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Racing against earthquakes

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November 2015

 

An ultra-modern earthquake research center was built from scratch in Messina in Italy within the space of one year. Engineers from Bosch Rexroth coordinated the project. The company designed the overall system and also supplied all the components for the earthquake simulators.

The world over, researchers are investigating ways of protecting people against the effects of earthquakes. Seismic isolators have been identified as a promising outline solution in this context. They cushion the foundations of buildings in the event of a quake – acting rather like the shock absorbers installed in cars. Bruno Fazzari, head of sales at Bosch Rexroth in Italy, explains, “The problem was that the isolators could be tested only in reverse thus far – they are attached to the foundation, and the building is moved by hydraulic pistons.” In reality, it is the ground that moves, not the building. To resolve this issue, researchers at the University of Messina on the island of Sicily hit upon the idea of building an earthquake simulator that allowed the isolators to be tested under realistic conditions at last.

After winning the competitive tender to supply the three test and research systems, the Italian project team of Bosch Rexroth lead by Andrea Palopoli started work immediately because the timetable was very tight. “Bosch Rexroth in Italy signed the contract in June 2014. It stipulated a July 2015 completion date for the laboratory, and training for the researchers in September. It was self-evident that we had a busy year ahead,” recounts Jack Bergmans, a project coach with Bosch Rexroth in the Netherlands who supported the Italian project team.

A pristine green field – but for the huge boulder

Apart from the technical planning, the company was responsible for the overall system as well as for overall site coordination. Fazzari takes up the story, “When we arrived at the construction site we encountered a green field and, occupying the exact location of the laboratory, a massive lump of rock that had to be removed first.” During that same week in June, the experts of Bosch Rexroth together with the university’s academics began, amongst others, to develop the mathematical models for the simulation and to write the software. In August Fazzari’s team placed orders with Italian suppliers to manufacture complex welded individual components. “The vibrating table, which has a lattice top with a surface area of 3.7 x 4.8 meters, called for precise welding. Once it was built, we individually examined around 40 tons of metal sheet welds. Yet, for the stress beam, it was imperative to find a partner capable of handling the enormous dimensions – the component contains 37 tons of steel and is 8.6 meters long, 2.1 meters wide and 1.6 meters high.” Also in August, the hydraulic components were ordered from our colleagues in Germany: hydraulic power pack units, valves and motor pump groups. As Bergmans recalls, “We were doing everything at the same time.” By December, the construction firm had laid the foundations and erected the external and internal walls.

Roof closed just before Christmas

As Christmas approached, the builders were putting the final touches on the roof. “The contract required it to be sealed before the end of 2014, but first we had to lift the vibrating table and stress beam inside. The only feasible route was through the roof, before it closed off.” Bosch Rexroth organized two heavy haulage vehicles to ship the parts from northern Italy to Messina, and a giant crane from Palermo. “The truck carrying the table suffered two flats during the journey, which kept us on tenterhooks until the last moment,” remembers Fazzari. On the night of December 23, guided only by its headlights, the crane finally hoisted the table and stress beam into the building to allow the roof to be closed after the Christmas break. Bergmans adds, “Shortly afterwards Sicily was covered by a layer of snow for the first time in decades. Luckily, the roof had already been sealed by then.”

While the construction works continued in January, the employees of Bosch Rexroth installed the table and beam. In February and March they laid the cabling for the hydraulics and assembled the cooler units and motor/pump groups. The building was completed in the summer and the research laboratory entered service in September. “We remained totally focused on the goal,” remarks Fazzari. “This approach continuously renewed our passion for the project and enabled us to overcome the tight schedule.”

Installing the vibration table. Right: Precision was of the essence when putting the vibration table in place – through the roof. Magnifier

Installing the vibration table. Right: Precision was of the essence when putting the vibration table in place – through the roof.

 
Inspecting the hydraulic power pack built by Rexroth prior to dispatch. Magnifier

Inspecting the hydraulic power pack built by Rexroth prior to dispatch.

The research center was completed in only one year. Magnifier

The research center was completed in only one year.

 
This is how the earthquake simulators work Magnifier

Test bed for seismic insulators

The insulators lie on the so-called vibration table and are pressed against the upper stress beam with variable pressures of up to 2,000 tons. The pressure simulates the weight of the building. Four hydraulic cylinders with maximum piston pressure of two million newtons move the table along the X and Y axes. All in all, the system offers degrees of freedom in six directions of motion.