Project Information

 Design Considerations

Preferred Option

 

EXISTING PEDESTRIAN OVERBRIDGE

  • Built in 1988 by TranzRail
  • Ownership transferred by agreement to WDC on 10 April 2001
  • Bridge is made of timber ramp beams and piles, steel truss bridge beam and supported on concrete columns, and timber decking
  • Main bridge span overstressed
  • Excessive deflections in bridge beam and supporting columns
  • Substandard seismic design capacity
  • Handrails substandard
  • Ramp gradients steeper than 1 in 12
  • Decking decay
  • Delamination of ramp beams
  • Deterioration of timber columns and beams/transoms
  • Top (and bottom?) chord spacers on bridge not fixed
  • Carroll Street ramp not aligned with pedestrian crossing

 

REPLACEMENT BRIDGE DESIGN CONSIDERATIONS

Design constraints

  • The requirement for vertical and horizontal separation from the KiwiRail rail tracks and overhead electrical transmission
  • The bridge centerline alignment to remain the same as the existing alignment to allow retention of the existing bridge piers and to comply with the KiwiRail Deed of Access
  • The need for an additional pier at mid-span to better support live and seismic loads applied to the bridge
  • The need to replace the superstructure, ramps and stairs.
  • The need to retain the skatepark in its present location at least until such time as an alternative, better site is identified, agreed and developed
  • The limited space available for placing and shaping the landings, particularly on the Carroll Street side due to the limited total area owned by WDC (2,263 m2 ) at least half of which is occupied by the skatepark, and the existing occupation (buildings, transmission gantry, etc.) on the Rora Street side.

 

PREFERRED OPTION

General

  • Contemporary, signature structure at pedestrian gateway to Te Kuiti CBD
  • Fully engineered to modern design standards
  • Stairs both sides
  • Uses existing concrete columns
  • Additional central pier beneath main bridge span
  • Total length 249.5m including ground ramps (existing bridge approx. 217m)
  • Intermediate landings at key transition points (pause points)
  • Clear width between handrails of 2067mm
  • Preliminary cost estimate $1.65m (February 2020)
  • NZTA subsidy 73%


Carroll Street landing:

  • Spiral design that references rail turntable
  • Spiral ramp gradient of 1 in 18 maximum (existing ramps at least 1 in 12)
  • Radius of spiral 12.1m to centreline
  • Feature courtyard area with basketball half-court at centre of spiral
  • Low planting to soften edges
  • Coloured concrete footpaths to connect with adjacent courtyard and parking areas
  • Ramp connects to SH3 pedestrian Xing
  • Cycle safety barriers at bridge exit onto Carroll Street

 
Rora Street landing:

  • Ramp entrance/exit already well positioned close to centre of town
  • Good connection with and proximity to the rail station, public toilets, pedestrian crossing and Visitor Information Centre
  • New stairs to be provided to shorten distance
  • Ramp length controlled by the existing KiwiRail electric gantry at the north end of ramp
  • The existing toilet block location in Rora Street is fixed
  • Switch-back ramp needed on Rora Street side to avoid KiwiRail signal cables and fibre-optic cable in rail corridor
  • Ramp gradients on Rora Street side 1 in 12 (similar to present gradients)
  • Existing trees adjacent to ramp to be replaced with low planting to improve visibility and personal safety, and visually connect town centre with bridge and landings


Handrails and lighting:

  • The handrail design is key to achieving the design outcome of spatial openesss.
  • As well as the safety aspects that the handrails and side cladding will provide, the materials used will also be a means of capturing and reflecting the Te Kuiti Town Concept Plan colour pastel.
  • Lighting will be designed to ensure night-time visibilty of the bridge. Foot-lighting and handrail light fittings will be used to accentuate the shape and form of the bridge.