Ground Improvement at York St. John University

Background

York St. John University embarked on the second phase of converting its old sports hall into a functional space for academic and medical purposes. Phase one, completed two years prior, transformed two-thirds of the hall into classrooms. The ongoing phase aimed to repurpose the remaining area by adding a steel structure to support two floors within the high-ceilinged sports hall. This required significant load-bearing improvements beneath the existing floor slab to support columns and walls, ensuring structural stability under increased weight.

Customer Alternatives

The university faced the option of excavating the existing slab to install traditional pad foundations and strip footings. However, this approach was deemed unsuitable due to the high costs, extended project timelines, and disruptive nature of the process. The noise, mess, and logistical challenges of such an operation in an active university environment posed significant concerns.

Injection tubes in location to strengthen line loads

Why Geobear?

Geobear’s solution was recommended based on its successful implementation during phase one of the project. Key factors influencing the decision included:

1. Speed and Efficiency: Geobear completed the project in four to five days, a fraction of the time traditional methods would have required.
2. Minimal Disruption: The process avoided the need for heavy machinery, excavation, and waste disposal, ensuring the university’s activities were not disrupted.
3. Sustainability: Geobear retained the existing concrete slab, eliminating the need for demolition, disposal, and new material transport. This approach reduced the project’s carbon footprint, aligning with prior studies showing Geobear’s solutions generate 53% less carbon than traditional piling methods.
4. Safety: Without large-scale excavation and heavy machinery, the project presented a safer alternative in a busy campus environment.

Geobear Solution

Geobear implemented its geopolymer injection technology, a process that stabilises and strengthens the ground beneath existing structures. The solution involved:

1. 

   Post-treatment handed back to client, minimum disruption

   Design and Execution:

   • Injection occurred on two levels beneath the slab.
   • For line loads, injections were carried out at one-meter intervals along the length.
   • For columns, injections were placed at four points per column to support load-bearing steel structures.
2. Basic Principle of the Process:
   The Geobear process uses a high-performance geopolymer material, which is injected into the ground through small, pre-drilled holes in the existing slab. Once injected, the material expands and hardens, compacting the soil and filling any voids. This creates a stable, load-bearing ground layer capable of supporting the increased structural loads. The precision of the injection ensures minimal disruption to surrounding areas.
3. Pre and Post-Testing:
   Rigorous pre- and post-testing ensured the solution met specified load-bearing requirements. The post-injection testing demonstrated that the treated ground could sustain the required structural loads with precision and reliability.

The approach minimised disruption, preserved existing materials and provided a sustainable, efficient solution tailored to the university’s needs.

Sustainable Benefits of Geobear’s Solution at York St. John University

By using Geobear’s geopolymer injection method at York St. John University, significant sustainability benefits were realised compared to traditional excavation and foundation replacement methods. Based on a life cycle assessment, Geobear’s solution reduces carbon emissions by over 53% compared to the traditional piled raft alternative. This is achieved by eliminating the need for extensive concrete and steel reinforcements, which are major contributors to embodied carbon.

The geopolymer injection process strengthens the ground beneath existing structures without removing or replacing the existing slab, avoiding emissions from demolition, waste transport, and new material production. Furthermore, the process generates minimal waste, as small quantities of material used in testing are returned with labourers, avoiding the need for large-scale disposal. This approach also bypasses the need for heavy machinery and extended project timelines, reducing fuel use and logistical demands.

Overall, the Geobear method not only accelerates project completion but also aligns with sustainable construction practices, minimising environmental impact while maintaining structural integrity.