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National Building
Research Organisation
Research & Development Programmes : 2001 -2002
Landslide Hazard Mapping Project
(LHMP) Phase III.
Preparation of environmental planning, development and management
tools for sustainable development in the shelter sector, using
environmental carrying capacity concept.
Air Quality Monitoring Programme
(NRC Funded)
Evaluation of Environmental Impacts of metal Crushing Industry and
formulation of strategies and criteria for the development of
Guidelines for the mitigation of associated ill effect.
Investigations on natural
resources used in construction industry
Alternatives to river sand
Alternatives to coral based building lime
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Three dimensional geotechnical
zoning of the Greater Colombo area and establishment of regularities
of physical and mechanical properties of sub-soils, in three
dimensions, for future infra-structure development. |
Geotechnical mapping of the Greater Colombo area
in three dimensions and preparation of block designs indicating
different soil types based on engineering (physical and mechanical)
properties and their variations and regularities. This project was
based on the soil investigations done over the past years.
With the use of GIS and ARC VIEW, these data are
systematized and transformed into 1:10,000 maps. A data base and a
model have been established using these information for the
geotechnical and geo engineering properties of the sub soils.
This database could be utilised for future
feasibility studies, project planning, preliminary design work and
underground construction as well as for heavy foundation
constructions.
Landslide Hazard
Mapping Project (LHMP) Phase
III
Mapping of an extent of 1440 sq. km of landslide
prone areas of the districts of Badulla and Nuwara Eliya, indicating
weighted hazard zones was completed in December 1995. The work was
extended to the district of Ratnapura and Kegalle during 1996-1998
and district of Kandy, Matale during 1999-2003.
The project is an extension of the LHMP Phase I &
II, completed in the districts of Badulla and Nuwara Eliya in 1995
and Ratnapura and Kegalle in 1998. Under the phase III the districts
of Kandy and Matale have been taken up. Up to date, the Kandy
district mapping is being completed. Field mapping in Matale is yet
to started.
The project is targeted to produce landslide
hazard zonation maps in a 1:10,000 scale for identified priority
areas of the districts for use by planners and decision makers. It
is also aimed at providing guidelines on improved land use planning
and regulated development in high-risk landslide-prone areas of the
districts for minimising the loss of life and property due to
landslides.
Research on economisation of building
structures under the composite action of structural element
Presently building structures in Sri Lanka are
being designed mostly according to British Standard Code of
practice. However low rise buildings are coming up in Sri Lanka with
structural elements which have been made economical than for those
recommended under BS Code of practice. They appear to be
structurally sound within the prevailing local context.
Therefore aim of the research is to find out how
much economisation could be achieved on building materials during
design if the contribution of composite action built within the
building structure is taken in to account.
Examination of theoretical research findings and
practical testing of structural elements designed under the new
method is in progress
Formulation of database of working rates for
building work in Sri Lanka
Automation of the Building Schedule of Rates (BSR)
to provide for automatic updating of rates in line with the
fluctuation of market prices/ rates of building materials, labour,
transport, equipment, fuel etc. are in progress.
Preparation of environmental planning,
development and management tools for sustainable development in the
shelter sector, using environmental carrying capacity concept.
This project was formulated with the objective of
developing environmental management criteria and conceptual
management models for the development of undeserved settlement.
Under this programme, service have been carried out at 16 state
initiated housing settlements and developing environmental
management systems using the services data has been carried out. A
draft final report has been compiled and submitted for
evaluation.
Air Quality Monitoring
Programme
(NRC Funded)
With the implementation of "Clean Air 2000"
Action Plan in 1992 the Environmental Division was identified at
national level to monitor ambient air quality and develop modeling
systems.
Air quality monitoring programme was executed by the NBRO
with the objective of identify and control the major sources of air
pollution and continued for Colombo from December 1996 to April
2001. Under this programme, the NBRO possesses a good air quality
and meteorology data base with respect to SO2, NO, NO2,
CO, O3, PM 10, and meteorological parameters such as wind
direction, wind speed, vertical wind speed, rainfall, ambient
temperature and solar radiation as five minutes averages at Fort and
Meteorological Department Colombo 7.
In year 2000, with the financial assistance from
National Research Council (NRC), Sri Lanka, the NBRO initiated a
programme to develop low cost air quality monitoring methods and the
NBRO is now monitoring air quality with respect to SO2
and NO2 weekly at ten (10) selected locations in Colombo
since November 2001.
The NBRO is now in the process of monitoring
ambient particulate and total lead levels at three (3) locations in
Colombo with financial assistance of USAID. This will be executed
simultaneously with the programme of Ministry of Environmental and
Natural Resources, to phase out leaded petrol in Sri Lanka.
The NBRO with Urban Development Authority (UDA)
is now planning to develop ambient air quality as a planning tool
for the urban development activities.
Special programmes are now being launched with
the Colombo Museum to assess the impacts of air pollution to their
archeologically important monuments, and also with Department of
Pediatrics, University of Colombo to assess the impacts of air
pollution to childhood
health.
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Evaluation of
Environmental Impacts of metal Crushing Industry and
formulation of strategies and criteria for the development of
Guidelines for the mitigation of associated ill effect. |
Under this programme NBRO has compiled a data
base on existing metal crushing plants in major districts of the
island with special reference to information on environmental
aspects as at present is in the process of commencing field surveys
at selected sites.
Investigations on natural resources used in
construction industry
Alternatives
to River Sand
Excessive extraction of sand from rivers has been
carried out almost to the level of complete depletion. Further
mining below Hanwella in Kelani Ganga and below Alawwa in Maha Oya
is not feasible at all. The removal rate of sand exceeds by three
times the annual transport rate of these rivers This situation could
post severe environmental hazards with respect to the coastal and
river regimes. Therefore it is imperative to discontinue further
extraction of river sand and find alternative solutions immediately.
The aim of their research project is to find out
alternative materials which are economically and environment
friendly.
Use of dune sand, crushed rock sand and
off-shore sand as alternatives to river sand have been
identified and carried out extensive studies on the above materials
Dune sand
A large extent of Dunes exist between Daluwa and
Kalpitiya in NWP. NBRO has carried out extensive studies on its
suitability for construction work.
Dune sand can be extracted for the benefit of
people in the area without adverse environmental effects and without
disturbing human settlements. A preliminary techno-economic
feasibility study has been carried out and a report on same has been
submitted.
Extraction of dune sand should be carried out
under the authority of the North Western Provincial Council avoiding
areas restricted by the Coast Conservation Department (under Mining
Licenses issued by the Geological Survey and Mines Bureau).
Several meetings have been held with NWPC
authorities but the outcome has not been satisfactory.
Most of the laboratory and field trails on sand
alternatives have now been completed.
Dunes existing in NWP have been surveyed and
the total quantity of sand available for exploitation has been
estimated. The quantity available has been roughly estimated at 15
– 20 Mln. cubic meters which is about 3 - 4 times of the total
annual sand demand for construction work.
Field studies have been carried out with the
assistance of ICC and SEC.
Off-shore Sand
Many countries especially in the west use
off-shore sand for construction work. In Sri Lanka, this source
would be exploited off-shore from Kalpitiya to Hambanthota for
environmental reasons. Sand dredging should not be carried out
within 15 m depth from water level, but beyond that dredging could
be carried out to a depth of 40 m.
Except for the salinity, off-shore sand closely
resemble river sand in respect other properties of which are
significant for producing concrete and masonry mortars. Modern sand
dredging equipment have the facility to wash the sand (to remove
salts) before discharging it on land. Even otherwise, sand could be
left for a period of time on land for natural washing to take place.
Some of the off-shore sand deposits in the
southern area contain shell fragments. This is not a critical factor
because shell fragments are not really harmful in normal concrete
structures and further it could easily be removed, if so desired, by
sieving.
Since the project envisages extraction of sand
beyond 15 m depth from the water level, there will be no
environmental effects on the shore. On the contrary, washing off of
shore sand has taken place due to extraction of sand from the
rivers, thereby preventing nourishment of the shore by natural
transportation of sand via the rivers and deposition on the shore.
In fact there is an ADB funded project underway to introduce sand
for nourishment of the shore by artificial means, at high cost.
The NBRO efforts in finding alternatives to river
sand are aimed at re-creating the environmental balance vitally
necessary to sustain the sea-shores, river banks and river beds and
prevent pollution of river waters.
A project on off-shore sand giving guidelines on
extraction has been submitted.
Sampling of offshore sand has already been
carried out in the area extending from Kirinda to Kalpitiya.
Laboratory tests on these samples have been completed. It is
proposed to carry out further sampling to cover the area from
Kirinda to Trincomalee after the monsoons.
Tests indicate that the samples (except in few
locations) very closely resemble river sand. Therefore off-shore
sand can replace river sand in many construction applications.
Presence of chlorides, however is a minor constraint and this aspect
is now been studied on bulk sampling subject to weathering..
Crushed Rock Sand
The laboratory investigations curried out by the
NBRO have shown that quarry dust could be used as partial
replacement for sand for some construction applications such as
concretes, manufacture of pre-cast concrete elements, cement block
etc.
Quarry dust in Sri Lanka is usually obtained as a
by product from aggregate production. This is mainly used in road
works, concrete, cement blocks and as a filler material.
Detailed laboratory studies have been carried out
on crushed rock samples drawn from five quarries One company has
already set up a plant in Horana to manufacture sand from quarrying
materials to comply with specifications for fine aggregate /
building sand.
Alternatives
to coral based building lime
The cottage industry which supplies over 80% of
building lime product from coral is mainly confined to the Western
and Southern coastal belt. Mining of offshore coral reefs for
building lime also causes disastrous effects. On the stability of
coastal lands due to increase coastal erosion, which has become an
issue of prime concern. NBRO has expended that research programme to
introduce alternative sources of calcareous materials with least
detrimental effect on the environment.
At present building lime is produced, mainly as a
cottage industry from the following resources:
- Coral limestone (inland deposits which may be legally mined)
- Shell deposits
- Dolomitic limestone
Coral stone (inland) and shell deposits are now
almost depleted and the most viable alternative is dolomitic
limestone.
Unlike other sources of lime which contain over
90% of calcium, dolomitic limestone is a double carbonate of calcium
and magnesium. Technology adopted at present in lime burning does
not allow the separation of magnesium oxide that will be produced
together with calcium oxide. Since the calcium carbonate dissociates
to form the oxide at a much higher temperature (~900 0
C) than the dissociation temperature of magnesium carbonate,
the resulting product gives rise to over burnt particles (containing
magnesium oxide) which are difficult to be hydrated. As a result the
lime produced will have –
- low calcium content
- low workability and
- high percentage of coarse particles
The magnesium content in dolomitic limestone
varies from about 8-21% and the calcium content of lime produced
will also be varied.
According to a recent survey carried out by the
NBRO, it was found that limestone available are coarse grained and
difficult to be fired. The NBRO has carried out laboratory trials to
improve the lime burning process in order to produce good quality
lime using dolomitic limestone as the raw material. (ITI is also
carrying out field trials on similar lines). Once these trials are
completed, it should be possible to introduce an improved technology
to produce dolomitic lime which could be used as building lime.
It should also be noted that even at present
dolomitic lime production is presently carried out on a rather large
scale, but as a cottage industry in several parts of central
province. The NBRO has also directed its research on an
environmental analysis of the use of dolomitic lime.
Interim report on the environment analysis has
been submitted
Further laboratory studies have been carried out
at NBRO using limestone from Matale. Process improvements have been
studied. Laboratory trials carried out have shown the need to reduce
the energy cost. NBRO has also carried out trials on using a
gassifier for lime burning.
Feasibility of producing lime-based materials
have been studied on a laboratory scale. NBRO trials have shown that
good quality sand-lime bricks (for which the energy requirement is
much less than that for clay bricks) could be produced provided that
the quality of lime is improved. Studies on hydration properties and
laboratory trials are now being carried out.
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