BREAD & BUTTER for Eberhard

Your average city centre development site isn’t where you would expect to find a 100 tonne Caterpillar excavator working. But when you visit downtown Zurich and the region’s premier multi-disciplinarians Eberhard, nothing is out of the question!

The University Hospital of Zurich (USZ) was founded in 1833 and is one of five similar centres in Switzerland. In one form or another, the USZ location was always a site for hospitals, with the first one erected 800 years ago. Remodelled and redeveloped over the years, the hospital is currently undergoing further works to enhance the treatment centres within the organisation.

Working together with another of Switzerland’s foremost construction companies, Marti, Eberhard are currently part way through the excavation for a new, huge eight storey basement complex which will provide space for a new emergency centre, over 300 beds and 23 operating theaters. The site had already been cleared of existing structures prior to Eberhard’s commencement on site. With works starting at a pace, Marti Spezialtiefbau installed over 4km of bored piles to ensure the existing structures and the ground they sat on remained stable. As the site is on a slope, Eberhard carefully designed their operations to use the point at which the site is level with Gloriastrasse to allow for easy access for vehicles to and from site.

With over 180,000m3 of material to be removed from the site to allow the construction works to take place, the company has employed some of the largest machinery in their fleet. Of the 180,000m3 of material to be extracted, over 50% is made up of sandstone layers of varying hardness. The first layers were extracted using buckets and ripper attachments on the company’s CAT excavators but as the dig deepens, the material gradually gets harder and the team on site led by Philipp Kast has had to resort to adding several Rammer hammers into the mix.

Eberhard has been a strong advocate of the Rammer brand since 1983 liking the tool’s build quality and robustness which is ideal for their business. Sold and serviced through their Caterpillar dealer Avesco AG, the Rammer hydraulic hammers are said to be more expensive to purchase than other similar brands but provide much higher levels of productivity and availability and also offer the ability to be rebuilt at a lower cost. ‘These are not throwaway units unlike some cheaper brands.’ Philipp comments. ‘They are very well made and offer our crews a tool they know will work each and every time on any material.’

The company is currently using 47 Rammer hammers of varying sizes in its mixed CAT fleet all of which have been modified to suit OilQuick headstocks allowing the safe and rapid swapping of hammer to buckets to remove the material. Working close to the piled wall is one of Eberhard’s CAT 330F excavators with a 2.35t 3288E hammer. The existing bedrock slabs still remaining between the cored piles were proving difficult to remove just with an excavator and ripper/bucket combination, so with the Rammer on the end of the stick, the remaining fragments of material could easily be cleared away. The gap between the anchored cored piles was ongoing filled with shotcrete.

They are very well made and offer our crews a tool they know will work each and every time on any material...

A second CAT excavator, this time a Next Gen 352 was also using one of the extensive Rammer fleet Eberhard possesses, this time it was a 4.8 tonne 5011E. At over 3.3m in height and carrying a 190mm diameter tool, the 5011E can give up to 620 blows per minute when in short stroke mode.

Whilst these two excavators take care of some of the tighter spots on the site, the bulk of the excavation work has been undertaken by a huge, 100 tonne CAT 390F excavator. Usually sporting a one-of-a-kind VA-boom, the excavator has been converted back into its original form at Eberhard’s extensive workshop facility just a few miles away. ‘We are able to swap and change arms and sticks around to suit our particular site or job applications.’ Björn Reiser commented. ‘When the 390F was called upon for this project it was a relatively simple and straightforward job to remove the VA-boom and replace it with the original mass excavation configuration.

Once out on site, the big CAT was quickly placed into the hardest material using a variety of attachments. Like all Eberhard excavators, the CAT 390F’s short stick was fitted with an OilQuick coupler, a huge OQ120, and was able to quickly change the ripper tooth, bucket and 7.5t Rammer 9033E hammer over in seconds. Delivering up to 645 blows per minute, the hammer easily dealt with the harder sandstone material on site. Working in close proximity to the hospital and other residential and commercial buildings meant the low noise emissions from the Rammer hammers meant the public were not disturbed too much during the excavation works.

From the excavation’s highest point, the Eberhard team will need to dig down over 23m through the gradually hardening material before the basement slabs can be cast. Working in the relative confines of the city centre means the material which is excavated also needs to

"We are able to swap and change arms and sticks around to suit our par ticular site or job applications...

be removed from site in a safe and considered manner. Between 1100m3 and 1200m3 of material will leave the site every day during the peak of the excavation works. Most of this material will be loaded by another Next Gen CAT, another 330. With a simple and effective traffic management plan in place, trucks enter the site before dropping down to a loading area where the material is placed in the tipper bodies in around 5 passes. The trucks then carry on around through the internal road before passing over a wheel wash where any mud is diligently washed off to ensure the Zurich streets are kept clean.

During our visit the wet weather had kept dust down but as the drier weather approached, the site teams had plans to introduce dust suppression methods around the excavation works.

As the operation worked its way towards the adjacent street, more Eberhard machinery was being employed to install additional drainage systems around the works. A CAT M318 wheeled excavator was being utilised to excavate for a new sewer connection. Using OilQuick technology again, but this time in the shape of an OQTR E19 tiltrotator. This highly specified machine follows the company’s mantra of supplying machines capable of undertaking a variety of work and whilst it was using the Scandi-style bucket to excavate the top layers of sandy material, even this machine had its own dedicated Rammer 1533E hammer waiting in the wings.

The scope of works being undertaken by the Eberhard team at USZ is testament to what a contractor is capable of undertaking when faced with a complicated task. Unlike many countries where the different levels of management and bureaucracy stifle the contractor undertaking the work, collaborative working to achieve an end goal is allowing Eberhard to deliver contracts many countries would find daunting.