| The research presented in this thesis has investigated the use of composite construction (a steel-concrete sandwich system) for the exterior, ice-resisting walls of an Arctic, offshore drilling/production structure. The composite system developed consists of two steel plates enclosing a concrete core. The system can be visualized as a reinforced concrete wall with the reinforcing steel (in the form of steel plates) on the outside.; The proposed composite ice-resisting wall configuration is simple from a fabrication and construction point of view. The outer and inner steel plates are fastened together with continuous, vertical steel diaphragms which are at a relatively wide spacing. No other welded details in the wall are required. This results in a significant reduction in labour-intensive welding, compared to a conventional, all-steel wall. The steel frame is self-supporting and therefore requires no additional formwork when concrete is poured. No additional reinforcing steel is required beyond that provided by the external steel plates and the diaphragm plates.; The testing program which was part of the research work consisted of sixteen quarter-scale beam specimen tests and three quarter-scale slab specimen tests. The tests showed the wall to possess high strength in both flexure and shear and to exhibit ductile modes of failure when the ultimate capacity is exceeded.; An analysis and design approach is presented which is consistent with the same generally accepted engineering principles used in reinforced concrete design; empirical equations, lower bound plasticity methods and upper bound energy methods. The methods showed good agreement with the test results and are also consistent with the limit states philosophy and provisions contained in the new CSA Standard for the Design, Construction and Installation of Fixed Offshore Structures.; Cost analyses were conducted which compared the cost of composite wall construction with those of reinforced concrete and all-steel construction. The comparison showed the composite wall concept to be cost competitive.; This work has demonstrated that a steel-concrete composite and sandwich wall is a viable concept, both technically and economically, for constructing the peripheral, ice-resisting wall of an Arctic offshore structure. |
