Sep. 08, 2025
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When you’re cruising down the highway or crossing one of our iconic bridges, have you ever thought about the unsung heroes of road safety—guardrails and bridge railings? These sturdy guardrails are more than just metal fixtures; they’re vital components in keeping everyone safe. Let’s dive into why they’re so important and how Driven Fence contributes to their design and implementation.
Bridge railings, also known as bridge barriers or parapets, are crucial safety components that serve multiple purposes on bridges. They play a key role in ensuring the safety and functionality of these structures by providing several benefits.
Vehicle Containment
One of the primary functions of bridge rails is to prevent vehicles from leaving the roadway. In the event of an accident, these barriers help keep vehicles from falling off the bridge, drastically reducing the risk of severe injuries or fatalities.
Pedestrian and Cyclist Safety
Bridge railings also separate vehicular traffic from pedestrian walkways and bicycle lanes. This separation provides a safe space for non-motorized users and minimizes the risk of collisions, making bridges safer for everyone.
Structural Protection
Bridge rails protect critical bridge components like piers, abutments, and girders from vehicle impact damage. By preserving the structural integrity of the bridge, they help minimize maintenance costs and extend the lifespan of the bridge.
Aesthetic Appeal
Who says safety can’t be stylish? Well-designed bridge rails enhance the appearance of a bridge and contribute to the visual appeal of the surrounding landscape. In urban settings or areas of cultural significance, aesthetic considerations are often a vital part of bridge design.
Materials Used in Guardrail Construction
Choosing the right materials for guardrails is crucial for their effectiveness and longevity:
Steel
Aluminum
Wood
Concrete
Traffic Flow Management
Guardrails help manage traffic flow by serving as visual guides for drivers. By helping maintain proper lane discipline, they reduce the risk of accidents caused by lane changes or merging issues.
Noise Reduction
Especially in busy urban areas, bridge rails can help reduce traffic noise for pedestrians and nearby residents. Some designs incorporate noise-absorbing materials, making them both functional and community-friendly.
Crash Energy Absorption
Modern bridge rail designs often come with impact-attenuating features. These features absorb and dissipate crash energy, reducing the severity of collisions and improving overall roadway safety.
Industrial Guardrails: Protecting More Than Just Roads
Driven Fence also offers guardrail design and implementation services for industrial settings. These sturdy barriers protect employees, machinery, and the structure of a facility from accidents.
Attention-Grabbing: Designed to alert and caution individuals in high-risk areas.
Impact Resistance: Constructed to absorb shock and maintain form under pressure, providing a long-term safeguard.
Customizable: Available in various sizes and designs to fit different industrial landscapes.
As a leading provider in the Midwest, Driven Fence specializes in designing and implementing guardrails that meet your specific needs. Whether it’s highway safety or industrial protection, we ensure durability and reliability.
Contact us to discuss your requirements of bridge guardrails. Our experienced sales team can help you identify the options that best suit your needs.
Custom Solutions: Tailored to suit the unique requirements of your project.
Expertise: Our team offers knowledgeable advice and top-notch service.
Chicago Fence Rental: For temporary needs, we provide a range of rental options including construction fencing, fence panels, and more.
Conclusion: Safety First with Driven Fence
Guardrails and bridge railings are critical for ensuring the safety and efficiency of our roads and bridges. They protect not only vehicles but also pedestrians, cyclists, and the structures themselves. By investing in quality guardrails, you’re investing in safety and peace of mind.
If you’re looking to enhance your property’s safety, contact Driven Fence today. We’re here to help with all your fencing and guardrail needs.
Most bridge barriers are located within the clear zone area of a roadway and thus create a fixed object that should be protected with the use of guardrail. This guide is intended to explain when and where guardrail is required on local bridge projects.
Note that for safety reasons it may be prudent to install guardrail on certain projects, even if the project doesn’t meet the requirements for guardrail. See FAQ – Q3 for funding information in these instances.
There are some useful tools for evaluating your current guardrail system on the MnDOT website. These tools can help you decide to repair or replace your current system.
MnDOT RDM Figure 10-7.01C (PDF) describes the requirements for guardrail locations at a bridge. Essentially if it’s a bridge that carries two-way traffic and the gutter to gutter width is less than two times the clear zone width (per the appropriate rules book chart), then all four corners need guardrail with end treatments. For all other situations, refer to the MnDOT RDM Figure 10-7.01C (PDF).
The MnDOT RDM Chapter 10 (PDF) is a good resource for information regarding guardrail system design and requirements.
This is not a recommended practice. If it meets the requirements for guardrail, then a variance would be required to remove the guardrail from the plans. Furthermore, it is advised to talk to the local agency attorney to discuss the ramifications of removing a required safety component.
Contact the District State Aid Engineer (DSAE) to discuss this funding issue. The DSAE will need to discuss this with the State Programs Engineer to see if bridge funds can be used.
Yes and no. For new bridges, the use of the new Type 31 guardrail system is required. There are occasions of crash repairs or bridge repairs when it is prudent to install portions of the old guardrail system. There is a new MnDOT Technical Memorandum which discusses the requirements for bridge preservation projects: Technical Memorandum No. 17-07-TS-02 (PDF).
The new Type 31 guardrail system was developed to meet the requirements of the new Manual for Assessing Safety Hardware (MASH) safety requirements for roadside barriers. It differs from the older W-Beam guardrail system in an increased height (old system was 27” and the new system is 31”) and a stronger Thrie-Beam connection (which transitions to a W-Beam away from the bridge) at the bridge. This new connection is much taller and has more connection bolts. It can only be connected to a Single Slope (Type S) Barrier or a Vertical Face Parapet barrier.
It is advised to use the new Type 31 guardrail system if at all possible.
No. The new Type 31 connection plate is simply too tall and doesn’t interface well with the sloped face of the older Type F barriers. The MnDOT Bridge Office has used a Type F to Type S barrier transition which transitions into the new Type S (Single Slope) barrier, of which there are standard connection details for. They are also developing transition details for Type G and Type J bridge barriers. Contact the State Aid Bridge Office if you’d like assistance in determining if this barrier transition is needed.
See the Technical Memorandum No. 17-07-TS-02 (PDF) for more details regarding existing bridges.
These cases should be looked at on a case-by-case basis. While the use of guardrail would help protect the trail users and the motorists, it also can present safety issues for the bicyclists using the trail. There are other issues in these cases, such as roadway curbs and/or drainage issues.
Contact the State Aid Bridge Office for guidance and/or help developing plans for these situations.
Yes, but approach panels are recommended. Approach panels offer room to get the guardrail connection away from the bridge superstructure, which in cases of traffic impact would lessen the damage to the bridge. Also, approach panels offer better drainage in the area of the guardrail, which would lessen the undermining of any guardrail posts and weakening the system in a crucial area.
If the shoulder has bituminous pavement, then the pavement limits can go beyond the guardrail and the steel guardrail posts can be driven through the pavement. This method can alleviate erosion issues at the guardrail posts.
If the bridge barrier is outside the clear zone (but the rules would require the use of guardrail), then per MnDOT RDM Figure 10-7.01C (PDF) we would require installing guardrail on the two traffic-side entry corners of the bridge.
There are occasions where a roadway intersection is within the limits of the designed guardrail system length. In these cases the guardrail can be curved around the corner. Depending on the design length of the system and the roadway design speed, it may be such that an end treatment may be waived in some cases [but an end anchorage would still be needed – see Std. Plan 5-297.692 (1 of 2) and Std. Plan 5-297.692 (2 of 2)]. These should be evaluated on a case-by-case basis and the DSAE and/or State Aid Bridge Office should be contacted early in the design phase of the project.
There are some curved guardrail detail sheets that are available upon request. These were sheets that were developed for standards but have not been released at this time. Contact the State Aid Bridge Office for guidance and details.
No, each guardrail system should be designed in accordance to the MnDOT RDM Chapter 10 (PDF)guidance. With that being said, the ‘Length of Need’ for many local bridges may fall within the minimum design lengths required for the complete system (transition at the bridge + W-Beam guardrail segment + end treatment).
In many cases the obstacles being protected are the bridge barrier and a water feature, so the LH (Lateral Offset to the furthermost point of the hazardous object) distance may simply be the clear zone distance for the associated roadway section.
The State Aid Bridge Office has an internal ‘Length of Need’ spreadsheet that we can share upon request, but simply using a graphical method may be the easiest way to come up with the design length needed (per the MnDOT RDM – Chapter 10).
There are two options for the installation of guardrail on low-fill concrete box culvert projects. Since the fill height doesn’t allow for a full length of guardrail post to be installed, there is a Standard Plan Sheet (Std. Plan 5-297.696) that will span up to 25’ without guardrail posts. This will essentially clear span the culvert.
The other option (but is not a standard detail) is a connection plate that is welded to the steel guardrail post and then is bolted through the roof of the box culvert. Contact the State Aid Bridge Office for details and CADD files if you want to proceed with this option. Please note that using this option will require some extra review time while we contact our Bridge Office Standards Unit for acceptance.
The new Type 31 guardrail system uses steel posts. The use of wood posts is pretty much confined to the repair of an older wood post guardrail system. Steel guardrail posts are now the norm.
The guardrail sheets to be used in a bridge plan could vary depending on the bridge details. If there is a barrier-separated trail on the bridge, then there might be a need for some custom modifications to some of the standard sheets.
For a ‘normal’ rural section local bridge (over water), use the following sheets:
If you are looking for more details, kindly visit Customized Steel Structure for Guardrail.
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