Economic Recycling and Conservation of Structures
Engineering focus on heritage structures was a development of the worldwide trend for heritage awareness. The International Council on Monuments and Sites (ICOMOS) was formed in 1965 as an international, non-governmental organisation dedicated to the conservation of the world’s historic monuments and sites. ICOMOS Australia, established in 1976, encourages responsible attitudes to the management of culturally significant structures through the ICOMOS Burra Charter.
TO RECONCILE THE HERITAGE-VS-USE CONFLICT
The Warren Centre decided to adopt this topic as a project because it saw great value in reconciling the inherent conflict between the heritage qualities of listed buildings with their ongoing use. In other words, it wanted to create an engineering blueprint for the quality environment of a building or structure that was sympathetic both to its heritage value and to its reuse.
The project had two main areas of concentration. The first was to develop a conservation strategy that followed the Burra Charter of ICOMOS in its method of establishing cultural significance, and in the specifics of a conservation policy. In other words, it would describe in detail what should or should not be done to a structure.
The second focus was to investigate all the other constraints that needed to be considered in appraising a structure. These constraints included:
- An assessment of structural adequacy, from first principles;
- A study of the building’s or structure’s economic viability, or a reconciliation of the conservation policy with the demand for financial returns on invested capital;
- An assessment of the consequences of removing old services and the impact of installing new ones;
- A diagnosis of materials problems and execution of appropriate remedial measures, with a separate examination of each material.
At the same time, the very breadth of the topic meant the project involved engineers from all disciplines. Its scope went much further than buildings; it embraced road and rail bridges, roads, dams, mining works, water resources and reticulation, electrical generation and distribution, harbours and marine engineering and any engineering fields where cultural significance and recycling might interact.
The closely-related subject of maintenance meant the continuous protective care of a structure’s fabric was integral to its conservation strategy. However, the study did not include the effect of earthquakes on old or recycled structures, or the need to upgrade structures to cope with seismic activity or structures built more recently than 1940. Nor did it include mechanical, electrical or other movable equipment. Fifty people, operating in nine task groups, carried out the project research.
GUIDELINES FOR CONSERVATION
The value of the guidelines established by the project team lay in their practicality. Firstly, they contained practical considerations for engineers and developers in their treatment of historically significant Australian structures. Secondly, they translated overseas experience into measures that were appropriate for local conditions. These guidelines included:
- Development of a conservation plan
- Legislation and planning requirements
- Reconciling conservation and economic conflicts
- Overcoming specific obstacles such as:
- functional inadequacy / strength inadequacy / services inadequacy / fire and accident safety
- Materials treatment, focusing on:
- structural timber masonry / structural metals / cladding metals / concrete foundations
The project recommended seven key principles for new and replacement services, all based on the Burra Charter. In summary, these were:
- Policies for conservation and provision of new services must be developed together;
- New services should not detract from the aesthetic, historical, scientific or social value of a structure;
- New services should be inconspicuous and should be concealed within the fabric of the structure;
- Those new services with the greatest visual impact should be located in areas of lesser significance;
- Proposed new services should be investigated to ensure that its operation will not cause damage to the structure or its contents;
- Consideration should be given to active rather than passive fire protection;
- Any new service should be designed to be sympathetic with its surroundings.
In addition, the project team addressed economic issues and user requirements.
SIGNIFICANT CONSERVATION PRACTICES
The project produced significant improvements to conservation and redevelopment practices, which now reflect the greater community concern for conservation of historic buildings and sites and for the continuing use of existing buildings. In Sydney alone, examples include:
- Conservation of the Pyrmont Bridge as part of the Darling Harbour redevelopment and the incorporation of the monorail as part of its new structure;
- Redevelopment of the Customs House building at Circular Quay as an exhibition space while conserving its external structure and appearance;
- Reuse of the Finger Wharf in Woolloomooloo Bay as a new residential complex;
- Preparation by the Maritime Services Board of drawings and specifications of cultural significance in all buildings when auctioning the Walsh Bay wharf site for recycling;
- Refurbishment by Leighton Holdings of the Commonwealth Bank building in Martin Place and of the Société Générale building at 350 George St.