Tramdepot Bern Ebe Ndozi Tram

Press Kit

Unique Properties

The external appearance of the hall is characterised by the lightness of the glass-aluminium shell. The use of white glass, the special surface structure and the staggered installation method (halved grid) result in a changing expression depending on the light. In grazing light, the white colour of the glass and the matt shimmer of the surface create a proximity to the bare aluminium sheets, giving the building a three dimensional expression.

Dimensions & Packaging

The extensive glazing in the truss levels of the beams and in the façades also ensures optimum lighting conditions and allows the hall to be operated without a heating system thanks to the solar radiation. To prevent overheating in summer, the SHEV flaps in the lower façade area (supply air) and in the high sheds (exhaust air) can be opened for night-time cooling. Rainwater is directed from the roof into the side gutters via the sloping surfaces of the longitudinal façades, from where it is fed into the washing system. A 3,600 m2 photovoltaic system on the sloping roof surfaces complements the building‘s sustainability claim.

The geometry of the hall results from the operational need for a maximum, column- free parking area. The roofing is supported over the entire length of the hall of around 200 meters by a shed roof structure made of steel trusses with spans of up to 90m (stage 3). A single row of columns separates the parking area from the service area with car wash, wheel processing area and maintenance building. The lifting doors of the front façade with door heights of up to 10m open and close vertically. The inner and outer supports are arranged in a V-shape for longitudinal reinforcement. They form a basic design motif in the structure and rhythm of the façade and thus characterize the overall appearance of the building. The external appearance of the hall is characterized by the lightness of the glass-aluminium shell. The use of white glass, the special surface structure and the staggered installation method result in a changing sculptural expression depending on the light.

Site area: 36,500 m2
Floor space: 15,200 m2
Floor area: 16,000 m2
Number of levels: 1st floor
Length: 202 m
Width: 165 m
Hight: 6 - 17 m
Building volume: approx.165,000 m3

Tags

Engeneering Architecture, Strip-shaped hall, Glass-aluminium shell, Extensible structure, Lightness, Structural system, Translucent façade

Production Technology

The expansion of the streetcar depot was conceived in several stages as early as the 2007 competition. With the expansion of the city‘s streetcar network, a denser timetable and new, longer streetcars, the need for depot capacity increased. Ten years after completion of the first stage, construction work therefore began on the second stage. This consists of expanding the depot from seven to a total of 15 sidings in the direction of Bolligenstrasse. In a third stage - not yet scheduled - an extension of eight workshop tracks is planned.

The extension will increase the span in the stabling area from 45 to 72 meters and in the workshop area from 68 to 95 meters. The considerable span for the column- free extension of the parking area was achieved with the gradual growth of the truss girders, which then function according to the principle of crane jibs. The main forces are absorbed by a middle row of columns, while the façade columns on the shorter span side are transformed from compression members to tension members with the extension.

Design Challenge

For the Bern tram depot, we proposed the principle of an extensible structure for the optimum utilization of the narrow plot with its sharp irregular angles. Here the structural system is sized to allow a step-by-step column-free expansion of the depot.
For the extension, the existing façade facing Bolligenstrasse was demolished and the materials separated and recycled. Temporary steel supports and a wooden wall ensured the functional usability of the hall during the two-year construction period. The upper and lower chords of the shed trusses are connected with steel purlins in the longitudinal direction to form a hall. Ribbed panels made of glulam complement the purlins and form shear-resistant connections with the trusses as stiffening discs. The connection between the upright ribs and the horizontal trapezoidal timber panels was produced in the factory using press-gluing. In order to be able to produce the 250 roof and wall elements as economically as possible, series of around 30 different types were created. The element production is based on a comprehensive 3D model, which was used to plan the serial prefabrication process, from element lists and machine data to loading plans. The large quantities required sophisticated logistics. To save on interim storage, production, transport and assembly were carried out in parallel.

Research

The expansion of the tram depot in three stages was already included in the design for the 2007 competition. This requirement necessitated intensive research and planning efforts. Penzel Valier's planning work therefore began directly with an optimisation process: the track system was condensed, the oblique perimeter was incorporated into the supporting structure and outer form, and the volume of the hall was reduced.
An open dialogue between the client Bernmobil and the general planner accompanied the planning and implementation and ultimately led to the ideal result.

Inspiration

At night, the building is transformed into a light, bright lantern. Inside, the light falls in according to the rhythm of the shed glazing, sometimes directly, sometimes in multiple reflections in the spaces between the schedules, thereby modulating the atmosphere in the hall. The colour scheme in anthracite (graphite coating of the wood) and black (steel) creates a calm background against which the light sets the scene for the parked vehicles.

Project Duration

2008-2011 (1st stage), 2019-2023 (2nd stage)
Bolligenstrasse 58, 3006 Bern

Operation Flow

Tram depot with service and maintenance area, bridge over freeway (1st stage), extension (2nd stage), additional workshop and maintenance facilities (3rd stage)
The expansion of the streetcar depot was conceived in several stages as early as the 2007 competition. With the expansion of the city‘s streetcar network, a denser timetable and new, longer streetcars, the need for depot capacity increased.

Patents

Copyrights belong to Penzel Valier

Image Credits

Images: Dominique Uldry
Video: Dominic Büttner