Triple Top Performance Just in Time

The rearrangement of the Roche Lot in Basel has been proceeding for more than ten years The Swiss pharmaceutical company F. Hoffmann-La Roche AG is restructuring the area of its production and research capacities at its traditional headquarters. With new administration and laboratory buildings at the spacious inner-city area, e.g. more than 4,900 modern working places will be created for international employees and jobholders which are currently working in different locations all over Basel.

To obtain this target the building density of the area situated directly at the banks of the river Rhine will be further increased and grow in height: Already in the end of 2015, the 178 m high Roche skyscraper (Building 1) was occupied. Currently, the 205 m high “Building 2” is being built, and almost simultaneously the new pRED research and development centre with four integrated office/laboratory buildings in various heights is built at its feet.

 Due to the inner-city location with limited access, the direct vicinity to residential areas, and the sustainability of the building processes that is consistently pursued by the building owners, building site and material logistics represent one of the biggest challenges for the executing companies. To reduce the traffic burden of tightly scheduled deliveries right from the beginning and based on the positive experience gained at the first Roche skyscraper (in total 55,000 m³ concrete volume), the concrete production for the two currently ongoing new projects was tendered out for mixing plants directly on the building site. Both the consortium ARGE Baumeister pRED of Frutiger AG and Anliker AG responsible for the four-section building complex and the company Marti AG in charge of building the Roche skyscraper opted for the container-mobile system technology offered by the Austrian specialist SBM Mineral Processing.

 

The positioning of the fully integrated SBM concrete mixing plants, their integration in the just-in-time raw material logistics system, and the appropriate supplying and conveying of the concrete quantities produced were meticulously considered in the project planning. Apart from the space-saving and ramp-free installation and the efficient feeding of the aggregates and cement silos, the responsible managers also profit from the flexible concrete discharge to concrete pump, crane bucket or mixer truck. Due to plant capacities comparable to stationary technology and modern control engineering, even large daily charges or very specific formulas are no problem at all. Heating systems for aggregates and water ensure easy and trouble-free operation in winter, too.

Double capacity in a very confined space

Since June 2019, the consortium ARGE Baumeister pRED of Frutiger AG and Anliker AG has been constructing the shells of the new pRED research and development centre (Pharma Research and Early Development). The ensemble of four tiered buildings (114 m, 72 m, 28 m, and 16 m high) has a shared underground carpark as a foundation and offers a total building volume of slightly above 600,000 m³. The consortium opted for two VARIOMIX^® 2000 CM 200 V with 200 m³ aggregate storage each, 82-t respectively 182-t cement silos (thanks to integrated additional silos) divided in 4 chambers, and a nominal capacity of the 2-m³/h planetary mixer of 80m³/h to provide the required some 100,000 m³ hardened concrete. In summer 2019, the new plants consisting of in each case 3 trailer-suitable container modules were delivered directly ex works SBM and placed in very confined spaces at the northern respectively southern edge of the pRED site (space required ca. 30 x 5 m). Concrete distribution is carried out via integrated buffer batch silos and a connected concrete pump per plant, by four distributors on the construction site as well as by crane buckets.

According to Frutiger Project Manager Tristan Michlig, both VARIOMIX^® plants reached their expected performance of 80 m³/h maximum each shortly after their installation and setting in August respectively September 2019. In single operation, the first plant provided more than 5,000 m³ hardened concrete already in the first four weeks– the joint daily top output comes to about 1,100 m³. In addition to the avoided traffic burden of the alternative 7.5 m³/10 m³ large mixer trucks, Tristan Michlig also appreciates the high flexibility to quickly produce special charges beyond the 2 to 3 standard formulas respectively the independence from the operating hours of the closest concrete suppliers some 10 km away. At the turn of the year 20/21, the ARGE team had already completed more than 80 % of the shell volume –the first VARIOMIX^® 2000 will leave the building site presumably in March/April, the second plant will stay on site till the projected end of the shell construction in August 2021.

Important jigsaw piece to ensure success

In December 2020, Marti AG completed the shell construction of the 50-floor ”Building 2“ two months ahead of schedule with the symbolic ”last concrete”. In the presence of the Roche building owners the construction team consisting of Marti Basel and Marti Zurich, that had already constructed “Building 1“ in the immediate vicinity, could once again celebrate the highest building in Switzerland in 205 m height. Foreman Toni Würsch called the contribution of the concrete plant deployed “an important jigsaw piece to ensure success”. In about 18 months shell building time the ten-year old plant VARIOMIX^® 1750 CM 170 V from the Marti inventory handled a total volume of about 45,000 m³ hardened concrete. Equipped with a 170 m³ aggregate storage, integrated cement silos (60 t/30 t), a 1.75 m³/h planetary mixer, multi-grade admixture facility and concrete discharge to mixer truck/crane bucket/concrete pump, the plant - that was taken over from the Doubrava programme by SBM Mineral Processing in 2013 - with its modular, container-mobile design is largely like the current VARIOMIX^® technology. Thus, this plant clearly shows the long-term profitability of SBM’s mobile concept.

The plant in Basel provided up to 500 m³ hardened concrete per day. Both the massive base plate (13,000 t steel/5,600 m³ concrete) and the 50 floors gradually tapering upwards were concreted up to the end height by means of a strong concrete pump and a central concrete spreader. Even the specifically required concrete mix including superplasticizer and a high proportion of fine sands was produced on the site. In total, more than 30 percent of the necessary material transports could be saved due to producing concrete directly on the site, says foreman Toni Würsch.

Technology with prospects

The Swiss Marti Group alone holds more than 20 mobile and displaceable concrete plants – 8 of them from SBM. With its manifold international activities in building construction, (special) civil engineering, engineering construction, and tunnelling, Marti Group is an important reference for the current SBM concrete technology. Apart from the flexible usability thanks to numerous expansion possibilities, especially the excellent mobility of the VARIOMIX^® and MINIMIX^® plants has been ensuring the big success of the quickly displaceable SBM plants in the Swiss market. All individual modules have practice-oriented dimensions (transport width max. 3,48 m). On the site the ready-for-use cabled and piped plant components can be easily and quickly installed on mobile foundations by one-crane-assembly in one day, or two days maximum.

Depending on the equipment, the series VARIOMIX plants reach an hourly output of up to 80 m³ hardened concrete. Due to modern control systems and high-precision dosing devices they easily keep up with stationary mixing plants as far as product diversity and quality are concerned, explains SBM sales expert Ing. Helmuth Neubacher. “With more than 40 VARIOMIX^® plants we are the market leader in Switzerland, and it is obvious that our mobile technology has gained an international footing,“ says Neubacher. Higher flexibility on the site shortens construction times by up to 10 percent, and no longer required concrete deliveries to the building site do not only help urban areas, but they also generally result in a better environmental balance – especially concerning the sensitive CO₂ issue.