International - special 2nd annual conferece on foundation decarbonization and reuse

With a focus on sustainability, the reuse of materials has become increasingly important in the construction industry. For Allnamics, this was the impetus last year to initiate a conference on this topic in the field of foundations. From May 28th to 30th, the '2nd annual Conference on Foundation Decarbonization and Re-use' will be held at the KIT in Amsterdam. "We want to raise awareness of the importance of and potential for reuse in this sector," says Remco Offenberg, managing partner of the company.

Keller has recently performed ground improvement with stone columns below both slab and structure of a large warehouse in Emmen (NL). The project was complemented by an extensive test program on the improved ground. In this test program a series of load tests and laboratory tests were made on two different aggregates, Natural Stone Aggregate (NSA) and Recycled Concrete Aggregate (RCA). The tests were conducted to validate Keller’s ground improvement design using Plaxis 3D for the warehouse to be built, as well as determining the suitability of using RCA in the columns.

The testing program has shown good results which confirm the possibility to carry out low carbon footprint ground improvement for warehouses.

Underground car parks (UCPs) are an option to increase the number of parking spots in densely populated areas. Many UCPs in the Netherlands incorporate permanent steel sheet pile (SSP) retaining walls, but not in Germany. This study compares retaining walls for a typical two level UCP in Berlin and shows that, similarly to a recent study for the Dutch market, a permanent SSP wall is more cost-effective than a secant pile wall and a diaphragm wall (difference ≥ 18 %). A Life Cycle Assessment (LCA) shows that the permanent SSP wall has the lowest carbon footprint (difference ≥ 156 %).

To continue support the reuse of existing foundations, an assessment of existing piles was implemented on a project in Brockville, Ontario, Canada, while the existing underpass structure built in 1967 was being demolished. This paper describes the scope and the results of the assessment program to evaluate the capacity, integrity, and durability of the existing steel H-piles. The program included pile extraction, visual examination, ultrasonic thickness measurements, and strength testing. Soil and groundwater sampling and corrosivity testing were also conducted, along with geophysical testing including parallel seismic and borehole magnetometer testing to verify the pile lengths.

This case study highlights the geotechnical design of civil structure "KW004", part of the A9BaHo project in the Netherlands, widening it from 37.5 m to 60 m. The existing foundation constructed with prefab concrete piles are reassessed in accordance with Dutch Standard NEN8707, while the extension will be constructed using bored soil displacement piles with permanent casing, designed according to Dutch Standard NEN9997-1. All 208 existing piles can be reused, saving an estimated 1211 tons of CO2 emissions which includes materials, transport and installation. This case study shows that reusing foundations is both feasible and profitable, offering significant CO2 savings alongside time and cost savings.

In our commitment to reduce carbon footprint, it is increasingly common to investigate whether existing pile foundations can be partially or even fully reused in the reconstruction or remodelling of existing buildings. However, such thinking is rarely applied on a large scale for critical infrastructure. This could all now change, thanks to Fugro’s artificial intelligence (AI) generated ground modelling that has seen the reuse of foundations to viaducts in the widening of the A9 Badhoevedorp-Holendrecht.

In late May of this year the second edition of the Conference on Foundation Decarbonization and Reuse will be held in Amsterdam. In this article the conference chair, Gerald Verbeek, describes the reasoning behind this conference as well as the objectives and goals that the organizers have formulated for this event.

“The foundation for a bright world” is Van ’t Hek’s vision on sustainable construction.
Van ‘t Hek is not only investing in Zero Emission plant and machinery, but also in ICT solutions and research to reduce its Carbon Footprint by reducing the usage of materials in their projects. Van ‘t Hek is well aware that close collaboration with clients, suppliers and other piling companies is a prerequisite to make a positive impact. A recent initiative is the recycling of drill mud while installing screw displacement piles with grout injection.

The ground improvement technique jet grouting always gives a large amount of return grout. The aim is to reduce the quantity of groutspoil and upgrade them to facilitate reuse. The “Koopvaarderschutsluis” project was used as a test project for the spoil treatment. While the technical lifespan of a lock is being extended, the lock remained in use. You will be taken through the steps taken to reduce the carbon footprint. In the end, after conducting an initial trial, the feasibility was proven and the further steps can possibly be taken in future to take reuse of residual materials one step further.