MILD STEEL OPEN BOX BEAM GUARD RAIL

We supply quality mild steel open box beam guard rails in complete structure composed of posts, beams with tie plates, clamp plates, fittings, fastenings including end beams and terminals. Various sizes are available while following listed for reference.

Open box beam guardrail is a type of traffic barrier used to provide guidance and protection from errant vehicles. The most common type of open box beam guardrail consists of two steel posts supporting an angled rail that is held in place by a horizontal cable. Main specifications and dimensions of open box beam guardrails include: height of 33-44 inches, post spacing of 12 feet on center, rail length of 12 feet, and rail thickness of 6 inches.

All steel parts after fabrication are galvanised by the hot dip process in accordance with BS 729.

Steel Beams are delivered in straight line with fine accuracy and ready for the construction of guard rail.

Open Box Beams and Fittings

Open Box beams size:
5mm thickness and trapezoidal cross-section
Material: Mild steel BS 4360 Grade 43A.
When a 4.8m long section is freely supported over a span of 3m with the traffic face uppermost and with a 20kN vertical force applied to the centre line of the span the maximum deflection shall not exceed 12mm.

Bolts, Nuts, Washer Parts
Beam sections are joined by fish plates, made from mild steel of equal quality to the beam, using bolts, nuts and washers Grade 6.9 manufactured in accordance with BS 4190 ISO metric black hexagonal bolts, screws and nuts, with galvanised finish to BS 729.

Posts
Manufactured from 5mm mild steel plate
Quality: According to BS 4360 Grade 43A formed in to a Z-section 110mm x 50mm x 8 kg/m.
Overall length and spacing of posts per required by customers.

Bolts
Ready for assembly
No sharp edges or projections to traffic.
Bolts, nuts and screws connecting beams to posts are ISO metric black hexagonal bolts to BS 4190 Grade 4.6 with galvanised finish to BS 729.

The entire length of the guard rail can be furnished with two-faced white and red reflectors every other post.
The reflector is min. 50cm2, prismatic type only.

Construction of Open Box Beam Guard Rails

Guard rail is erected to present a flowing alignment.
Post holes excavated to the line and levels per customers requirement.
Over excavation of post holes is backfilled with Class C Concrete up to the level of the post butt.
Posts are sheathed in polythene 25 microns thick for a length of 500mm and set in Class A Concrete.

The overall horizontal alignment of guard rail shall not depart from the road alignment by more than + 30mm, nor deviate in any two successive section lengths from the straight or required radius by more than 10mm.

The metallic beam shall be at the specified height, of 610mm to centreline, above the edge of the nearest adjacent carriageway or hardstrip within a tolerance of + 30mm. In addition the deviation from the straight shall not exceed + 5mm in any two successive section lengths.

No site drilling or curring of beams and posts will be permitted without the prior approval of the Engineer. Under no circumstances will flame cutting equipment be used for cutting beams and forming holes.

Provision for expansion and contraction in beam sections shall be made at 48 metre intervals. In no case shall the top of posts extend above the top of the rail members.

Each end of each continuous installation of guardrail member shall be finished with an angled beam and terminal piece, in accordance with the drawings.

After the beams, clamp plates, braces and other parts of the structure are in place, the guard rail shall be accurately aligned, bolts and other fastenings securely tightened, and the entire structure brought to a smooth, taut and well finished condition. Special fish paltes with a red painted finish shall be used for joining beam sections on radii less than 335m.