Behaviour and Design of Fastenings

Synopsis

Many of us have been using embedded and post-installed anchors in concrete for some time now. However, many engineers have poor understanding of the failure modes and mechanisms used to verify their adequacy. Of even more concern is that many of us just design anchors on a static basis without understanding the response under applied dynamic loading, including low cycle and high cycle fatigue and response under high strain-rate loading (e.g. blast).

So, it is with great pleasure we have the opportunity to hear from Professor Eligehausen, who is a world leader in this subject, with many excellent publications and papers all well supported by extensive testing.

Cast-in anchors and post-installed anchors/reinforcing bars are often used in practice. Tension loads are transferred directly into the concrete (cast-in anchors) or, for post-installed anchors, by bond stresses from the steel element (threaded rod or reinforcing bar) to the mortar/resin and from the mortar/resin into the concrete. The bond strength depends on many parameters such as type of product, drilling method, cleaning of drilled hole, temperature of mortar and base material, concrete conditions (cracked, un-cracked) and sustained load. The influence of these parameters will be explained. In particular based on the results of extensive testing at the University of Florida and the University of Stuttgart the behaviour of bonded anchors under sustained loads will be discussed and conclusions for the design of fastenings with bonded anchors according to draft European Standard EN 1992-1-4 and ACI 318 Appendix D will be given.

Furthermore, tests and assessment criteria according to EOTA Technical Report 023 (2006) and ICC-ES AC308 (June 2013) will be explained. The design of these connections is done according to a code for reinforced concrete (e.g. Eurocode 2) as for cast-in place deformed reinforcing bars. Based on the results of tests on connections between column and foundation under static and reversed cyclic loading it will be shown that this design approach is conservative. Furthermore, it will be discussed if these connections may be designed as fastenings with bonded anchors.

About the speaker

Professor Rolf Eligehausen graduated from the Braunschweig University of Technology and got his PhD from the University of Stuttgart. He has more than 30 years of experience in research and testing of anchor technology. He is Chairman of the fib Special Activity Group SAG 4 on "Fastenings to Concrete and Masonry Structures" and the CEN Working Group WG 2 "Design of Fastenings in Concrete" and a member of ACI Committee 355 "Anchorage to Concrete". He has authored and co-authored more than 250 papers on reinforced concrete fastening techniques and his book "Anchorage in Concrete Construction" (with Malleé & Silva) is widely viewed as the seminal publication on the topic.

Programme

6:00pm - Registration and welcome refreshments
6:30pm - Chair’s opening remarks
6:35pm - Presentation by Professor Eligehausen
7:35pm - Questions and Answers
7:50pm - Closing remarks from Chair
7:55pm - Close of lecture

Further information

This evening meeting is jointly organised by SECED, ICE and IStructE and chaired by Ian G. Smith (Atkins). Non-members of the society are welcome to attend. Attendance at this meeting is free. Registration is required via http://www.ice.org.uk/Event?ID=2574. The event can also be viewed online (https://ice-org.webex.com/ice-org/onstage/g.php?t=a&d=704318191). For further information, please contact Greg James (tel. 020 7665 2229).