Modern structural engineers face enormous challenges meeting demands for urban intensification in large metropolitan areas, desire for landmark monumental structures in developing communities and high order for green buildings in progressive economies. Planners and architects are demanding taller structures and unusually sculpted post modern buildings, all while owners request efficiency and economy of space and practicality of construction.
In addition to new creations, structural engineers continue to be upgrading existing structures for seismic loads, renewed utility and longer endurance.
We have used Tuned Mass Dampers (TMDs) to mitigate problems of vibration and excessive deflection of tall towers and carried out extensive modeling and investigation on the design of Multi-purpose "Tuned Liquid Dampers" for tall buildings and special annular slush dampers for tall wind towers.
Two TMDs are present in the antenna of the Canadian National Tower in Toronto Canada to assure its operation at various wind speeds. The 104 m antenna mast, installed on top of a 450 meter high concrete shaft serves as the support for TV and FM transmitters. The response of the antenna to high winds has been monitored and analysed since 1982, confirming the theoretical design and expectations of the system.
Larger size wind turbines being developed require taller wind towers for support, which are prone to excessive vibration. We have, in collaboration with the research institutions and universities in Canada, developed design methods for annular Tuned Liquid Dampers, a unique slosh damper fitting the geometry of over 150 meter tall wind towers, effectively reducing vibrations and deflection of the assembly.
Post-Tensioned Concrete, Pre-tensioned Steel and Fabric
We have, very successfully used vertical post-tensioning in concrete and pre-tensioning of fabric (case of the CN Tower in Toronto) and pre-tensioning in steel (case of the Pyramide Des Grand Louvre in Paris). Post-tensioning made the slender and pleasing silhouette of the CN Tower possible, while pre-tensioning of high strength steel made the transparency of the elegant Pyramide Des Grand Louvre achievable.
Retrofitting of Existing Structures
CFRB (Carbon Fibre Reinforced Polymer) and GFRB (Glass Fiibre Reinforced Polymer) can be used to increase the capacity of walls, slabs beams and columns of existing buildings and to protect buildings against explosion.
We have used this system for the reinforcement of damaged buildings and structures and to upgrade the utility of existing concrete structures.
About the speaker:
Jamil is a professional engineer and consultant , manager and principal partner of the award winning consulting engineering firm of NCK Engineering Ltd. of Toronto. He has over 30 years of experience in the design, supervision and management of important complex projects in Canada and overseas. His special interests and practical experience are in the design, monitoring and maintenance of tall towers, high-rise buildings and special structures. Mr. Mardukhi obtained his M.A.Sc degree from the University of Toronto in 1974. He has been involved in the design , construction and monitoring of the CN Tower in Toronto, 350 meter tall tower in Mexico, The Pyramid of the Louver in Paris and many complex projects in Saudi Arabia, Moscow, Trinidad and the UAE. Mr. Mardukhi has also been in charge of all inspections, monitoring and maintenance work of the CN tower, since 1976.