This address covers the development of transport links in New South Wales in the 19th Century, with particular reference to Armidale. The influences on the development of a transport network and how it occurred during the fledgling years of the Colony and more localised areas, such as Armidale, set the scene for future development and growth in the 20th Century and may well influence what happens in the 21st Century. In planning and developing expansion of transport networks and systems, it is often very useful to be aware of and appreciate how existing networks and systems developed and how they impacted on local communities at the time. Often situations have changed little in some areas and therefore some valuable lessons can be learnt from decisions, events and development in bygone years. This serves as a useful means of learning from past actions.

This address covers the development of transport and transport networks in NSW in the 19th century. The influences on transport and how it occurred during thejqedging years of the colony set the scene for future development and growth in the 20th century, and may well influence what happens in the 21st century. In planning and developing expansion of transport networks and systems, it is often very useful to be aware of and appreciate how existing networks and systems developed. Often situations have changed little in some areas, and therefore some valuable lessons can be learnt from decisions, events and development in bygone years. This serves as a useful means of learning from past actions.

This paper describes the evolution of large road bridges in NSW, citing examples of various timber and iron genres in northern NSW. In particular it highlights the high proportion of iron bridges constructed in northern NSW over approximately a 25-year period from around 1870. Various postulates are canvassed as to why that might have been so. Financial astringency forced the engineering profession to account for deteriorating economic conditions and political imperatives. Typical of such major changes was a dramatic swing from substantive and expensive iron road bridges to more slender, astutely-designed and economical timber truss bridges. These colonially-designed "lean and mean" timber truss bridges were a far cry from the earlier, stockier, high maintenance versions that were inherited from British/European designs. In some respects such innovative local design was a symbolic way of releasing the restraining shackles of the colonial past and the spawning of a new nation. For over 40 years these new-style timber bridges, of successively improved forms, dominated timber truss bridge construction in NSW, to the extent that NSW was euphemistically known as the "timber bridge state". It was not until innovations and improvements were made in steel production, steel-fixing and concrete technology in the early 1930s that the newer materials started to replace timber.

Many short span timber beam bridges in regional New South Wales are of unknown reliability, have high traffic loadings and were designed according to codes, many of which have since been superseded. Because asset managers are delaying their maintenance for fiscal reasons, a high proportion of these bridges are structurally degraded and potentially unsafe when excessively loaded. In regional areas, a prioritised maintenance program can be a cost effective alternative to bridge replacement. Such older bridges will require continuous monitoring by low cost methods to assess the temporal probability of their failure. This paper examines the potential for measuring the mid-span deflections of girders caused by high traffic loads to obtain continually updated indicators of the structural health of girders. The mid-span deflection data of a case study bridge were continuously measured using a laser based measuring system, recently developed by the first author. An analysis of the deflection data is used to obtain a reliability index and the probability of bridge failure. Reliability indicators such as these can be used, in conjunction with continuous deflection monitoring, to prioritise cost effective maintenance of older timber bridges in regional New South Wales.

This paper reports on the novel use of a high-speed camera to record dynamic movements of a structure under in-service loading without the need for disruptive dedicated proof-loading. For local and state road authorities this represents a significant reduction in resources needed and avoids disruption to existing traffic flow. In regional Australia there are many short span timber beam bridges of unknown reliability. A case study of one multiple span bridge is examined in this paper. Many timber beam bridges were built in the 19th and 20th centuries and were designed to codes that have since been extensively revised. The original design factor of safety for these structures, with new timber, was anticipated to be about five, but full size element testing has historically been used to show that some in-service aged girders have had a factor of safety of about two. Uniform gross vehicle loads have increased and can have significant impact on multiple span bridges. To determine the level of safety for these bridges requires the application of new measurement techniques. The technique used involved a staff, a vernier and a high speed camera. A staff was attached to the mid-span of each girder and its movement monitored with a vernier at ground level. Dynamic movement was recorded with the camera as a vehicle crossed the test-case multi-span bridge at Gostwyck, NSW. The mid-span deflections caused by the test vehicle were compared to data obtained using a simplified SAP2000 model of the bridge and the mid-span influence line inferred.

This paper identifies a method of measuring the mid-span deflections of timber bridge girders when loaded by traffic. There are many short span timber beam bridges of unknown reliability in regional Australia that have high traffic loadings and many of these bridges were designed according to older codes. In order to identify the current safety index and probability of failure of these girders while in service, it is necessary to measure their deflections under normal and actual loadings. Because of the large numbers of girders that need to be measured, it is important to use a low cost method that is quick and easy to set up in the field. The method proposed here involves a laser source which is adjusted to produce an image of the laser on a graduated chart mounted at the mid-span of the bridge girder. The source is mounted on a stable support. Traffic loading deflects the girder and the chart moves up and down synchronously. A high speed camera is used to record the movements of the chart relative to the image of the laser. The chart was inscribed so that any movement of the image could be easily read from the graduated scale. A video recording was made of the chart movements relative to the laser source and the recording was analysed to identify the peak movements. The results show that, when the girder is loaded by moving traffic loads, the peak deflection, the dynamic resonant behaviour of girder deflection and the recovery can be readily identified.

This address covers the development of transport and transport networks in New South Wales in the 19th Century. The influences on transport and how it occurred during the fledging years of the colony set the scene for future development and growth in the 20th Century and may well influence what happens in the 21st Century. In planning and developing expansion of transport networks and systems, it is often very useful to be aware of and appreciate how existing networks and systems developed. Often situations have changed little in some areas and therefore some valuable lessons can be learnt from decisions, events and development in bygone years. This serves as a useful means of learning from past actions.

This paper provides background to the various road transport routes between Grafton on the North Coast and the Northern Tablelands of New South Wales and why the Grafton-Glen Innes line was eventually chosen. The development of the Grafton-Glen Innes link and its evolution through to the contemporary line are discussed along with some unique circumstances and events of that period. Not only was local competition active among towns vying for direct road links, but also competing with the burgeoning rail network, expanding throughout NSW. Eventually rail won out and remained the dominant form of land transport in the area well into the 20th century. However, that win had some losses in other areas, resulting in change to town and population dynamics and patterns of settlement.

Whilst the area is very broad and can become quite technical in content, the following discussion and report will endeavour to be as simple as possible... To assist in understanding the Island's problems and possible solutions in relation to roads, it will be necessary to transverse some preliminary discussion on roads.

As far back as 1969 Boomi Shire experienced damage to structures and roads by the movement of wheat by road generally with vehicles over-loaded by between 30 and 60%. Following the good wheat harvest of 1978/79 Council again critically appraised the damage to timber bridges, of which it had some 41 on Main and Council roads. In view of an additional $40,000 damage caused to bridges alone, it was decided to seriously review the situation of vehicle overloading generally. Such a review was influenced by the following factors: • A dramatic land use change in the Gwydir Valley as a result of Copeton Dam water distribution and to a lesser extent the MacIntyre-Barwon Valley and resultant increase in grain and cotton production, • The then Grain Elevators Board (GEB) (subsequently the Grain Handling Authority, GHA) as a policy decision, installed 60 tonne weighbridges for wheat and other grain receivals at each of some 12 silos in the area, and • The fact that a two month wheat cartage season had extended to about a 10 month cartage season (of various commodities), coupled with increased livestock numbers at the large Moree Saleyards.