From a gasworks site to the city district
From a gasworks site to the city district

From a gasworks site to the city district

A new urban quarter is planned for the site of the former Sandrain gas­works in Bern. The level of soil pollution clearly reflects the effects of 90 years of gas pro­duction. Marti’s consor­tium ensures that the contam­inated soil is properly pre­pared.

From 1876 to 1967, the Sandrain gas­works pro­duced the city gas for Bern. The gas was initially used to light the streets and alleys of the city center. Later, it was also used to power cooking stoves, household heaters, and engines. In 1967, pro­duction came to a stand­still after the city of Bern was connected to the long-distance gas network. The factory was de­commis­sioned shortly thereafter. The site has since been idle and used for cultural pur­poses, storage, and even as a parking lot. In 2020, the City of Bern ac­quired the site in order to use it as building land. Energie Wasser Bern (ewb) has set out to hand over the “ärdeschön” (beauti­ful) site to the people of Bern as its final task.

MARTI RENOVATES

The required reno­vation works started at the end of August 2021. The main manu­facturing building of the gas­works used to be located in the core zone. Marti Infra AG is a specialist in the re­mediation of contam­inated sites and re­sponsible for the planning and over­all concept within the Marti con­sortium. Marti Bern’s special civil engineering de­partment is completing the work on-site: The area was cleared and prepared, the top­soil was removed, and the grading and sur­facing work was per­formed. In addition, sewer and utility lines were rerouted, filtration wells were in­stalled to lower ground­water levels, and a water treat­ment plant was con­structed.

At the beginning of winter 2021, Grund- und Tiefbau AG Solothurn in­stalled the sheet pile walls around the ex­cavation site so that the ground­water within the core zone could be lowered. In order to minimize the noise impact on the sur­rounding properties, they used a specially developed vibrating pile driver equipped with additional sound ab­sorption.

The protective tents were set up on the site in January 2022. Approx­imately 9,000 m² of floor space was en­closed: The renovation peri­meter (core zone) was under a double tent, a sluice, and an inter­mediate storage area. Elaborate exhaust air systems and negative pressure in the tents prevent bad smells and dust emissions from being released into the air.

“Many people don’t even fully appre­ciate how time-con­sum­ing it is to triage such heavily con­tam­inated soils. We’re creating some­thing for the future here, for sustain­ability. That makes us proud, too!”
Joel Kaufmann,
Foreman, Marti AG Bern

Hard Facts

  • Elaborate exhaust air systems and negative pressure in the tents prevent bad smells and dust emissions from being released into the air
  • Excavation is performed in a protective tent under strict safety conditions; approximately 9,000 m² of floor space is enclosed
  • Soil material ranging between 1.5 to 7 m is excavated; pollutants at even greater depths are extracted from the ground with around 800 boreholes, down to a depth of 11.5 m

the stakeholders include

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