STRUCTURAL ENGINEERING DETAILING OFFICE TUTORIAL- GRATING

A structural platform or civil platform is normally a horizontal surface at an elevated level usually provided for maintenance and easy access (operation) to required items such as valves, instruments, etc. Sometimes pipes and piping items can be supported from platforms.

OPERATING: Used for personnel movement for operating the valves/switch panels only
MAINTAINANCE: Used for maintenance of valves/equipment
MANIFOLDS: Several pipes are branching in
PIPING LAYOUT: The piping layout will reflect the needs of the platforms.
SIZE AND ELEVATIONS will be provided
PIPE SUPPORT LOADING (IF ANY)
NORMAL LIVE LOADS
Access walkways: 250 kg/sq.m
Operating floors: 500 kg/sq.m Special case(heat exchanger): 750 kg/sq.m

Depending on the use of structural platforms and space availability, ladders or staircases are used for ascending and descending purposes,

A grating is a flat metal frame with rows of bars across it, which is fastened over a window or a hole in a wall or the ground. Steel grating is used in industrial and commercial structures designed for high and impact loads in platforms and stairways.

A grating is any regularly spaced collection of essentially identical, parallel, elongated elements. Gratings usually consist of a single set of elongated elements but can consist of two sets, in which case the second set is usually perpendicular to the first (as illustrated). MADE UP OF CARBON STEEL ALUMINIUM STEEL AND STAINLESS STEEL Friction -0.78

STANDARDS

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BS EN 10025/28/20 Steel, Stainless steel aluminium respectively

ASTM A1011/A1011M CS TYPE 2- STEEL

ASTM, A36 /A36M SS TYPE 1

ASTM A666 TYPE304 304L AND 316 316L STAINLESS STEEL

SPECIFICATIONS

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Load type
W-11-2 (1/316) STEEL WELDED 19-30 BEARING BAR SPACE 2-50 CROSSBAR SPACING BEARING BAR SIZE OF STEEL MATERIAL ( P-PRESSURE LOCKED, SG-SWAGED BAR, SGF- SGF-SAVAGED FLUSH TOP, R-RIVETED, DT- DOVETAIL, SGI- SWAGED I-BAR)
DEEPLY LOAD BAR FB 20X 5, MESH SIZE, PATTERN CROSS BAR TYPE MATERIAL, LOAD BAR TYPE SUCH AS SERRATED AND SURFACE TREATMENT SUCH AS GALVANIZED

The grating has four types

Press locked
Welded
Swage
and Rivetted Smooth or serrated gratings

further, Electro Forged Grating, Welded Grating, Press Locked grating, Serrated grating, Flat grating, flush top grating, radially cut and Straight cut grating.

Anchor

– A device by which grating is attached to its supports

Band

– A flat bar welded to the end of a grating panel, or along the side of a cutout, and extending neither above nor below the bearing bars.

Load Carrying Band

– A band used to transfer load between bearing bars.

Trim Band

– A band which carries no load, used primarily for appearance and closing open ends.

Bearing Bars

– Load-carrying main elements made from steel, aluminium or stainless steel, extending in the direction of the grating span

Bearing Bar Centers

– The distance centre-to-centre of the bearing bars.

Carriers

– Flats or angles which are welded to the grating panel and nosing of a stair tread and are bolted to a stair stringer to support the tread.

Clear Opening

– The distance between faces of bearing bars in rectangular gratings, or between a bent connecting bar and a bearing bar in a riveted grating.

Cross Bars

– The connecting bars which extend across the bearing bars, usually perpendicular to them. The may be bent into a corrugated or sinuous pattern and, where they intersect the bearing bars, are welded, forged or mechanically locked to them.

Pressure-Locked Grating

-Pressure-locked means bearing bars are locked in position by crossbar deformation instead of riveting or welding. Several proven methods include:• the Expansion of an extruded or drawn tubular cross bar;• Extruded cross bar deformed or swaged between bearing bars;• Press assembly of rectangular cross bars into slotted bearing bars.

Radially Cut Grating

– Rectangular grating which is cut into panels shaped as annular segments, for use in circular or annular areas.

Reticuline Bar

– A sinuously bent connecting bar extending between two adjacent bearing bars, alternately contacting and being riveted to each.

Rivet Centers

– The distance center-to-center of rivets along one bearing bar.

Riveted Grating

– Grating composed of straight bearing bars and bent connecting bars, which are joined at their contact points, by riveting.

Serrated Grating

– Grating which has the top surfaces of the bearing bars cross bars, or both, notched.

Cross Bar Centers

– The distance center-to-center of the cross bars.

Curved Cut

– A cutout following a curved pattern.

Cutout

– An area of grating removed to clear an obstruction or to permit pipes, ducts, columns, etc. to pass through the grating.

Electro-Forged

– A process of combining hydraulic pressure and heat fusion to forge bearing bars and cross bars into a panel grid.

Finish

– The coating, usually paint or galvanizing, which is applied to the grating.

Flush-Top Grating

– A type of pressure-locked grating in which the cross bars and bearing bars are in the same plane relative to the top surface of the grating.

Grating

– An open grid assembly of metal bars, in which the bearing bars, running in one direction, are spaced by rigid attachment to cross bars running perpendicular to them or by bent connecting bars extending between them.

Hinged Panel

– Grating panels which are hinged to their supports or other grating parts.

I-Bar

– An extruded aluminium bearing bar having a cross-section shape of the letter “I”.

Length

– Refer to Span of Grating

Nosing

– A special “L” section member serving as the front or leading edge of a stair tread, or of grating at the head of a stair.

Span of Grating

– The distance between points of grating support, or the dimension of the bearing bars in this direction.

Straight Cut

– That portion of the cut edge or cutout of a grating which follows a straight line.

Swaging

– A method of altering the cross-section shape of a metal bar by pressure applied through dies.

Toe Plate

– A flat bar attached against the outer edge of a grating or rear edge of a tread, and projecting above the top surface of the grating or tread to form a lip or curb.

Tread

– A panel of grating having carriers and a nosing attached by welding and designed specifically to serve as a stair tread.

Welded Grating

– Grating in which the bearing bars and cross bars are joined at their intersections by either electro-forging or conventional hand welding.

Width

– The overall dimension of a grating panel, measured perpendicular to the bearing bars, and in the same direction as the cross bars.

Toe Plate

– A flat bar attached against the outer edge of a grating or rear edge of a tread, and projecting above the top surface of the grating or tread to form a lip or curb

Support Cleat

Support fixed to concrete or steelwork around the perimeter of flooring

Nosing

A special L section member is used on the front of treads and grating at the head of stairs, both for visual safety and to sustain the edge

Know about Anchor blocks, G clips, Saddle clips, and Kick plates.