Anthony Mills writes that the principal objective of this article is to investigate the `best cost performance' and possible `best design practice' for structural frames in buildings in Australia. The study was based on pricing a number of standardised building frame designs in five Australian cities. The results produced show the cost of producing the same building designs in different locations, using similar building methods.

Comparisons in construction performance are relatively uncommon because `like-for-like' building projects are rare. By utilizing a standard model project variables like building quality, ground conditions and access were eradicated, thereby facilitating an unbiased comparison of building cost. Hence, results of this research are a good indicator of building costs for structural frames.  Using 6 alternative frame designs across 4 different building grids, this research provides cost comparisons of 24 medium-rise (10 storeys) structural frame designs in five Australian cites. 

Prior to this research, no construction cost data existed on structural frames used in multi-rise buildings. It is believed that cost comparison information would aid developers, builders, specifiers and other stakeholders in decision making. This study attempts to provide some insight into the cost drivers that impact on the choice of structural frames in commercial buildings.

Past research using standard cost models
Comparative studies have been attempted for many years (Edkins & Winch 1999; Meikle 1990; Price 1991) and many different methodologies have been used with varying degrees of success. Any sort of comparative study has a number of inherent problems, the most common being that of true representativeness of the data with typical buildings in the real world.

In construction these problems are particularly complex because buildings are rarely identical. In most cases there is no truly standard project that can be used for the basis of comparison.

Further complication factors like; local materials supply, industrial relations, climate and taxation, tend to make buildings unique. In spite of the difficulties, when comparisons can be made they do form very useful insights into the choice of building designs and construction. The role of this research was to develop a number of cost models that represent the most common forms of construction of structural frames in Australia.

Methods previously employed to compare construction performance internationally have been categorized into one of three approaches, namely, pricing studies, macroeconomic studies and case studies (Edkins & Winch 1999). Each approach has its own advantages and limitations, mainly in terms of comparability and representativeness.

In pricing studies, experienced professionals in different locations are asked to price buildings on the basis of identical drawings, specifications and bills of quantities. This method involves experienced professionals in different places pricing identical buildings, so to some extent it solves the problem of comparability, but does not completely reflect the `real' situation (i.e. representativeness) of different locations.

The study is based on 24 standard designs that excluded site conditions and other similar items, in order to ensure comparability. The aim of the study was to provide a realistic appraisal of the cost of different popular structural frame options used in typical multi-rise commercial buildings. The next section considers the range of buildings typically found in Australia.