quality and disaster resistance, and how these traditional quality measures have worked for different
prevailing construction types. It can often be noted that vernacular technologies have evolved over time,
learning from disasters that have occurred. Traditional timber frame constructions (for example in Turkey,
or the dhajji dewari in Pakistan and quincha in Peru) all have good earthquake resistant records and have
been used successfully in reconstruction without having to be regulated. In such cases, the advice and
guidance by architects and engineers working for aid agencies, or researchers and academics, often helped
to overcome slight weaknesses and execute construction in the best possible way. Over time, standards,
guidelines or manuals may emerge from this.
4. The impact of the disaster is disproportionately large compared to its magnitude.
An earthquake with magnitude 5.5 or less, a cyclone classified as a tropical storm rather than a hurricane
or typhoon, or flooding that happens every few years rather than once every century can be expected to
cause only minor damage to most buildings, and most of this damage should be repairable. Only rarely
would a building collapse from such disasters. If a scenario emerges whereby medium magnitude events
cause several buildings to collapse or be seriously damaged, it should serve as a wake-up call. Possible
causes need to be investigated and actions taken to make buildings more resilient, even to potentially
more powerful future events. It could be that particular buildings more prone to damage, take priority in
retrofitting. Attention also needs to be given to producers of building materials and components to ensure
their products are not poor quality. The regulatory framework can also be examined; for certain types of
construction such as reinforced concrete, it can be very difficult for inspectors to identify problems or visit
all construction sites frequently. Better quality at the building site remains important (see PCR Tool 10:
Quality Control) - having appropriate standards and regulations can facilitate that.
5. Most buildings withstood the disaster well.
This is the ideal scenario and it is important to look into the reasons for it. What types of buildings turned
out to be particularly resilient and what are their significant characteristics? What made people decide
to select this particular type over other options? How have standards and regulations and the methods of
building control contributed to this good performance? What do builders and materials producers do to
control quality? Lessons from this can then be applied to other construction that performed less well, or to
other potential disaster areas.
Applications
Relatively few countries have standards and
regulations that cover the hazard resistance of
non-engineered low-rise residential and commercial
buildings, and most of these are developed
countries. There is now growing recognition of the
particular vulnerabilities to natural disasters of
such buildings in developing countries. In many
cases, this has led to the production of guidelines
for strengthening simple buildings. However,
convincing householders as well as local authorities
that these can be effective remains problematic.
There have been documented cases of builders
not implementing standards even after extensive
training and demonstration, and of householders
removing timber or bamboo struts or cross-bracing
to use as fuel or to sell. Development agencies,
researchers and building inspectors alike tend to
pay very little attention to the alterations owners
make to buildings, or their eventual lack of
maintenance, once they are in use.
There are also positive developments however.
These have often combined appropriate regulation
with a significant level of community-based
decision making and involvement in quality control.
They involve the merging of formal top-down official
regulatory processes that in some developing
countries only cover a small part of construction
activities with some of the bottom-up ways found
in informal housing and building. What follows are
some examples that have aimed to extend building
standards and regulations to a wider audience,
including builders of non-engineered construction.
11