Guest
I am erecting an environmental containment for a 250 foot tall tower structure that will be abrasive blasted to remove coatings. The tower is 250' x 40' x 7' and is a land based part of a gas pipeline cable suspension bridge spanning a large river.
The plan is to use tubular steel outriggers and cables to support a verticaly mobile containment-screen curtain. The curtain will be raised via air tugger motor and snatch blocks attached to a single "dollar ring" outrigger. The central concern is the design strength of the dollar ring, as it will need to support the entire curtain during daily hoisting. The curtain will be subject to wind and wind gust loading which will add to the raw load the outrigger and dollar ring must support.
While the potential wind and gust load can be huge, this is effectively mitigated by the relatively low tear strength of the containment screens. The screens will rip before the anchored cables or support outriggers give way. I know this from experiance on elevated water tanks. (the primary reason for the mobility of the curtain is so it can be lowered quickly when the wind rises) But the elevated tanks allows the "dollar ring" to be centered on the structure. Our tower project will require the ring to be lateraly offset.
I would like to review my design with a structural engineer having experiance in this type of work.
Thanks
mrkpaint@swbell.net
The plan is to use tubular steel outriggers and cables to support a verticaly mobile containment-screen curtain. The curtain will be raised via air tugger motor and snatch blocks attached to a single "dollar ring" outrigger. The central concern is the design strength of the dollar ring, as it will need to support the entire curtain during daily hoisting. The curtain will be subject to wind and wind gust loading which will add to the raw load the outrigger and dollar ring must support.
While the potential wind and gust load can be huge, this is effectively mitigated by the relatively low tear strength of the containment screens. The screens will rip before the anchored cables or support outriggers give way. I know this from experiance on elevated water tanks. (the primary reason for the mobility of the curtain is so it can be lowered quickly when the wind rises) But the elevated tanks allows the "dollar ring" to be centered on the structure. Our tower project will require the ring to be lateraly offset.
I would like to review my design with a structural engineer having experiance in this type of work.
Thanks
mrkpaint@swbell.net
