One-liner Building Construction & Material - 02

One-liner Building Construction & Material 

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Technical term's of pitched roof :-


➤ Truss -  A roof truss is a frame work, usually of triangles, designed to support the roof covering or ceiling over rooms.
Span -  It is the clear distance between the supports of an arch.
Pitch -  It is the inclination of the sides of a roof to the horizontal plane. 
Rise - It is the vertical distance between the top of the ridge and the wall plate .
Ridge - It is defined as the apex line of the sloping roof.
Eaves - The lower edge of the inclined surfaces is called eaves.
Hip - It is the ridge formed by the intersection of two sloping surfaces, where exterior angle is greater than 180°.
➤ Hipped end - It is the sloped triangular surface formed at the end of a roof.
Valley - It is a reverse of a hip. It is formed by the intersection of two roof Surfaces, making an external angle less than 180°. 
Verge - The edge of a gable, running between the eaves and ridge, is known as a verge. 
Ridge piece/ beam/board - It is the horizontal wooden member, in the form of a beam or board, which is provided at the apex of a roof truss. It supports the common rafters fixed to it. 
Common rafters or Spars - These are inclined wooden members running from the ridge to the eaves. Depending upon the roof covering material, the rafters are Spaced 30 to 45 cm centre to centre. 
Purlins - These are horizontal wooden or steel members, used to support common rafters of a roof when span is large. Purlins are supported on trusses or walls.
Battens - These are thin strips of wood, called scantling, which are nailed to the rafters for lying roof materials above.
Cleats - These are short sections of wood or steel (angle iron), which are fixed on the principal rafters of trusses to support the purlins.
Hip rafters - These are the sloping rafters which form the hip of a sloped roof
Boardings - They act Similar to battens and are nailed to common rafter to support roofing material.
Template - This Is a square or rectangular block of stone or concrete placed under a beam or truss, to spread the load over a larger area of the wall. 

Types of pitched roof :-

➤ Lean to roof - This type of roof which slope in one direction.
➤ Gable roof - This type of roof which slope in Two direction.
➤ Hip roof - This type of roof which slope in four direction.
➤ Mansard roof - This type of roof which slope in four direction but each slope has break.
➤ Deck roof - This type of roof which slope in four direction but plane surface is formed at top.
➤ Gambrel roof - This type of roof which slope in two direction but there is break in each slope.
Building Construction & Material mcq

Suitable span of pitch roof :-

➹ Single roof -

➤ Lean to roof - upto 2.40 m.
➤ Couple roof - upto 3.6 m.
➤ Couple close roof - upto 4.2 m.
➤ Collar beam roof - upto 4.2 m.

➹ Double roofs - upto 4.8 m.

➹ Trussed roof - 

➤ King post truss : 5-8 m.
➤ Queen post truss : 8-12 m.
➤ Steel trusses : for span >12 m.

Formwork One- liner Building Construction & Material :-


➤ Formwork is a temporary structure. Construction used as a mould for the structure, in which concrete is placed and in which it hardens and matures.
➤ The cost of formwork may be up to 20℅ to 25℅ of the cost of structure.
➤ The operation removing the formwork is commonly known as stripping.

Time duration for different components structure used in formwork .

➤  Walls, columns and vertical sides of beam - 24 to 48hr
➤ Slab soffits (Props left under) - 3 days
➤ Beam soffits (props left under) - 7 days
➤ Removal of props to slab spanning upto 4.5m - 7days
➤ Removal of props to slab spanning over 4.5m - 14days
➤ Removal of props to beam and arches spanning upto 6m - 14days
➤ Removal of props to beam and arches spanning over 6m - 21days

Technical terms of thermal Insulation :-


Thermal conductivity (k) - The thermal conductivity of a material is the amount of heat that will flow through an unit area of material, of unit thickness in one hour, when the Difference of two temperatures is maintained at 1°C.
Thermal conductance (c) - It is the thermal transmission of a single layer structure per unit areadivided by temperature difference between the hot and cold  faces.
Thermal resistance (R) - It is the reciprocal of thermal conductance. {R = L/k}
Where, L is thickness.
Total thermal resistance (RT) - The total thermal resistance is the sum of the surface resistances and the thermal resistance of the building unit itself. 
Thermal resistivity (l/k) - This is the reciprocal of thermal conductivity and is denoted by 1/ k. 
Surface coefficient (f) - It is the thermal transmission by convection, conduction or radiation from unit area of the surface, for unit temperature difference between surface and surrounding medium.
Surface resistance (1/f) - It is the reciprocal of surface coefficient.
Thermal transmittance (U) - Thermal transmittance is the thermal transmission through unit area of the given building divided by the temperature difference between the air or other fluid on either side of the building unit in steady state condition.
Thermal damping (D) - It is dependent on thermal resistance. {D = 100*(To - Ti)/To}
Where, To is outside temperature Ti is inside temperature .
Thermal time constant (T) - It is the ratio of heat stored to thermal transmittance of the structure. {T = Q/U} .
Thermal insulationThermal insulation is used to indicate the construction or provisions by way of which transmission of heat from or in the room is retarded.

➹ Heat transfer -

Conduction - It is direct transmission of heat through a material.
Convection - Heat is transmitted by convection in fluids and gases as a result of circulation.
Radiation - Heat transferred by radiation through space in the form of radiant energy.









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