TC Final Responses
FINAL RESPONSES FROM INTERESTED PARTIES TO REPORTS ON TRAFALGAR CENTRE
(Excluding southern extension)
1 Trafalgar Centre is not a post disaster evacuation centre.
2 Nothing stating that the building must close.
T&T report 8.0 (1) – Quote: “allow continued use of facilities for as much of the work as practical.”
3 Legal opinions on the TC have misrepresented the situation. No definitive statement should have been made until extremely important items and omissions in the draft/interim report had been addressed. The current situation reinforces the above point.
4 Amendment Bill going through house right now – Maurice Williamson, Quote: “and the new building standard is different in every town across the country”.
5 Specifications for TC on disk.
6 T&T Trafalgar Centre – Preliminary Statement of Lateral Spreading Risk.
Quote: “Our final report will include greater detail and cost estimates for potential remediation measures suitable for this site. This data is provided as an interim report to allow others to consider the potential implications of lateral spreading to the structure. Analysis and assessment is ongoing and interim findings will be reviewed as further assessment is completed.” End quote.
7 R O Davis claims foundations will fail but they don’t know what depth the piles are.
8 Dunning Thornton, 25 October 2013, state that T&T’s geotechnical report suggests the site is prone to liquefaction – 30 – 35% - but accept that they have no knowledge of the pile depths.
9 Technical items for consideration:
9.1 Report on Trafalgar Centre
Appendix B in geotech report Clause 16.1.1 states that reclamation fill above water table is not likely to liquefy, yet the authors talk about surface sand boils (28067 KB 6.6.3)
9.2 Report on Trafalgar Centre
Appendix E Table 1 shows calculated settlements of piles for the different return period earthquakes. The graph shows a settlement of 100mm to 150 mm (only the timber floors could be affected.)
9.3 Report on Trafalgar Centre
Appendix B Fig.6.1 shows the Japanese grading curves.
6.2 shows the site grading curves superimposed on the liquefaction guidelines. The superimposed lines are largely outside the grading curves of concern.
9.4 Report on Trafalgar Centre EC 3445, 5865 KB
Refers to driven piles 2.1.3 which were not used
9.5 Report on Trafalgar Centre EC3445, 28, 067 KB
T&T item 8, Trafalgar Centre assessment.
No mention of post tensioned cables.
9.6 HCG Seismic Evaluation Report.
Item 2.11.2 speaks of slender frames in what is the Victory Room.
9.7 Trafalgar Centre Plans Building permit Co. 69 233 KB
Pages 60 and 157 describe driven piles which we know were substituted with in-situ piles.
9.8 Did the foundation investigation include the deep piles?
The answer appears to be NO.
9.9 Core samples show clay bound gravels –
The reports speak in a confusing manner.
9.10 Concrete strength is in specifications.
9.11 T&T report on foundations infers that the ground beneath the foundation beams has minimum strength. The foundation beams are designed to span from pile to pile, not be supported by the ground.
9.12 Nowhere in the reports is there recognition of the fact that the foundation is a multiple structure as shown on Sheet 28 of the TC plans.
9.13 Alec Louverdis states that the piles, strip footings and piles under the timber floor will fail by punching through a relatively thin layer of gravel to a liquefied zone below. For the main piles to fail in this manner it has to be assumed that they are only about four metres deep. As they are nine to twelve metres deep, they will be in much denser gravel (as shown by the cone penetrometer tests) which are not likely to liquefy. The piles under the timber floor are on pad footings and were designed with wedges to correct any settlement expected in the underlying fill.
9.14 In the reports it is stated that if the ground liquefies the foundations will spread and cause the arches to collapse. The proposal is to install ties across the building at ground level. Nowhere is it acknowledged that ties already exist.
9.15 For the piles to fail in shear as stated in the latest T&T report, the piles would have to develop the horizontal load in passive pressure on the pile which is not considered possible with the likely movement in the fill material. In the North building the timber floor was designed as a diaphragm to transfer the horizontal loads to the bracing walls as in typical house construction.
9.16 Rod Davies states there are strong arguments for and against liquefaction.
9.17 If typical river gravels liquefied there would have been reports of this happening in New Zealand. There are many bridges founded in river gravel that would have been close to a moderate earthquake. Most recently there must be bridges close to Christchurch founded in river gravel.
Section 177(d) of the Building Act states that NCC has 12 months to appeal
Fire rating on southern end - floors and ceiling do not appear to comply
The Final Report has been perused. It is alarming to find that the only alteration in the final is the elimination of the word “draft”. The same statements referring to the draft being an interim report are still displayed in the final report, including the interim reference to costs.
The reference to the principle of shear load in the supplementary paper is accepted. To apply the principle without taking into account the fact that unsatisfactory material extends to at least 3m at the TC site is bordering on irresponsibility.
What does Alec Louverdis mean by “bulbed piles on pad footings” and in which document did he find reference to pile depth of 3 metres?
Section 124 (1) © Building Act 2004:
This notice is remiss in that it has failed to recognise that the Disaster and Emergency functions vacated the TC before December 2013. It also failed to recognise that the requirement to bring the building up to 67% of NBS was ruled unenforceable in October 2013.
Incorrect statements from some NCC staff have created considerable confusion in the minds of councillors and must be recognised.
The final report continues to quote a Joe Kennedy as to the status of the TC. The final report also repeats the following “Our final report will include greater detail” etc. “This data is provided as an interim report to allow others to consider the potential implications of lateral spreading” etc.
Initially T&T presented a draft report for consideration. It is unfortunate that it was taken up by over-zealous participants in the process to mean definitive. A normal process of quiet consideration of the draft report would have avoided the maligning of Nelson’s primary multi-function centre.
John Treweek, who worked for the contractor who installed the Frankipiles in 1971 claims that they struck water in two holes only. It is accepted that site conditions can change.
A draft of responses to the TC reports was presented to the Mayor and Deputy-Mayor on 19 February 2014.
For the benefit of anyone without the knowledge of “Conditions of Contract”, it is acknowledged within the construction industry that where there are ambiguities in either the specifications or plans of any project, that the specifications take precedence. In the case of the TC specifications, the stipulated pile depth is clearly stated, including appropriate engineering requirements based on previous detailed site investigations.
Because of the seriousness of the fact that incorrect information has been distributed and that few, if any, of the above points have been addressed, Councillors would be advised to rescind the motion to close the Trafalgar Centre and reconsider the whole issue.
By not acting immediately, the repercussions i.e. community concern, sports disruption, the detrimental effect on retailers and tourist operators, the lack of maintenance on the building and the serious loss of income will be severe.
Kerry Neal – TC Construction Details Researcher
Ian Hatton – TC Designer and Site Engineer
David Brathwaite – Civil Engineer
Mike Hislop – Former Principal, Building Control Office, NCC Active Building Consultant
Team members are ready and prepared to take part in the process of reconsidering the Trafalgar Centre issue.
K C Neal
Ph: 545 1709
Cell: 0274 454 606