Stevin Laboratorium - Micro2MacroStevin Laboratorium - Micro2Macro


Bas van Schooten
Mekelweg 15, 2629 JB Delft
TU Delft faculties CiTG, 3ME & BK (Civil Engineering and Geosciences; Mechanical, Maritime and Material Engineering;Architecture and the Built Environment)

The Stevin lab develops important insights in the behaviour of engineering materials and structures, under realistic loads and conditions, leading to important scientific breakthroughs.

It is unique in Europe because of its ability to go from small scale material properties to full scale structural failure tests for a wide range of engineering materials and structures. Also, research on innovative recycling techniques is carried out, preparing for a fully circular engineering sector.

The Stevin lab consists of a Macro and Micro lab. Its unique large scale facilities include the Mega Hexapod and full scale test facilities for concrete and steel structures, roads, railways and the Circular Engineering Lab. In the Microlab, an ESEM, nano-indentor and Mercury Intrusion Porosimetry (MIP).

In the Stevin lab materials and structures are tested in representative conditions to allow upscaling to industrial levels and/or provide a basis for inclusion in (international) Standards.

The key characteristic of the Stevin laboratory is the testing of engineering materials and structures across the scales, including full scale validation tests.
As such, it features on the one end full-scale test facilities, which inlcude high-bearing capacity floors on which structures can be mounted and subjected to both static and dynamic loads up to 10.000 kN. The 10 ton overhead traveling cranes facilitate testing of structures up to 40 m long, 20 m wide and 8.5 m high. These are used to test bridges, buildings, houses, windmills etc. Additionally, there is a measuring couch for railway testing and the LINTRACK facility for pavements.
On the other end of the scale the Stevin lab has a micromechanical laboratory. This microlab enables testing of materials and material behavior on nano to microscale, with i.e. ESEM and nano-indentation. Small scale facilities for the testing of asphalt concrete and bio-materials (i.e. FTIR, Dynamic Vapour Sorption equipment) are also available.

Additionally, the Stevin lab has climate controlled rooms, a drying room, a workshop for preparing specialized concretes and bituminous specimens. Recent additions to the facilities include the hexapod and ice-rooms. The hexapod is multiaxial test device for fatigue, ultimate strength and dynamic tests. It is a unique set-up that uses six independent hydraulic cylinders to apply forces and moments independently in all spatial directions on real scale specimen up to 1m³. Its maximum frequency of 30 Hz allows it to simulate 20 years lifetime of a structure in a few weeks. The ice-rooms allow ice to be traced as it forms, deforms and breaks during interaction with a cylindrical structure. It will provide crucial input for offshore wind application in regions where lakes or the sea occasionally freeze. The laboratory also has specialized equipment to test asphalt pavements as well as railways. The new loading facilities in LINTRACK are unique worldwide in providing realistic full scale traffic loading at the surface, while the circular scaled test track for railways allows testing of dynamic wheel-rail contact.

Another unique facility within the Stevin lab is the Circular Engineering Lab (CEL), which facilitates large-scale experiments on newly designed high-end recycling processes. Waste flows, ranging from metallurgical industries to End-of-Life concrete from infrastructure, but also synthetic waste flows from products that do not yet exist like car-parts from polymer-fibre-metal composites, can be processed in innovative treatment lines at capacities close to industrial scale (up to 50 tons/h). New concepts for process lines can be quickly implemented and tested.

The kind of research facilitated in the Stevin lab consists of material characterisation in the Microlab, using for example ESEM or nano-indentation and mechanical tests determining strength, stiffness and rheological properties on specimens varying in size from several millimetres to tens of meters. These tests can consists of response, failure or fatigue tests using load levels varying from a few Newtons to Mega Newtons and loading rates and frequencies from millimetres per minute to km/h, and from 0,1-30 Hz for large specimens.

Some recent, concrete examples of the typical across-the-scales research that involves various facilities in the Stevin lab, showing the combination of experiments and modelling used are:
• development of test methods for asphalt pavement of steel bridges, including the testing of adhesion in the lab, which was used in models that were validated in full scale LINTRACK tests,
• concrete material and structural testing used to predict the structural capacity of concrete bridge girders, which is validated by testing actual girders
• the effect of induced earthquakes on unreinforced masonry buildings through experiments at structural, component and material level combined with validation of models for the assessment and retrofitting of existing buildings.

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