Maintained Load Testing

MLT is typically carried out on deep piled foundations or zone pads. Using either a large stack of load above the foundation to react against or the more efficient reaction system incorporating other foundation elements, the force is applied with hydraulic actuators. The resulting movement, or displacement, is measured using electronic displacement transducers. Load is applied in stages and maintained until the rate of movement drops below a defined value.

All of this is implemented automatically by our system but with the option to control the test remotely should any changes be required. Numerous safety protocols run throughout the test to monitor and curtail loading should the need arise. The same remote connection allows our clients to view the test as it proceeds via our secure online portal. The result of the test is a Load vs. Displacement curve which can then be used by designers to assess the ultimate capacity of the foundation.

MLT is performed on foundations to either verify the serviceability of working elements used in the structure or as an exploratory process to inform the design. The former is known as a proof test where the foundation is taken to 150% of its working load and must not displace more than defined in the project specification. These tests are used for commissioning and often stipulated as essential by the designer; typical specifications and industry guidance states that 1% of all piled foundations installed need to be load tested. The latter is known as a preliminary test where the foundation is taken to geotechnical failure, sometimes more than 500% of working load, to fully corroborate the ultimate capacity. Preliminary testing is an invaluable resource to designers which can help economise on design and save significant cost and time.

In addition to determining overall capacity, it is also incredibly useful to gain more insight into the interaction between the foundation and the ground it is installed in. This can be achieved through the use of highly accurate instrumentation that is installed in to the foundation before MLT takes place. By using instrumentation such as strain sensors and extensometers, data can be acquired which shows how the load transfers in to the surrounding soils along the length of the foundation. This can really help to understand the design and offer opportunities to optimise.

Every construction project is different and can present new challenges that need to be overcome. We provide standard solutions to MLT requirements using well-established systems and proficient personnel. We are also the only UK Testing House who is UKAS accredited for MLT demonstrating our commitment to quality. However, where we really excel is in providing a solution to scenarios that others cannot address. From our years of experience and passion to constantly innovate our services, we provide a robust and reliable MLT service that will help keep all projects on the track to success.