In addition the laboratories house a range of specialist equipment for testing both asphalt and concrete samples either manufactured in-house or obtained from external sites or manufacturers.

Structures Hall

The key feature of the Structures Hall is the strong floor that enables structural elements and beams to be tested either statically or dynamically at loads of up to 1,200 tonnes. Testing can be undertaken using standard or purpose built test rigs and a fully automated data collection system is available to monitor and record load, deflection and strain data from a range of instrumentation during the testing process.

Loading is achieved either by using hydraulic jacks powered by the main hydraulic pump which operates at 3000 psi and delivers oil at a rate of 180l/min, or smaller Enerpac jacks that operate by hand or electrically driven pumps. Various jacks are available which can apply static loads up to 300 tonnes and dynamic loads up to 100 tonnes in both compression and tension. As well as being used in the laboratory the Enerpac loading jacks are also available for on site testing, as is a portable hydraulic jacking system that can generate loads of up to 8,000kN.

In addition to load testing using hydraulic loading jacks a 4m long, 5 tonne mass pendulum rig can be used to provide controlled impact loads for the development and performance assessment of various test specimens ranging from bridge columns to crash barrier systems.

Laboratory based test equipment

Other facilities within the main Structures Hall include smaller dedicated loading machines such as the 150kN Instron and 500kN Avery Denison, that can be used for both compressive and tensile load testing.

There is also a 250kN Schenck fatigue machine for dynamic load testing at frequencies up to several Hertz, depending on the required load and specimen displacement. Other equipment used in the measuring, monitoring and performance assessment of structures includes ground penetrating radar (GPR) and acoustic monitoring systems. There is also a 1m3 environmental cabinet which can operate over temperature and humidity ranges of -40oC to +120oC and 0% to 100% respectively.

Geotechnical and Sustainable Engineering Assessment

TRL hosts a wide range of geotechnical and sustainable engineering capabilities and technologies. Our facilities enable a wide range of testing, from performance assessment of geosynthetic materials to full scale trails of highway and landscaping structures.

Slope Engineering

We can assess the physical properties of geosynthetics and their interaction with soil, with site damage strength effects and pull out techniques pioneered in-house and which are now accepted as industry wide standards. We use our specialist capabilities to carry out high quality trials combined with extensive performance monitoring to reduce the risk of slope failures.
Our planted vegetation trials on slopes constructed from both natural and waste/alternative materials, have significantly contributed to private and public sector organisations developing and improving their slope engineering and product development related capabilities.
Our testing facilities include the capability to assess the performance of:
Soil nails
Engineering and bio-engineering materials and processes
Innovative piling techniques

Retaining Structures

Our non-destructive ground penetrating radar (GPR) capabilities are used to assess the condition of masonry walls and carry out sub-structure assessments, including void location.

Ground Penetrating Radar for pavement investigation

Ground Penetrating Radar (GPR) is a non-destructive technique used to obtain construction information about the pavement and its internal features continuously along the road. GPR equipment consists of transmitter and receiver antennae coupled to a control unit, generally mounted on a survey vehicle.

How does GPR work?

GPR equipment consists of transmitter and receiver antennae coupled to a control unit, generally mounted on a survey vehicle.
There are two types of antennae design;
Dipole antennae (close to the ground) (A) and
Horn antennae (spaced further from the ground) (B).
As the vehicle travels, the transmitter emits short electromagnetic pulses into the ground at predetermined intervals. When the signal passes through layer interfaces part of the signal will be reflected back to the receiver at interfaces of different materials or internal features.

The time duration between each pulse and reflected signal is digitally recorded in conjunction with the distance between pulses. This information can be used to enhance pavement condition information obtained from visual condition, coring and trial pits and help the engineer decide on remedial actions required for worn pavements. GPR, in conjunction with calibration cores, can provide 100% coverage of the network at a small fraction of cost of equivalent coverage by coring.

Practicality

GPR requires sufficient contrast between layers in order for them to be visible and their thickness determined.
In the UK, calibration coring are highly recommended in order to obtain accurate and reliable layer thicknesses.

Where to use GPR?

Network Level (at traffic speed)

Construction information
Construction changes
Scheme level (at slow speed, requiring traffic management)
Construction information
Construction change
Relative moisture variation
Voiding (C)
Reinforcement mapping/Dowel bar assessment (D)
Material volume calculations
Crack depths (E)

Legislation

Any GPR operator in the UK must hold an OFCOM License to undertake GPR on network in agreement with the EuroGPR code of practice and the DMRB.

Training

This equipment is very specialised and requires training for the operation and data processing and interpretation. The data interpretation is subjective.

Health and safety

Any operator using this piece of equipment should comply with the Health and Safety regulations (COOH, site operation procedures)

Buried Structures

TRL's testing facilities are used to assess the performance and maintenance requirements of pipes and culverts and have lead to independent validation of new pipes, chambers and associated drainage systems. Our testing has also significantly contributed to the development of design standards, advice notes and new European standards.

For utility companies, testing includes trench reinstatement studies, trenchless construction and full-scale structural testing of pipe work and access chambers. We also have the capability to undertake tunnel and building ventilation assessments, often in association with emergency response teams using our artificial smoke production facilities.

Earthworks

Our leading testing facilities enable performance assessment to be made of compaction plant treatment of highway capping and fill materials with chemical and natural additives, and the development of new specifications for recycled bituminous planings. Using our range of specialised monitoring equipment, we also have the capability to assess and advise on operation and construction-induced ground vibration.
These mainly sustainability focused projects help reduce dependency on natural aggregates and enable construction operations to achieve realistic environmental and financial savings.

Geoenvironmental

Our expertise in testing and assessing the properties and uses of recycled aggregates and materials for road construction has set standards in the UK and Europe that others are now adopting. This includes the in-situ and laboratory assessment of mechanical and chemical behaviour and the investigation of the new test methods to predict in-situ performance.

For more information contact:
David Blackman
Laboratory Manager
Telephone: +44 (0)1344 770296
Email: dblackman@trl.co.uk

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