MacKimmie Block & Tower Redevelopment

Calgary, Canada

The MacKimmie Block and Tower at the University of Calgary aims to reduce and eliminate carbon emissions with a passive design that minimizes energy use.

MacKimmie Block & Tower Redevelopment

Calgary, Canada

The MacKimmie Block and Tower at the University of Calgary aims to reduce and eliminate carbon emissions with a passive design that minimizes energy use.

Comprising an existing 14-storey concrete frame tower and a five-storey steel framed block connected by a two-storey concrete link building, MacKimmie Block and Tower is the tallest building within the university’s main campus.

The block and tower originally served as a library but were repurposed for administrative and classroom spaces, including 500 new study spaces for the faculties of Nursing and Social Work. The redevelopment included adding two floors to the existing tower, replacing the existing cladding system with an energy efficient system, and improving the quality of the interior light.

The complex is striving for certification with the Canada Green Building Council’s new Zero Carbon Building Standard, aiming to reduce and eliminate carbon emissions by designing passive controls and minimizing energy usage while optimizing interior comfort.

location

Calgary, Canada

Budget

$240 M

LEED Certification

Targeting LEED® Platinum; Targeting Net Zero

Size

16,820 m² (181,000 ft²)

Award of Excellence – Buildings

Canadian Consulting Engineers

Award of Excellence

Consulting Engineers of Alberta (CEA)

Architect

DIALOG

Client

University of Calgary

Role

Structural Engineering Consultant

Green City

Mayor's Urban Design Awards

Tree of Life Award

Canadian Consulting Engineers

Challenge

An inefficient cladding system led to poor thermal performance.

Solution

An innovative inner and outer curtain wall system was used to greatly improve thermal performance for this building, with solar PV fully integrated within the curtain wall system as the building strives for net-zero.

Challenge

Designing an addition of two floors to the existing building.

Solution

Entuitive completed an extensive study of the existing tower structure and determined that removing the heavy library loads, utilizing live load reduction allowed by the current code, and removing the heavy precast panels allowed the addition of two levels without any modifications to the robust lateral load resisting system.

Challenge

Rebar cages were found to be misaligned in some of the columns in MacKimmie tower, leading to a reduced concrete cover, potentially exposing the re-bar steel to higher temperatures in fire scenarios. Any fire engineering interventions are limited by the boundaries of the existing structure. Ideally, it can be proven that the existing condition is safe in fire without any interventions. Naturally, eliminating the need for repair/upgrading work entirely is the least invasive/easiest solution for the contractor.

Solution

A thermal analysis of the column sections with misaligned rebar cages allowed us to determine the impact on material degradation, and hence load-bearing capacity under fire that the reduced concrete cover had. The impact of misaligned rebars was found to not have a significant impact on the residual load-bearing capacity, and no remedial works were necessary.

Challenge

To strengthen waffle slab floors after coring these to accommodate mechanical and electrical services, steel plates were attached to the soffit of the floor slabs. Since the steel plates would be exposed to fire from below, it was necessary to determine whether they required fire protection to maintain the load-bearing capacity of the overall floor in case of fire.

Solution

Calculation of the residual load-bearing capacity of the existing concrete waffle floor slab, including cores, based on the Canadian concrete design standard CSA A23.3 Annex B and Eurocode 2 Part 1-2, as well as using the load combination for extreme events in NBCC 2015, demonstrated that the floor slab maintained sufficient load-bearing capacity in fire without relying on any contribution from the steel plates. This meant that fire protection of the steel plates was redundant in the event of a fire, and resulted in a significant cost savings relative to the prescriptive guidance which said to apply spray-applied fire protection to the exposed steel.

Learn more about how Entuitive approaches engineering challenges, and discover why Engineering Performance matters for your project.

MacKimmie Block & Tower Redevelopment