For construction purposes, four (4) 710 HC-L32/64 Litronic Liebherr Luffing Tower Cranes (or comparable) will be placed at each corner of the site providing maximum picking radius to erect structure. If not possible two larger cranes may be set up at opposite corners in order to erect in sequence and in tandem at times in order to keep structure from overturning as it rises in elevation.
The cranes will be tied back to rising vertical posts that will be have axial bracing for maximum load bearing strength in x, y, and z directions.
Once the cranes are in place they will be in coordination with each other and servicing their own quadrant composed of the integration and composition of three (3) types of segments: vertical pipe, horizontal ring pipe, and diagonal ring pipe.
Fabricated pipes will be sent over by barge and placed on a temporary barge acting as a job site yard (jsy) and a storage yard for segments being erected. The barge would be accessible/ roll on-roll off.
Truckable loads coming from the barge storage will be a maximum of 40 foot (curved pipe
or vertical pipe). Each trailer will contain 4- 6 segments that will be assembled on timber mats.
There will be several cherry pickers (<50 ton mobile cranes) for assistance in stick building truckable loads into maximum loads for allowable picking capacity for tower crane to set in place.
During the shift before erection, the necessary pieces will be trucked in a linear path down 33rd street and 31st street.
The vertical pipes will be erected by tower crane erection, with axial bracing installed between two vertical segments to prevent buckling and increase erection time for the increase in structures.The horizontal pipes will be erected in a similar fashion, yet they will be erected in a sequential order of pre-spliced pieces on the ground. The spliced segment will vary between 3 & 8 segments depending on the picking radius. Various segments will include structural tabs that will serve when attaching diagonal rings. The diagonal rings will be placed in a piece by piece fashion according to the already erected horizontal rings.
There will be shielding over the building below in order to prevent debris and equipment to interfere with structure or roadway and population on the ground.
Access will be provided by installing prefabricated platforms at higher elevated sections of pipes of project. The lower 200 foot portion of the project will be access through man lifts and temporary falsework.
Another method of access would be a Safespan platform that is common on bridge rehabilitation projects. This method of access would act as a shield and an access platform that can easily be transferred to higher elevations as the structure height increases. Post tensioning strands are suggested for the sequential erection of the horizontal pipe rings in order to successfully maintain proper adhesion in the system and prevent inconsistencies in the ring radius. This reinforcing method will also benefit the tower crane tie back support by providing it greater stability.