Downloaded 273 times
![Location of window in a building
Place such that we get maximum ventilation and wind
Depends on size of room, climatic conditions, utility
and architectural point of view.
For 30 m3 inside volume Provide 1 m2 window area
Breadth of window =
1
8
x [width of room + height of room]
15 % of floor area = area of window opening
10 % of floor area = Glass panel area](https://image.slidesharecdn.com/moduleiv-190924163836/85/Construction-Materials-and-Engineering-Module-IV-Lecture-Notes-45-320.jpg)
Uploaded bySHAMJITH KM
Construction Materials and Engineering - Module IV - Lecture Notes
The document discusses various basic components of building construction including substructure, superstructure, foundation, plinth, beams, columns, walls, arches, roofs, slabs, lintels, parapets, staircases, doors, windows and other elements. It provides descriptions of each component, their functions and materials typically used. Foundations discussed include isolated spread footing, wall/strip footing, combined footing, cantilever/strap footing and mat/raft footing for shallow foundations and pile, well/caisson and pier foundations for deep foundations. Flooring materials and requirements are also summarized along with technical terms for doors and windows.
More Related Content
Similar to Construction Materials and Engineering - Module IV - Lecture Notes
Construction Materials and Engineering - Module IV - Lecture Notes
- 1. Construction Materials and Engineering Module- IV Shamjith Km shamjithkeyem@gmail.com Department of Civil Engineering Government Polytechnic College Manjeri
- 3. Basic building components Substructure Super structure 1.Foundation 1. Plinth 2. Beams 3. Columns 4. Walls 5. Arches 6. Roofs 7. Slab 8. Lintel 9. Parapet 10. Staircase 11. Chajjas 12. Lift/ramp 13. Doors 14. Windows 15. Sunshade 16. Ventilator 17. Plinth beam 18. Chimney Portion of building located below ground level Portion of building located above ground level
- 4. Foundation1 Transmit load fromsuperstructure to subsoil For uniform distribution of load To provide level surface for construction of superstructure To reduce load intensity To assure settlements are within permissible limits To assure soil does not fail in shear To prevent side wise movements Most important part of a building
- 6. Plinth2 Structure between groundand floor Prevents entry of rain water in to the building Prevents entry of animals and insects Generally, Plinth height = 45, 60, 90, 120 cm Plinth should not be less than 45 cm Transmit load of super structure to foundation Plinth provide a level surface Plinth supports walls
- 7. Beams3 Horizontal structural element Takesloads from slabs and transfer to column beneath Usually beams are made of RCC and steel Takes vertical loads, shear forces and bending moments Slabs are provided above beams Beams are supported on either walls or columns
- 8. Column4 Vertical structural element Takesloads from beams and transfer to foundation Usually columns are made of RCC and steel Takes compressive loads Long columns fails by buckling Short columns fails by crushing
- 9. Arches5 Normally a curvedmember with wedge shaped blocks Carry weight of structure above the openings Used in buildings, bridges, etc Usually made of concrete, bricks, or stones
- 10. Walls6 Building blocks ofbricks or stones Load bearing walls supports slab weight In framed buildings, acts as partition walls Provides privacy and protection from heat, cold, dust, noise Divides the building space to useful rooms Walls support roof Gives a structural looking for building Provides shelter
- 11. Roof7 Uppermost (slab) portionof a building Provides privacy and protection Provides aesthetics to the building Usually made of RCC, wood, tiles, steel, asbestos, etc Protects the building from direct rain and heat May be flat, arch, curved or slopped in shape
- 12. Floor8 To provide levelwalking surface Provides neatness to building Flooring is done above plinth level/slabs Provides privacy and protection from heat, cold, dust, noise To provide useful area for working/placing equipments
- 13. Doors9 To provide accessto various areas in a building Provides entry and exit system to rooms Protection from theft and robbery Usually made of wood, steel, fabrication works, etc Provides privacy and shelter Can be made in different shapes and sizes - aesthetics
- 14. Windows10 To get properventialation Provides fresh air and light inside the room Protection from theft and robbery Usually made of wood, steel, fabrication works, etc Provides privacy and shelter Can be made in different shapes and sizes - aesthetics
- 15. Sunshade11 It is atype of cantilever slab It extends from walls It protects from rain water It controls amount of direct sunlight through windows It is constructed above lintel
- 16. Openings12 Provides entry andexit without doors Ventilation and light Plinth beam13 Beam or belt covering provided above plinth level To prevent entry of water (dampness) To provide additional support for load transferring & walls
- 17. Lintel14 Horizontal structural member Transfersload above doors & windows to beneath Usually made of RCC or steel Width of lintel = width of wall Provided above doors and windows
- 18. Staircase/lift/ramp15 Safe access fromone floor to another Support for movement between floors Usually made of RCC or steel Suitable provision to escape in case of fire For vertical transportation
- 19. Chejjas (Eaves)16 Overhanging coverfor windows and doors Protects from rain water Provide aesthetics to building Protects from external sunlight
- 20. Parapet17 Low protective wallalong the edge of a roof, bridge, or balcony. Made above flat roofs It act as a protective edge from falling Parapet
- 21. Foundations Transmit load fromsuperstructure to subsoil For uniform distribution of load To provide level surface for construction of superstructure To reduce load intensity
- 22. Foundations Shallow Deep 1. Isolatedspread footing 2. Wall/Strip footing 3. Combined footing 4. Cantilever/Strap footing 5. Mat/raft footing 1. Pile foundation 2. Well/Caisson foundation 3. Pier foundation Shallow depth Depth ≤ Width Depth is high Depth > Width Weak soils
- 23. 1. Isolated spreadfooting Most common and economical type Generally used for ordinary buildings Have independent footings Each column has its own footings Footing may be rectangular, square or circular in shape
- 24. Isolated footings maybe of three types:
- 25. 2. Wall/Strip footing Eachstrip contains number of footings Helps to distribute loads from columns to ground Strip will be along direction of wall A group of columns share single lengthier footing
- 27. 3. Combined footing Footingsmade common to more than one column Uniform distribution of loads Opted when columns are closely spaced Opted when dimensions of one side is restricted
- 29. 4. Cantilever/Strap footing Nearbyfootings connected using a strap/beam When edge of footing cannot extend beyond property line
- 31. 5. Mat/raft footing Usedwhen bearing capacity of soil is poor Load from number of columns is distributed by a single large footing called mat.
- 32. Raft behave asa single unit Used for heavy construction works in low load bearing soil
- 33. 1. Pile foundation Usedwhen bearing capacity of soil is poor Pile is a slender (long) member with a small CSA Used to transmit foundation loads to a deeper rock strata Pile transmits load either by skin friction or bearing Used to resist uplift and provide stability against lateral and overturning forces.
- 36. 2. Well/Caisson foundation Providedbelow water level for bridges Caisson means ‘box’ Construction of structures in water Dams, bridges, etc
- 38. 3. Pier foundation Usedwhen heavy load is transferred to the ground
- 39. Flooring Permanent covering givento a floor Provides walking surface Materials: Wood, stone, ceramic, terrazzo, etc
- 40. Requirements of agood floor 1. Good appearance 2. Can be easily and effectively cleaned 3. Should provide comfort on using – less noise 4. Cost should be reasonable 5. Should have sufficient damp resistance 6. Should be strong and durable 7. Should be fire resistant 8. Should have sufficient hardness 9. Should have minimum maintenance 10.Should be smooth, but don't slipper.
- 41. Materials used forflooring Cement or lime concrete Bricks/tiles Marble Glass Ceramic Plastic Mud and murram Wood Cork Linoleum Flagstones Asphalt Rubber
- 42. Doors and windows Primarilyfor air circulation, privacy and light Made of wood, concrete, steel, aluminum, etc Door is a movable barrier secured in a wall opening Designation of doors and windows 10 DS 20 Module width Single Shutter door Module height Note: 1 module = 100 mm
- 43. Location of doorin a building Preferably at corners of a room (20 cm from corner) If two doors in a room, face them each other Number of doors should be kept as minimum Place such that we get maximum ventilation and wind Depends on size of room, climatic conditions, utility and architectural point of view. Place such that we get maximum light
- 44. Height of door= Width + (1 m to 1.2 m) Eg:- H = 1 m + 1.0 = 2.0 m H = 1 m + 1.2 = 2.2 m Width of door = (0.4 to 0.6) x height Thumb rules for height and width Eg:- W = 0.4 x 2.0 = 0.80 m W = 0.6 x 2.0 = 1.20 m (Residential buildings)
- 45. Location of windowin a building Place such that we get maximum ventilation and wind Depends on size of room, climatic conditions, utility and architectural point of view. For 30 m3 inside volume Provide 1 m2 window area Breadth of window = 1 8 x [width of room + height of room] 15 % of floor area = area of window opening 10 % of floor area = Glass panel area
- 46. Technical terms 1. Head– top most horizontal part 2. Sill – lower most horizontal part 3. Post 4. Mullion – vertical sub divide 5. Transom – horizontal sub divide 6. Horn – horizontal projections of frame 7. Holdfast 8. Style – vertical outside member of shutter 9. Jamb – vertical surface of an opening 10.Reveal – exposed vertical surface of an opening 11.Rebate – rectangular recess around frame to receive door 12.Stop – block of wood fixed on backside of a door 13.Architrave – mouldings around door or window frame 14.Ground – additional wooden supports to architrave
- 48. Jamp – Verticalsurface of door opening
- 49. Reveal – exposedvertical surface of an opening
- 50.
- 51. Types of doors 1.Battened and ledged doors 2. Battened, ledged and braced doors 3. Battened, ledged and framed doors 4. Battened, ledged, braced and framed doors 5. Framed and paneled doors 6. Glazed doors 7. Flush doors 8. Louvered doors 9. Revolving doors 10.Sliding doors 11.Swing doors 12.Collapsible doors 13.Rolling shutter doors 14.Wicket gate
- 52. 1. Battened andledged doors Ledge Batten Hinge
- 53. 2. Battened, ledgedand braced doors Ledge Hinge Batten
- 54. 3. Battened, ledgedand framed doors Ledge Batten Hinge
- 55. 4. Battened, ledged,braced and framed doors Ledge Batten Hinge
- 56. 5. Framed andpaneled doors Top rail Panel Mid rail Style Bottom rail
- 57. 6. Glazed doors Toprail Glazed Panel Mid rail Style Bottom rail
- 58. 7. Flush doorsSheets are placed at back and front
- 59.
- 60. 9. Revolving doors Usedfor Queue controlling Entrance and exit at same time Suitable for buildings where there is heavy rush of foot traffic
- 61.
- 62.
- 63. 12. Collapsible doors Visibilityto both sides is obtained Ventilation is also obtained
- 64. 13. Rolling shutterdoors Drum Rolling shutter LockHandle Saves space
- 65. 14. Wicket gate Eg:Jail doors Wicket door
- 66. Types of windows 1.Fixed windows 2. Sliding windows 3. Pivoted windows 4. Double hung windows 5. Louvered windows 6. Casement windows 7. Metal windows 8. Sash windows 9. Corner windows 10. Bay windows 11. Dormer windows 12. Clerestory windows 13. Lantern windows 14. Gable windows 15. Ventilators 16. Skylights
- 67. 1. Fixed Windows fixedto the wall without any closing or opening operation
- 68. 2. Sliding Windows windowshutters are movable in the frame Eg: Buses, bank counters, etc
- 69. 3. Pivoted Windows Pivotsare provided to window frames Pivot is a shaft which helps to oscillate the shutter Types 1. Horizontal 2. Vertical
- 70. 4. Double HungWindows Consist of pair of shutters attached to one frame Shutters are arranged one above the other
- 71. 5. Louvered Windows Providedfor the ventilation without any outside vision Eg: bathrooms, toilets and privacy places etc
- 72. 6. Casement Windows Widelyused and common – Ordinary window shutters attached to frame and can be opened and closed like door shutters
- 73. 7. Metal Windows Generallymild steel is used Very cheap and have more strength Eg: Public buildings
- 74. 8. Sash Windows Typeof casement window with panels fully glazed Space between rails is divided into small panels by mean of small timber members called sash bars or glazing bars
- 75. 9. Corner Windows Providedat the corners of room Light / air can enter room in two different directions
- 76. 10. Bay Windows Projectedfrom wall to increase the area of opening Enables more ventilation and light form outside
- 77. 11. Dormer windows Providedfor sloped roofs Enables more ventilation and light Enhance aesthetic sense of room
- 78. 12. Clerestory Windows Providednear roof heights Provided for room which has greater ceiling height than the other rooms
- 79. 13. Lantern Windows Providedfor over the flat roofs Provided more light & air circulation to the interior rooms
- 80. 14. Gable Windows Providedfor sloped roof buildings Provided at the gable end of sloped roof
- 81. 15. Ventilators Provided forpurpose of ventilation in the room Provided at greater height than windows nearer to roof level
- 82. 16. Skylights Provided onthe top of sloped roofs To admit more light into the rooms Provided parallel to the sloping surface Can be opened when we required
- 83. Lintel Horizontal flexural memberwhich bridges gap of the opening and which permits construction of walls above it. Width of lintels is usually same as that of wall Beam provided over an opening for door, window, cupboard etc., in a wall
- 84. 1. Wood Lintel Single/morepieces of wood used Sometimes strengthened by steel plates at top and bottom (Flitched beams)
- 85. 2. Stone lintels Stonesare cut to required width of the wall Depth of stone piece = 0.1 x Span Used only for small spans (stone is weak in tension)
- 86. 3. Brick lintel Forsmall span openings Well burnt, good quality bricks used Curing time: 7-14 days Needs temporary form work at time of construction
- 87. 4. R.C.C. Lintel Forlarger spans - form work needed Provided with suitable reinforcement Commonly used in building now days
- 88. 5. RSJ Lintels(Rolled steel joists) Provided at large openings when loads are heavy Jointing is done with bolts
- 89. Sunshade Cantilever structure constructedto protect building from direct sunlight and splashing of rain water. Usually of width 600 mm and 100 mm thickness. Provides comfort to users If RCC, monolithic casting with lintel is done May be constructed with lintel or independently Designed slope should be provided for easy draingae
- 90.
- 91. Canopy and Sunbreakers Structures constructed to control amount of direct sunlight through building windows. Heat insulation, shading and protection from raining. Aesthetic appearance
- 92. Arches Structure constructed to spanacross an opening Small wedge-shaped units joined with mortar 1. Keystone 2. Voussoir 3. Extrados 4. Impost 5. Intrados 6. Rise 7. Clear span 8. Abutment Supports loads acting above the openings
- 93. Arches Arches transfer loadsas inclined loads whereas lintels transfer loads as vertical loads. The structure constructed of stones or bricks, jointed together with mortar. Used mainly for beautification purposes
- 95. Technical terms 1 Keystone Wedgeshaped unit at the crown of an arch 2 Voussoir Wedge shaped units of an arch 3 Extrados (or back) External curve of an arch 4 Impost Projection of a pier/abutment
- 96. Technical terms 5 Intrados Innercurve of the arch 6 Rise Vertical distance b/w highest point on intrados & springing line 7 Clear span Clear horizontal distance b/w the suports 8 Abutment End support of an arch
- 97. Technical terms 9 Piers Intermediatesupports of an arcade 10 Arcade Arcade means a series of arch 11 Soffit Inner surface of the arch (same as intrados) 12 Crown Top point of an arch
- 98. Technical terms 13 Skewback Inclinedsurface of a pier perpendicular to load direction 14 Springing lines Imaginary lines connecting springing points 15 Springer First voussoir at springing level on either side of an arch. It is immediately adjacent to the skewback
- 99. Technical terms 16 Haunch Lowerhalf portion of arch b/w crown and skewback 17 Height of arch Perpendicular distance b/w intrados and extrados 18 Ring Circular course forming an arch 19 Spandril Irregular triangular space formed b/w extrados and horizontal line drawn to the tangent.
- 101. Types of Arches ShapeNo.of centers Workmanship Material 1.Flat arch 2.Segmental 3.Semi-circular 4.Semi-elliptical 5.Inverted 6.Pointed 7.Relieving 8.Horse-shoe 9.Stilted 10.Venetian 11.Florentine 1.One centered 2.Two centered 3.Three centered 4.Four centered 5.Five centered 1.Rough arch 2.Axed/rough cut 3.Gauged 1.Stone arches 2.Brick arches 3.Concrete arches
- 102. Flat arch1 Apparent shapeis flat Skewback forms an angle of 60o with horizontal
- 103. Segmental arch2 Common typeused in buildings One centre – below springing line Skewback – inclined (perpendicular to load)
- 104. Semi-circular3 Line of actionof load - vertical Skewback - horizontal Centre of arch = midpoint of springing line
- 105. Semi-elliptical4 Arch has morethan one center (3 or 5) Shape of semi ellipse Centre of arch = midpoint of springing line
- 106. Inverted arch5 To increasebearing power of soil Placed below foundation Eg: british bridges
- 107. Pointed or gothicarch6 Consist of two curves meeting at apex of triangle Triangle – equilateral or isosceles triangle Isosceles – Lancet arch
- 108. Relieving arch7 Constructed overa wooden joist or flat arch
- 109. Horse-shoe arch8 For architecturalconsiderations More than a semi-circle Center above springing line
- 110. Stilted arch9 Semi-circular shapeattached to tops Springing line passes through tops of vertical portions.
- 111. Venetian arch (Tuderarch)10 Depth at crown > depth at springing line Four centers on springing line
- 112. Florentine arch11 Florentine archwith semi-circular intrados
- 113. Vertical Transportation Four majormodes of vertical transportation are: 1.Stairs 2.Escalators 3.Lifts (Elevators) 4.Ramps
- 114. Staircase and itslocation Should provide easy access to all in the building Check for good lighting and ventilation Should have convenient approaches and spaces Stairs should be located near main entrance in case of a public building. In residential buildings stair should be placed centrally.
- 115. Types of staircase Straight stairs Turning Stairs Geometrical stairs Circular stairs 1.Quarterturn 2.Half turn 3.Three quarter turn
- 116. Straight stairs1 All stepsleads in one direction only May consist of one or more flights Used when space available is long, but narrow
- 117. Turning stairs: Quarterturn stair2.a Have a turning of one right angle – 90o Bifurcated stair If a quarter turn stair is branched into two flights at a landing
- 118. Turning stairs: Halfturn stair2.b Have a turning of two right angles – 180o May be dog legged or open well (newel) type dog legged stair Open well stair
- 119. Turning stairs: Threequarter turn2.c Have a turning of three right angles – 270o May be dog legged or open well (newel) type
- 120. Circular / helical/ spiral stairs3 Steps radiates from the centre No intermediate newel posts or any landings Flight consists of winders only
- 121. Geometrical stairs4 Of anygeometrical shape
- 122.
- 123.
- 124. Standards for staircase as per KBR If no.of floors > 4 : provide two staircases (One for fire escape) Minimum width = 1.2 m Minimum width of thread = 30 cm Maximum height of riser = 15 cm Minimum height of handrail = 90 cm Minimum = 3 steps, maximum = 12 – in a flight Reduce use of spiral staircase No.of risers = Total height of floor/height of riser No.of treads = no.of risers - 1
- 126. Technical terms 1 Baluster Verticalmember fixed b/w string and handrail for safety 2 Balustrade (Barrister) Combined framework of handrail and balusters 3 Flight Unbroken series of steps b/w landings 4 Going Horizontal distance b/w faces of two consecutive risers
- 127. Technical terms 5 Handrail(Guard rail) Inclined rail over the string for safety. 6 Headroom Vertical distance b/w tread and overhead obstruction. Should be > 2 m If less than 2 m, heads of people hits the obstruction 7 Landing Horizontal platform b/w two flights which facilitates change in direction and provide opportunity to take rest.
- 128. Technical terms 8 Newelpost Vertical member provided at beginning & end of a flight 9 Nosing Projecting part of tread beyond the face of riser. 10 Pitch Angle of inclination of stair with floor. Should be <38o 11 Rise Vertical distance b/w two successive treads
- 129. Technical terms 12 Riser Verticalportion of a step that supports the thread. 13 Run Total length of stair in a horizontal plane (includes landing) 14 Scotia Additional finish/moulding provided at bottom of nosing
- 130. Technical terms 15 Soffit Undersurface of a stair 16 Step A combination of tread and riser 17 String Inclined member of a stair which supports ends of steps 18 Tread Horizontal upper portion of a step
- 131. Technical terms 19 Waist Thicknessof structural slab in case of RCC stair 20 Walking line Approx. line of movement of people on a stair during ascent/descent. It is 450 mm from the hand rail from centre of handrail.
- 132. A vertical transportationsystem Lift Moves people and goods b/w floors Electrically operated equipment If building height exceeds 10 m or > 3 storeys, provide lift
- 133. Lift can beprovided inside or outside the building Lift - location Inside near staircase or independent to staircase Outside with access to the building landing Need to provide easy access for all building users Not preferred at corners Should give provision for future expansions, if any Provides much comfort to the users
- 134. Cab/Car Buffer Landing level Trailing cable Landingdoor Counter weight Machine room Lift shaft Lift pit/well
- 135. 1. Lift car/cab Lift– Technical terms Vertically moving cabin in which passengers and goods are transported. 2. Lift shaft/hoist space in which the lift cabin moves. 3. Machine room Room from which the lift functions are loaded and controlled
- 136. 4. Lift pitor Lift well Lift – Technical terms Specially dug hole into which the lift is "housed" 5. Buffer Provided in lift pit for safe landing of cab at bottom 6. Counter weight or balance weight a separately guided mass that partly counterbalances the cabin and secures ropes pressure to a driving pulley.
- 137. 7. Trailing/suspension cable Cablewhich holds car and counter-weight Lift – Technical terms 8. Governor Controls speed of the lift 9. Passngers Passenger capacity assumed as 68 kg/person
- 138. Ramps When large numberof persons/vehicles have to be moved from floor to floor. Is a uniformly sloping surface or inclined plane. Occupy larger space than stairs and lifts Easy for sick people to climb on ramps
- 139. Ramps Maximum gradient =1 in 10 Minimum width = 1.2 m Minimum height of handrail = 80 cm
- 140. Escalators Power driven, inclined,continuous stairways used for transporting passengers in airports, malls, etc Operate automatically without operators Provided with moving handrails.
- 141. Ceiling Overhead interior surfacethat covers the upper limits of a room – provided below roof/slab Not considered as a structural element
- 142. To reduce theheat transfer from the roof Functions of ceiling To improve appearance To conceal all ducts, pipes, wiring and light fittings To reduce volume of the room Improve its air conditioning Improve acoustical quality – sound proof
- 143. Materials used forceiling Wood Gypsum board Plaster of paris Thermocol Extruded Aluminium Acoustical boards Glass mirrors Metal Sheets
- 144. Types of ceilings Suspended ceiling False ceiling Ordinary ceiling •Also called as drop ceiling • Consists of panels that hang a few inches below the main structural ceiling • Area above dropped ceiling is called plenum space
- 145. A dropped ceilingor secondary ceiling hung below the main (structural) ceiling False ceiling To conceal all ducts, pipes, wiring and light fittings Acoustic balance and control in a room Aesthetic improvement
- 146. Should be durableand portable Requirements of good ceiling Material used should be light in weight - drop Should be water/sound/fire proof Should have aesthetic looking after installation Should possible to install easily Should have enough strength and integrity Possible to cast in any shape – flexible in nature
- 147. Roof Uppermost part ofbuilding which protects building from snow, rain, sun, etc Structural elements may be trusses, portals, slabs, domes, etc
- 148.
- 149. Important technical terms 1Barge board Wooden boards fixed on gable end of a roof 2 Battens Thin wooden strips fixed on rafters to support roof ceiling 3 Cleat Small wooden blocks to prevent sliding of purlins 4 Eaves Lower edge of slopping surface of a roof
- 150. Important technical terms 5Purlin Wooden pieces placed horizontally on principal rafters 6 Common rafter Intermediate rafters supporting roof covering 7 Ridge piece Wooden piece provided at the ridge line of a slopping roof 8 Wall plates Long wooden members embedded on top of walls to receive the common rafter.
- 151. Should be durable– against rain, wind, snow, and sun Requirements of a good roof Should provide desirable insulation from heat and sound Should be structurally stable and sound – take loads Should be well drained – slope/drainage facilities Efficient water proofing Fire resistant Good appearence
- 152. Classification of roofs Pitched (slopping)roof Flat (terraced) roofs Curved roofs 1. Single roof 2. Double or purlin roof 3. Trussed roofs
- 153. Pitched (Slopped) Roofs Usedin places where rainfall and snow fall is high Slope > 10o (may be 45o -60o ) Preferred for large span structures like workshops, ware houses, factories, etc 1
- 154. Types of pitchedroof Single roofs Double or Purlin roofs Trussed roofs Span < 5 m Span > 2.4 m For higher spans 1. Lean to roofs 2. Couple roofs 3. Couple-close roof 4. Collar beam roof 5. Collar and scissor roof
- 155. Single roofs Span <5m Commo rafters are provided to each slope without any intermediate support. Commo rafters have single span No purlins A
- 156. Lean to roof(Pent/Aisle roof) Maximum span = 2.40 m Generally used for sheds, verendas, etc 1
- 157. Couple roof Maximum span= 3.60 m 2
- 158. Couple-close roof Legs ofcommon rafters connected by a tie beam 3 Maximum span = 4.20 m
- 159. Collar beam roof Tiebeam raised and placed at a higher level 4 Maximum span = 4.80 m
- 160. Collar and scissorroof Two collar beams 5
- 161. Double or Purlinroofs Span > 2.4 m Intermediate supports are introduced (Purlins) Also called as ‘Rafter and Purlin roof’ B
- 162. Trussed roofsC If spanis more, a frame work of slender members are used to support sloping roofs - trusses A number of trusses may be placed lengthwise to get wall free longer halls. For spans up to 9 m wooden trusses may be used but for larger spans steel trusses are a must. Carpentry joints, Bolts and straps, rivets or welding are made to connect various members at a joint End of trusses are supported on walls or on column
- 163. 1 King posttruss : 5 to 8 m 2 Queen post truss : 8 to 12 m 3 Mansard truss 4 Truncated truss 5 Bel-fast (bow string/latticed) truss : 30 m 6 Steel truss 7 Composite truss Types of trussed roofs
- 164. 1 King posttruss 2 Queen post truss 3 Mansard truss 4 Truncated truss
- 165. Flat (terraced) Roofs Usedin plain areas where rainfall is less and climate is moderate Nearly flat (Slope < 10o) 2 Treated with water proofing chemicals Types 1. Madras terrace roof 2. Bengal terrace roof 3. RCC roof
- 166. Curved roofs Thin curvedsurfaces which transfer load by membrane compression Caves are having natural shell roofs 3 To cover large column free areas required for auditoriums, factories, etc. Domes
- 167. Roof Coverings forPitched Roofs Selection depends upon: 1. Climatic conditions 2. Fabrication facility 3. Availability of materials 4. Affordability of the owner Types Thatch Shingle Tiles Slates AC Sheets GI Sheets Aluminum sheets PVC sheets
- 168. Thatch Covering Thatch isa cheap roof covering of straw, reed, etc Tied with ropes or twines to the supporting structures. 1 Suitable for small spans residential buildings in villages Supporting structure consists of round bamboo rafters
- 169. Shingles Are split orsawn thin pieces of wood Commonly used in hilly areas for low cost housing 2 They are nailed to supporting structures They have very poor fire and termite resistance
- 170. Tiles Clay tiles areeasily available at lower costs supported over battens which are in turn supported by rafters or trusses 3 Can be easily manufactured and placed in position They give good interlocking and appearance
- 171. Slates Grey sedimentary rockthat can easily split into thin sheets A good slate is hard, tough, durable and have rough texture 4 Used in areas where slate quarries are nearby They do not absorb water they give ringing bell like sound when struck
- 172. A.C. Sheets (Asbestoscement) Consists of 15 per cent of asbestos fibres evenly distributed and pressed with cement Fixed to the steel purlins using J-bolts and washers 5 Commonly used as covering materials in ware houses, godowns or for larger halls
- 173. G.I. Sheets (GalvanizedIron) Corrugated sheets fixed to steel purlins using J-bolts and washers Galvanization of iron makes them rust proof 6 Durable, fire proof, light in weight and need no maintenance
- 174. Aluminum sheets Aluminum islighter in weight Good anti-rust effect 7 Durable, fire proof, and need no maintenance Resistant to rot and rust, and insects like termites.
- 175. PVC sheets Polyvinyl Chloride(PVC) sheets are flexible Good damp proof 8 Durable and need no maintenance Not suitable for high temperature regions
- 176. Comparison of GIand AC Sheets G.I Sheets A.C Sheets Sheets are thin Not as thin as G.I sheets Light in weight Slightly heavier Do not break while handling Chances of breaking Chances of corrosion No corrosion More noisy if something falls Less noisy Less fire resistant More fire resistant Less resistance to acids More resistance to acids Costly Less costly
- 177. Method of arrangingand fixing - to the battens, rafters and purlins Principal rafter is part of roof truss Purlins are placed for required lengths at regular gaps They are connected using suitable bolts/joints Common rafters are placed above these purlins Battens are fixed above these common rafters providing suitable overlaps. Sheets should be laid with smooth side upwards. Hole for fixing should be drilled. Don’t punch/hammer Sheets should be properly cut to avoid gaps/spaces
- 178. R.C.C Roofs Reinforced cementconcrete roofs Concrete takes compressive loads and steel takes tensile loads coming above the roof. Roofs are supported over beams/load bearing walls Can be simply supported or cantilevered Usually monolithically cast with beams May be slopped or flat roof
- 179. Flat slab construction Aflat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams
- 180. Types of FlatSlab Construction 1 Simple flat slab 2 Flat slab with drop panels 3 Flat slab with column capital 4 Flat slab with both drop panels and column capital
- 181. Simple flat slabFlat slab with column capital Flat slab with column capital and drop panel Simple flat slab
- 182. Causes of dampnessin roofs 1 Poor quality of construction material 2 Bad design 3 Fault in construction 4 Rain water falling on walls, parapets, etc 5 Inadequate roof slopes 6 Leakage in the building components
- 183. Weather proof courseto flat roof 1 Injection Grouting For Cracks 2 Bitumen coating 3 Screed concreting 4 Epoxy Coal Tar 5 M-Seal 6 Silicon Sealant By applying any of below techniques, roofs can make weather/water proof
- 184. - Concluding theSubject - Module What we learned 1 Building materials 2 Ornamental materials for finishing 3 Construction technology 4 Building components
- 185. A good teacheris someone who can learn from their students, who can learn with them, and learns for them. - Thank You -
Editor's Notes
- #2 Engineering structures are composed of materials.