Downtown Chicago is a regular haunt for helicopter lifting operations. One recent job was a bit larger and more complex than normal. Rob Edgcumbe was there for GAR to see the teams at work.
Helicopter lifting tasks are something that GAR has covered in the past and we had another opportunity recently to watch a complex project being carried out. The job was carried out in two parts. The first was undertaken by Midwest Helicopters of Willowbrook, Illinois. The second involved Construction Helicopters of Howell, Michigan.
The building that was the focus of the project was the Merchandise Mart. Sitting along the Chicago River, in the heart of the city, the Merchandise Mart is a huge building. Built in 1930, it was the largest building in the world at that time with 4 million square feet of space, and only lost that title when the Pentagon was constructed. Originally, it was a storage facility for Marshall Fields, the department store. Now it is predominantly used by fashion and interior design businesses as their showrooms and also as a venue for trade shows.
The building takes up an entire city block and the roof is 100m above the ground but, with one side of the building fronting the river and narrow city streets on the sides, the ability to undertake any substantial construction work is limited without causing significant disruption to the surrounding area. This is made even harder in that one side of the building has a street with an elevated railway over the top of it. This is part of Chicago’s “L” system and disruption to service can only be allowed to happen in rare cases. Helicopters therefore were the most viable way of getting a substantial amount of equipment to the roof, and in place.
The building is installing a new system of air conditioning and these lifts were a major part of this project, with the installation of new chiller units on the roof. Construction Helicopters had the task of lifting these in to place with its Eurocopter Super Puma. However, before any of those units could be put in place, the supporting structures needed to be assembled and there were nearly two hundred of the pieces that make up these structures to be lifted in to place first. Unlike some tasks though, this was not just a case of lifting items up to the roof but also it was to allow the assembly work to be completed in one go. Midwest Helicopters was assigned this task for which they used one of their Sikorsky S-58Ts.
The assembly of the frames required a great deal of coordination with the ironworkers on the roof of the building. Mounting points for the structures had already been installed ahead of time and the ironworkers were on the roof to receive the pieces as they were lifted, guide them to their final location and bolt them in to place. This sounds relatively simple but, since the operating time of the helicopter is at a premium, the next piece was already swiftly on its way. Consequently, the previous piece had to be in place and bolted down as quickly as possible before the team moved to the next location. The only time for a break came when the helicopter had to go and refuel, otherwise the team was flat out.
The structural steelwork was laid out on the street in front of the Merchandise Mart and on a barge moored in the river in front of the building. Bringing in the majority of the steel on the barge avoided the need to move a large number of trucks in to position to support the flow of material and also provided a segregated area to work. On smaller lift tasks an important part of the process is only having support people in the lift area when needed, and moving trucks with loads in an out is tricky given their limited manoeuvrability and the time pressures of a lift. Having multiple trucks makes this a lot more difficult to coordinate. During a lifting operation, it is normal to have to close off the surrounding streets in order to provide a sterile area in which to work and, with the barge being part of the operation, it was also necessary to patrol the river to keep boat traffic away. Given that the Chicago River is very busy in the summer months with tourist boats, river taxis and pleasure craft, this was an additional complexity to add to the task.
The multiple lifts required to assemble the steel were going to take a lot of time. Consequently, permits had been obtained for more than one day in case the job took longer than scheduled. The goal though was to try and lift all pieces in to place in one day, which required the helicopter to refuel multiple times. The city of Chicago does not allow helicopters to land so each refuelling required the helicopter to return to its base outside the city. This also provided an opportunity for a crew change. This type of flying is very intensive and having a regular break allows the crews to maintain their focus.
Two sections of the roof were having structures assembled. The smaller area on the east side of the building was first and then the west side was completed. Each section involved the installation of vertical posts and then the addition of cross members to complete the frames. The vertical posts were simpler to locate since they bolted directly to the mounting pads while the helicopter held them in place. The cross members were slightly more complex since they had to be accurately located and supported while they were secured, but also required some adjustments to get the final alignments correct. Some of these were at the top of the posts, so the ironworks had to swiftly climb to the top, carry out the adjustments and bolt them in place, all while being in the down-draft of a helicopter.
The process ended up flowing very well and, despite a slight delay to the start due to a minor technical issue with the helicopter, the entire lift was completed within the planned one day. The fine weather certainly didn’t hurt although the higher temperatures and strong sun made for a tiring work environment for all concerned. That said, all of the structures were lifted and assembled and the river traffic was able to continue without too much trouble. The need for the additional day of disruption was avoided.
The second part of the job came a few weeks later. Lifting the chiller units required the Super Puma rather than the S-58T. The Sikorsky can lift up to 4,500lbs which is sufficient for many chiller units. However, the units for this project were considerably larger – hence the reason the Super Puma was drafted in. Lifting the chillers in to place was a relatively straightforward task for an experienced crew. There were quite a lot of them though so it was necessary for the Super Puma to head off to refuel once during the task. Since Construction helicopters do not have a local base, they refuelled at Midway International Airport, a 5-10 minute flight from downtown.
As before, the loads were brought in by barge and lifted from the river. The same restrictions were in place as for the first lift with regard to local road and river traffic. As with the assembly work from the frames, good coordination was required between the lift team and the workers on the roof. Guiding the chillers in to place requires a great deal of focus. Securing them quickly so the next load can be brought up is vital. Combined with this was the need to install units across the different parts of the roof so the team was kept very busy. Again, the challenge was met and the units were all installed by mid-morning and the local area could swiftly return to normal.
Installation of this equipment by any other means would have been a far more complex and time consuming task. Getting a crane in place to lift and install such heavy equipment across such a large, remote and elevated area would be difficult, if not impossible. The restrictions on the surrounding roads would be significant and long lasting. The use of helicopters to carry out the job allowed two weekend days to see the limit of disruption for the neighbourhood. Meanwhile, it provided quite a sight for those visiting the city, so had entertainment value as well!
The author would like to thank the teams at Midwest Helicopters and Construction Helicopters for their help in preparing this feature.