Limit State Design in Australia
Some Limit State Design Experiences in Australia
S.R. Lo
University of New south Wales, ADFA campus, Canberra, ACT 2600, Australia r.lo@adfa.edu.au
Abstract: Current limit state geotechnical codes in Australia are briefly discussed. Selected geotechnical projects that benefited from the use limited state design are briefly presented.
1
INTRODUCTION
Limit state design in Australia has a short history. The first limit state geotechnical code was introduced by AUSTROAD, an umbrella organization representing the interests of all state road authorities, in early 90s. Geotechnical design codes in Australia are developed by Standards Australia and various state road authorities. The former is referred to by an AS number. As its name implies, Standards Australia has been developing codes intended for applications in Australia in general. As Australia is a spatially large country and the ground conditions and practices vary across Australia, geotechnical codes developed by Standards Australia tends to be flexible. The various state road authorities in Australia have also been developing their own codes, either individually or collectively via AUSTROAD. Currently limit state geotechnical codes in Australia are: AUSTROAD (1992), AS 2159 (1995), R57 (2002) and AS 4679 (2002). AUSTROAD (1992) is mainly for the design of piles and footings although it also contains brief recommendations on the design of simple retaining structures. AS 2150 (1995) is for piling. R57 is for the design of reinforced soil wall. It was developed by the Roads and Traffic authority, New South Wales, as a design specification. AS 4679 (2002) is for the design of “common” earth retaining structures, including reinforced soil walls. It has been adapted for use by other state road authority such as Queensland Main Road and referred to by a different reference.
partial material factors fm (i). The two factors are simply related by Φ m (i)=1/fm (i). In LRFD, R* is obtained by applying a
S.R. Lo
University of New south Wales, ADFA campus, Canberra, ACT 2600, Australia r.lo@adfa.edu.au
Abstract: Current limit state geotechnical codes in Australia are briefly discussed. Selected geotechnical projects that benefited from the use limited state design are briefly presented.
1
INTRODUCTION
Limit state design in Australia has a short history. The first limit state geotechnical code was introduced by AUSTROAD, an umbrella organization representing the interests of all state road authorities, in early 90s. Geotechnical design codes in Australia are developed by Standards Australia and various state road authorities. The former is referred to by an AS number. As its name implies, Standards Australia has been developing codes intended for applications in Australia in general. As Australia is a spatially large country and the ground conditions and practices vary across Australia, geotechnical codes developed by Standards Australia tends to be flexible. The various state road authorities in Australia have also been developing their own codes, either individually or collectively via AUSTROAD. Currently limit state geotechnical codes in Australia are: AUSTROAD (1992), AS 2159 (1995), R57 (2002) and AS 4679 (2002). AUSTROAD (1992) is mainly for the design of piles and footings although it also contains brief recommendations on the design of simple retaining structures. AS 2150 (1995) is for piling. R57 is for the design of reinforced soil wall. It was developed by the Roads and Traffic authority, New South Wales, as a design specification. AS 4679 (2002) is for the design of “common” earth retaining structures, including reinforced soil walls. It has been adapted for use by other state road authority such as Queensland Main Road and referred to by a different reference.
partial material factors fm (i). The two factors are simply related by Φ m (i)=1/fm (i). In LRFD, R* is obtained by applying a
References: AUSTROAD (1992) “Austroads Bridge Design Code”. Sect 2 Design Loads. AUSTROAD, Sydney 1992. Mak J. & Lo S.R. (1996) Towards a limit state design specification for reinforced soil walls. Int Symposium on Earth Reinforcement Practice, Fukuoka, Japan, Nov 1996, 415-420. R57 (2002) “Design of reinforced soil walls”., Road and Traffic Authority, New South Wales, Australia. Lo (2001) “The application of numerical analysis to innovative design of geosynthetic reinforced soil wall”. Proc of 10-th Intl Conf. on Computer Methods and A dvances in Geomech., Balkema, 1245-1250. Lo (2002) “Partial factors and non-linear ground structure interaction”. Proc ICE., Geot Engr J., 156[1], 35-46. Padfield C.J. and Mair R.J. (1984) “Design of retaining walls embedded in stiff clay”. CIRIA Report 104. Simpson B. (1992) “Partial factors of safety for the design of retaining walls”. Geotechnique, 42[1], 131-136. Simpson B. and Driscoll R. (1998) Eurocode 7- a commentary. Construction Research Communication Ltd, Watford, U.K. SPG3 Reinforced Zone SPG2 SPG1 Fig. 2. RSW Abutment (SPG = Settlement Profile gauge). The “high” movement was believed to be a serviceability challenge. But such a point of view can only be substantiated by having an analysis that can predict the observed high movement under service condition and can be taken to ultimate condition. This was achieved with a non-linear numerical analysis that can simulate load paths in the form of construction, load application, 2