Safety Measures On Narrow Bridge

To

The Concessionaire,

Subject: Safety measures to install on or at a narrow bridge.

Dear Sir,

During the site inspection, it was observed that there were no safety measures on the narrow bridge or restricted carriageway width. Additionally, the narrow bridge lacks any warning safety signs or elements that could alert and secure the user, thereby preventing possible collisions.

As per Article 18 safety requirements of the CA, ”The concessionaire shall comply with the provisions of this agreement, applicable laws, and applicable permits and conform to the good industry practices for securing the safety of the user. In particular, the concessionaire shall develop, implement, and administer a surveillance and safety programme for providing a safe environment on or about the project highway and shall comply with the safety requirements set forth in Schedule L (”Safety Requirements”).

In this regard, it is suggested that proactive safety measures be put in place. Such as hatching on the paved shoulder with raised pavement edge lines or markers. Additionally, place appropriate signage in front of the narrow bridge. This will alert you to avert the collision of vehicles with the crash barrier.

The taper part, also known as the nose length advanced to the narrow bridge at Km. 20+150, should be appropriately marked with hatch marks. This is as stipulated in the codal provisions of IRC 35. This measure is to illustrate and caution against the reduction in paved width and carriageway upon the narrow bridge.

Important safety implementations at narrow bridges (other than widening a bridge) are crucial for reducing the hazards associated with a narrow bridge.

The safety treatment recommendations for the restricted-width, narrow bridges were fundamentally similar. The only changes were in the management of the approach rail after it moved onto the bridge. Also, the addition of clear markings served as a visual help for drivers.

The following safety treatment recommendations apply to restricted-width, narrow bridges.

You can apply the following to either lower the likelihood of accidents or lessen their severity.

• Modification of approach grades is necessary when there is a problem with the continuity of the longitudinal and cross-fall grades. Major changes in the longitudinal and cross-fall grades of the approaching carriageway should be considered.
• Realignment of the carriageway is necessary when problems with sight distance are evident and traffic measures are not working. Realignment of the bridge may be the only acceptable alternative.
• Consideration for safe vehicle passage on a narrow bridge is necessary to protect the structure against vehicle collisions. By positioning structural components at a safe distance from the line of users and providing suitable protection, we can minimise the hazard of errant vehicles hitting them within the clear zone.
• Provision of a smooth bridge rail: A flexible crash barrier or metal beam crash barrier decreases the probability of snagging or catching and increases the probability of redirection with less damage to vehicles. Additionally, the installation method may lead to an increase in the bridge’s absolute width. Thus, this alternative may be extremely desirable, especially if frequent bridge impacts with railings have been observed.
• Install approach guardrails. Structures that comply with the regulations must have railings and crash barriers along their edges. requirements.    At restricted or narrow-width bridge locations, the installation of an approach guardrail or metal beam crash barrier is a norm related to highway safety. The approach guardrail serves several functions, including redirecting errant vehicles at critical points and preventing vehicles from impacting the ends of bridges. IRC 119 stipulations require the correct tying of the approach rail to the bridge end and/or bridge rail system.
• Provision of road markings. The pavement markings aid in diverting traffic away from potentially hazardous situations. Examples of such markings include chevron and diagonal markings on a narrow bridge, as well as hatch and prohibitory markings. Compliance with hazard markings, provided ahead of diverging, merging, and around a hazardous location, is crucial. An appropriate sign must always accompany the hazard marking.
• Place Road marking edge lines: Road marking Edge lines are effective visual guides for the road user or driver. They are useful for demonstrating width continuity from the approach roadway to the structure. Edge lines can also be used in the transition from a wide roadway approach to a restricted-width bridge.
• Hatch markings lead to the narrow bridge. These marks, showing where lanes get narrower, happen often with small bridges or roads. If a lane’s width shrinks, these lines help drivers adjust from a wide lane to a slim one, and the other way around. They led the way to the slim bridge, reminding drivers to watch out for change. The front end, or ‘nose,’ of the bridge should also have clear hatch marks, as IRC 35’s guidelines say. These rules act like a picture, warning about the slimmer road or bridge ahead.

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• Eliminate the road marking centerline for one-way operation. When a bridge must carry only one lane of traffic, it’s essential to erase the central lines that divide two lanes. This applies both to the bridge itself and the roads leading to it. Changing from a two-lane bridge to a single-lane requires a specific traffic drawing application.
• Provide pavement transition markings. Mark transitions on the pavement. When a road leads to a bridge and their widths aren’t the same, you’ll see pavement transition marks. On roads where vehicles move fast, a single line at the edge might not be enough. In those cases, consider diagonal markers on the shoulder, rumble strips, and raised reflectors. According to IRC 35 rules, these markings make it clear and warn drivers about the decreasing width of paved lanes and roadways at narrow bridges.
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• Install reflective road markers or studs. These reflective markers help guide drivers safely during rainy weather and dark hours. Before approaching a narrow road bridge or a lane with a narrower width, strategically place the markers with the appropriate color. Place these reflective studs on both sides of the carriageway. Additionally, they should be placed along the narrow bridge from km. XX to km. XX to ensure safe passage at all times.
• Install a narrow bridge sign. If the bridge’s width doesn’t meet the project highway standards or if it’s much narrower than the approaching road, we needed a warning sign to tell road users about the upcoming narrow bridge. To show and warn about the decrease in the paved width and roadway on the bridge, we’ll use a sign as guided by IRC 67.
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• Install stop, yield, or signalization. Place appropriate signs such as one-lane, yield, stop, and advance warning. This is in accordance with site circumstances when a bridge is less than the standard width.
• Install a narrow bridge sign. Where a bridge width is less than the standards of the project highway or where the bridge width is substantially less than the approach width, an advance warning sign of the narrow bridge ahead should be placed as per IRC 67 to illustrate and caution against the reduction in paved width and carriageway upon the narrow bridge.
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• Install stop, yield, or signalization. Place appropriate signs (such as one-lane, yield, stop, and advance warning) in accordance with site circumstance requirements when a bridge is less than standard width.
• Transition shoulders to bridges: It’s important to warn road users or drivers when there are significant discontinuities, such as a shoulder dropping at the bridge. Road paint markings, delineators, or pavement reflective road studs, depending on site circumstances or deemed fit for the site, can accomplish this.
• Advisory speed signs. In accordance with IRC 67’s requirements, narrow bridge locations must have appropriate advisory speed signs in addition to warning signs.
• Thermoplastic bar marking is a softer treatment that reduces speed on narrow bridge locations. The application should span the entire width of the carriageway and extend to the narrow bridge. The Approach speed, as outlined in Table 11.1 and Fig. 11.2 of IRC 35, shall determine the number of sets of bar markings.
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• Environmental control: Roadside distractive commercial ads, distracting lights, and other roadside disturbances in the immediate vicinity of restricted narrow-width bridge sites should be considered for control or elimination. Excessive roadside activities pose an undesirable distraction to road users.
• Approach bridge delineation: Navigating narrow bridges at night appears to be particularly hazardous. It is important to provide the road user or driver with appropriate delineation of the bridge approach and railing. Positive nighttime delineation of the width transition is also desirable.
• Delineators: Safety requirements dictate the provision of delineators, also known as guideposts. Install these in series along the roadway’s side to show the roadway’s alignment. Delineators are particularly beneficial at locations where the alignment might be confusing or unexpected. These locations include lane reductions, transitions, and curves.

Conclusion

We explicitly instruct you to submit the compliance report for the above-cited instructions. This is in accordance with the agreement provisions to ensure a safe and smooth traffic flow on the project highway.

Thank you, and we assure you of our best service at all times.

[Yours Sincerely,]

[Insert the name of the authorised person].

The Concessionaire,

Subject: Measures to implement on or at a narrow bridge. And requests for compliance with concessionaire regulations

Dear Sir,

This pertains to the subject matter discussed in the cited reference. Currently, the preparation of designs and good construction drawings for structures is in progress. We would like to draw your attention to the following, in addition to the guidelines outlined in Schedule B (Development of the Project Highway) of the concession agreement. These guidelines are crucial for the design, construction, and rehabilitation of both new and existing structures.

Guidelines to be considered for structures, especially the Narrow Bridge, during the development and construction phases

The following section provides a brief overview of the scope and work associated with “project structures that are newly constructed and existing to retain.”

When designing and building bridges and other structures, adhere to the following guidelines:

• The design of all cross-drainage structures for the new carriageway must ensure that the railing kerbs’ outermost faces match the width of the approaches’ roadways.
• To match the new road cross sections, we must enlarge the existing structure.
• The concessionaire under the contract will undertake the retention of the proposed existing bridges, rehabilitation of the foundation, substructure, and superstructure of all kinds, including but not limited to the repair of honeycomb, spalled concrete, corroded and exposed reinforcement, filling of cracks by epoxy injection, vegetation removal, replacement of bearings and expansion joints, profile correction course pier protection, dismantling of existing parapets and railings, and replacement of the same with crash barriers
• The cross-sectional elements for structures must align with the drawings of the corresponding structures in the drawing volume. All the bridges, cross-drainage structures, and other structures shall be designed in accordance with the design standards. Unless otherwise noted, the design of all bridge cross-drainage structures and many other structures for the widened highway must accommodate a six-lane capacity. The existing retainable structures shall be widened (extended) to match the new road cross sections, as required.
• Longitudinal Gradient and Cross Slope: The maximum longitudinal gradient on the bridge shall be consistent with the gradient of the approach roads as per relevant IRC codes. The cross-slope on the bridge deck shall be consistent with the cross-slope of the adjoining roadway. One must consider the stopping sight distance when exiting a bridge. This is especially important when building bridges near intersections.
• Approaches to the Bridge: The approaches on either side of the bridge for a length of at least 15 m shall continue to have the same horizontal profile as that provided for the bridge. Where necessary, we may suitably increase this length to ensure the minimum sight distance required for the design speed. However, in difficult geometric situations, the minimum length of approaches with the same horizontal profile may not be insisted upon, provided the user’s safety concerns are not compromised.
• The following aspects of O&M requirements should inform the general design requirements: functional requirements, structural requirements, construction requirements, environmental requirements, durability requirements, aesthetic requirements, and future widening requirements of the structure.
• Crash Barriers: Suitably designed crash barriers of flexible barrier, semi-rigid barrier, and rigid barrier subjected to the site circumstances requirement shall be considered.
• Railings, Parapets, and Guide Posts: The railing or parapet should be designed for loads and forces as per relevant IRC codes.
• Illumination: All bridges should be equipped with illumination. Provision for cabling, mounting, and installation of luminaries shall be considered in the design and detailing.
• Road Signs and Signals: The overall planning for the bridge must include an appropriate plan for road markings, signage, delineation, and signals (where necessary).

Thank you, and we assure you of our best service at all times.