We are carrying out essential maintenance work to New Haw viaduct on the M25 between junctions 10 and 11. Our work involves replacing four bridge expansion joints which have reached the end of their serviceable life.
Expansion joints are incorporated into bridges to allow them to expand and contract safely as weather temperatures fluctuate, avoiding causing damage to the road surface and the structure.
We will carry out work affecting the carriageway overnight, when traffic flows are at their lowest. We will require some full closures of the carriageways, but during the day no lane closures or speed restrictions will be necessary. We will only close one carriageway when a full closure is required.
During the scheme a weight restriction of 120 tonnes will be in place 24 hours a day, 7 days a week.
An innovative temporary ramping system, similar to the one used during joint replacement projects on the QEII Bridge and Gade Valley viaduct schemes, is being used so that road workers have easy access to the work site. This will improve our efficiency and will allow the road to remain open during daytime hours without having to enforce a reduced temporary speed limit.
You may notice a change in the look of the carriageway when the ramps are installed but the changes will have minimal effect on ride quality and safety will not been compromised. The ramps will be removed once works are complete in each location.
We began work to replace the joints on the southern end of the structure in May 2016 and we are due to complete in April 2017.
The work at the northern end of the structure will begin on 8 April 2017, and is scheduled to be completed at the end of December 2017.
We will need to implement a number of restrictions and closures to carry out these works. Weekday (Monday to Friday nights, inclusive) overnight lane closures will be required, closing three out of four lanes in one direction, at a time. Diversions will not be required, as road users will pass the work site in one lane, although a temporary speed limit of 40MPH will be place overnight. We will be working between the hours of 9:30pm and 5:30am, except on Friday night where working hours will be between 10pm and 6am. The expected delay for this type of restriction is between 10 and 20 minutes.
We will also need a series of Saturday night closures. The road will only be closed in one direction at a time. Traffic will be diverted on a clearly signed diversion route, using the hollow square symbol. The expected delay for drivers using the diversion route is between 35 and 40 minutes.
Saturday night closure times will vary, depending on the nature of the works. Some Saturday night closures involve more complex work, including the removal of the old joints and the concreting of the new joints. As such, it will be necessary to close the road for an extended period of time, between 9pm and 8am. Other Saturday closures will take place between 10pm and 6am.