BUILDING BRIDGES.

A new link spanning the Sound between Sweden and Denmark unites the countries economically and culturally and connects southern Scandinavia to central Europe.

The official opening in July this year of the Oresund link joining Sweden to Denmark will be momentous. For while signifying the end of Sweden's (and Norway's) isolation from the rest of Europe, it will unite two metropolitan areas -- Malmo in the east, and Copenhagen in the west, each with a rich cultural life -- and establish the Oresund Region as an industrial entity capable of growth and attracting investment. The concentration of IT research, biomedical and pharmaceutical industries in the region is already formidable with the potential of becoming internationally pre-eminent.

Measuring about 16km in extent, the new link is part of a system of others either completed or planned in and around Danish waters connecting the road and rail systems of Sweden and Norway with central Europe. No-one of course quite knows the psychological, political and economic implications of this. Developments under way on each side of the Oresund link, and the steady growth of a dynamic modern business centre may constitute a powerful attraction for southern Europe.

On the Swedish side, an adventurous housing exhibition will be opened next spring. Entitled Bo01 The City of Tomorrow, it will consist of a new residential district of 600-700 dwellings constructed in Vastra Hammen (the western docks) of Malmo. These are being designed by internationally known architects such as Santiago Calatrava and Ralph Erskine, as well as younger Danish and Swedish practices.

In Denmark, the new town of Orestad (AR June 1995) is taking ambitious shape to the west of Copenhagen airport. This town, billed as the 'city of the future', is being built to serve what may be the most powerful new cultural and business centre in northern Europe. At a simpler level, young Danes, attracted by lower house prices and cost of living, are starting to settle in Sweden and commuting to Copenhagen.

Environmentally, the Oresund scheme presented problems because obstructions in the Danish straits can damage the fragile ecosystem of the Baltic sea. Once an inland lake, the Baltic is the world's largest body of brackish water with a unique marine life, in which species normally associated with fresh or salt water live side by side, and are dependent on intermittent influxes of saline and oxygen rich water from the open seas into the sea's deeper waters. Waters flowing through the Sound are an important part of the system and the link had to obstruct the exchange of water as little as possible. [*] And it had to respect the tranquillity of the bird sanctuary at Saltholm, an island about halfway across the Sound (to which cattle are still ferried by boat to summer pastures). The link is a toll-funded motorway and railway, made up of several parts joined into one smooth whole. On the Danish side, proximity to Copenhagen airport made a bridge undesirable. Instead, the link begins at an artificial peninsula off the island of Amager, south of Copenhagen, where a concrete tunnel slips under the sea and emerges at the new island of Peberholm halfway across the Sound and south of Saltholm. By degrees, the tunnel (which accommodates motorway and railway side by side), turns into a double-decker bridge with cars above and trains beneath and from a distance it looks as though the structure has emerged from a hole in the sea. Measuring about 8km in total, the bridge describes a slow curve across the sea; at the same time it rises gradually to a central cable-stayed bridge over the big international shipping lane, Flintrannan, before descending to Lernacken and the Swedish coast. (Here the railway carries on through a tunnel.)

The gentle swell of the great curves and the lack of dramatic abutments, relates to the wide sea and the rolling landscape on either side. Standing in the middle of the bridge on a misty day, when land, sea and sky become fused and there is only structure disappearing into nothing, is an extraordinary experience of transience.

(*.) The oresund Bridge paper no 990890 by Klaus Falbe-Hansen, Ove Arup & Partners.