July 30, 2020, marked the final concrete slab pour for Michael Garron Hospital’s (MGH) Ken and Marilyn Thomson Patient Care Centre structure. Concrete pouring activities for the eight-storey structure and four levels of underground parking began back in May 2019.
To mark this exciting milestone, Gabriele Mabrucco, Superintendent at EllisDon, answered some of the most frequently asked questions about concrete pouring activities at MGH.
How much concrete was installed during a typical pour onsite?
The amount of concrete poured varied on a daily basis from 10 cubic metres to over 400 cubic metres. Our final slab pour was approximately 360 cubic metres.
How much concrete was required to build the new Patient Care Centre?
Approximately 26,000 cubic metres were required to complete the new structure.
How many concrete trucks were required to complete the structure?
Approximately 3,000 trucks were required to complete the concrete structure. On days with large concrete pours, 20 to 40 concrete trucks accessed the site.
What is concrete made out of?
Concrete is made of three components: cement, water and an aggregate such as stone or sand. The ratio between these three is modified based on the strength and consistency required.
Is a certain temperature required in order to pour and cure the concrete?
Yes, the ambient air temperature must be above freezing for concrete to properly set. In order to continue working in the winter months, slabs were heated from below to ensure that the concrete didn’t freeze as it was poured or while it cured.
How do you level the concrete after it is poured?
After concrete is poured, the mixture is leveled using either a float or power trowel depending on the specified finish.
How long does it take for a concrete slab to cure?
A concrete slab can be walked on after approximately two to 12 hours, depending on a number of factors including the type of concrete, the water/cement ratio, the ambient temperature and the amount of sun. The reshores, which are the metal supports installed below the storey being poured to evenly distribute the weight, can be removed once the strength of the concrete reaches 70 percent of the design capacity. This typically takes between one to seven days depending on the type of concrete.
What material is used the most onsite?
Concrete and steel are the two most commonly used materials onsite. Steel (also known as rebar) is installed inside the concrete to provide it with extra strength and prevent the concrete from cracking or breaking.
MGH is proud to be celebrating the completion of concrete pouring activities for the Patient Care Centre. Don’t miss a moment of the action onsite; watch the construction activity LIVE here.