The trusses are structural members and comprise of one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. The triangular members arranged in series and supported on the walls.
Major use of steel trusses is being done in the construction of large span structures such as industries, factories, Auditoriums, Cinema Theatres, Shopping Malls, Concert Halls etc.
But the use of steel trusses is not limited to various types only. Major use of trusses is also seen in the construction of bridges.
Roof coverings used over Steel trusses
RCC roof can be used over the trussed construction but usually to keep the roof lightweight, asbestos sheets are used as roof covering.
Plastics sheets are also used as roof covering.
In this article, we are going to discuss in detail about the Tubular Monitor Roof Truss.
“Tubular Steel Roof Truss” is also largely used for large span constructions but the lighting arrangements in these kind of roof is different from that of “Tubular Monitor Roof Truss”
Tubular Monitor Roof Truss
- This is a flat roof with raised portions called monitors, used to admit light.
- This type of roofing gives a more uniform level of daylighting than North light system.
- Main lattice girders span the shorter distance.
- Lattice girders connect between the main columns and intermediately to the main girder.
- The depth of the girder is about 1/8th or 1/12th of the span.
- The monitor frame tubes are welded to the monitor girder, these are roofed on the top surface and have patent glazing to the tiles.
- Curved socket plates are welded to the column in two halves, the column arrives on the side with the bottom sockets in position and the top ones are site welded after positioning of the girder.
- A detail at D is at the foot of the glazed opening light. A metal enclosure plate is screwed to the roof decking and to the Purlin angle.
- After roofing, felt is laid, the roof is sealed by a lead flashing.
- The glazing bars are screwed to angle frame to which the opening gear is attached.
- Detail at G is shown at F is a junction of the monitor roof and the top of the glazed opening light.
- The angle purlin is bolted to a tee cleat welded to the top tube of the monitor. Welding is done instead of bolting.
Uses of Tubular Steel Monitor Roof Truss
It is used in large span constructions such as:
- Large Community Meeting Halls
- Industrial Work Zone
- Shopping Malls
It is seen that these trusses are used in large span structures that require large amount of natural lighting for their efficient functioning.