• Design included large open spaces and curved walls.
  • Key bracing walls were limited.
  • Heavy stone wall cladding needed to consider seismic and high wind loads.

Challenges met:

  • Slender steel portal frames were incorporated in the building fabric.
  • This provided lateral bracing to support the roof over large open spaces.
  • Reinforced masonry with specific engineering design foundations stabilised the wall cladding.

4-Storey Terrace Housing Development


  • Wall bracing for large open spaces.
  • Steel transferring beam under IT wall.
  • Multi-step basement with limited height.
  • Steep excavation 1.5m from neighbour’s 3-storey reinforced concrete building.

Challenges met:

  • 1/2 steel portal design to hide steel portal leg inside timber wall frame.
  • Composite section capacity design reduced size of steel floor beam.
  • Temp. reinforced concrete propping wall.

Originally constructed approximately 100 years ago, this former industrial building is one of only a few brick structures remaining in Christchurch. Our client saw the potential of the building and made the decision to retain the original structure, provide strengthening and a new office fit-out. EDC provided a new steel framework within the building that not only strengthens the building well over 67%NBS but enhances the industrial look of the building.

Working with buildings of this vintage is always challenging as invariably there is no record of the construction.  Given that the existing structure is not necessarily square and true to begin with, enhancing old building materials up to modern standards is complicated, by establishing a strong relationship with the client and contractor we were able to keep construction progressing through all setbacks.

Although not an old building, this warehouse was constructed with lightly reinforced precast panel walls. After identifying concerns with the panels, EDC provided a strengthening design to bring the building close to 100% NBS. Working closely with the contractor, we were able to provide a new internal steel frame that could be installed whilst the warehouse remained fully operational.

The building code has moved quickly in a short space of time meaning that some reasonably new buildings can have low seismic strength.  We had a great dialog with the building owner and were able to discuss any technical issues.  A key requirement was that our design had to be carried out during the standard working day, around the tenants’ business activities.  To enable this we minimised site welding to eliminate fire risk and kept member sizes small.



This multi-unit residential development consists of 8 two-bedroom social housing units. With difficult ground conditions and a tight site, a collaborative approach from the Geotechnical, Structural and Civil teams enabled us to be proactive in addressing a variety of construction issues.

These issues were often identified during inspections and working collaboratively enabled us to discuss the issues in-house and provide immediate feedback and design changes to implement onsite.

EDC were engaged to complete the structural design for a new public storage facility located on a greenfield site. The main features of the facility were a lower level storage area formed by cutting into the existing natural slope and a three-storey office facility fronting the building.

To develop a cost effective solution for both the low-level structure and the three-storey facility at the front of the site.

Challenges Met:
The engineering aspects of the work was relatively straightforward however it was necessary to work closely with the architect and the proposed contractor to develop effective and build-able solutions that satisfied the clients requirements.

EDC were engaged to provide a structural solution for the alteration, extension and remediation repairs to an existing Auckland CBD 10th storey penthouse.


  •  Limited access – via a lift.
  • The need to use all lightweight materials as much as possible.
  • An existing membrane to the deck that was leaking.
  • Having to incorporate the new structure within the confines of the existing penthouse.

Challenges Met:
Whilst calculations provide a lot of answers to the problems in the situation, EDC provided a solution consisting of composite/steel portal frames that could be brought up in the lift and fabricated on the rooftop relatively simply.

EDC help a flying house take off.

EDC Christchurch was charged with the earthquake repair design for this house located on Kahu Road next to the Riccarton Bush Reserve. This house is regarded by many a landmark around the neighbourhood, due to its Hanmer marble wall cladding and garden walls. As part of the repair process, the ground storey is to be demolished and re-constructed and therefore the top storey had to be lifted up, removed and temporarily stored before it will be put back on the new ground floor later this year. EDC specified temporary strengthening to ensure the upper storey structure could withstand the lift. Structural engineers Sam Polson and Tony Dong observed intently and with the help of some calm weather, an expert team of house lifters and millions of dollars’ worth of construction plant, the lift was completed successfully.

Multi-level dwelling on a steep site which overlooks Redcliffs. Constructed from combination of timber and masonry.  The house was badly damaged as a result of the Canterbury earthquakes. EDC initially inspected in June 2012 to view the damage.

Global movement of the dwelling and earthquake shaking caused severe lining damage, tilt of the building, floor settlement and voiding beneath the floors, damage to the waterproofing which led to leaking of the integral retaining walls and damage to retaining walls across the site.

EDC designed repairs in 2014, which included, among other things, breaking out areas of floor in the kitchen and garage and excavating behind the retaining walls to repair the drainage. These works were extensive and difficult given the digger had to sit within the room.  Jim The Builder carried out the works.

The new Piko Wholefoods premises sits on the same CBD site as the original building – which was demolished after the earthquakes. The new design respectfully incorporates the original concrete frame, which played a key role in saving lives.

The new building is constructed of laminated timber columns and beams with steel cross bracing, exposed at street level through fully glazed elevations.

The use of timber frame construction as the major structural element presented a challenge for the ground floor of the adjacent building, with regards to fire rating the party wall at the first floor level.

EDC’s engineering design played an integral role in Piko Wholefoods selection as a category finalist in the 2017 Timber NZ Wood Design Awards.

YSL merchandising stand at Farmers Albany


  • Easily seen overhead signage to accommodate busy foot traffic.
  • Bracing hidden within the design.
  • Visual design to not dominate products.

Challenges met:

  • Interlinked diagonal & shear connection bracing hidden within the design.
  • Polished steel frame supporting signage.
  • Bracing non obtrusive to customers.

EDC provided Geotechnical and Structural design of three two-storey architecturally designed homes on a 600 m2 site.


Large open plan areas at the ground floor limited the available space for the structural elements, which was further complicated by varied roof heights, roof overhangs and the addition of louvres.

Challenges met:

  • Providing geotechnical and structural disciplines in-house allowed an optimized yet resilient design for the foundations consisting of a suspended slab on piles.
  • Within the superstructure steel portal frames and beams allowed the clean architectural look to be maintained.

Architecturally Designed Lifestyle Block


  • Large open spaces with vaulted ceilings.
  • High wind zone with limited key bracing walls.
  • Cut-and-fill site adjacent to flood plane.

Challenges met:

  • Steel frame supports open plan living.
  • Alternative timber solution used for exposed glulam beams and trusses.
  • Rib-raft concrete foundation over cut-and-fill site to minimise potential differential settlement.

EDC provided geotechnical and structural engineering services for the temporary housing to assist flood affected residents in Whakatane. The development consisted of 20 temporary cabin structures based at the Whakatane Holiday Park.

With the clock ticking, and accommodation urgently needed for those displaced by the floods, our Whakatane based geotechnical team swung into action and carried out the site works to confirm the ground conditions and provide recommendation on foundation design. With the baton passed, our structural engineers designed a cheap and simple to construct timber foundation that could resist the very high lateral spreading expected at the site, and accept the new portable units. Complex ground conditions need quality design solutions. EDC geotechnical and structural engineers worked together to develop a great solution under immense time pressure.

EDC’s geotechnical assessment highlighted this site to be on soils prone to liquefaction. Owing to the significant depth to non-liquefiable soils, and with guidance from EDC, the client opted to mitigate the liquefaction risk to foundations using deep stone column ground improvement. EDC’s geotechnical team provided ground improvement design and added value through assisting with contractor selection. A contractor with a low-vibration column installation method was chosen, avoiding the potential for damage and concern at neighbouring properties. Installation works were supervised and validated by EDC, to the regulator’s satisfaction, using CPT’s and seismic cross hole testing.

Synergy was provided through EDC also undertaking structural design, providing a robust but economical foundation and superstructure design.

  • Structural: Koru House, Tawharanui


  • Structural: Durham Street, Christchurch

  • Structural: Magdala Place, Christchurch

  • Structural: Armagh Street, Christchurch

  • Structural : Safe Store, Westgate

  • Structural - Hobson Street, Penthouse, Auckland

  • Structural: Kahu Road, Christchurch - Stage 1

  • Structural: Redcliffs, Christchurch

  • Structural: Piko Wholefoods

  • Structural: Farmers YSL stand

  • Structural: Merivale, Christchurch

  • Structural: Robinson Road, Coatesville

  • Temporary Housing - Whakatane

  • Structural: BestStart, Barrington, Christchurch