MINUTES OF WELLINGTON BRANCH TRAINING AND NETWORKING EVENT
held on Wednesday, 12th July 2017 at 4:00pm at Hutt City Council 30 Laings Road, LOWER HUTT
Welcome: Wayne Goodfellow – Branch Chairperson
Attendance: Steve Kallahar (Wellington City Council), Barry Harlen (Wellington City Council), Peter Burnet (Wellington City Council), Walter Hill (BOINZ), Anna Kaiser (GNS Science), Matt Gertenberger (GNS Science), Bruce Glasgow (Artisan), Richard London (Facio Ltd), Wayne Goodfellow (Fire and Emergency NZ), Craig Ewart (Hutt City Council).
Apologies: Tom Edhouse (BRANZ), Maggie Kay (Wellington City Council), Bruce Symon (Realsure Ltd),Peter Laurenson (MBIE), Michael Portenes (Realsure Ltd), George Mason (Porirua City Council), Rob Tierney (Holmes Farsight), Michelle Te Ohaere (BOINZ), Nick Hill (CEO BOINZ), Richard Nation (NPI), Craig Watson (Kapiti Coast District Council), Adrian Cullen (South Wairarapa District Council), Chris Scott (Wellington City Council), Katharine Wheeler (Kapiti Coast District Council), Peter Webb (Mainland Claims), Matt Grant (MBIE), Natalie Hardy (Holmes Farsight), Mike Reedy (MBIE), James Firestone (NZFS), Murray Usmar (MBIE), Gary Higham (MBIE), Jack Lyons (BRANZ).
Minutes and Matters Arising:
The previous minutes were accepted as an accurate record of the previous meeting and have been made available on the BOINZ Website.
Moved: Bruce Glasgow Seconded: Steve Kallahar
Correspondence In/Out:
• The BOINZ Senior Building Officials Forum is 23rd to 25th August 2017, registration now open.
• 50th Anniversary this year, members were encouraged to invite colleagues to join BOINZ and take advantage of the levy waiver this year.
• BOINZ Board update was read to members, giving an update on recent board activities.
General Business:
• Barry Harlen thanked members for his nomination as the Ryanfire 50th Anniversary Award recipient at the BOINZ Conference in May.
This is the first time this award has been presented, and was awarded as part of the 50th Anniversary celebrations to one person in each branch, as an acknowledgement of service and commitment to furthering the success of the institute. Barry for many years has been our unsung hero, dedicating numerous hours to the branch and working behind the scenes, encouraging members to value their profession and promote the institute. His continued support of the Wellington branch executive and our membership helps make Wellington branch the vibrant and inclusive branch that it is today.
• Walter Hill provided an update on the Training Academy and milestones achieved so far.
Highlights included; 112 people have trained since May 2017. The NZ Diploma in Building Surveying Level 6 has been launched for full time study. The Institute is currently working with Educational Partners to create a cadetship in employment pathway. The Institute is now offering a Solid fuel heating course in conjunction with the NZ Home Heating Association. If you are interested in training please contact Walter on training@boinz.org.nz
Site Visit: Hutt City Council – Seismic Upgrade of a Heritage Building
Figure 1: The main entrance of the refurbished Hutt City Council building.
Members braved the rain and were met by building control team leader - Craig Ewart and taken on a tour of the facility to see the upgrade of the heritage building and hear about the seismic structure put in place to support it.
Figure 2: Members meet in the main foyer – in the background is a new public access corridor used to access to meeting rooms
Members learned about the Beam and portal structure that was tied back to the main structure so that the old heritage façade could be maintained. The steel windows were refurbished and special double-glazed units manufactured to fit within the existing steel frames.
Figure 3: Double-glazed safety glass units specially made to fit within the existing steel frames.
Members were shown the new seismic frames and shear walls inserted within the existing building structure. At the rear of the building a new moment resisting frame was created to give the building lateral stability. The old windows were removed and a new atrium created to bring South light into the office spaces.
Figure 4: View of the old rear of the building and new atrium, with a close up of a seismic frame holding it together.
Figure 5: A glazed roof and rear wall bring natural light into the building, with steel frames providing seismic restraint.
Figure 6: A steel plate stairwell runs up the inside of the building hanging off the steel portal frames.
Figure 7: Members looking across the stair landing into the break out spaces across the atrium.
Figure 8: Hutt City staff now get one of the best views in town, looking out on to the park behind the Council buildings.
72 Screw pile were constructed to anchor the building. Allowing the façade to be retained. The building was then rebuilt using permanent steelwork.
Members also learned about the new heat rejection system installed as part of the rebuild. It is used as part of the heating and cooling system in the building. At each pile three loops of service pipe were installed to utilise the ground water temperature as a cooling source. The way it works is to use the constant 10°C ground temperature to cool or preheat the building as required. This makes the building services more energy efficient, by using the ground to release or absorbing excess heat.
Figure 9: Members experiencing the new bright office with its open plan layout and specially designed break out spaces.
The building was able to have open floor plates because of the used of shear walls (cleverly hidden near the toilet blocks and stairs) and a new diaphragm slab that locked the structure together to the new seismic resisting frames.
Figure 11: The new Council Chambers – designed to enable members of the public to come and join in Council meetings.
New Council Chambers were built with special afterhours access so that members of the public can come along and join in the Council meetings. This was one of the original design parameters for the upgrade brief to ensure building security could be maintained, while providing greater functionality and access to the public spaces – including the ground floor meeting rooms, community spaces and upper floor access to the Council Chambers.
Figure 10: Members assemble in the new Council Chambers for the GNS Kaikoura presentation.
Members were then given the opportunity to use the Chambers for the remainder of the meeting.
Further information can be found at http://www.hcc.govt.nz
Guest Presentation: Kaikoura Update – Anna Kaiser and Matt Gertenberger
Anna Kaiser Seismologist & Matt Gerstenberger Seismologist from GNS Science will present "A seismological overview of the M7.8 Kaikoura earthquake: How did the ground shaking unfold and what does the earthquake mean for future hazard?"
Members were taken on a step by step analysis of the seismological unfolding of the Kaikoura earthquake. During the presentation Anna and Matt explained the ground motions of the Hikurangi subduction zone, the North Island dextral fault belt and its interaction with the 20 plus Marlbourgh faults running through the Kaikoura region.
Anna explained that the length of ground shaking and the direction of the quake propagation to the North was one a major contributing factor to the damage seen along the Kaikoura coastline, where up to 11.8m of uplift occurred.
Over the two minutes of shaking the earthquake wave front moved up the rock spine of the Southern Alps along the East coast and shockwaves were then echoed on the West coast around Kapiti where ground conditions were softer. The earthquake energy released caused some amazing land deformations.
The Papatea Fault experienced significant shear displacement which was very distinct. The specific features being caused by peak ground acceleration in the area moving the land North.
Figure 12: 3m uplift with a shear rock face - GNS Science
Matt further explained that in Wellington, we had some unexpected ground accelerations occurring due to the way the earthquake ground waves bounced around the Wellington harbour, exciting soft soils to exceed 1:500-year ultimate limit state (ULS) movement modes. Members learned that these peak accelerations are what caused a number of buildings in Wellington to apparently fail.
Whilst significant damage had occurred in them, the buildings themselves had experienced and performed to ULS design load forces. What was unexpected was the localised nature of these forces occurring due to ground resonances triggered by ground waves reflecting in the harbour basin.
Members were shown a video of the dynamic displacement model showing a time lapse of the ground movements as the earthquake moved through the earth through the various fault lines. Data for this model was obtained from the GNS Global positioning locators situated around the country. The primary wave front was shown to move at 0.4m/s and members could see the way it bounced in the Wellington Harbour causing peak accelerations around the waterfront.
Figure 13: GNS Ground acceleration propagation model showing the effect on different height buildings in Wellington as the earthquake ground wave approaches from the South.
Members were then able to ask questions and discuss Wellington’s specific seismology and ground acceleration profiles. Earthquake intensity is rated using the Modified Mercalli Scale (MM scale).
One question related to the forecasting of Aftershocks. Matt talked members through the different models of prediction. One of the most widely used models uses “Omori’s Law of Aftershock Decay” which models the time scale and return probability. In simplified terms Fusakichi Omori predicted that the probability of an aftershock the same intensity occurring was 5x as likely in the first day, then 5x in a 10-day period, then 5x in a 100-day period, then 5x in a 1000-day period. He noted each time there was a subsequent earthquake the time frames reset.
The prediction model was developed from studies of previous earthquakes and Omori’s statistical formula has been refined and modified only a couple times since he first proposed it in 1894!
In real terms this means we can expect 10x more MM5 events as MM6’s and 10x as many MM6’s as MM7’s. So for one MM7 event (Kaikoura), we can expect 100 MM5 event, 1000 MM4 events as aftershocks.
Figure 14:left Kaikoura aftershock probability map – GNS Science. Right: Fusakichi Omori - Wikipedia
Further information can be found at http://www.gns.cri.nz
Special Thanks to:
• Anna Kaiser – Seismologist at GNS Science
• Matt Gerstenberger – Seismologist at GNS Science
• The Hutt City Council team for showing us around the site and offices.
6:00pm - Close of Event
Richard London
Wellington Branch Secretary
