Commemoration of the Official Opening of the Wairoa Bridge By Her Majesty Queen Elizabeth II

COMMEMORATION
OF THE
OFFICIAL OPENING
OF THE
WAIROA BRIDGE
BY
HER MAJESTY
QUEEN ELIZABETH II

7th February 1990

Emergency declared

A Civil Defence Emergency was declared in Wairoa at 3.30am today. Heavy rain, thought to be part of Cyclone Bola, drenched the district and the river began to spread and rise.

At the outset fears were held for the safety of the […]

Picture 8.3.88 courtesy of Daily Telegraph

A town torn apart…

The small north-island town of Wairoa is built on the north and south banks of the Wairoa River in Northern Hawkes Bay, and is home to a close-knit rural community of some 5000 people.

On 8 March 1988, the lives of Wairoa’s citizens were turned upside down when Cyclone Bola descended from the east, cutting a swathe of destruction through Hawkes Bay and dropping more than 150 mm of rain on the area in less than 48 hours.

Wairoa residents watched in horror as their river was transformed into a raging torrent which plunged towards the sea, carrying huge masses of debris which quickly accumulated against the bridge piers.

For a few hours the 50 year old bridge shuddered and twisted under the enormous pressure. Eventually, it gave way, leaving a 110 metre gap.

The effect was critical – not only had the bridge been the main pedestrian and vehicular access between the town’s two sides, it had also carried all the town’s power, telephone, water and sewer links. With these severed, Wairoa became two towns overnight, without essential services and almost totally isolated from the outside world with major slips and flooding blocking all access roads.

A Civil Defence state of emergency was declared and more than 350 northern Wairoa residents were evaculated [evacuated] from their flooded homes.

News of Wairoa’s devastation quickly spread throughout the country and aid poured in from all quarters as authorities mobilised emergency procedures.

Temporary accommodation, medical and welfare centres were established and the local newspaper issued daily Civil Defence bulletins.

At the same time as the immediate welfare and safety of the community was being ensured, urgent discussions were underway to find a solution to the paramount problem – how to restore the bridge link across the river to rejoin the town…

How the gap was bridged…

WORKS Corporation, with 100 years of experience in designing and maintaining New Zealand’s State Highway network of roads and bridges, was on the scene during the critical hours before and after the disaster.

When the old bridge was washed away and it became apparent that conventional emergency bridging could not span the huge gap, WORKS and local authorities quickly established priorities for the restoration of access and vital services.

These were:

Construction of a pipe-bridge
Within 24 hours, WORKS Consultancy Services had designed a suspension pipebridge to carry water and sewer pipes, power and telephone lines to the river’s southern side.

Resources in Wairoa were limited and timing was short. Components were designed and fabricated in WORKS Civil Construction Napier workshop then transported to Wairoa by air.

In just two days all components were on site, and within a week a team of WORKS Civil Construction, Wairoa District Council and other local contractors had completed the pipebridge structure and pipe laying.

Conversion of the railway bridge
Priority number two was to reinstate a vehicular connection between the river’s north and south sides. It was determined that, although some distance from the town, a railway bridge which had been similarly used after the major 1931 earthquake could be converted to carry road traffic.

WORKS Consultancy Services began immediate survey of the bridge’s approaches and determined that 1.25 km of new roading would be required – so two shifts worked around the clock, contending with record rainfalls and very soft foundation ground to complete the job.

Erection of a pedestrian footbridge
Although a ferry service was available for emergency transport across the river, high flood levels were limiting its effectiveness.

It was crucial that a 24 hour pedestrian link between Wairoa north and south be established without delay.

WORKS Consultancy Services designers decided upon a Bailey suspension bridge design for a single footbridge structure.

WORKS Civil Construction was commissioned by the Wairoa District Council to build the bridge which, having a span 12 metres longer than the standard Bailey design, required critical adjustments to be made in minimum time.

Construction of the new state highway bridge

The design solution for the new bridge illustrates WORKS Consultancy Services’ expertise and has won acclaim for its aesthetic appearance and dramatically improved seismic and hydraulic characteristics.

The design comprises six 32 m-span, post-tensioned, notched I-beams on flared, single column piers, each with four 900 mm diameter raked piles founded 3 m into bedrock (see inset).

The bridge superstructure can be jacked up to allow for any rise in sea levels and for maintenance of the bridge bearings.

The deck is jointless over its 200 m length, giving superior seismic performance and a smoother vehicle riding surface.

Essential services which run along each side of the bridge are masked with concrete fascia panels which give the structure a clean visual line.

CLIENT:   Transit New Zealand Ltd (formerly National Roads Board)

BRIDGE:
Site investigations, design, project management and construction supervision   WORKS Consultancy Services

Principal contractor:   McConnell Dowell Constructors Auckland

Sub contractors:
Emmett Bros Ltd, Wanganui Firth Certified Concrete, Napier   Richardson Drilling Co., Palmerston Nth Hook & Steel Ltd, Hamilton

APPROACHES:
Site investigations, design, project management and construction supervision:   WORKS Consultancy Services

Principal contractor:   WORKS Civil Construction

Sub contractors:
Wairoa District Council
Emmett Bros Ltd, Wanganui
Firth Certified Concrete, Napier
AA Knight, Wairoa
Fletcher Reinforcing, Napier
John Gardner Electrical, Gisborne
Ian Dick Concrete Contractor Ltd, Napier
Russell Asphalts Ltd, Napier

Works and Development Services Corporation (NZ) Ltd

Works and Development Services Corporation (NZ) Ltd (known as WORKS) is a multi-disciplinary consultancy-construction organisation. Formerly the Ministry of Works & Development, the corporation can claim over 115 years experience in planning, designing, project management and construction of much of this country’s infrastructure.

The corporation is structured into three operating divisions to provide innovative, efficient and competitive services to its clients.

WORKS Consultancy Services
Design, development and project management work covering 16 primary disciplines, including:

Civil and structural engineering, earthquake engineering, architecture, costing and scheduling, dam surveillance, fire protection, geothermal engineering, hydrological services, laboratory services, mechanical and electrical engineering, pipeline services, power engineering, project management, property management, quantity surveying, technical library and information services, economics and planning.

WORKS Civil Construction
WORKS Civil Construction provides a major national contracting capability. Maintenance and construction services are carried out for all civil projects including roading, bridging, earthworks, port facilities, and river and marine protection works. Site and subdivision development, concrete construction and pipeline construction are also undertaken, with special units involved in steel fabrication, construction plant hire and geothermal drilling.

WORKS Property Services
A full range of maintenance management services is provided, designed to keep buildings and associated facilities functioning and in proper repair.

Engineering capabilities include electrical, mechanical, environmental, security and public health, with a wide range of trades to cater for light construction, refurbishment, landscaping and maintenance work.

For further information on WORKS’ services contact:
Business Development Manager,
Works & Development Services Corporation,
Box 12-041, Wellington (Tel. 04/496-1300)

or any of WORKS branches nationwide.

REUNITED!

Wairoa (17 Dec) The two halves of this North Island township were finally joined today after a “separation” of 21 months when the new bridge across the Wairoa River was re-opened to road traffic.

A traditional Maori blessing was given to the new bridge as locals lined the riverbanks.

James White & Associates

WORKS

Works and Development Services Corporation (NZ) Ltd