Enlargement joint innovation on River Nene viaduct

Nationwide Highways has sanctioned the usage of a brand new Swiss variant of enlargement joint that has now not been utilized in the United Kingdom prior to.

A big enlargement joint at the River Nene viaduct, between junctions 12 and 13 of the A14, must be changed having reached the tip of its operating lifestyles. The brand new joint is designed to cut back noise, make long run upkeep more uncomplicated and permit motorists to proceed the use of the street whilst the maintenance are performed.

The paintings, to be undertaken by means of highways specialist Direction One Infrastructure, is predicted to take 3 months however to stay the street open up to conceivable, leading edge bridging plates are being put in spanning the excavated space, which will also be raised to permit get right of entry to for in a single day operating and reduced for site visitors to go with the flow within the daylight.

With out the use of those transient bridging plates, that are winched and locked into position all through the works, the path would want to be closed to all site visitors 24/7 for a number of weeks.

One of the most options of the brand new enlargement joint is a handy guide a rough unencumber gadget so it may be changed in a single day will have to the will ever rise up, considerably decreasing disruption. It additionally has noise decreasing plates to decrease the noise created by means of automobiles riding over it.

The joint is a changed Tensa Modular LR-LS gadget, together with the usage of noise decreasing sinus plates, manufactured by means of Mageba in Switzerland.

A lot of these bridge joint are used on lengthy span bridges in the United Kingdom and throughout Europe, referred to as section 8 joints, in connection with the related Ecu Technical Approval Tips (ETAG) bankruptcy.

The joint is designed by means of the producer in response to Eurocode design requirements for bridges as applied by means of Nationwide Highways’ Design Guide for Roads and Bridges.

As defined by means of Nationwide Highways, the joint is composed of quite a lot of transverse lamella beams that strengthen the rubber seals between, given the joint it’s watertightness. Those lamella beams are supported from longitudinal beams supported between the bridge deck and the abutment which might be designed to supply motion and rotation in all 3 instructions. The joint makes use of specifically designed low friction and extremely sturdy bearings between the each the beams and the bridge interfaces to house all deck motion with out moving horizontal forces into the construction.

The joint spans a 400mm hole, with a most design longitudinal motion of 243mm, preset at 50mm between rails at 14C for set up. The entire joint metal parts are scorching dipped galvanised to 140 microns minimal thickness previous to meeting for extraordinarily prime corrosion coverage.

The Nene Viaduct joint has two specific adjustments that make it other from standard:

• the addition of sinus plates above the lamella beams to each scale back noise and make stronger trip high quality (averting the acquainted clunk of riding over enlargement joints).
• an integral ‘Fast-Ex’ gadget that permits the joint to be got rid of and changed with out affecting the rest of the bridge construction.

The ‘Fast-Ex’ removing gadget contains a ‘2nd pores and skin’ equipped at interfaces with the receiving construction, with the modular joint bolted into this extra metal interface. The second one pores and skin is forged involved with the receiving construction.

All the way through long run substitute or upkeep of the joint, the second one pores and skin will stay in place as a casing, permitting the joint to be got rid of by means of unbolting. This add-on “Fast-Ex” gadget has now not been utilized in the United Kingdom prior to and is supported by means of innovation investment. The preliminary prices are roughly 10% of the joint fabrication and buy prices, with out a further build up in related set up prices.

The joint is fabricated in metal and forged in concrete into the unique concrete bridge deck. Along with the above, cautious attention has been undertaken within the design of the joint to deal with metal fatigue problems bobbing up from the cyclic loading nature of highway site visitors that experience prior to now plagued the sturdiness of this sort of joint.

The gadget was once proposed by means of Mageba, the joint producer, which is raring for this to be followed UK-wide given the possible financial savings for long run upkeep in each site visitors disruption and set up prices for substitute joints.

The joint is a substitute for a modular strengthened rubber pad sign up for with central bridging plates and aspect bearing parts of vulcanized rubber on metal plates, which required vital ongoing upkeep and led to problem in acquiring substitute parts as those was out of date.

The brand new joint has a design operating lifestyles of fifty years, with the minimal length prior to primary upkeep of 25 years and minor upkeep of 10 years. Minor upkeep is predicted to be restricted to the substitute of seals and equivalent minor parts that don’t require vital disruption to site visitors to switch.

Paintings at the scheme will get started on Friday 29^th August, beginning at the eastbound carriageway, after which transfer to the westbound carriageway till the scheme is finished in December.

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