Thursday, 18 October 2012

The Millennium Bridge Inclined Lift

The Millennium Bridge and access link lift were as their name implies, constructed to mark the Millennium.

The lift was provided to link Peters Hill and Pauls Walk for persons who are unable or prefer not to use the adjacent stairs.

The Bridge was featured in the film “Harry Potter and the Half Blood Prince”.

The success of the Tate Modern Gallery on the South side of the Bridge has meant that the bridge and lift has become a tourist draw and now takes considerably more traffic than was originally envisaged. Consequently the use of the lift has substantially increased.

The City of London decided that the lift was in need of upgrading to cope with this increased use. The plan was to ensure the lift was completed for the River Pageant celebration for the Queens Diamond Jubilee as well as the fast approaching Olympics and Para Olympics.

The City of London appointed Dunbar & Boardman as consultants for this project and the first task was to complete a detailed feasibility study of how these works would be undertaken and the source most suitable equipment for the project.

Following the report, the City of London undertook the necessary approvals for the funding of the works from the Corporation and planners, due to the highly sensitive location and sight lines to St Pauls Cathedral. Dunbar & Boardman produced a detailed specification for the works and sought the most suitable contractors.

Hütter Aufzuge of Hamburg, Germany were selected as the engineers/ manufacturers for the replacement lift as they have an extensive and proven track record of inclined lifts, for both internal and external locations including lifts in public areas such as metro systems.

Whilst Hütter were able and willing to supply the equipment, they would seek a local contractor to undertake the installation with their support and back up.  This was also useful to ensure that the installer was UK based for on-going maintenance.

Axis Elevators have a reputation for special ‘one off’ installations in London and the South and have successfully completed a number of complex projects for Dunbar & Boardman and were therefore considered to be the most suitable contractor to install this lift. Axis were subsequently appointed by the City of London as the main contractor to supply and fit the inclined lift.

The principle of the design was to ensure that wherever possible, conventional lift parts were used to ensure maintainability and reliability as well as obtaining the necessary notified body approvals and certification.  This included the lift arrangement having a counterweight rather than a closed loop rope tensioned system previously utilised.  Hence the use of a Ziehl Abegg gearless machine, Ziehl drive and recovery system, Schneider “Lisa” control panel, optically connected Sematic doors and VVVF door drives etc.

The doors were a particular concern as the lift arrangement has entrances on opposing sides of the car, which means coupling the doors conventionally is complex and was a major contribution to unreliability on the original lift.  The Sematic wireless system was selected due to the car and landing doors being independently driven but connected via an optical coupling making the system more tolerant to minor variations in the car position due to load in the car or weather conditions.  The equipment is also available with the appropriate level of protection for an external installation.

Due to the planning restriction the doors had to be glazed and the operator mounted on the underside of the car which was the first time this type of Wireless Sematic door system had been installed in this configuration.

Once the necessary approvals had been agreed, instructions were placed and the manufacturing could commence whilst the final stages of planning the site works were undertaken.  Due to the programme completion dates the site work needed to be undertaken between January and May 2012. Consequently the site had to be fully weather proofed as well as having a hoarding fully encapsulating the lift enclosure for public safety.

Fortunately the winter weather was not as bad as recent years although recent water proofing was extensively tested! 

One issue arose during the design stages was the relevant Regulations and Standards applicable to the ‘lift’, as its angle of inclination was 13.6°. This meant it fell outside of the strict interpretation of EN81, and could be technically classified a ‘cable way’, even though the original lift was certified under the Lift Directive.

During Consultation with the HSE Transportation and Safety Unit it was agreed with the Department for Transport, that provided the lift was the same platform size and speed as existing, and complied with EN81, it could be certified under the Lift Directive but would also satisfy the Essential Safety Requirements of the Cable ways Directive (where applicable).
This was completed and included in the Technical Dossier for Handover.

The lift was completely replaced during this period including the supporting truss, guide, car, entrance, drive etc. The only retained items were the original glass enclosure and concrete supports.

The lift was delivered in three stages from Germany then stored locally before being brought to site as needed, due to the limited space available.

The main components were inspected in the Hütter factory prior to dispatch by the City of London and Dunbar & Boardman.  The installation process was aided by the co-operation of the FM team at Millennium Bridge House as well as The City of London School who both adjoin the site.

The installation was completed on time and the lift was available for public use during the Jubilee River Festival weekend.

People Involved

Client:                City of London - Steve Daley, Alan Prosser
Consultants:       Dunbar & Boardman – Chris Meering, Tim Piggott, Peter                                  Boardman
Manufacturers:   Hütter Aufzuge – Achim Hütter, Deiter Fehse
Installer:            Axis Elevators – Ian Rutherford, Keith Hodges, Andrew Longcroft, Bob Hobbs,    Steve
Site Team:        Lee Johnson, Steve Tiegan
Notified Body:   Lift Cert – Malcolm Miles

HSE Transportation and Safety Unit: Robert Cooper and Adebayo Ige
Dept for Transport: Steve Berry