Greenburn Opencast Coal Mine - River Nith Crossing

Greenburn Opencast Coal Mine

River Nith Crossing

A long-disused branch line was reopened to provide rail access to a new opencast mine in Ayrshire. The original intention was to demolish the derelict timber viaduct across the River Nith and replace it with a steel structure. However the cost, and difficulty of access for a large crane, led to a rethink and this rare example of timber engineering was able to be preserved by using it as falsework for a concrete bridge, supported on new steel piles threaded through the existing trestles. The timbers were surveyed, and the extent of internal decay was such that great care was necessary to ensure that they could carry the weight of wet concrete. The completed bridge is self-supporting and independent of the timbers.

Employer: Kier Engineering Services

Contractor: Kier Construction

Failsworth School, Oldham - ETFE Roof Steelwork

Failsworth School, Oldham

ETFE Roof Steelwork

The school was designed around an irregular shaped central atrium 120m long and up to 20m wide covered by tensioned ETFE panels supported by a continuous steel frame. The load from the roof had to be shared between 42 supports while providing sufficient articulation to accommodate thermal effects and wind loads. It was also necessary to allow for replacement of individual panels while maintaining the tension in adjacent panels.

Innovative thinking and special articulating support design allowed the elegance of the original architectural concept to be maintained while solving the problems of its implementation.

Employer: Kier Engineering Services

Contractor: Kier Build

Hong Kong Mass Transit Railway - Contract 501A - Zone C Temporary Steelwork

Hong Kong Mass Transit Railway

Contract 501A

Zone C Temporary Steelwork

This is the main concourse area of the Central Subway which links the Hong Kong Central underground station with the terminus of the Airport Express Line. The concourse was excavated 20m below the eight lanes of Connaught Road, four of which were on the approach ramp to the Pedder Street Underpass. The approach ramp, a temporary traffic deck, major utilities and a footbridge pier were all supported on piles passing through the excavation, between which the heavy tubular steel struts designed for loads up to 1200 tonnes had to be threaded.

A complicating factor was the heavy surcharge load at one end from adjacent multi-storey structures not being able to be resisted at the opposite end which had large openings into tunnels. The irregular web of steel tubes was designed to transmit the loads to where they could best be resisted.

Employer: Kier International

Foryd Harbour Pedestrian and Cycle Bridge - Design Study

Foryd Harbour Pedestrian and Cycle Bridge

Design Study

This study was produced in response to a design competition for a new pedestrian and cycle crossing of the harbour at Rhyl in North Wales. The requirement was for a low cost bridge with an opening span. This proposal has 3 identical cable stayed sections, one of which would swing open. The design is intended to have a nautical feel in keeping with the resort style surroundings.

Employer: Kier Engineering Services

Great St Mary's, The University Church, Cambridge - Bell Frame

Great St Mary’s, The University Church, Cambridge

Bell Frame

Cambridge’s University Church was given a new ring of 12 bells to celebrate the 800th anniversary of the founding of the university. Careful studies were made of the interaction of the bells with the 16th century tower in order to minimise the movement of the tower and bells when they were rung. Even 1mm movement can seriously affect the handling of a bell weighing more than 1 ton, and the steel frame was designed to deflect less than 0.5mm under the combined dynamic load of all the bells.

Employer: Kier Engineering Services

Channel Tunnel Rail Link, Contract 250 - Ripple Lane Portal

Channel Tunnel Rail Link, Contract 250

Ripple Lane Portal

The portal is a 500m long structure within which high speed trains descend from ground level to the starting point of the bored tunnels between Dagenham and Kings Cross. Originally designed with diaphragm walls, a value engineering proposal to completely redesign the structure using permanent sheet piles was accepted by the client, resulting in significant savings.

This view shows the launch chamber for the tunnel boring machines, the circular shape providing a large unobstructed space for assembling the TBMs, and an area behind the headwall backfilled with foam concrete allowed the tunnel drive to start without expensive ground improvement work.

Employer: Kier Engineering Services

Contractor: Nuttall - Wayss & Freitag - Kier JV

Channel Tunnel Rail Link, Contract 250 - Wayside Ventilation Shaft

Channel Tunnel Rail Link, Contract 250

Wayside Ventilation Shaft

The original design for this 20m deep ventilation shaft was rectangular with diaphragm walls. As a result of a value engineering initiative by the contractor, an oval shape was adopted using secant piles.

Space limitations precluded a conventional circular design, but it was demonstrated that the stiffness of the surrounding ground was sufficient to maintain the shape of the shaft without either temporary or permanent internal support.

As a result the secant piles could be unreinforced, and several hundred tonnes of supporting steelwork eliminated, with consequent cost and programme savings.

Employer: Kier Engineering Services

Contractor: Nuttall - Wayss & Freitag - Kier JV

Frog Island, Essex - Waste Management Facility, Bio-MRF Building

Frog Island, Essex

Waste Management Facility, Bio-MRF Building

The substructure for this building beside the Thames, including the below ground waste reception pits, was completely redesigned on behalf of the contractor as a cost saving exercise. Permanent sheet piles around the pits eliminated a requirement for tension piles, short precast piles replaced much longer CFA piles, and pile caps became smaller avoiding excavation below water level.

Further savings were made when similar ideas were adopted for a second facility nearby.

Employer: Kier Engineering Services

Contractor: Kier Construction

Plover Cove Reservoir, Hong Kong - Tei Mei Tuk B Pumping Station

Plover Cove Reservoir, Hong Kong

Tei Mei Tuk B Pumping Station

The pumping station had to be built in one of the deepest parts of the working reservoir, with the possibility of unpredictable changes in water level up to 15m occurring at any time.

A cofferdam capable of resisting flotation appeared impractical, and it was decided to lower the reinforced concrete shell of the pumping station into the water as it was built. A steel lowering frame with 16 centre-hole jacks was built, providing a lifting and lowering capacity exceeding 8000t.

Permanent piles were installed in advance, initially extended up to support the base slab until it could be lifted. The challenge of making structural connections to the piles underwater was successfully overcome.

Employer: Gammon Kier JV

Sri Racha Jetty - Thailand

Sri Racha Jetty

Thailand

The contractor-designed jetty has a 2.8km approach and a 450m long jetty head capable of accommodating two 200000t bulk carriers on the outer face. The 9m wide approach roadway has to pass over an older conveyor structure.

The jetty is built of steel tubular piles and pretensioned and reinforced precast concrete units with an insitu topping. A substantial preconstruction period allowed the preparation of precasting and prestressing beds with the result that almost all the offshore work was carried out in a 9 month period. The piles were pitched and driven from a large crane barge, and the superstructure was designed to be erected without needing temporary works.

Employer: Kier International

Tower Wharf, Northfleet - Covered Berth

Tower Wharf, Northfleet

Covered Berth

Designed and built by Kier for Seacon, the warehouse extends out over the River Thames to provide a covered area for loading and unloading steel rolls, lead ingots and forest products directly between a ship’s hold and the warehouse floor. The warehouse has three 35m wide bays, each with a 40t overhead crane.

Between the berth and the sea-wall the storage area is a piled deck designed for loads up to 13 tonnes per square metre. This was built using 100t crawler cranes working out from the sea-wall, driving cased and steel tubular piles and building the deck with precast units and in-situ concrete. The cranes moved onto the completed deck when sufficient strength had been gained.

Employer: Kier