June 7, 2012

Collaboration key for Darlington, Ontario office project

DON PROCTER

correspondent

By their very nature design-build contracts foster teamwork – key consultants and contractors must work together if milestone deadlines are to be met.

That kind of collaboration has been a top priority on a contract for a three-storey office and warehouse at the Darlington energy complex for Ontario Power Generation where the architect, structural engineer, general contractor and owner have had to “mesh” to push along the design during construction.

“If that teamwork wasn’t in place, milestones would never have been met,” explains Stefano Trentin, project manager, Tresman Steel Industries Ltd., the steel design/fabricator of the project.

Tresman fabricated 1,800 tons of structural steel for the project which includes a 160,000-square-foot warehouse and 124,000-square-foot office building.

Trentin says the steel team was under pressure to complete the project on a fast-track schedule, no easy feat, considering the agenda.

“This project has many different aspects — a large office, large warehouse, crane bays, moveable partitions and a mechanical penthouse that feeds the entire structure.”

The warehouse has three crane bays, including bays with 65-foot and 37-foot ceilings.

One bay was designed to accommodate a 20-tonne crane is 108 feet wide; another fits a 15-tonne crane.  

Trentin says building that type of structure is common on large projects like Darlington.

The long-span joists were supplied by Canam Canada. “With their help, we were able to design long spans with minimal depth that allowed more clearance.”

Ample material laydown space and good access to the site eliminated headaches builders often face on tight sites.

The complex’s office building presented challenges different from the warehouse for the steel crew. Trusses, for instance, had to be erected along perimeter walls to accommodate the clear-span open concept design of each floor.

“It made for a challenge to plumb the building once an area was installed,” says Trentin.

For design certainty, Tresman teamed up with the engineer and the architect to ensure problems didn’t develop during drafting.

“The detailing went smoothly which in turn made the fabrication run clean. No piece became too complex to complete.

“The tricky part was piecing it together on site,” he says.

The office building erection, which met the milestone deadline, was done by St Peter Steel Inc.

As complex as the design might sound, Trentin says Tresman’s design consultant, Dorlan Engineering Consultants Inc., kept the complex as simple as possible to stay within budget and allow for speed of erection.

“As the design-builder, our intention was to provide the most economical structure within the budget – a building that is pleasing to the owner and can be erected to meet the very tight schedule.”  

Trentin says general contractor McKay-Cocker Construction Ltd. set up a schedule of ongoing meetings with key players to make sure everyone was in sync.

“You can never have enough meetings at the beginning of a design-build project because you are designing a structure to meet the client’s everyday needs on a short schedule.” But issues did come up, ranging from mechanical interferences to variations in roof slopes.

“The important thing was that the design and drafting had to stay only one step behind or the schedule would be lost.”

Tresman’s detailing team, Draft-Tech Inc., chose Tekla detailing software to model and produce shop fabrication diagrams. The steel went into place with no issues.

Building Information Modeling (BIM) wasn’t used but Trentin sees it becoming “a common fixture” on many projects because it integrates all drafting models (from structural steel to mechanicals).

“That means changes can be made prior to erection so fewer issues crop up on site.”

The Darlington project started last December and was completed this March. Tresman remains on the site providing additional work.

Print | Comment