Multicrete Contracting

Zu Project for Pre-Con Builders

PRE-CON BUILDERS

Project Overview

The Zu project was the redevelopment of an existing hotel at 425 Wardlaw Ave in Winnipeg, Manitoba. The project consisted of the demolition of an existing hotel and bar and the construction of a new four story apartment building with a 5th floor penthouse. The main floor is leasable commercial space and includes underground parking. Pre‐con Builders, acting as the general contractor, sourced Multicrete Systems Inc to construct 280 lineal feet of 8” concrete foundation walls with pilasters below grade at the parade level.

Project Scope

Shotcrete Construction

Multicrete Systems Inc collaborated with the structural engineering team, Tower Engineering, to design a foundation wall system utilizing shotcrete as the structural component. Due to the space constraints of the project site, the client was seeking to maximize the footprint of the building. Multicrete Systems presented Pre‐Con Builders with a unique concrete wall installation to be applied using shotcrete. With the design of the shoring panel system, using 6” x 8’ x 20’ trench boxes, Multicrete was able to maximize the footprint of the building by placing the shoring panels behind the shoring piles gaining a full 2’ of overall distance vs conventional lagging between piles.

The temporary shoring served as a backdrop to install a fully weatherproofed below grade exterior wall. The first layer of the wall system was a layer of 2” rigid insulation held in place using a lumber forming system at the top and bottom of the walls. A waterproof fabric membrane was then applied to the surface insulation complete with a flat drain tile system. The reinforcing steel was then tied and fed between the shoring piles. Shotcrete was then applied to the backdrop of the weatherproofing membrane over the insulation to create a solid concrete foundation wall. The shotcrete was applied in two layers, the 6” thick base layer being Multicrete’s own proprietary XPR Shotcrete.

XPR shotcrete, with its integral accelerator, is suitable for application in colder conditions. Achieving 20 mPa in 3 hours and a final strength of up to 45 mPa, XPR allows the contractor to remove the shoring in as little as 24 hours so it can be moved to the next application area. Within as little as 2 hours, the 2” HPC topcoat can be applied to finish the surface. Multicrete’s HPC blend is designed to adhere to vertical surfaces and is a highly workable product for a smooth polished concrete finished surface.

Multicrete Contracting - Zu Project - Shoring Panel
Figure 1 – A typical shoring panel being lifted into place behind the shoring piles to serve as soil containment and the backdrop to install the shotcrete wall system.
Multicrete Contracting - Zu Project - Wall Section
Figure 2 – A typical wall section: Shoring panels, Waterproofing membrane, 4” rigid insulation ready for reinforcing installation.
Multicrete Contracting - Zu Project - Reinforcing Shoring Panels
Figure 3 – Reinforcing installed and passed through the shoring panels.
Multicrete Contracting - Zu Project - Shotcrete Base Coat
Figure 4 – Base coat of Multicrete’s XPR shotcrete being applied to the wall surface.
Multicrete Contracting - Zu Project - Shotcrete Base Coat XPR
Figure 5 – Base coat of XPR shotcrete applied over a section wall ready to accept a 2” layer of topcoat shotcrete HPC. The pilasters were then formed on one side and shotcrete was applied in the same manner as the walls.
Multicrete Contracting - Zu Project - Finished Wall with Cure
Figure 6 – A finished section of wall shown here with a white pigmented cure and seal after finishing the surface.
Multicrete Contracting - Zu Project - Finished Wall and Pilaster
Figure 7 – A finished section of wall adjacent to a pilaster.
Multicrete Contracting - Zu Project - Schematic
Shotcrete Equipment

Multicrete Systems Inc fabricates and distributes shotcrete equipment and is an authorized dealer of the Aliva line of shotcrete products fabricated by Sika Canada. Sika components are often integrated into Multicrete’s unique designs of specialized and custom shotcrete equipment.

The highly portable Aliva 252 shotcrete unit was used for the Zu project. The unit was fully integrated with Multicrete’s controls system and is capable of spraying coarse aggregates up to 20mm. The shotcrete unit is a “dry” applicator, meaning the dry, pre‐blended aggregates pass through the applicator nozzle using compressed air and exit the nozzle at 40psi. The water is introduced to the dry concrete mist at the nozzle, and consolidates the mix prior to contact with the receiving wall surface. Concrete consistency can be adjusted immediately simply by controlling the flow of water at the nozzle. With the Aliva 252, the application rate can be as much a 300ft² of concrete at 6” within an 8‐hour work day.

Multicrete Contracting - Zu Project - Aliva 252 Shotcrete Machine
Figure 8 – Aliva 252 Shotcrete Machine

Final Product

Multicrete shotcrete systems can apply to a variety of installations including concrete walls, underground tunnels, slope stabilizations and more. Using shotcrete as a concreting method saves time as well as the cost of wood forming materials. The Zu project was completed on time and with the original quoted amount to engineered specifications. The result was a fully weatherproofed concrete foundation wall which used less Labour and materials than conventional form work systems.

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