Published on: August 13, 2010

ÅF – Hansen & Henneberg sent us images of a project they did for Danish Road Directorate. It is a lighting design for a Motorway Bridge with the aim of increasing the security of the vehicular traffic below.

A thorough description of the project by ÅFHH follows:

—

Introduction

The two motorway bridges in question had been identified as an accident black spot. In re-cent years a number of accidents had occurred in the immediate vicinity of both bridges in-cluding a collision with the railway bridge. The bridge’s V-shaped columns create a highly unfortunate and narrow gate-like impression as the columns are positioned very close to the road and lean forward over it. Accidents could have been avoided if the narrowing road sec-tion under the bridge had been more clearly and suitably illuminated.

An assessment was made of the bridge’s illumination – the conclusion being that a standard road lighting would not provide illumination sufficient to overcome the complexities pre-sented by the bridge’s construction. It was further decided that, in order to prevent illumina-tion of the railway bridge creating too great a contrast and thus further problems for the road bridge to the west, it would be necessary to come up with a solution which incorporated the illumination of both bridges.

In keeping with the principles of the Danish Road Directorate’s handbook ”Smukke Veje” (Beautiful Roads) which proscribes that roads should, where possible, sit comfortably with the surrounding landscape, the illumination creates a recognisable and integrated visual im-pression with an unusually aesthetic quality.

The lighting concept

The area’s illumination has thus a dual purpose: creating a clearly marked and safe section of roadway and providing original aesthetically pleasing lighting and a unique experience for the motorist.

The concept addresses both these requirements at the same time as transforming the ”black holes” under the bridges into visible and inviting portals, ensuring safe passage and creating a local landmark in an area which, at night, is normally unremarkable.

The concept builds on the notion of the ”soft” surrounding countryside and transfers these features of the landscape to the ”hard” motorway environment, creating a human version of a fauna tunnel / passage.

The lighting for the bridges is designed to link them, using clearly-identifiable common fea-tures, and to highlight unique features so as to create a night-time impression of each bridge particular to the bridge in question.

The lighting design

Two different types of lighting are used. The first type uses chiaroscuro (the interplay be-tween light and shadow) to create contours on edge beams facing oncoming traffic. The sec-ond type, ”atmospheric lighting”, illuminates the bridges’ supporting columns with coloured light.

The bridges’ edge beams are illuminated using gobo projectors (projectors, that give of light in a particular pattern) equipped with standard metal halide lamps. The gobo projectors are attached to poles at the edge of the motorway and in the central reservation. Coloured at-mospheric light illuminates the column’s fronts and in between the columns using linear LED luminaires.

The lights used are thus suitable for inclusion in the Danish Road Directorate’s standard maintenance program.

The railway bridge

Gobo lighting

The gobo lighting consists of fir tree patterns characteristic of the trees in the surrounding area. Chiaroscuro is thus used to create a unified impression that refers both to the surround-ing plant life and landscape.

At the same time the gobo lighting frames the bridge’s form clearly, creating an innovative visual impression with clear associations to a wood in which pine needles are framed against the dark night sky.

The light is shielded and ”cut”, so that it only falls on the bridge’s edge beams. In this way unwanted spill light is avoided providing clarity for both motorists and train drivers.

Atmospheric illumination

Atmospheric light is created by using greenish light to illuminate the areas in-between the V-formed bridge columns. This green colour creates an inviting atmosphere and provides a further connection to the surrounding countryside – as well as strengthening the impression of a passage.

When passing under the bridge the play of light and shadow between the columns recalls the patterns of light and shadow between tree trunks.

The road bridge

Gobo lighting

The gobo lighting along the bridge’s edge beams features projections of the characteristic graphical contours of foliage.

This form of illumination also serves to precisely frame the bridge’s shape. The light’s organic forms and the fine interrelation between light and shadow, create an impression of passing under trees’ foliage or traversing a path bordered by trellis-work.

Atmospheric illumination

The bridge’s columns are illuminated with green light which helps create a link between the two bridges. The colour was selected in order to create a friendly and inviting atmosphere, and the vertical illumination of the columns underscores the visual impression of trunks sup-porting a leafy canopy.

Implementation

Gobo projectors are mounted on poles in the central reservation and hard shoulder. The beams of light they generate are angled in a similar way to that used to illuminate road signs.

Linear LED luminaires are affixed to the bridge ceiling near the columns which they illumi-nate.

The project was nominated for / won several awards listed below:

• DEN DANSKE LYSPRIS 2009 (Danish Lighting Award) – 2. Place
• IALD 2010 ”AWARD OF EXCELLENCE”
• LUMIVILLE 2010 – 1. Place ”ESCAPE PUBLIC”