Journals >> Abstract VOLUME 10. No. 1 ( June 1997)
Adventure Tourism : ( Arthur Tyndall
Risk assessment methods. The risks involved with adventure tourism are compared with every-day risks that are acceptable. Codes of practice are discussed in the light of how adventure tourist structures may be used. Active and passive adventure tourism is defined. Examples of risk estimation are given and a figure of 1 in 50,000 is suggested as a maximum level of risk appropriate to active adventure tourism operations. Two principles are postulated which suggest that the public's acceptance of risk is not based on logic and that safety measures introduced are "consumed" by risk taking in other areas. Key elements in assessing new adventure tourist ventures are suggested. The prediction of hazard is discussed with particular reference to prediction of the threat of snow avalanche. The personal liability faced by the expert who predicts and or approves is considered and in the interests of public safety accountability should not be infinite. The engineering profession is challenged, along with the politicians and the legal profession, to devise a better solution than infinite personal accountability.
Sheathing Contribution to Wall Element Strength and Stiffness : ( G. Beattie, B Deam)
A degree of interaction exists between the timber framing members and linings or sheathings of timber framed buildings. The purpose of this paper quantifies this by the following:
- The stiffness enhancement of timber studs sheathed with internal and external sheet materials when subjected to simultaneously applied axial and face loading
- The stiffness enhancement of timber top plates provided by internal and external sheet materials
- The strength of connections typically used between top framing plates and truss or rafter members under uplift loading.
- The paper describes physical testing and results that confirm analysed solutions to the composite action
The Auckland Zoo Rainforest Project : ( S. Biggs)
The paper outlines the design of a cable-tension structure for the zoo rainforest area creating a more natural environment for Auckland Zoo?s monkeys. Structural design features of the rainforest project are the timber pole raised walkway and viewing platforms and the siamang enclosure - a tension cable structure supporting stainless steel mesh roof and walls. The site geology was one of extremes. Across the 50 metre site the foundation materials ranged from shallow basalt, to stiff clay and deep soft silts with an isolated five metre deep pocket of peat.
Some Stability Issues for Tilt-up Precast Panels Under in Plane Seismic Loading : ( B.J Brown )
Materials handling requirements are driving the design of warehouses constructed with tilt up concrete cantilever panels with height to eaves of 12 m and more. Whilst in plane seismic shears for these walls are relatively low, boundary wall fire rating requirements will often dictate the minimum flexural strengths provided at the base , thereby limiting the potential for introducing local yielding starters, as recommended in Ref.1. With panel thicknesses (range 120 mm - 175 mm), careful consideration of panel stability is required to achieve compliance with NZS 3101:1995(1) provisions. This paper considers the load effects requiring consideration, and offers a design approach which (whilst strictly outside the NZS 3101 "Approved Document" provisions) might provide a reasonable prediction of performance, and be adequate as an alternative solution for compliance with Building Code Clause B1 "Structure".
PROJECT REPORTS:
Quay West Apartments, Auckland : (Ashley Smith)
The Quay West apartment building in downtown Auckland is 35 storeys and is the tallest purpose-built residential building in the country, and the first multi-storey building in recent times to incorporate a post-tensioned floor system.The basement and podium floors cover almost the entire site and are approximately rectangular in plan, whereas the 28 storey tower above the podium is located nearer to one corner of the site and is L-shaped in plan. The structural system used in the tower to resist lateral loads imposed by wind or earthquake, comprises shear walls on the south and east sides and moment frames on the north and west sides. The shear walls include the central core walls and also "outrigger" shear walls which are interconnected by coupling beams designed to absorb seismic energy in the case of a major earthquake.The tower floor system was originally designed as precast double tees on precast beams. However several advantages were foreseen with an insitu flat plate post-tensioned floor system, when compared with precast.
James Hardie Building Products Warehouse : ( C.J. Nicholas )
The final outcome of the planning process for this project was to provide a structure of 76 metres clear span with no internal columns supporting the roof, with walls on three sides only, covering approximately 9400 sq.metres of floor space. Substantial discussion and planning occurred at the concept stage in order to achieve the size, shape, and operational requirements of the building commensurate with the future operations of the Company. Aisle widths, volumes of the various products, working space, visual clarity, security, safety and truck movements for both inwards and outwards goods.
ARTICLES FOR DISCUSSION :
Reinforcing Steel: Compliance with NZS 3402 1989 : ( D. Bull)
This article seeks to highlight the provisions of NZS 3402:1989: "Steel Bars for the Reinforcement of Concrete." Firstly by emphasising the performance characteristics necessary for reinforcement used in structures in New Zealand, involving ductile performance for seismic design and presenting aspects of NZS 3402 which may not guarantee these characteristics. Secondly, by describing in some detail the quality assurance measures that shall be adhered to for the supply and acceptance of reinforcement. This seems particularly relevant today as there are currently available a number of sources of reinforcement from outside New Zealand.
P-Delta Actions and the Loadings Code : ( R. Fenwick, B. Davidson )
An answer to an earlier article by E.J. Forrest raising questions as to P-Delta actions and limited ductility buildings. In this article a number of questions were raised about the treatment of P- delta actions in the Loadings Code. This very complex issue has been an active area of research at the University of Auckland for seven years. This activity was initiated when it was realised that a design procedure for P-delta actions was required for the code and that no appropriate method could be found in any major overseas code. The initial Loadings Code committee in the late 1980s, decided to have a uniform risk design spectrum. Prior to this date secondary actions in structures, which were sensitive to P-delta actions, were generally covered by having artificially high design spectrum values over a considerable portion of the design spectrum. The reduced margin of the 1992 Loadings Code required including P-delta actions to enable structures with a consistent seismic performance to result from applying the code design criteria.
Comments on the Previous article : (E.J. Forrest )
Concern is raised as to the need to design structures to avoid collapse for the ultimate limit state condition, where damage is expected and it?s effects on elastically responding structures or limited ductility structures, which will become "loose" with deflections due to cracking and straining of members.
