Subsidence compromises the integrity of a building. While concrete underpinning and ground improvement can help to slow or stop a building from subsiding further, sometimes this is not enough.
In warehouse and manufacturing environments for example, it is crucial that a building is level and stable to ensure the safety of the facility. Therefore, raising and re-levelling a building can be a necessity.
Why is re-levelling so important?
Uneven or sloping floors immediately create trip and fall hazards, while also affecting the stability of walkways, gantries and elevated work platforms. This greatly affects the ability for workers to carry out routine tasks safely. A sinking floor often indicates that the building’s foundations need reinforcement or remediation, which is particularly important when the floor needs to support the weight of heavy machinery. In warehouse and manufacturing environments, it is crucial to the safe operation of forklifts, pallet jacks, cranes and delivery lorries that the floor is stable and flat.
A subsiding building also adds adverse stress to walls and roof structure leading to longer-term issues if not addressed. Aside from this, it also has an adverse impact on the value of the building.
How to safely raise and re-level a building
Lifting a building is not a straightforward task as many variables come into play. Often, structural engineers opt for traditional concrete underpinning, as a way to mitigate the risk of ‘over-lifting’ which can be damaging. To re-level a building accurately and safely, engineers need a precise degree of control.
Mainmark implements its highly precise and effective JOG Computer-Controlled Grouting technology, which makes it possible to substantially lift a building’s foundations, back to level, while not impacting the surrounding area, this degree of accuracy is crucial. To achieve this, multiple small injection ports are installed throughout the foundations of a building and along the structural pads of the subsided section. Through these ports, JOG high mobility cementitious grout is injected slowly, under precise monitoring. Injection takes place via multiple ports a few seconds at a time, to gently raise the structure in a uniform and incremental way, effectively “floating” the structure, a millimetre at a time.
The monitoring data from the manual or robotic system is fed back to the controller who alters the program in the computer and directs the flow of grout to the individual injection ports.
In some cases, to successfully lift a building safely and accurately, a two-pronged approach may be needed. Mainmark’s proprietary Teretek resin injection solution can be used to fill any voids, raise the floor level or provide additional ground improvement below or around the JOG injection area. Teretek is unique in that it delivers both ground improvement and re-levelling with a fast, non-invasive process likened to key-hole surgery. As with JOG, constant monitoring of the process ensures that it is successful.
Mainmark | JOG and Teretek® used to raise and re-level a 3,700m2 warehouse in Pontefract
For more information on structural and subsidence concerns or to arrange a free site visit and assessment visit: https://mainmark.co.uk/
By Victor Chirilas
Victor is the Operations Manager at Mainmark UK, with over 10 years’ experience in project management and construction management. Having joined Mainmark in 2009, he has managed projects in Australia, the UK and New Zealand including the remediation of the Christchurch Art Gallery which was shaken by the 2010 and 2011 earthquakes that hit New Zealand’s South Island, the old Bank of New Zealand building in Kaiapoi and Ultima Furniture’s warehouse in the UK.