b'FEATURETD TERRACEANDREW VOTHPh.D., P.Eng., Associate RJC EngineersCollaborative steel solutions for a sculpted skyscraperBY::ANDREW VOTH, PH.D., P.ENG., ASSOCIATE, RJC ENGINEERS (AVOTH@RJC.CA, WWW.RJC.CA)The City of Torontos already dynamic skyline has once again been enhanced with the addition of a new sculpted and sloped skyscraper: TD Terrace. Located at 160 Front Street West at the corner of Front and SimcoeStructural steel also provides the ability to create large column-free Streets, the newest space for TD Bank is a 47-storey, 240-metre-tall slopingspaces by allowing long floor plate spans between the concrete core and steel-framedcommercialtowerthataddsapproximately1.2millionthe perimeter faade. Spans between 13 metres and 15 metres varied square feet of Class A office space to Torontos financial core. Along withover the height of the building and were important to form the complex the incorporation of a six-storey masonry heritage building faade, thesloped geometry of the building, and also to provide efficient tenant building offers four levels of below-grade parking and bike storage with aspaces. Structural steel, because of its high strength-to-weight ratio, was dedicated underground PATH connection and a four-storey podium withalso important in keeping the structure as minimal as possible, including tenant amenities, set to be occupied in 2024.keeping column sizes relatively small compared to concrete construction. From its beginning, Adrian Smith + Gordon Gill Architecture designedBeyond the more typical reasons why steel was the best material for the the towers unmistakable sculpted silhouette to be a response to theTD Terrace, structural steel was critical in making the complex building local environment. By orienting the main axis of the building parallel togeometry possible in three areas: the sloping geometry of the building the sites prevailing winds and tapering the building at both the top andfaade, the architectural feature inlets and the curved crown volume bottom, the winds lateral loads on the structure are minimized. The shapeat the top of the structure. The structural challenges of the buildings of the building also had a significant impact on the pedestrian realm bycomplex geometry also led to fabrication and connection challenges, minimizing wind effects at grade and creating a spacious landscaped areawhere a close collaboration between Walters and RJC Engineers was in stark contrast to the compressed neighbouring sidewalks. The irregularessential to make the project a reality.shape, the clients vision and the demanding structural requirements of this unique building also created many challenges that could onlyA Team Approach to a Challenging Designbe overcome with the use of innovative steel solutions and significantNo project is without design challenges, but 160 Front was unlike any collaboration between RJC Engineers and Walters Inc. other that required close collaboration between engineer and fabricator to make the architectural intent a reality.Advanced Steel for Complex Geometry The towers sculpted sloped shape required that the perimeter steel DeveloperCadillacFairviewwithAdrianSmith+GordonGillcolumns were sloped for the entire building height. Column geometry Architecture and B+H Architects began working on the projectchanges occurred at approximately every three floors and spliced one over 10 years ago with key features in mind, including state-of-themetre above the floor (as opposed to at floor level) to allow for better art faade, sustainable strategies, efficient use of space and speederection accessibility. With each change in column slope the structural of construction, among others.steelfloorplatesresolvedtheunbalancedkickforcebacktothe The use of structural steel had significant advantages to addressingconcrete core. Very early in design, working points of the change of some important requirements of the project. A hybrid structure approachinclination of the columns were coordination between the architects, with a concrete core, structural steel framing (approximately 9,500 tonnes)Walters and RJC to ensure the splice locations minimized the structural and structural steel outriggers has a significant advantage for speed ofimpact, lifts were within crane restrictions and splices were in locations construction over a conventional all-concrete structure.well suited to fabrication, all while still maintaining the architectural intent. 32|WINTER 2023/2024 ADVANTAGE STEEL'