Building Construction & Maintenance Engineering (General Engineering) (SSC JE)

The platform at the end of a series of steps of staircase is known as landing.
Tread–A stair tread is the horizontal part of step in which a person will stand.

Flemish bond–
• It is arrangement by bonding which consist of alternate header and stretcher is very course.
• In bond the alignment of vertical joints to fall in same straight line queen closewr half is provided next quoin header.
• Every alternate course in this case starts from header.
• These bond are further of two types–
(a) Double flemish bond
(b) Single flemish bond.

Quoins–
• It is the outer of exterior angle on the face side of wall.
• It is generally kept 90º
• In brick masonry, quoins refer to he corner stones or brick that are positioned at the external corners of a building or structure. They provide both functional strength and aesthetic appeal, contributing to the overall durability and visual impact of the construction.

Geometric design of stairs–
• Geometric design of stairs mean selecting the rise, going, shape, number of steps in a flight, width of steps and size of landing.
• The following requirements of a good stairs may be noted while finalizing the geometric design.

Rise–Rise of all steps should be same. In residential building it should be 150-175 mm while in public building it is preferably 120-150 mm.

Going–In residential building going of 250 mm is desirable and in public building it is 270-300 mm.
• The following empirical formula is to be used for fixing the rise and going:
2r + g = 550-650 mm
where,
r = rise
g = going

Granolithic flooring–This is a wearing surface provided over the cement concrete surface. This floor provides a hard wearing surface for public building such as office, schools, colleges, hospitals, banks etc.

Granolithic finish is economically used for those places which are required to resist heavy wear and for which attractive finish or appearance is not required.

In industrial building hard wearing surface can be achieved by granolithic flooring. The thickness of granolithic finish may vary from 25 to 35 mm depending upon the service the floor is expected to give.

Terrazo flooring–This type of flooring is becoming more popular and it is used in hospitals, offices, schools, colleges and in residential building.

Mosaic flooring–This type of flooring was commonly and popularly used in high class residential as well as public buildings. But now days it is not much used.

The ribbed floor is a type of RCC floor. Ribbed flooring is designed for use as a self supported suspended floor, mostly, this type of floor is used in commercial buildings.

This type of floor is used to reduce the total weight of the floor. It is light in weight and economical as it requires less concrete as compared to others. When the ceiling of the floor is made by hollow tiles then it is know as hollow tiled ribbed floor. Hollow tiled ribbed floors are fire proof, bound proof and light in weight.

Dog legged staircase–
• A dog legged stair consists of two or more straight flights of steps giving access from one floor to another arranged parallel to each other in plan, with their inner ends vertically over each other.
• There is no "well" between the flights in the simplest form of the stair a level landing is placed across the two flights at the change of direction or turn.
Open well stair– • An open well stair consists of two or more flights of steps, so arranged in plan that a clear space, called a "well" occurs between the outer ends of the steps, the space being clear for the full height between the floors with which the stair communicates or even continued through more than one storey.
• This stair requires more space than other types and is capable of very much variation in arrangement.

Rise–The vertical distance between any two adjacent treads in a stair is called as rise.
Pitch or slope–The angle between line of nosing and horizontal surface is called as pitch.
Balusters–The vertical member of wood or metal that support the handrail.
Nosing–The projecting part of the tread beyond the face of riser is call as nosing.

Span–The horizontal distance between the supports of an arch is called span.
• Extrados– Outer curve of an arch.
• Intrados– Inner curve of an arch.
• Soffit– It is the inner surface of an arch. Sometimes, intrados and soffit are used synonymously.
• Voussoirs– These are wedge-shaped units of masonry, forming an arch.

Newel post–It is the vertical member placed at the ends of flight to support the end of string and hand rails.
String–It is a sloping member which supports the end of steps in a staircase.
Pitch–It is the angle of inclination of the flight of the stair with the floor. Winders–They are expensive in construction as well as dangerous for the users. They should be provided at the lower end of the flight, when their use become essential.