SEISMIC BASE ISOLATION

Minimising Earthquake Damage

Meccanico retro-fits commercial and industrial infrastructure to incorporate seismic base isolation. We are unique in New Zealand – providing a complete service from heavy lifting, to foundations and levelling. Meccanico lifts the building or structure, mounts base isolators, then lowers the structure onto the seismic bearings; isolating (decoupling) it from the ground.

Protecting People & Property

Seismic base isolators minimise earthquake damage by reducing seismic energy transferred to the building or structure from the foundations. This greatly increases the probability that occupants are unharmed, structural integrity is retained and the building/structure remains operational. An added benefit of installing seismic base isolators is increased property value.

Museum of New Zealand, Te Papa Tongarewa

Seismic base isolation is commonly used for medium-rise masonry (stone or brick) and reinforced concrete structures. Notable buildings in New Zealand employing base isolation technology include Te Papa, Parliament House, and the William Clayton building in Wellington, and Christchurch Women’s Hospital – which remained fully operational after the February 2011 earthquakes.

Elastomeric & Sliding Base Isolation

Both types of base isolation take the weight of the building/structure, dissipate seismic forces and allow foundations to move horizontally during an earthquake. Base isolators used in New Zealand include elastomeric bearings, modular sliding bearings e.g. friction pendulums (curved/spherical sliding bearings), and flat sliding bearings.

Lead Rubber Bearings (LRB): Invented by New Zealander, Bill Robinson, lead rubber bearings have a lead core which converts seismic (kinetic) energy into heat energy during an earthquake. The lead softens, then reverts to its original shape and can do so many times without losing strength. Rubber provides flexibility – enabling the base isolators (bearings) to very gradually return the building or structure to its original position. Layers of steel allow the bearings to move horizontally during an earthquake, whilst restricting vertical movement.

How do base isolators work?

Unique Heavy Lifting System

Meccanico’s hydraulic-controlled Modular Synchronised Positioning System is the only one of its kind in New Zealand. Custom-designed and built in Holland, it is extremely precise, spreads loads evenly around the full system and provides synchronised pressure. Crucially, the speed of our heavy lifts lowers the cost of retro-fitting seismic base isolators.

Safer lifts: To achieve safe, even weight distribution throughout every stage of the lift, before performing the lift our lifting system weighs the building/structure to determine the COG (Centre of Gravity). We then place multiple, heavy duty hydraulic pump units around the building, bridge or structure. Distances from the pumps to lifting points are kept equal and to a minimum, creating a much more efficient, safer lifting and lowering action, and significantly less vibrations (as compared to most heavy lifting companies’ systems, which work with just one very large pump unit and extremely long hoses).

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Structural & Earthquake Strengthening

Meccanico can also provide structural remediation and strengthening to meet compliance requirements and improve seismic performance. This can include earthquake strengthening for buildings classified as Earthquake-prone, and unreinforced masonry buildings (URM) – especially important in at-risk regions of New Zealand, such as Christchurch and Wellington. Learn more