Council on Tall Buildings and Urban Habitat
 

CTBUH Summer Tours 2009 - Blue Cross Blue Shield Tower

17 July 2009, Chicago

.

BCBS Tower
Blue Cross Blue Shield Tower, Chicago

        


The final tour of the CTBUH Summer Study Tour series was held on Friday, 17 July 2009, as CTBUH members and tour guests gathered at the Blue Cross Blue Shield Headquarters in downtown Chicago. Chicagoans have watched the progress of the major vertical building expansion since 2006, as builders have nearly doubled the size of the massive building, adding 24 new floors to the original 30 stories. The original 4400 occupant building will be able to house 8000 occupants at completion.

Senior Project Manager Lou Rossetti of Walsh Construction and Partner/Project Director Joseph Dolinar of Goettsch Partners led the study tour, which was made up of professionals from various design engineering, architectural and planning firms, fire safety consultants, as well as construction and project management companies. Rossetti and Dolinar first gave an in-depth overview and video presentation, then took the group through the construction site to view the 30th floor planned conference facility, then a typical office floor, and finally the rooftop of the new vertical expansion.
.
.
.

The video presentation showed the planned construction sequence with timing schedule and measures utilized for conducting the full scale construction project on-site with an existing business, without interrupting the client’s business operations.

  

Senior Project Manager Lou Rossetti of Walsh Construction

Partner/Project Director Joseph Dolinar of Goettsch Partners  

Phase 1 of the construction at 300 E Randolph was completed 6 September 1997. When asked why the client, Health Care Service Corporation (an independent licensee of the Blue Cross and Blue Shield Association), did not build the full building from the start, Dolinar stated that the client never intended to lease out space to multiple tenants. The original design was built with 30 stories and a one-tenant lobby. Though the timetable for the expansion was never cast in stone, the expansion was always part of the original building design.

  
Project leaders give construction planning video presentation to tour guests
Interior hoist takes tour guests to construction site

When planning the original building, designers made many special provisions for the future expansion, accommodating for future vertical transportation systems, future structural loads, and future finish construction material availability.

The lobby atrium of the Phase 1 project was designed with space for the expansion’s vertical transportation systems. On 26 December 2006, Phase 2 began with the addition of temporary partitions and safety netting in the atrium lobby for the two new banks of elevators with eight cars each. Three freight elevators were designed in the original structure, when normally only two would have been required of a building that size, allowing one freight elevator to be completely dedicated to construction use.

   

New elevator core with safety netting

Lobby atrium originally designed for Phase 2 vertical transportation systems

The original structural loads and caissons were designed for the loads of the full 54-story building. Concrete core sheer walls of the Phase 1 project transition in the top two floors to steel core. The Phase 2 expansion utilizes two steel cores, four sides with 2-story diagonal X-bracing. Continuous monitoring of foundations and columns during vertical expansion has measured no detectable changes in the original foundations and only minor compression in columns, as expected.

  
Amazing southern views of Chicago parks and skyline
Massive typical office floor space

Early in design of Phase 1, attention was paid to what materials would be available for future expansion. The choices to use stainless steel, a stone from a very large quarry for future availability, and a Viracon glass in a standard color were made, and with a 10-year spread between construction phases, the successful choices are evident in the finished product. Though different manufacturers of the curtain wall system were used, and a higher performance curtain wall installed in the expansion, a seamless transition is maintained between old and new. An open mid-section between the two phases at the time of the tour has been left for the purpose of hoisting construction materials and product to the 31st floor. To fully unite the curtain wall, an exterior monorail is used for installation. Later this year, Walsh will be finishing the enclosure with a snap-in panel from the interior on the south façade.

  

Rossetti explains logistics of expansion project onsite with client operations

Construction staging and reception on 29th floor transition space

The site itself has offered some major construction advantages, especially the multi-levels of roadways below the building. The loading dock, located in lower levels, allowed much construction delivery from below street level. A designated lane closure on North Columbus Drive allowed most steel to be hoisted from the street. In December 2007, Walsh began concrete work. The site has allowed every yard of concrete and spray fire-proofing for Phase 2 to be pumped from lower Randolph Street. Site advantages have allowed construction to maintain 24/7 ongoing operations, plus provide public safety for occupants.

   

View north to Chicago River

Rossetti reviews construction challenges with tour guests


Phase 1 designers and construction managers even worked closely with Chicago city officials as to just how Phase 2 would occur. When Phase 1 was designed and built, downtown Chicago was mainly a business district. It was assumed much of Phase 2 construction could take place at night, to not disturb daytime operations of the building client. However, as Phase 2 began in 2006, the neighborhood had become very much a residential district, requiring continuous construction sensitivity, not just during the work week.

Dolinar fields questions from industry professionals    

    View south from BCBS Tower

Even though work has been done in two shifts, seven days per week, the desire to interfere as minimally as possible with the client’s day to day operation has been a main focus of Walsh Construction. An extra-large canopy was built on Randolph to maintain an architectural front entrance of the building as an operating business, and special emergency exits were constructed on the North & East sides. Over 4,000 health service workers come and go each day virtually unaware of construction crews working in the same building. Walsh has worked on sound proofing construction and enclosures, especially on upper floors where much transition work takes place, even building two concrete slabs between the working deck and the occupied areas of the building.

   
 Enclosure of Phase 1 rooftop allows for 25 foot ceilings in the new 30th floor conference center Construction crew applies exterior column facade at 30th floor

The initial steel that was set was done on the weekend to not disturb the client’s work in the upper floors. Construction workers entrance in the lower level Pedway and a 34th-floor cafeteria delivery keeps construction crews out of the main flow of the client’s business operations. Walsh is proud that no single incident has been reported between occupants and job personnel, as crews maintain a ‘guests in their house’ demeanor and focus on treating occupants with respect.

  

Forty-foot free standing rooftop screen wall in construction

BCBS construction nears completion

Construction of the tower cranes was also a difficult, logistical challenge with the building occupied. The team built a model for working out the details. A total of four new hoists with rails were required for the project. Since they could not put a skip hoist on the building exterior, a slab was poured from the 29th floor on top of the low rise structure as a pad for interior skip hoists with two banks. When complete and able to remove, that pad will be used for conference room areas. A derrick was built for the initial steel frame. Then a new 17-ton derrick was used for the finished steel frame and was still in use during the tour. When the crew is all done hoisting pieces to the top, that derrick will come down the front of the building.

In November 2007, steel began to be brought up by the two cranes. In May 2008, Walsh began the structural steel frame addition. In October 2008, the new cooling towers were completed. The Phase 1 building housed 24 cooling towers, utilized by this building as well as the Aon Center, 340 E Randolph, and several other neighborhood buildings. A rooftop parapet and tower decking was left early on to guard the ventilation, so existing cooling towers would not be affected by construction. In December 2008, eleven larger high-performance cooling towers were installed on the new roof. In January 2009, all existing enclosed towers were removed.

  
Eleven new high-performance cooling towers on building rooftop Project heads: Joe Dolinar, Partner/Project Director, and Lou Rossetti, Senior Project Manager (far right) lead CTBUH staff and construction industry professionals on BCBS Vertical Expansion Project Study Tour

Removal of old rooftop mechanical systems allows for a 25-foot high ceiling on the 30th floor, which is being converted to a spectacular conference center enabling multiple rooms available for corporate functions and charitable organization use, with seated dining of 120 or more before tremendous city views.

Rossetti reported that by the year end 2009, Walsh will be able to remove safety nets. The project is on target for a March 2010 final occupant certification. After answering many questions of guests, Rossetti stated that this project has been one of the most fascinating and challenging of his life.

Blue Cross Blue Shield Tower, a massive member of the Chicago Skyline

The CTBUH would like to thank Lou Rossetti and Joe Dolinar for leading this Study Tour, for their prepared technical presentation and the added dynamics of the input and questions of various construction industry professionals who joined this final tour in the series of CTBUH 2009 Summer Study Tours.



Picture Gallery
Click an image below to enlarge. Photos courtesy of Jan Klerks, Marshall Gerometta, Phillip Oldfield and
Walsh Construction.

       

Blue Cross Blue Shied downtown neighborhood

Open between Phase1 and Phase 2 construction

Lobby with Phase 2  new construction Phase 2 new elevator core
.
New elevator core with safety netting
Hoist panel Interior construction hoist shaft
.
View north to Chicago River Construction video presentation for tour guests Construction staging and reception on 29th floor
Rossetti reviews construction challenges Transition floor at 29

Willis Tower through structural supports

Lou Rossetti of Walsh Construction
Joseph Dolinar of Goettsch Partners

High ceilings at 30th floor planned conference center

View from planned conference center Crews apply column facade. Tour guest Thomas Fridstein of Perkins Eastman Amazing southern views of Chicago parks and skyline
Typical office floor space 13'-6" floor to floor height Dolinar fields questions from industry projessionals North facade completion BCBS construction nears completion Rossetti explains logistics of expansion project
Eleven new high-performance cooling towers Rooftop cooling towers and screen wall Rooftop screen wall BCBS Vertical Expansion Project Study Tour A massive member of the Chicago Skyline