GFRPs, Heritage Timber, Education, Sustainable Concretes, Performance Based Fire, New Instruments and More!

Summer conferences

We have an exciting two weeks ahead. The research team will be visiting 4 conferences in the coming weeks to present 6 presentations. In addition we will have a 7th presented at ASFE and this will be announced at a later date. The below are brief descriptions of each. Open access versions will appear at a later date.

CSCE Symposium in Vancouver (May 31st to June 3rd)

Mass Heritage Timber Performance in Fire presented by Arlin Otto. The paper looks at a comparison of timber performance in fire of three unique types of timbers. The paper will also discuss adhesive bleeding seen in LVL panels .

The Strength of Lego

Capped and Uncapped (2×1 brick) Lego specimens before compression tests

Had an absolute grand time crushing Legos with Hailey Todd and the virtual ventures summer camp at Carleton University this week. Thought Id pass on some of the results we observed. Unlike the previous study conducted for the BBC where only one Lego block type was tested, we really wanted to understand what happens with Lego under a realistic building configurations and loading scenarios. So we took typical Lego blocks of 1×1, 1×2, 1×3 and 1×4 brick sizes and tested them in a loading actuator with compressive displacement control (mm per minute).

What we observed was that as the size increased so too did the ability to carry load (see graph below). Though it was not proportional to the added stud-brick for each block. We did not cap the Legos because we wanted to see the full effect. Basically the failure mechanism is as follows, the test begins with load being applied and the Lego brick ‘stud’ is pushed into the block giving a flat loading surface along the top of the block, there is a small elastic phase and then we begin to crush the Lego block (its peak load). Later we did cap the Lego and saw some interesting differences in peak load and failure pattern (see below).

lego results
Elementary school students as part of the virtual ventures summer camp at Carleton crushed Lego to introduce them to how building materials behave under load. An unexpected non-proportional trend in load increase with brick area increase was observed.

We opted to use Lego as a teaching example as its a relatable building material to youths. I think its a gate way to show them just how strong materials are when you can relate them to the day to day lives, obviously we get them hooked there, and progress to crushing concrete and breaking steel much after.

After testing the 2×1 brick Lego. The uncapped Lego failed at 4.2 KN; whereas the capped lego failed at 3.7 KN. Both blocks terminated with the same deformation level in mm. Not the different failure mechanisms are because the load is applied differently throughout the lego.

New Book on Post-tensioned Concrete in fire

A new book will be published by Springer titled; Structural Fire Performance of Contemporary Post-tensioned Concrete Construction. The book is available now. You can now order or download it here . The book features:

Our book is a concise account of PT concrete behavior in fire.
Our book is a concise account of Post-tensioned concrete behavior in fire. It is an essential first stop for new researchers and firms trying to understand this structural system in real fires.
  • A follow up to my highly cited Fire Safety Journal 2011 literary review paper – doubling the amount of tests analyzed;
  • New insights on bonded post-tensioned concrete construction;
  • Concise account of three large scale multi span post-tensioned concrete floor high temperature tests;
  • Updated five phased deflection theory on post-tensioned concrete continuous members in fire; and
  • New evidence regarding the origins of the standard fire test and discussion regarding that test’s relevancy to unbonded post-tensioned concrete construction.

The book aims to provide raw and valuable test data (restraint, tendon stress, slab temperatures, deflection etc.) from the three large scale tests fire tests on post-tensioned concrete. This information will be useful for structural design firms and researchers interested in understanding concrete structural systems in fire.

A three span continuous post tensioned slab strip before testing under elevated temperature.
A three span continuous post-tensioned concrete slab strip before testing under elevated temperature. An account and raw data of these tests is provided in the book.

Developed based on my internationally recognized doctoral thesis (improving and expanding on portions from: chapter 2 – literary review and chapter 5- large scale testing of concrete slabs), the book represents a balanced and essential overview of the subject. Other chapters and portions of that thesis are being developed for publication elsewhere (future post to come).

The book was copy-edited by a communications intern on my research team and co-authored by the University of Edinburgh’s Luke Bisby. Our goal was to create a highly accessible book for entry undergrad students to senior engineers.