Thursday’s sessions began with a presentation on sustainability. Aspects involving natural, human, social, and financial capital were discussed. Also, the general negativity towards concrete in the news media, however, the speaker viewed this as actually directed toward urbanization rather than the concrete itself. The population is growing and demands infrastructure. The primary source of emissions when producing concrete is the production of clinker. This can be reduced through supplementary cementitious materials. For example, New Zealand has pumice and other natural products to replace up to 40% of clinker in concrete.
Other presentations on Thursday included one by two representatives from NCTIR on the $1.2 Billion repair of the road and rail system resulting from damage due to the Kaikoura earthquake. Their vision was moving mountains to reconnect communities. The two aspects of the project highlighted as key to its success include the organization’s mindset: one team, trust, respect, and dare to innovate and behaviour: connect the dots, drive the solution, and make it happen.
Learnings from the project include:
1) issues came down to communication and
2) “how do we involve the whole supply chain?”
Tim Shannon at Lewis Bradford Consulting Engineers presented on Tūranga, the new Christchurch Central Library. The architectural design was pre-set without room for change. Low-damage constraints were also in place. This generated the selection of a rocking shear wall system to resist ~75% of the lateral load and steel MRF for ~25% (located around the perimeter). One point highlighted regarding the wall system selected is that rocking isolates the walls from peak earthquake accelerations. Two presentations were given relating to concrete codes and updates. The average age of concrete standards is 18 years compared to the recommended 5-7 years.
Thursday evening was a social event held at Forsythe Barr Stadium. The event consisted of bottomless cheese, dumplings, and Korean fried chicken, beverages, and mingling.
Friday began with an interesting, but rough presentation via Skype from a gentleman in France about tall building design. He had been involved with the design of Burj Khalifa, The Emirate Towers, Sun Tower, Broad Group J220, and Jean Nouvel, among others. He discussed difficulties in design, the use of concrete throughout the projects, special considerations due to height, and difficulties encountered during construction.
Another interesting presentation Friday discussed challenges facing the aggregate sector. Difficulties have arisen due to public indifference, legislation such as “no new mines on conservation land” where 32% of available hard rock is located in New Zealand, and lack of planning (i.e. aggregate is not even considered). An example given was Transmission Gully where 5,000 ton/day of aggregate was required according to the plan, however, no plan was set in place to obtain this aggregate and the required quantity per day has never been achieved.
Other issues around aggregate include urban sprawl – people build by quarries and then complain about the noise. Aggregate can only be obtained by digging it up or importing. There are only 3 deepwater ports in New Zealand, which generates severe economic and environmental consequences if the aggregate is imported.
Other presentations discussed the results of recent testing such as testing for Reid inserts. One finding from these tests regarding NZS3101 Chapter 17 was that for uncracked concrete the code is conservative by 2%-19%, but for cracked concrete, it is un-conservative by 9%-23%.
During the session after morning tea, Evie presented on the literature review completed on the efficacy of epoxy resin injection as a repair strategy for damage reinforced and unreinforced concrete. The presentation went well and was a positive experience.
Friday afternoon was our ‘fun session’. Ed, Evie, and Michael went on the Seasider Rail Tour. It was rather drizzly in Dunedin, but the train ride was still great fun.
Later on, was a social event preceding the formal dinner. The canape servers were kind enough to cater to our ravenous appetites and left the remainder of each dish by out ‘BMC station’ near the door. Unfortunately for other attendees, when the servers switched directions, some of the fresh appetizer dishes never made it past the ‘BMC station’.
The MC for the formal dinner was a famous rugby referee Paddy O’Brien. The dinner began with the most popular song from Phantom of the Opera performed on the 3,600+ pipe Organ, which encompassed a full wall of the hall. Awards were given for various achievements and a delicious dinner was served.
Saturday’s presentations focused on testing at UC, University of Auckland, and Tongji University and covered Hollowcore floors, beam extracts from a building in Wellington damaged by the Kaikoura earthquake and a fullscale building with rocking walls and two different floor systems. Alessandro Palermo concluded the conference with a presentation on the Genoa, Italy bridge collapse in 2018. He discussed the designer, maintenance issues, and cause of failure.