Joint standards

Ongoing investments in keeping up to date with evolving – and very demanding – European specifications for gaining Europe-wide assessments of expansion joint design and manufacture will keep mageba at the forefront of this field for years to come.

Efforts towards achieving widespread product specification across Europe in relation to bridge expansion joints have had mixed results to date, resulting in periodic modifications to the approval process that manufacturers such as mageba must always take into account. In 2013, European Technical Approval Guideline ETAG 032, “Expansion Joints for Road Bridges”, was issued by the European Organization for Technical Assessment (EOTA) as a basis for expansion joint manufacturers to gain a European Technical Approval. However, in mid-2013, the construction product regulation introduced a process for European Technical Assessments, ETAG 032 was replaced by a number of European Assessment Documents (EAD) which may be used by manufacturers to obtain a European Technical Assessment (the current meaning of the initialism “ETA”). These EADs are as follows:

  • 120093-00-0107: Flexible asphaltic plug expansion joints for road bridges

  • 120109-00-0107: Nosing expansion joint for road bridges

  • 120110-00-0107: Mat expansion joint for road bridges

  • 120111-00-0107: Cantilever expansion joints for road bridges

  • 120112-00-0107: Supported expansion joints for road bridges

  • 120113-00-0107: Modular expansion joints for road bridges

These EADs provide a more comprehensive specification for the technical assessment of expansion joints, paving the way for more ETAs to be granted for various types of expansion joint. This new level of assessment of expansion joints significantly exceeds any other common national specification for expansion joints in Europe or on an international level, especially in relation to the very demanding field and laboratory testing specified. For example, over-rolling tests using trucks on specially prepared test specimens, with statistical evaluation of data measured during the testing, serve as a viable basis for the assessment of the dynamic behaviour and fatigue design of the tested expansion joint.

Other examples include fatigue testing and wear testing of components and subsystems for the assessment of fatigue resistance and durability, and full-scale kinematic testing to prove movement capacity. Examples of such testing in relation to the especially demanding assessment of mageba’s TENSA®MODULAR expansion joint are shown in the photos, and further details can be found in this mageba paper presented at the 2020 Istanbul Bridge Conference.

At mageba, we welcome this new development as a better basis for the assessment of expansion joint performance, recognising that the resulting expansion joints will be far more robust and durable than those that are designed to comply with any other widely used standard. Higher standards benefit society both economically and environmentally, by minimising expansion joint maintenance and replacement works on bridges and reducing associated traffic disruption, so anything that improves the quality and durability of expansion joints should be welcomed by all. And for a manufacturer like mageba, which has focused on innovation, quality and testing for decades already, this new assessment and approval regime is another opportunity for us to differentiate ourselves from the other suppliers for whom the new requirements will be much more demanding.

The new European Assessment Document (EAD) approach to enabling manufacturers to gain European Technical Assessment (ETA) approval of their products has validity across Europe and influence in other regions around the world

The assessment and approval process demands expertise and independence from testing facilities, checkers, technical assessment bodies and certifying bodies – as shown here for the 2021 assessment of the TENSA® Type RS HP expansion joint

Example of the very demanding nature of this European approval system: Compared to TL/TP FÜ (Germany) or AASHTO (USA) standards, modular joints will be designed with the distance between support bars (which span the bridge movement gap) almost halved

Example of the very demanding nature of this European approval system: Compared to TL/TP FÜ (Germany) or AASHTO (USA) standards, cantilever finger joints will be designed with finger plates approx. 25% thicker

Dynamic assessment of the TENSA®MODULAR expansion joint – a complex exercise in terms of dynamic amplification and upswing factors, requiring special expertise in the field of measurement and data analysis

Fatigue testing of welded site splice of a centre beam of a TENSA®MODULAR expansion joint, for evaluation of detail category for design purposes

Static loading test setup, including temperature chamber, for testing the sliding components of the TENSA®MODULAR expansion joint at extreme temperatures

Wear test setup for testing the long-term wear performance of the sliding components of the TENSA®MODULAR expansion joint

Fatigue test setup for testing the long-term fatigue performance of the sliding components of the TENSA®MODULAR expansion joint

Watertightness testing of the strip seal design used by the TENSA®MODULAR (and TENSA®GRIP) expansion joint, involving repeated opening/closing movement cycles

Full-scale movement testing of an 18-gap TENSA®MODULAR expansion joint (longitudinal movement capacity 1800 mm) – including combined longitudinal, transversal and vertical movements