Journals >> Abstract VOLUME 11. No. 2 (September 1998)
Engineering in Need of Heroes ( Published by kind permission of the Economist )
The article discusses the fact that the modern engineers are relatively unknown despite their outstanding work.... Ted Happold, an engineer who worked on the Sydney Opera House and the Pompidou Centre in Paris, once wryly remarked that while everybody knew Whistler's grandmother, nobody knew that his father was a distinguished engineer. He might have added that Whistler's uncle was one as well.
While Happold had a point, everybody does know of the man whom Whistler and McNeill went to Britain to meet, George Stephenson, renowned as the father of the railways. In Stephenson's time engineers were quite often famous. For almost a century after 1760, they bathed in the reflected glory of their amazing creations. The peak of glory occurred at about the time of the Great Exhibition in 1851, which an engineering historian, L.T.C. Rolt, has called "the high noon of engineering".
Twist in NZS 4203 : 1992 ( Paulay T.)
Existing provisions of the New Zealand loading code [1], relevant to the torsional response of buildings designed for ductile response at the ultimate limit state, are claimed to be irrelevant. These provisions follow closely the trends adopted the world over. In these codes the estimation of torsional strength demands are specifically based on elastic response with disregard to displacement demands on various elements. Some of the restrictions imposed by our code, are considered to be restrictive and unrelated to ductile structural response. The critical quantity to be considered in ductile response is claimed to be strength eccentricity, based on the nominal strength of elements, as constructed. Two specific examples with extreme stiffness eccentricities are examined to demonstrate that exceeding code-imposed limits does not result in detrimental features of ductile behaviour. The comparison is based on the evaluation of simple torsional mechanisms developed in ductile systems.
Moment-Resisting Steel Framed Seismic-Resisting Systems with Semi-Rigid Connections : ( Clifton G.C., Butterworth J.W., Weber J.)
HERA is involved in a long-term research project to develop a new form of moment-resisting steel framed (MRSF) seismic-resisting system which maximises the seismic-resisting attributes of steel as a material. Its outcome will be the development of an innovative form of MRSF seismic-resisting system that can be brought back into service following severe seismic attack, more quickly than is possible with existing seismic-resisting systems. The system under development utilises standard I-section members for the beams and columns, with these members connected via semi-rigid joints that can rotate (open and close) during a design level severe earthquake and beyond, while suffering minimal structural damage under the design level event.
Design Procedures for Moment-Resisting Steel Framed Seismic-Resisting Systems with Semi-Rigid Connections ( PART 2) : ( Clifton G.C., Butterworth J.W., Weber J.)
This paper, which is a companion paper to the previous one presents step by step design procedures for MRSF frames with semi-rigid joints. Clause numbering and references follow on from the previous paper to simplify cross referencing.
The design philosophy and target performance criteria for the semi-rigid systems are then presented. All of this material is summarised from [2].
Design procedures for the MRSF systems using these joints are then given, followed by details of analytical modelling undertaken on representative frames to establish their time-history response to a range of earthquake records.
Problems with the Design for Shear in Circular Concrete Members : ( Fenwick R., Lipscombe P. )
In reviewing the design of circular reinforced concrete columns in two recent projects it has been found that inadequate shear reinforcement has been provided. This problem arose due to the difficulty designers experience in interpreting some sections of the concrete standard NZS 3101:1995. In particular problems occur in finding the shear that can be resisted by the concrete mechanisms and the use of the equations for the design of hoops or spiral reinforcement.
In this note the background to some of the code clauses is discussed and a worked example is given to illustrate their use.
Modifications to NZS 3404 Resulting from Development and Testing of MemDes : ( Bird G. )
This paper covers some refinements to the Steel Structures Standard, NZS 3404, resulting from the development and testing of the structural steel design program, MemDes.
PROJECT REPORTS
Taranaki Combined Cycle Power Station : ( Simpson A., Keals-Smith T. )
In the wet winter of 1997 the first large power station construction in New Zealand for over a decade was well underway. And unlike previous large New Zealand power stations this was not government sponsored, but a privately constructed scheme by Stratford Power Ltd, a joint venture between Fletcher Challenge Gas Power Ltd and TransAlta Energy Corporation.
It was also the first installation of the new flagship state-of-the-art GT26 turbine for ABB Power Generation Ltd. The Swiss based ABB had been awarded a turnkey contract for the project, providing the generation technology and fully constructing the works. Worley Consultants were engaged by ABB as local consultants to provide civil, structural, architectural and building services design.
Piled Slabs For Domestic Construction : ( Chapman J. )
A system of driven timber piles in place of the typical domestic strip footing is presented as a suggested addition to NZS 3604. The economics of this approach is also discussed and the saving from the need to found at a depth below the shrinkage level of the soil.
COMPUTER CORNER :
3D Computer Aided Drafting in Today's Engineering Office : ( Scott W.K. )
The tools of the professional Engineer today take many forms and now, more than ever, Engineers are reliant on being aided by computers in all aspects of their daily work. 3D programs have become almost a necessity not only to take away the guess work in designing but to ensure that all components from various disciplines fit together, long before they are manufactured or delivered to site. 3D programs available today have the provision to clash check the structure which helps to almost eliminate on-site rectification work. The cost of which can be enormous, not to mention the loss of time and the damage to the reputation of the Engineer.
X-Steel is a 3D modelling/detailing and material listing program for structural steelwork. Since its launch onto the market in the UK in 1993 it has become one of the most advanced and user friendly systems available today.
