Johs Holt as

Johs. Holt as works within the following areas:

• Bridges
• Offshore structures
• Rehabilitation
• Full scale measurements and structural monitoring

The company

The company was established in 1957 by Johannes Holt, graduated from the Norwegian Institute of Technology in 1939. The main activity from the beginning was design of bridges, but also industrial buildings, houses and swimming pools were part of the activity during the first decades. A milestone in the company’s history was the design of the City Bridge of Stavanger, the first major cable-stayed bridge in Norway, opened in 1979. The design was made in co-operation with Prof. Dr. techn. Arne Selberg, internationally well known for his pioneering works on design and aerodynamics of suspension bridges.

The development of offshore oil production on the Norwegian Continental Shelf began in the early seventies. Johs. Holt as has participated in the development and design of offshore platforms for the North Sea.

In the late eighties the company was engaged by the Public Roads Administration to prepare guidelines for Submerged Floating Tube bridges. Based on these guidelines a conceptual design for crossing the Høgsfjord strait of length approx. 1350m was presented in 1992. Since then Johs. Holt as has assisted the Bridge Division of the Road Authorities in development and updating of rules for design and construction of road bridges.

The beginning of the nineties introduced a prosperous period in bridge building in Norway. A second milestone in the company`s history took place with the opening of the Skarnsundet cable-stayed bridge in 1991. The main span of 530 m was the longest cable-stayed span in the world, and is still the longest for a span entirely in concrete. The bridge is very slender, with a horizontal slenderness ratio: Main span/width of bridge deck = 40,8. The bridge has received several awards, among them the prestigious FIP Award of Outstanding Structures 1994.

Another remarkable project is the Bergsøysundet floating bridge, opened in 1992. The 845 m long tubular truss girder is supported by 7 separate pontoons. The bridge is horizontally curved. Wind and current forces are transmitted by arch action to the abutments, either side. At the opening it was the longest floating bridge in the world without anchorages to the sea bottom.

Johs. Holt as has performed the detail design and the construction engineering of the Uddevalla bridge in Sweden. The bridge has a total length of 1712 m of which the central cable-stayed part is 772 m. The bridge carries 4 lanes, and the main span over the navigation channel is 414 m. The main contractor, SKANSKA AB, was awarded the design-build contract in January 1997 on an alternative design proposed by Johs. Holt as.

Johs. Holt as also works with multidiscipline railway and traffic projects involving co-operation with architects, transportation planning consultants and other specialized firms. Examples are the Granfoss-line project including road tunnels and the Gardermoen-Eidsvold railway line including the Eidsvold railway station.

Personnell and equipment

The company has a staff of well-qualified engineers, some of them with more than 40 years experience. Each project is approached with an open mind in order to find the best solution for the client. This enables us to perform engineering services of high standard. Several bridge analysis programs are used in the office. Quality control of work is made in accordance with the ISO 9001 requirements.

Some reference projects, major Bridges

Skarnsundet Bridge, Nord-Trøndelag
Cable stayed bridge of length 1010 m. The main span has a length of 530 m and was, when completed in 1991, the longest span in the world for this type of bridges. The bridge has received several awards, among them the FIP (Fédération Internationale de la Précontrainte) Award for Outstanding Structures 1994.

Uddevalla bridge, Sweden
High level bridge of total 1712 m. The central cable-stayed part of the bridge has a total length of 772 m and a main span of 414 m. The bridge cross-section in the stayed spans is a composite structure of an open steel grid and precast concrete elements. The bridge was completed May 2000.

Hølendalen Bridges
These bridges consists of 3 balanced cantilever bridges with span 80 – 128 – 128 – 80 m. One bridge is a double track railway bridge and the two others are double lane motorway bridges.

Bergsøysundet Floating Bridge, Kristiansund (Krifast)
Floating bridge of length approx. 845 m supported by 7 separate pontoons. The bridge superstructure is a horizontally curved tubular steel truss. The pontoons are made of high strength lightweight concrete. The analysis and detailed design were carried out in co-operation with Veritec, Norway.