Building construction in hilly regions requires comprehensive planning, site selection and design for slopes and sustainable concrete construction practices.
Deprived of picturesque views, fresh air and accessible flat lands in the cities, people have finally started to resort to hilly regions searching for their perfect abodes.
The economic growth and rapid urbanization in hilly regions have further encumbered the real estate development with an onus of developing multi-story buildings. Hilly regions, though tempting to construct a structure at, have wide variations in geology, geomorphology, climate, altitude, and materials resources.
The unpredictable geological situations and on-going development activities, precarious climatic variation, hydrogeological conditions result in different types of hazards like landslides and mud flows in these areas which make planning and design of buildings in a hill settlement a herculean task.
Building Construction in Hilly RegionsThere are four major points that should be etched into your mind when planning to construct a building in any hilly region:-
- Check for Landslide-Vulnerable areas
- Check for Slope and sequence of rock structures
- Check for existing subsurface water
- Check for existing streams
2) Comprehensive Planning:
Garnering topographical data:It involves detailed study of geological maps so that the engineers are aware and understand the geological formation of the site of the proposed development. Topographic map and aerial photographs of the site and abutting areas should be examined to know the geomorphological features, previous and present land use, current development, construction activities, problem areas like previous slope failure, etc. The knowhow of the site-histories particularly previous landslides and underground services is very important for the planning of the layouts and designs.
Site ReconnaissanceIt helps confirm the information acquired from the topographical data and also to obtain additional information from the site. For hill-site development, it is also very important to locate and study the protuberances to identify previous landslides or collapse that can act as an indicator of the stability of the existing slopes.
Site investigationFor a hill-site construction, site investigation should be carried out in at least two stages. First stage consists of boreholes and sometimes also includes geophysical survey. The locations of the field tests should be carried out with an objective to obtain the overall subsurface condition of the site like general depth of soft soil, hard stratum and most important, the depth of bedrock. Normally the boreholes are spread out to cover the whole site and placed at areas of potential major cut and fill. Soil samples (disturbed and undisturbed) should also be collected from the boreholes to carry out laboratory tests for the necessary soil and rock parameters for preliminary geotechnical design of the slopes, foundations and retaining walls. In addition, the ground water profile should also be assessed. Long term monitoring of water table is also needed in sensitive and critical areas. The general information on the subsurface profile and properties will be useful when planning the cut and fill and formation of the platform because the depths of hard stratum and bedrock will have major influence on the cost and construction time of earthworks. Once the preliminary layout of the hill-site development is confirmed, the detailed site investigation should be carried out to obtain the necessary information for detailed geotechnical designs. In the detailed site investigation field tests can be carried out at the following locations:
- Areas of major cut and fill.
- Retaining walls
- Buildings or Structures with Heavy Loading.
3) Design of SlopesThe phenomenon of slope failure transpires in much the same ways throughout the world with the basic causes do not differ greatly with geological and geographical locations. Therefore, the same methods of assessment, analysis, design and also remedial measures can be applied. The solemn difference is that in tropical localities, the climate is both hot and wet causing deep weathering of the parent rocks and the slopes are of weaker materials. For man-made slopes, there are many factors that can contribute to slope failures:
- Amiss or improper design, analysis or construction.
- High intensity rainfall
- Lack of maintenance
4) Sustainable developmentSustainable development is the continued ability of a society, an ecosystem, or any such interactive system to function without exhausting key resources and without adversely affecting the environment. Construction technique should be developed with locally available, easily workable materials which are mostly environmental friendly (like timber, stone mud and bamboo) and have good climatic resistance and have little or negligible impact on environment of hill settlement. Though cutting of trees for obtaining timber will result in loss of precious vegetation, it needs to be suitably augmented by afforestation in hilly areas. In contrast to this, contemporary materials are manufactured from raw materials, which are available on particular locations and are transported to different parts of the country after manufacturing.
Green Building Materials for Hilly region:
- Steel framed construction
- Sandwich panels (amalgamation of two fiber reinforced cement sheets)
- Aerated concrete panels
- Gypsum plasterboards