Session 3 low cost housing


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Session 3 low cost housing

  1. 1. Housing in Developing Countries – Areas of Concern 1. Severe shortage of houses in developing countries specially for poor people. 2. Severe problem of management of agro industrial waste in developing countries. 3. Mounting pressure on non renewable energy resources. Non- availability of energy efficient technologies for converting agro industrial waste and renewable local resources into alternative materials. 4. Expensive & scarce building materials and components
  2. 2. •Need for energy efficiency and environmental protection in manufacturing technologies. • Need to develop cost effective construction technologies to mitigate the effects of natural hazards. • Need to create employment and skill improvement opportunities leading to poverty alleviation. • Need to substitute expensive & scarce building materials and components by low cost locally available materials to suit local design typologies. Housing in Developing Countries – Areas of Concern
  3. 3. Major Causes of High Building Costs • Expensive materials • Lack of necessary building skills • Lack of guidelines in selection of appropriate building packages • Designs • Materials • Methods • equipment
  4. 4. Low Cost or Cost Effective Housing • Aims to reduce the cost of construction and at the same time not sacrifice any element of safety or serviceability of the house over the life cycle. • strong, • durable, • functional, • aesthetic, • environment friendly, • ecologically appropriate, • energy efficient • affordable and adaptable • cost-effective materials • appropriate technologies in construction
  5. 5. Various aspects for cost reduction • Optimisation of land use • Functional design of buildings • Optimum use of building materials • Rationalisation of specifications • New construction materials and techniques
  6. 6. Technology Selection Criteria • Saving in cost, initial as well as recurring. • Saving in consumption of imported or scare materials, even if no saving in cost is achieved. • Saving in time of construction. • Utilization of waste materials even if no saving is achieved. • Saving in quantum of skilled labour even if no saving in cost is achieved. • Achieving better utilization of equipment but not necessary leading to optimum saving in cost. • Better utilization of space. • Better layout for economy in external services
  7. 7. Bamboo as a Material for Housing and Buildings – Indian Experience
  8. 8. Characteristics affecting usefulness of bamboo as construction material - the strength of bamboo culms - their straightness - lightness combined with hardeners - range and size of hollowers with good physical and mechanical properties, low shrinkage and average density, it is well suited to replace wood in several applications
  9. 9. Major Uses of Bamboo in Construction • Scaffolding • Reinforcement • Roofing • Walling • Doors & Windows
  10. 10. Bamboo – Nature’s Gift [A material for cost effective and disaster resistant housing] As a Raw Material Properties: 1. High tensile strength 2. Very good weight to strength ratio 3. Pressure tolerance upto 3656 kg/cm2 4. Easy to handle with simple tools 5. Renewable raw material Building Material 1. Environment friendly 2. Energy efficient 3. Cost effective Weaknesses 1. Has short durability compared to wood 2. High moisture and starch content 3. Prone to fungi and beetle attach 4. Service life of untreated bamboo 4-6 years in exposed conditions Treatment & Preservation Preservation (Traditional methods): Curing; Smoking; Soaking; Seasoning Chemical Treatment: Boric acid; Borax; Boron; (Dip diffusion or modified Boucherie processes) Mechanical Process for Cutting, slicing, knot removing and slivering Mat weaving from Slivers Hot Processing and Binding Composite Building Materials •BMBs, BMPB, BMCS •Bamboo Lumber •Sandwiched panel •Bamboo based shutters •Bamboo flooring Bamboo House Bamboo – Raw Material to Finished Product
  11. 11. Bamboo has lower natural durability against attack of fungi and insects - requires treatment to increase durability - difficult to be treated by normal preservative methods in dry conditions. - Best carried out in green conditions. IS9096:2006 : Code of Practice for preservation of bamboo for structural purpose Covers : Type of preservations, Treatment procedure for structural purposes like post, scaffolding, walls, trusses etc.
  12. 12. Preservatives Recommended - Coal Tar Creosote - Copper – chrome - arsenic compositions - Acid- cupric – chromate composition - Copper – chrome- born composition - Boni Acid – boxes - Copper zinc – napthanate Abietates
  13. 13. Process of Preservation IS 401:2001 Code of Practice for Preservation of Timber 1. Surface application ( brushing, dipping) 2. Hot & Cold Method 3. Boucheire Process 5. Inter Nodal Injection 4. Diffusion Process
  14. 14. Structural Provision of Bamboo Part 6 : Structural Design Section 3: Timber and Bamboo: 3B. Bamboo National Building Code. Material Specification - Physical and mechanical properties of 20 species of bamboo - 16 species found suitable for structural purpose and densified in Group A,B,C.
  15. 15. New Technology Development
  16. 16. Pre-fab Double walled Composite House Developed a technology for Pre- fab Double Walled Composite House with IPIRTI, Bangalore. Material used are Bamboo Mat Board for walling, BMCS for Roofing with steel framed structure . Salient features are ease in transportation, speedy erection at a reasonable cost. Most suitable for emergency structures during post disaster events.
  17. 17. Two Storey Bamboo Housing System Developed the technology with IPIRTI, Bangalore using bamboo based components. Material used are Bamboo coloums, Bamboo grid walls, BMCS for Roofing, bamboo composite beams with steel and bamboo and bamboo composite slab. Development of this technology will enable construction of two storey houses in the bamboo growing regions.
  18. 18. Bamboo Mat Ridge Cap for Roofing Developed the technology with IPIRTI, Bangalore for replacement of the present practice of using flat boards to avoid perforations. Salient features are: Dimensionally stable Ready & easy to fix Non permeable Suitable for wide range of roof angles. Compatible with BMCS.
  19. 19. Other projects completed in NE Region  Construction of 2 Cafeteria Buildings in Kisama, Nagaland.  Construction of 2 demonstration structures using bamboo based technologies in Shillong, Meghalaya  Organisation of number of training programmes on bamboo based technologies.  Preparation of detailed feasibility reports for production ofbamboo based components like BMCS, BMB etc.
  20. 20. Challenges ahead • Increasing durability • Developing efficient jointing system • Developing prefab system • Developing composite system to deal with natural hazards • Growing bamboo of structural grade • Setting up of more production centers • Studying other bamboo which are available but not used in construction • Capacity building of artisans
  22. 22. What are the Requirements of an Effective Housing System? • Must be cost effective. • Must be capable of a fast rate of construction. • Must be adaptable to any structural design or architectural layout. • Must produce high quality, durable and low maintenance structures. • Must produce structures that are resistant to meteorological and/or seismic conditions.
  23. 23. MONOLITHIC CONCRETE HOUSING FORM WORK TECHNOLOGY • Hand-held reusable aluminum formwork system for forming cast-in-place concrete housing. • The System also controls the scheduling of the other trades involved in the construction; – steel reinforcement, – mechanical and electrical, – concreting.
  24. 24. MONOLITHIC CONCRETE HOUSING FORM WORK TECHNOLOGY • Can be used for any type of housing from; low rise single or double storey housing, to walk- up apartments, to high rise towers. • Can be used for any income level of housing from low income, to medium income, to luxury condominiums.
  25. 25. Features of the System • Versatility • Speed • Quality • Durability • Cost
  26. 26. Versatility • Architect is not required to change the building layout to suit the Mascon System. • Capable of forming any type of structural design for any type of housing. – Column & Beam Design – Loadbearing Wall Design
  27. 27. Versatility • The System is unique in that it forms all of the concrete in a building including; – walls – columns – beams – floor slabs – staircases – balconies – window hoods – storage lofts • No need for bricks, blocks or plastering.
  28. 28. Speed • Multi-Storey Housing - structures are completed at the rate of four days per floor - regardless of floor size. • Single or Double Storey Housing - structures are completed at the rate of one house per day. • To increase the speed of construction, several “sets” of formwork equipment can be provided.
  29. 29. Quality • Precision in fabricating the Mascon formwork results in accurate and consistent forming of the concrete. • The quality of the concrete finish is the same regardless of whether the System is used for low cost housing or luxury housing.
  30. 30. Durability of Housing Units • All concrete (walls, slabs, staircases etc.) are poured monolithically, therefore, there are no construction joints and no problems of leaking joints. • The result is a rigid reinforced “box” structure that is structurally very durable and very resistant to meteorological and seismic conditions.
  31. 31. Why is this System So Cost Effective? • Highly reusable formwork. • Forms all the concrete in a building. • Unique construction cycling. • Uses locally available materials - i.e. concrete and reinforcing steel. • Requires unskilled labour only and no cranes. • Loadbearing wall structural design.
  32. 32. Internal View of the Aluminum Formwork
  33. 33. Entire Four Storey Superstructure Completed in 16 Days
  34. 34. Each Double Storey House Completed at the Rate of One House per Day
  35. 35. Rigid & Strong formwork Panels Produce Smooth Off-form Concrete Finish
  36. 36. Square Openings Allow for Easy Fitting of Doors and Windows
  37. 37. Note - Surface Mounting of Electrical to Save on Costs
  38. 38. Electrical, However, is Usually Buried in Concrete with PVC Conduits
  39. 39. PVC Electrical Conduits for Floor Slabs
  40. 40. Unique Method for Propping of Floor Slab Formwork
  41. 41. Undisturbed Prop Head Soffit of Floor Slab After Removal of Floor Slab Panels
  42. 42. Forming of Soffit of Staircase
  43. 43. For Low Cost Housing - No Internal Plastering Required - Only Paint
  44. 44. For Medium to High Cost Housing - A Thin (3mm) Skim Coat of Plaster is Applied Before Painting
  45. 45. For Low Cost Housing - No External Plastering Required - Only Paint
  46. 46. No External Plastering Required - Only Spray Applied Finish
  47. 47. Mascon Aluminum Forms are Handheld NO Need for Cranes
  48. 48. NO Need for Cranes for Concreting with the Mascon System as Concrete Pumps Can Be Used - Low Rise to High Rise
  49. 49. 57 Innovative Building Technologies: Hollow Interlocking-Compressed Stabilized Earth Block (HI-CSEB)
  50. 50. 58 Innovative Building Technologies: Machine that produces HI-CSEB, developed by Auroville Earth Institute, Tamil Nadu, India Aurum Press 3000
  51. 51. 59 HI-CSEB  Economical/affordable, environmentally friendly, easily available, stronger, energy saving and simple to manufacture  Better Thermal Insulation  Warm in winter and cool in summer
  52. 52. Technical /Engineering Aspects Block Production Material selection Soil Identification – Top soil and soil with organic matter should not be used. Grain size distribution - more of sandy is preferred. Gravel (mm) Sand(mm) Silt(mm) Clay(mm) 20 to 2mm 2 – 0.02 0.02 – 0.002 0.002 - 0
  53. 53. Some basic test for identifying the suitability of soil •15%gravel, 50%sand, 15% silt, 20%clay Granularity (Grain size distribution test) •Compress a moist soil by hand •Difficult to compress – gravely soil •Very easy to compress – Clayey soil -Compressibility (Ease of the soil to be compressed) •Smells Rotten – lot of humus •Musty – humus •Agreeable smell – no humus - suitable for construction Humus (presence of organic materials0 •Difficult to break – clayey soil •Breaks easily – gravely soil Plasticity ( Capacity to withstand deformation) •Wash the hand on which the soil paste was made •Soils grains does not stick on the palm – Gravely soil •Thin film of soil stick on the palm – clayey soil. Cohesion(Property of the soil grains to remain together)
  54. 54. Proportions • Cement : Soil (1 : 6) • Water content = 25 liters for one bag of cement • Varying the ratio esp. the cement has the proportionate cost involved • The ratio can go up to 1 cement to 10 soil 62
  55. 55. Same basic data on CSEB Properties Values Dry Compressive Strength @28days 3 – 6Mpa (N/sqmm) ( +10% after 1 year, 20% after 2years) Wet compressive strength @28days (3days immersion) 2 – 3 Mpa Dry bending Strength @28days 0.5 – 1 Mps Dry Shear Strength @28days 0.4 – 0.6Mpa Density 1700 to 2000kg/cum Water absorption @ 28days after 3 days immersion 8 to 12 % by weight Energy Consumption 110MJ ( Kiln fired bricks = 539MJ)
  56. 56. Comparison with other building blocks Properties CSEB (HI - 245) Ordinary class III brick Concrete hollow blocks Size 245x 245 x 95 195 x 95 x 75 390 x 190 x 190 Weight 8kg 3kg 16kg Compressive strength (28days) 30 – 60kg/cmsq 35kg/cmsq 45kg/cmsq(approx) Cost (Nu.) 13 per block ( 1:6 mix ratio) 11 per brick @ Thimphu 38.00 per block @ Thimphu For a 250mm thick 1msq wall in a load bearing building @ Thimphu Block Numbers Cost(Nu) HI - CSEB 40(Approx) 520 Ordinary second class brick 166(approx) 1496.00 Hollow concrete Block 19.5(approx) 741
  57. 57. Block production machines Two Machines in the market 1) HI – CSEB Block machine – Habitech centre, Thailand 2) AURUM PRESS 3000 – Auroville,India Designer/ manufacturer Auroville Earth institute/ Aureka, Cost of Press Rs 69,800.00 Cost of Mould ( 1 set) Rs 41,500.00 Max Blocks size 245 x 245 x 95 Compression force 150KN( 15 tones) Production capacity per day with 7 workers 500 Blocks (average) Designer/ manufacturer Habitat centre , Bangkok Cost of Press 73,500.00 (Nu) 2008 rate Cost of Mould ( 1 set) - Max Blocks size 300 x 150 x 95 Production capacity per day ( 6- 7 workers) 500 average
  58. 58. Pilot House Construction – SQCA using HI – CSEB 245 • Two storied load bearing structures - serve as model for the earthquake resistant design features • Sample Blocks test results Soil sample source Average Compressive Strength Proposed construction site (1:8 mix ratio 22 kg/cmsq Buddha Dodema site ( 1: 8) 33 kg/cmsq
  59. 59. 67 SQCA – Pilot Project
  60. 60. 68 Hollow Interlocking –Compressed Stabilized Earth Block (HI-CSEB)
  61. 61. Some other buildings using HI-CSEB 69
  62. 62. Advantages 1. Use of cheap & locally available materials 2. Job opportunity for local people 3. Biodegradable materials 4. Energy efficiency and eco friendliness 5 – 15 times less energy consumed than fired brick and around 3 – 8 times less emission 5. Transferable technology 6. Import Reduction 7. 7. Cost effectiveness 8. 8. Minimum mortar required 9. 9. Keys that interlock with each other provides better integrity 10. 10. Hollow provisions for laying vertical and horizontal reinforcements to improve the lateral load resisting capacity 11. 11. Ease and Fastness in construction 12. 12. Fire resistant
  63. 63. Limitations • Only for low rise structures: maximum 2 storey • Strength very much dependant on the properties of soil • Too much stabilization(cement) will make no economic sense • Interlocking features do not provide air tightness. Minimum gap is formed due to which termite/air current can pass.