Metal beam crash barriers are an efficient road safety device that protects the vehicle and its occupants in the event of an accident and acts as an outstanding visual aid for drivers, particularly at night.
Metal beam crash barriers are located on approaches to bridge structures, at horizontal curves, and at locations where the embankment height is more than 3 m.
In this article, we shall discuss the material specifications, construction operation, erection, and advantages of metal beam crash barriers.
Material Specifications
- The metal beam rail and the railing post shall be made of corrugated sheet steel beams of the class, section, type, and thickness as specified in the plans.
- All complete steel rail elements, posts, terminal sections, nuts, bolts, hardware, and other steel fittings shall be galvanized.
- All railing elements shall be free from rough or sharp edges and abrasions and shall not be kinked, twisted, or bent.
- Unless otherwise specified, the steel beam elements and terminal sections shall be galvanized (zinc-coated, 0.55 kg per square meter, minimum single spot).
- All galvanizing works shall be done after fabrication.
Construction Operations
- The grade and line of railing shall be true and as shown in the plans.
- The railing shall be carefully placed prior to fixing in place to ensure correct alignment, proper matching at abutting joints, and camber throughout its length.
- The holes for field connections shall be drilled with the railing in place in the structure at proper grade and alignment.
- If the sections are not galvanized, the railing steel posts shall be painted one shop coat (primer) and three coats of paint after erection.
- Any part of the crash barrier below ground shall be painted with three coats of red lead paint.
- The splices and end connections must be strong enough to allow the rail parts to reach their maximum design strength.
Installation of Posts
- The holes must be excavated or drilled to the depth specified in the drawings, or the posts may be driven using permitted methods and equipment, providing they are constructed in the appropriate location and are free from deformation, burring, or other damage.
- All post holes excavated or drilled must be large enough to allow for appropriate post-placement and enough room for backfilling and tapping.
- The holes must be backfilled with chosen earth or stable materials in layers no thicker than 100 mm, with each layer properly tamped and rammed.
- The post holes that are drilled in rock and holes for anchor posts shall be backfilled with concrete.
- The posts for metal beam guardrails on bridges shall be bolted to the structure.
- Anchor bolts must be placed at the appropriate location and height using templates and thoroughly verified.
Erection of Crash Beam
- All guardrail anchors must be installed, and attachments must be fabricated and assembled in the locations specified on the drawings.
- All bolts or clips used to secure the guardrail or fittings to the posts must be tightly pinned.
- Each bolt must be long enough to extend at least 6 mm through and beyond the entire nut.
- In the case where such extensions might interfere with or endanger traffic, the bolts shall be cut off flush with the nut.
- All railings must be built, pulled, and adjusted so that the longitudinal tension is consistent over the entire length of the rail.
Tolerance
In a length of 3 meters, the posts must be vertical with a tolerance of no more than 6 mm.
Advantages of Crash Barrier
1. Reduced Traffic Jams and Congestion
The crash barriers have a significant influence on decreasing traffic congestion and bottlenecks. Less traffic congestion leads to safer and more efficient driving.
2. Increased Road Safety
The significant advantage of employing the crash barrier is enhanced highway and road safety, which results in fewer accidents. These crash barriers are intended to improve road safety by shielding cars and drivers from collisions.
These crash barriers are useful in preventing an out-of-control car from entering the opposing lane, therefore avoiding direct collisions.
3. Low Maintenance
The crash barriers require less maintenance than any other type of road safety barrier. They are tough and can readily sustain severe hits. Furthermore, the crash barrier is designed to last at least 30 years with minimal maintenance.
FAQs
Metal beam crash barriers are an efficient road safety device that protects the vehicle and its occupants in the event of an accident and acts as an outstanding visual aid for drivers, particularly at night. They are located on approaches to bridge structures, at horizontal curves, and at locations where the embankment height is more than 3 m.
The advantages of the metal beam crash barrier are:
1. Reduced Traffic Jams and Congestion
2. Increased Road Safety
3. Low Maintenance
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