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ASTRACT In 1981 Wärtsilä (Turku, Finland) was commissioned the construction of three large catamaran type crane vessels. In the design of the vessels the determination of the wave loads acting on, and the strength of the bridge structure connecting the hulls received considerable attention. They were subject of a thorough investigation in the course of which theoretical calculations and model tests were performed at MARIN (formerly NSMB) in Wageningen, The Netherlands. The paper describes the design procedure for the bridge structure, which is based on a probabilistic approach. It also highlights some typical results of the calculations and tests. 1. INTRODUCTION In the late seventies Wärtsilä received a technical inquiry for a large catamaran type crane vessel from Sudoimport on behalf of the Ministry of Gas Industry of the USSR. A detailed inquiry in 1980 was followed in 1981 by a contract for a series of three vessels. In 1984 a fourth vessel was ordered. The first ship was delivered in 1984. Before and after the signing of the contract design work and research was carried out. In the course of the investigation theoretical calculations and model tests were performed. Attention was paid to various hydrodynamic aspects of the vessel such as resistance and propulsion, manoeuvring and especially the motion characteristics in waves. One aspect of the design, the hydrostatic and hydrodynamic loads in the bridge structure connecting the hulls, received special attention. In this paper the method used to determine design loads and the results of theoretical calculations and model tests will be discussed. 2. THE VESSEL The special type of vessel was selected by the owners, who have experience with catamaran crane vessels operating in the Caspian Sea . The type has certain operational advantages which single hull crane vessels lack, for instance:–wide working deck for operations and transportation; –shallow draft; –large hydrostatic stability eliminating the need for heel compensation systems. An additional advantage for the owners resides in the fact that the two hulls and the bridge structure can be prefabricated and transported separately to the Caspian Sea for final assembly. A general arrangement of the vessel is shown in Figs. 1 and 2. The main dimensions are shown in Table 1. The Kone-Gusto revolving crane is designed for a 600 tonnes lift at an outreach of 39 m, see Fig. 3 and Photo 1. The maximum speed of 11.S knots, combined with the large deck area make the vessel very suitable for the transportation of construction modules. The vessel is designed for worldwide operations. 3. DESIGN PHILOSOPHY Since the vessel is the largest in the world today, since no standard design methods and rules were available and since the vessel was the first of its type to be built by the yard a comprehensive research effort was started. The rules of the USSR Register of Shipping offered no stringent guidelines for the design of the bridge structure, therefore the yard had to decide on a design philosophy.
In underground air-raid shelters there are located many functions for civilian use, for instance storage and sports. In Turku, Finland, an underground shelter is being built in which two ice-hockey rinks will be situated in adjacent halls. The unusually long spans of the halls (32 m) presume thorough site investigations and accurate calculations. The construction site is composed of firm crystalline rock. Excavation and strengthening work will take place in many different stages. CIVILIAN USE OF UNDERGROUND BOMB SHELTERS IN FINLAND According to Finnish legislation new buildings of a volume of at least 3000 m shall be provided with air-raid shelters. The air-raid shelter can be built either in the basement of each building or, alternatively, regional shelters can be built with spaces provided for several buildings, blocks or a whole district. As the Finnish bedrock generally is of good quality~ in almost every place there is rock available, the large regional shelters are almost always built in rock. In the rock shelters the space reserved for one person is 1.1...1.2 m. Usually the rock shelters have plenty of hall space which can be used for civil purposes. The designing and constructing of rock shelters should always be programmed so that the intended civilian use is known already at the initial stage of the designing process, thus making it possible to design the spaces, technical equipment, passages and entrance structures above ground purposefully. from the point of view of the use as well in crisis as in normal times. When the constructing of the rock shelters started in the early sixties in Finland, the shelters were designed to be used in normal times as simple storage rooms or car parks. When the first shelters were completed it was discovered and generally accepted that the shelters could, with small additional expenses, be equipped for more exacting use and activities. In the rock shelters of today the civilian use is more versatile than earlier. Halls for gymnastics and playing ball, running tracks for athletics, places for jumping and throwing have been built in the shelters and in two towns there are public swimming pools in the rock shelters. In addition to that, provided in the rock shelters. bowling alleys will be built. rinks will be built. hobby rooms for young people and rooms for musical training are In the shelters being designed 'at 'present, cinemas, small, theatres, In the rock shelter of the Varissuo -residential area in -Turku two ice THE ROCK SHELTER IN VARISSUO The building of the Varissuo residential area in Turku was started in 1978 and by now about 60% of the dwelling houses have been built. The total area of the dwelling houses is about 320,000 m2, excluding schools, nursery schools, business buildings etc. The topography of the area varies and there are large exposures of rock. It is possible to build the regional rock shelter for the whole residential area, as the area is being built centralized and rapidly by one and the same builder, the population of the area is sufficient and the bedrock is suitable for the purpose.
A 14.5 km long tunnel in bedrock constitutes an essential part of the heat transmission line by which district heat will be transmitted starting in 1982 from Naantali Power Plant to consumers in the region. This report examines the financial and technical factors which led to the choice of the tunnel alternative, as well as the tunnel design including investigations and studies related to it. The report examines also the environmental harm and risk factors caused by rock excavation and the use of tunnel in a population center. The concluding part of the report deals with the time schedule, mode of implementation and cost of project. BACKGROUND Imatran Voima Oy's Naantali Power Plant, 3 × 133 MW, constructed in 1958–1978 is situated on the border of a densily populated region comprising two coastal towns Naantali and Raisio and one coastal city Turku. There are 200 000 residents in this region. Until recent years the buildings have taken care of their own heating with their own boilers with the exception of small area heating systems. Steep escalation in the prices of oil - the fuel primarily used - has made the transfer to district heat and to concentrated production of heat more economical in large production units using cheaper fuel. After 1982 the major part of the district heat required by the Turku area will be produced with coal at Naantali Power Plant. Because of this the condensing units with a capacity of 133 MW will be altered to produce district heat. Owing to improved efficiency one unit will produce in addition to 90 MW of electric energy also about 170 MW of district heat. However, the construction of the heat transmission system with its stand-by and peak heat centres form the major part of the project as far as costs are concerned. In order to take care of the construction of the district heat line and heat transmission to consumers at a maximum distance of 25km, the municipalities in the region and Imatran Voima Oy have established a limited company by name of Turun Seudun Kauko Lampö Oy. Alternatives The terrain in the Turku region on the shore of the Baltic Sea comprises rocky hills and between them valleys filled with soft clays. It was found that the varying and difficult foundation conditions would increase the cost of an ordinary district heat channel to be sunken in the ground owing to great need for piling and supports in the excavation. Likewise placing large approx. 1.4 × 2.4 m DN 800 district heat culvert in the narrow street areas of the old city would have caused expensive alteration works in the existing municipal pipelines and cables as well as great difficulties in traffic arrangements. It would have been impossible to avoid lowering of the ground water level in sections where the ground water level is high. Even crossing of water courses, with railways and highways would have been cost-increasing details.