Journals >> Abstract VOLUME 11. No. 1 (April 1998)
Displacement and Ductility Compatibility in Buildings with Mixed Structural Systems: ( T. Paulay, J.I. Restrepo)
Elementary but largely forgotten principles, relevant to the seismic behaviour of structural systems comprising elements with very different characteristics, are reviewed. In such structures the system displacement at the ultimate limit state may be associated with very different displacement ductility demands imposed on elements. It is shown how, by simulating nonlinear ductile structural response with bilinear modelling, the unavoidable restrictions on the system ductility capacity, necessary to protect elements with the smallest displacement potential, can be readily determined. To illustrate the application of fundamental principles a few simple examples are presented.
The Stability of Pagodas in Earthquakes: ( Gibson J.A.)
This paper looks at the amazing fact that Japan's Pagodas have withstood the onslaught of earthquakes for over a thousand years, while other structures nearby have collapsed. No exhaustive scientific explanation is proffered. The material is published to raise the question. WHY? A suggestion is made about the future direction of our research.
A Rollformed Steel Truss in a Suspended Concrete Flooring System: ( Stubbings G. )
Speedfloor is a suspended concrete flooring system using a rollformed steel truss for permanent support. The product uses the properties of the two distinct components (concrete and steel), to its advantage. The truss depth and the concrete thickness are changed depending on the span, point loads and other loads induced by the structure.
A Study of Industrialised Floor Systems Available in New Zealand : A Comparison with Boxed and Poured Slabs : The Effects on Seismic Design: ( E. Forrest )
This paper is a study of the various industrialised floor and decking systems available to the design engineer in New Zealand with a preface covering the development of these systems since the 1950's. The reasoning behind the development of the systems and the relationship to earthquake design of the various features and their effects is also covered. The thinking at the time is put into the perspective of today's ideas. The importance of the slab as the seismic diaphragm for distributing the forces in the horizontal plane, and the influence on beam yielding is discussed. A study in this regard, of the boxed and poured slab is is made and the similarity with some systems. Details are given by each manufacturing firm participating in the study.
Engineered Anchor Systems For Masonary Reinforcement : ( Smith Clive V.)
There are many unreinforced masonry structures in New Zealand in need of structural strengthening. In addition there is an increasing awareness about the necessity of maintaining our historical and heritage structures without the use of visually intrusive structural techniques. This article describes the development and merits of the Cintec Anchor System, which is a unique combination of structural and materials technology, engineered to provide an invisible repair to structures in need of retrofitting.
PROJECT REPORTS
Viaduct Basin Redevelopment: Halsey Street Wharf: (Stuart Tucker)
The America's Cup 2000 project is currently under construction within Auckland's Viaduct Basin. The project includes construction of new wharf structures and reclamations, and significant dredging of the basin. When completed, the project will provide space for up to eleven America's Cup syndicate bases, with a media and hospitality centre provided on a new island located within the Basin.
The Halsey Street Wharf is the largest of three new wharf structures. It is approximately 150 metres long by 80 metres wide, with a nominal 24º skew. The wharf is supported on approximately 260 precast concrete piles. The wharf will use some 4300 m³ of reinforced concrete and 700 tonnes of reinforcement during construction.
ARTICLES FOR DISCUSSION
Slenderness of Concrete Walls : NZS 3101 : 1995 Requirements : Discussion paper ( Bull D.)
The author discusses some current designs of tilt-up wall construction that appear to go well beyond the limits of the concrete standard. He points out the reasons for the t/H limits set and the need for adhering to them. He discusses localised buckling and over-all buckling.
The Building Act, The Ten year Limitation Period and the Ethics of Engineering : With a Reply by Mr Cashin : ( Esli Forrest, & B. Cashin )
The author discusses the fairness and ethics of the ten year limitation period of Clause 91 of the Building Act. He gives a example case to illustrate the issues. This is an extension of the article in Vol. 10. No.2 in which the anomaly between the fifty year stability and durability requirements of the building code and the ten year limitation period are discussed. Mr Cashin's reply is given with the article.
COMPUTER CORNER:
Non-Linear Seismic Analysis of Unreinforced Masonary Buildings : ( Bell D.K. )
The NZSEE Draft Guidelines for Assessing and Strengthening Earthquake Risk Buildings' specifies that a non-linear computer analysis is required to accurately assess the stability of un-reinforced masonry buildings (URM) under seismic loading. This paper discusses the implementation of non-linear URM analysis with a three-dimensional finite element program. URM3DX.
MATERIALS CORNER
Cathodic Protection of Reinforced Concrete : NZ Experience ? an Update ( Lawson M.J. )
Cathodic Protection (CP) has been relied on extensively for many years in preventing corrosion of steel structures in water and soil. It has also been used with success since the 1970's for protection of reinforced concrete bridge decks in the northern hemisphere. During the 1980's development of anode systems extended the application to other elements of structures and buildings. Despite widespread acceptance of CP internationally, there has been limited use in New Zealand.
This article aims to raise confidence and highlights the fact that CP technology is available here as an engineered solution, has a track record and offers a cost effective option for rehabilitation of reinforced concrete structures. in our predominantly coastal environment.
Hybeam: An all Wood, Engineered I Beam (Bier Hank)
Hybeam is a range of I beams with Hyspan laminated veneer lumber (LVL) flanges glued to a plywood web to form beams of depth 246 mm, 300 mm and 360 mm. These beams are available in lengths to 12 m. The Hyspan LVL flanges are manufactured to AS/NZS 4357: "Structural laminated veneer lumber" and the plywood web to AS/NZS 2269 "Plywood - Structural". The durable phenolic adhesive joint between the flange and web is factory made under a third party audited quality control procedure. Hybeam and Hyspan are manufactured by Carter Holt Harvey Engineered Wood Products in South Australia and are now available throughout New Zealand.
