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Mar 2020 : Seismic performance tests in collaboration with Imperial College London




Large-scale beam-column tests incorporating Bartec/Fortec and Griptec couplers located at the expected plastic hinge zone, together with un-spliced rebar specimens, have been performed under loading simulating seismic load conditions.


Highlights of the test include:

  •    Both coupler systems allowed the development of ultimate rotation levels that are likely to be adequate for typical seismic design situations.

 •  The capacity was largely the same for all non-axially loaded members, suggesting that the use of Bartec/Fortec and Griptec couplers do not notably influence the member capacity.


Please read full article below:






The seismic performance of reinforced concrete members incorporating Dextra Bartec/Fortec and Griptec couplers




Ductility is a key performance characteristic for concrete reinforcement used in seismic design. The ductility of mechanical rebar splices, when used in seismic design, is therefore also extremely important and sometimes not sufficiently considered in product standards and testing practices.


Dextra recently collaborated with Imperial College London, in an experimental study and associated numerical assessment, into the performance of mechanical slices in dissipative regions of reinforced concrete members.


Monotonic and cyclic uniaxial ‘in-air’ and ‘in-concrete’ tests on 16mm and 20mm Bartec/Fortec and Griptec mechanical splices, as well as non-spliced reference members, were firstly performed.


After obtaining a detailed insight into the uniaxial behavior of the mechanical splices, large-scale beam-column members of 300×300mm square cross-section and 1,350mm cantilever length were tested.


The specimens were subjected to reversed cyclic lateral deformation, with or without co-existing axial load. Three specimens were provided with couplers in the expected plastic hinge zone while for comparison a fourth specimen had continuous longitudinal reinforcement.


Prior to the large-scale member tests, predictive numerical simulations were performed in order to steer the experimental assessment.


Seismic Performance Tests

Christmas Party



Specimens preparation a) reinforcement cages, b) members after formwork removal


Seismic Performance Tests

Christmas Party

Specimens preparation a) using Bartec/Fortec, b) using Griptec


The load-deformation responses showed that both uniaxial “in air” and “in concrete” Griptec couplers seemed to provide marginally less ductility than Bartec/Fortec splices and non-spliced specimens.


However, it is thought that the ratios between coupler and rebar length considerably influenced the performance of the in-concrete tie members. The comparative assessment between in-air and in-concrete tests show lower ultimate deformations on in-concrete members in comparison with in-air samples.


For the large-scale beam-column tests, the capacity was largely the same for all non-axially loaded members, suggesting that the use of Bartec/Fortec and Griptec couplers does not notably influence the member capacity.


With regards to ductility, both coupler systems allowed the development of ultimate rotation levels that are likely to be adequate for typical seismic design situations, although Bartec/Fortec performed slightly better due to its shorter length.



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References

Bompa, D. V., & Elghazouli, A. Y. (2019). Inelastic cyclic behaviour of RC members incorporating threaded reinforcement couplers. Engineering Structures, 180, 468–483. https://doi.org/10.1016/j.engstruct.2018.11.053

Bompa, D. V., & Elghazouli, A. Y. (2018). Monotonic and cyclic performance of threaded reinforcement splices. Structures, 16, 358–372. https://doi.org/10.1016/j.istruc.2018.11.009



About Dextra

Operating since 1983, Dextra Group is a manufacturing, freight forwarding and trading company specialized in supplying the construction and industrial sectors. We have activities in more than 55 countries through our network of affliates and partners.

The world leading manufacturer of rebar mechanical splices, we also engineer and produce innovative architectural and geotechnical solutions in high performance steel and FRP composite materials.

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Vision & Mission

To be a global leader in engineering, manufacturing and delivery of high value added quality products and services for the construction industry.

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Managing Team

From day one, Dextra has self-managed its growth as a private equity Group, still fully owned by its founders and managers.

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History

Dextra Group has developed through a long history, during which it encouraged those with an entrepreneurial spirit and constantly strived towards innovation and growth, leading to diversification. Our three main activities are manufacturing, trading and project forwarding, all within the construction and industrial sectors.

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Working at Dextra

Dextra Group, funded in 1983, is a 900-people strong organization operating within the construction, building material, industrial & forwarding sectors.

With multiple teams on all continents collaborating on a daily basis, Dextra makes a point to build a strong inclusive multicultural work environment mixing people of various nationality and promoting gender equality in the workplace.

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