Bridge & Culvert Barriers
Bridge & culvert barriers are specifically designed to provide safe vehicle containment and redirection when installed on an elevated structure. Designers should consider the barrier containment level, the impact loads transferred to the structure and the ease of repair and replacement when selecting the most appropriate safety barrier system.
Safe Direction bridge and culvert barrier solutions are evaluated in accordance with MASH TL3 or MASH TL4 to comply with the crash test conditions described in AS 5100.1. Our barrier options include systems featuring surface mounted posts, side mounted posts or guardrail beams that can span up to 16m between posts.
When upgrading the safety of an existing bridge or culvert structure an important design consideration is the impact loads transferred to the structure. Our innovative crash tested designs provide options that reduce or eliminate these loads extending the life of the bridge or culvert structure.
CrocGuard is a revolutionary bridge & culvert barrier spanning up to 16m between abutment posts.
HammerBeam combines the strength of thrie-beam guardrail with the yielding behaviour of the RamShield W-Beam post.
Featuring a triple rail design, VGAN 400 is manufactured from lightweight, special grade aluminium providing safe vehicle containment.
The RamShield Transition provides a smooth, snag-free connection between steel guardrail barriers and rigid barriers, such as at bridge parapets.
Frequently Asked Questions
What is a culvert?
A culvert is a structure that allows water to flow beneath a road, typically carrying stormwater or natural drainage under the roadway. When located near the road edge, culvert headwalls and wingwalls can become rigid roadside hazards requiring shielding by a safety barrier.
Can a traditional guardrail safety barrier be modified for attachment to a bridge or culvert?
Guardrail barriers are typically assessed with posts driven into the ground. Whilst many provide a baseplate option, these variants are designed for installation on strip footings requiring sufficient clearance behind the barrier to accommodate dynamic deflection. Without specific crash testing, placement of these barriers on the edge of an elevated structure presents a risk to vehicle occupants, since the dynamic interaction between the errant vehicle and the barrier as it deflects is unknown.
What are the key performance features of a bridge or culvert barrier?
A bridge or culvert barrier should demonstrate safe vehicle containment and redirection when installed on the edge of an elevated structure. The safety barrier system should also prevent damage to the bridge or culvert structure since the life span of the structure may be comprised if steel reinforcement becomes damaged or exposed to atmospheric contaminants and water.
How are bridge & culvert barriers evaluated?
The crash test performance of a bridge & culvert barrier is documented in AS 5100.1 Bridge Design. This standard classifies barriers as Low Performance Level, Regular Performance Level, Medium Performance Level and Special Performance Level. The selection of the performance level is based on an assessment of the risks relevant to the site and considers road alignment, vehicle speeds, traffic volume and the consequences of the vehicle penetrating the barrier.
The Standard states that bridge barriers must be crash-tested and approved in accordance with the Manual for Assessing Safety Hardware (MASH).
What is the crash test criteria for a Low Performance Barrier?
A Low Performance Barrier shall be crash tested to the requirements of MASH Test Level 2 (TL2), demonstrating containment of a 2270 kg pick-up truck travelling at 70 km/h and 25 degrees.
What is the crash test criteria for a Regular Performance Barrier?
A Regular Performance Barrier shall be crash tested to the requirements of MASH Test Level 4 (TL4), demonstrating containment of a 2270 kg pick-up truck travelling at 100 km/h and 25 degrees and a 10,000kg rigid truck travelling at 90km/h and 15 degrees.
What is the crash test criteria for a Medium Performance Barrier?
A Regular Performance Barrier shall be crash tested to the requirements of MASH Test Level 5 (TL5), demonstrating containment of a 2270 kg pick-up truck travelling at 100 km/h and 25 degrees and a 36,000 kg articulated truck travelling at 90 km/h and 15 degrees
When should I select a MASH Test Level 3 (TL3) compliant barrier?
It is recommended that a MASH TL3 compliant bridge and culvert barrier be installed when the design vehicle is a passenger car and the roadway post speed exceeds 70 km/h.
Is a transition required when connecting a rigid bridge barrier to a downstream guardrail barrier?
Yes. A transition is the connection between two different types of safety barriers, designed to provide a smooth, structurally compatible, and crashworthy change in stiffness, height, or containment level.
Should I choose a thrie-beam or w-beam bridge and culvert barrier system?
The triple corrugation design feature of thrie-beam guardrail provides numerous advantages when installed along the edge of a culvert including:
- Lower dynamic deflection,
- Wider lateral catching area,
- Less prone to vehicles under-riding the safety barrier system,
- Higher rail mounting height providing improved stability for high-centre-of-gravity vehicles
- Increased strength and capacity.
