 |
Crystal Water Beach | |
| Northwest Frontier Province Pakistan Bob Culbert, October 8, 2005 |
||
Northwest Frontier Province Pakistan
PAKASTAN PROJECT
by: Professional Engineers magazine (July 06)
Pakistan Earthquake
October 8, 2005 a 7.6 Mw magnitude Earthquake struck at 8:50 am
Pakistan Standard Time leaving over 80,000 dead, 100,000 injured and
more than two million homeless, the Earthquake ranks among the worst
natural disasters in the history of Pakistan and the Indian subcontinent.
The epicentre of the Earthquake was located approximately 15 kilometres north of Muzzaffarabad the administrative capital of Azad Jammu and Kashmir (AJK). Most of the damage occurred in AJK and the Mansehra District of the North West Frontier Province (NWFP).
World Vision / Builders Without Borders Partnership World Vision Pakistan (“WVP”) has been active in Mansehra District of Northwest Frontier Province (“NWFP”) since 2003 supporting community development, infrastructure rehabilitation and disaster preparedness activities.
Following the Earthquake WVP commenced an 18 month Recovery and Rehabilitation phase, to be followed by a 36 month Reconstruction phase.
Picture: Bob and Ali
Prior to commencing construction, WVP engaged Builders Without Borders to undertake an assessment mission to examine the requirements for rebuilding 80 two and three room schools in the remote Siran Valley region.
Builders Without Borders provided a civil Engineer Bob Culbert and and a structural Engineer Saqib Khan for this three week mission, to the Mansehra District, a region with mountainous terrain and difficult weather conditions.
The Siran Valley rises in elevation from approximately 3,300 feet above sea level at Mansehra rising up to 5,000 feet at Jabori and Sacha Kalan and 6,200 feet at Manda Gucha. The terrain becomes increasingly rugged Northward up the Valley towards the Karakorum Mountains. The climate is characterised by cold winters with snow at higher elevations, mild springs, hot summers with monsoon rains, with cooling through autumn to winter.
School Damage Overview
Virtually all school buildings in this region are government built, and every
community has an elementary school, even the remote villages.
Anecdotal evidence suggests catastrophic damage occurred to a much
higher proportion of public schools than nongovernmental buildings in this
area. Poor quality of construction and lack of seismic design has been faulted in these building collapses. Most school buildings collapsed either
totally or partially.
Initial Assessment Observations
• It has been long recognised that school buildings are especially vulnerable
to and frequently collapse during earthquakes and this trend is unlikely to
change unless individuals, communities, governments and engineering and
planning bodies discuss and devise designs and strategies to mitigate and
address this problem.
• Design of buildings to resist earthquakes involves controlling the damage
to acceptable levels at a reasonable cost.
• The internationally recognised standard for the minimum expected seismic
performance of school buildings is that they are able to avoid collapse
when subjected to large earthquakes.
Picture: Nomads
• Most countries with advanced earthquake expertise stipulate the
performance objectives of school buildings as loss prevention and low risk
of injury to the occupants but do allow for some repairable structural
damage.
• School buildings around the world have different configurations and are
built of different materials. Reinforced concrete (RC) moment resisting
frames; RC dual systems (frames with shear walls); light steel frames;
mixed steel frames with wood and concrete; concrete and masonry
construction; and braced timber frame construction can be cited as a few
examples in this regard.
• Each of these construction types has its own benefits and disadvantages
given the building size, location, material cost and availability, etc. Also,
each material and building configuration may be potentially less or more vulnerable during seismic events depending on whether it has been
engineered and constructed properly.
• Low strength stone masonry buildings have shown poor performance in
the past earthquak
es and should be avoided in high seismic zones. The
inclusion of special earthquake-resistant design and construction features
may increase their seismic resistance but they may still not become totally
free from heavy damage and even collapse in case of a major earthquake.
• Reinforced concrete and steel construction requires a high level of skill for
design, construction and inspection besides these materials being more
expensive than brick masonry. Also, transporting prefabricated steel
sections or large quantities of concrete aggregate to remote sites could be
cost prohibitive and construction and supervision quality could possibly be
compromised.
• Sound timber design and construction practices do not seem to be well
entrenched in Pakistan while unreinforced brick masonry buildings have
not fared too well in the past earthquakes.
Picture: Musa ka Mussllah (Moses Mountain)
is 13,000 feet at the head of the
Siran Valley
where the worst
of
the earthquake struck).
• Given the requirement for small, 2 and 3 room primary school buildings,
confined brick masonry could be the appropriate technique for
reconstruction.
• There is well-documented evidence from around the world showing
satisfactory performance of confined masonry buildings; this building
technology therefore seems to be a logical choice for use in school
reconstruction.
• If properly designed and constructed, confined brick masonry has the
potential to show adequate performance by limiting damage to low or
moderate levels during severe seismic events. This choice is further
supported due to ready availability of baked clay brick masonry and at
least semi-skilled masons in the NWFP.
