Environmentally friendly




Environmentally friendly

mageba Lead Rubber Bearings (LRBs) are being used to seismically isolate the anaerobic digester at a modern food and green waste treatment facility in California, greatly reducing waste brought to landfill sites and producing valuable biogas and fertilizer
At mageba, we are always striving to protect the environment, e.g. by improving efficiencies and reducing waste in all company activities. Perhaps most significantly, we do it by maximizing the quality and durability of our products, which minimizes impacts on the environment – and on structure owners and users – from avoidable product replacement works. It is therefore especially pleasing to have the opportunity to contribute to the construction of a modern facility that has the primary purpose of reducing landfill and converting waste into energy.

For many years, California has been leading the way in working towards a cleaner future – not only in the USA, but also in an international context. For instance, the 75 Percent Initiative, launched by California in 2011, sets out the state’s declared goal of achieving a 75% reduction in total waste by the year 2020 – primarily by waste reduction at source, recycling, and composting / dry anaerobic digestion. The last of these approaches involves minimizing the amount of biological waste sent to landfill sites, instead anaerobically treating it at specially built facilities. This significantly reduces greenhouse gas emissions, which are given off as biological waste in a landfill site decomposes naturally.

In the Californian town of San Luis Obispo, halfway between Los Angeles and San Jose (home to mageba USA’s west coast office), a modern food and green waste treatment facility is being built. The facility, which is to be commissioned in the summer of 2018, will considerably reduce the volume of green waste sent to landfill, in the process producing renewable biogas fuel and high-grade fertilizer. The facility’s key element, its anaerobic digester, must be protected against earthquakes, and this is being achieved by seismically isolating the structure from the ground. To this end, the structure will be supported by LASTO®LRB isolators, 52 in total, each designed for a design displacement of 60 mm (2.4 inches), a vertical load of 5,000 kN (1,124 kips), and a horizontal load of 1,057 kN (238 kips) at the design displacement. The elastomeric bearings have a diameter of 800 mm (31.5 inches), and a lead core of diameter 260 mm (10.3 inches) which is suitable for the target natural frequency and provides energy dissipation. They are designed and fabricated for an operating temperature of -15 to 40 °C (5 to 104 °F).

The performance of the isolators was verified prior to use by comprehensive laboratory testing. Full “type testing” was carried out on two prototypes, and factory production control (FPC) testing was carried out on all 52 isolators prior to delivery to site. As a result, these high-quality bearings can be expected to serve a long, maintenance-free life, minimizing environmental impacts from repair and replacement – a very appropriate benefit for this particular facility.


Representation of the anaerobic digester, which is being seismically isolated from ground movements by 52 LASTO®LRB bearings


Packing of LASTO®LRB bearings for transport to site


Transport of the LRBs to site in California – carefully packed to prevent damage of any sort


View of the LRBs following installation to support the anaerobic digester


Construction of the anaerobic digester on top of the installed LRBs