer.
• Damp proofing
This necessary protection is not in the lexicon of traditional
Newar design and materials, but it is critical
for palace courtyard structures and other residential
buildings whose walls rise from grade, where materials
in the zone of cyclical rising damp (between the dry upper
walls and the damp foundations/lower walls) suffer.
Without damp proofing, progressive rotting of timbers
and deterioration of brick in this zone- roughly from
knee-level to shoulder level - weaken the structure and
reduce its seismic resistance. A damp proofing course (eg
copper sheets) can be inserted in situ in a retrofit with
some difficulty, but is worthwhile (eg Patan Museum;
Sundari Cok).
In the discussion of rebuilding projects with reinforced
concrete ring beams in the foundations, concrete can
economically play a dual role in damp proofing as well
as unifying the structure. At the classic Newar temples,
atop their high plinths, rising damp is less of an issue
although still a factor to address when rebuilding.
At the Manimandapas, damp proofing is a critical function
of the proposed concrete slab below grade because
it protects the wooden lakansi beams which hold the column
bases with their vulnerable end grain cuts sitting
less than a meter above grade. Protecting these column
base connections from rot is a key to the survival of the
structures in an earthquake.
• A story set in stone at fallen temples
A common pattern of failure appeared after the earthquake
in the classic multi-tiered temples with an outer
timber arcade of columns on the ground floor. As the
earthquake shook the temple with a combination of
vertical and lateral forces, large bearing loads were partially
relieved from the base stones under the columns.
Since there is no direct connection holding the stones
back to the plinth, the outer corner of the top plinth
(threshold) level was rotated out of place by the column
resting on it. Telltale rotated stones are still visible today
at plinths awaiting the rebuilding of temples-, eg at the
northeast corner of the Harishankara. The column base
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