摘要:

Artificial islands are being used in the Beaufort Sea to conduct exploratory drilling for hydrocarbons. By May 1977, 15 islands had been built in water depths ranging to the 5 fathom isobath (8.5 m). Ice up to about 7 ft (2 m) thick covers the Beaufort Sea for 9 months of the year and has a considerable influence on construction methods and island design. The islands need sufficient sliding stability to withstand the forces generated by the moving ice; and the possibility of ice ride-up has to be considered. Islands can be built either during the winter by trucking gravel over the ice or in the short arctic summer using dredges. Temporary slope protection is needed to avoid beach erosion during the short summer months. Slope protection is designed to match the measured and predicted sea state, which also influences the island freeboard needed to avoid wave overtopping. Slope protection methods include anchored polyfilter cloth, sandbags and sacrificial beaches. Optimum island designs have to account for constructional constraints, working area needed, ice action, wave action and geotechnical factors.

ISSN:0315-1468    

DOI:10.1139/l78-011

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

This paper outlines a new algorithm for the automated design of rigid plane steel frames having multiple loadings, displacement constraints, stress constraints and fixed geometry. The most significant contributions are, first, a method developed for incorporating into an optimization program the requirements of the specification CSA S16-1969 so that the program automatically uses realistic allowable stresses and, second, a procedure introduced for selecting actual sections that correspond to the theoretical solution. Elastic analysis is used and the optimum design is selected on the basis of minimum cost using the preliminary design factors recommended by the Canadian Institute of Steel Construction. Several examples, including a 10-storey, 1-bay frame, are included to demonstrate the capabilities of the algorithm.

ISSN:0315-1468    

DOI:10.1139/l78-012

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Three large well-known hydrologic models, the Streamflow Synthesis and Reservoir Regulation, the National Weather Service River Forecast System, and the Saskatchewan River Model No. 6, were calibrated and verified on a 2000 km2watershed in northern Ontario over two spring snowmelt periods. Although results obtained were adequate it was thought that a smaller simpler model could be designed that would give results at least as good with much less expenditure of time, money, and effort. Details of the relative performances of the three existing and one new model are given and comparative hydrographs are shown. Although use of the models on only one basin cannot provide conclusive evidence of the models' relative goodness, the results obtained do show significant differences between the models as well as certain advantages for the new model.

ISSN:0315-1468    

DOI:10.1139/l78-013

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The CN Tower is the tallest free-standing structure in the world. The later part of the slip-forming operation of the superstructure was carried out during the coldest period of the Canadian winter. Protection had to be designed therefore to overcome several problems. From the results it is concluded that graduated protection offered reliable and economic means of crack prevention and strength development throughout the winter slip-forming operation.

ISSN:0315-1468    

DOI:10.1139/l78-014

出版商:NRC Research Press    

年代:1978

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l78-015

出版商:NRC Research Press    

年代:1978

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l78-016

出版商:NRC Research Press    

年代:1978

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l78-017

出版商:NRC Research Press    

年代:1978

数据来源: NRC

ISSN:0315-1468    

DOI:10.1139/l78-018

出版商:NRC Research Press    

年代:1978

数据来源: NRC