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Publications (86)
Concrete filled steel tubes (CFTs) are efficient members in structural applications including bridges, buildings and piled foundations and their use in the building industry is increasing. To date their primary use has been in axial applications, with the design methodology based on theory and tests of columns under loads applied axially or at rela...
Controversy has risen about the suitability of small-scaled pushout tests to satisfactorily model the behavior of shear connections in composite beams. However, the determination of the strength of the shear connectors from full-scale composite beam tests is expensive, complicated, and subject to modeling inaccuracies. The results of several compos...
Most of the design approaches currently used around the world take into account the weakening effect of trapezoidal types of steel decking in the vicinity of a shear connection by applying a reduction factor to the nominal strength that the same connection would have in a solid concrete slab. Numerous push-out test results on shear connections inco...
Geometric imperfections, commonly in the form of depressions at the circumferential welds, are present in most metal silo structures and can greatly reduce the structure's buckling strength. These imperfections sure close to axisymmetric in form. This paper describes the measurement system which was developed for an experimental study of this pheno...
Composite columns are a combination of two traditional structural forms: structural steel and structural concrete. As composite columns were generally developed after steel columns and reinforced concrete columns, their design approach could have been based on either steel or concrete design methods. However, steel column design methods have differ...
An extensive experimental program was undertaken to investigate the behaviour of secondary composite beam shear connections incorporating trapezoidal steel decking. Based on the test results, a new design proposal to determine the shear connection strength was developed, which also incorporates the application of stud reinforcing devices that have...
The paper summarises the results of an extensive review of various push-out test series in order to determine the mean strength of headed stud shear connectors in solid slab applications. It also investigates the influence that different test set-ups can have on the connector strength. Based on the findings, an analysis of previous test series of s...
In order to investigate the complex behaviour and various load-transfer mechanisms that can occur in secondary composite beams incorporating the Australian trapezoidal decks, a number of carefullydesigned push-out test series were performed. Specific failure modes in conventional specimens were intentionally induced by varying critical parameters i...
Secondary composite beams incorporating trapezoidal profiled steel sheeting laid transverse to the longitudinal axis of the steel beam can exhibit unwanted brittle failure modes with low stud strength and poor ductility. Tests in Australia have identified a special type of longitudinal shear failure occurring in the concrete flange over the top of...
Concrete filled steel tubes (CFTs) are efficient members in structural applications including bridges, buildings and piled foundations. Their design has been based on theory and tests on columns under load applied axially or at relatively small eccentricities. For loading at large eccentricities or loading in pure flexure in the beam situation, the...
Haunches can be formed as part of a solid slab to increase composite beam depth or they can occur directly in primary composite beams incorporating open rib trapezoidal steel decks with the concrete ribs, often narrow, laid parallel to the longitudinal axis of the steel beam. In solid slabs, haunches can be designed to provide full shear connector...
The flexural behavior of steel beam sections subjected to flexural loading is studied extensively in the chapter, and detailed design methods are developed. The chapter presents a number of experiments carried out to investigate the flexural behavior of webs in high-strength steel beams. An experimental program is conducted to study the behavior of...
The chapter describes finite element models of centrally loaded, simply supported, and partially restrained 1-sections that are used to investigate stability failure for a range of beam lengths and for a range of individual cross-sections. Two characteristic buckling modes can be distinguished: a lateral mode for long models and a buckling mode tha...
Fibre reinforced polymer (FRP) composites have been providing practical solutions to structural problems in the aerospace, automotive and manufacturing industries for many years, although the benefits of FRP composites have only recently been expanded to include the bridge construction industry. Research into FRP composites for bridge construction...
Beams with an I-shaped cross-section (I-sections) are widely used in the building industry throughout Australia and internationally. The Australian Standard AS4100 provides guidelines for the design of such beams. Numerous failure modes are taken into account in these design rules including stability failure modes where such beams buckle out of the...
Depending on the geometry of a cylindrical structure, three different stability failure modes under wind loading can be observed. In low cylinders, the radial compression at the meridian facing into the wind causes a buckling mode similar to the cylinders under constant radial compression, while very long cylinders display a failure characterized b...
The use of concrete filled thin walled steel tubes in structural applications is widespread, particularly for axially loaded members. While extensive experimental studies is carried out on tubes subjected to primarily axial loads, some with limited eccentricities, few studies are carried out into the flexural behavior of such members. This chapter...
For composite steel-concrete beams, it is well known from tests that the shear capacity of welded-stud connectors can be reduced by the presence of profiled steel sheeting if it has an open-trough profile where the open-trough ribs, usually trapezoidal in shape, are laid transverse to the steel beam. Rib shearing failures with open-trough profile d...
Most Australian steel deck profiles have a reentrant narrow open steel rib, a closed lap-joint rib, or a combination of both. A series of tests has been conducted to examine the influence of the narrow open steel rib on the performance of the shear connection in composite beams with the profiled steel sheeting ribs laid perpendicular to the beams....
Brittle rib shearing failure comprises horizontal splits that form in the concrete between the tops of the steel sheeting ribs in pans where there are shear connectors, while the failure surface locally avoids the studs by passing over their heads. It has been reported in the literature to have often occurred in push-out and beam tests. It is now m...
The design of composite beams using rational partial shear connection theory is well established and has been included in design codes such as Eurocode 4 (1) and the more recent Australian Standard AS 2327.1-1996 (2). However, the design of composite slabs has previously been based on empirical methods. Australian steel decking profiles exhibit str...
Concrete filled steel tubes are efficient members in structural applications including bridges, buildings and piled foundations. Their design has been based on theory and tests on columns under load applied axially or at relatively small eccentricities. For other cases, their design has been extrapolated due to little research. The effects of both...
The Australian Standard AS 2327.1-1996 Composite Structures — Part 1: Simply Supported Beams has a number of aspects that differ from other existing codes and standards such as Eurocode 4. These include: construction stages and minimum construction loads; rational procedures for moment-shear interaction in conjunction with partial shear connection;...
Steel box sections are usually fabricated from flat plates which are welded at the corners. The welding process can introduce residual stresses and geometric imperfections into the sections which can influence their strength. For some thin-walled sections, large periodic geometric imperfections have been observed in manufactured sections. Subsequen...
Steel silos and tanks are constructed from plates which are rolled to the correct curvature and welded together to form strakes. Several strakes of curved plates, placed on top of each other then form the completed structure. At each circumferential weld, a slight hourglass depression occurs essentially forming axisymmetric imperfections which are...
The design of bridges is typically split into two, quite distinctly different stages: the design of the overall structure on the one hand; and the detailed design of the individual components on the other hand. Typically the overall design takes place on generalised and simplified models of the bridge structure. Section forces and displacements gai...
During the construction of bridges, significant displacements can be introduced into the structural system and are often compensated for with a pre-camber. The calculation of the exact shape of such a pre-camber is often a complicated and time-consuming task. In this paper, a system is introduced which allows the automatic computation of pre-camber...
The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during t...
The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during t...
Controlling cracking is a factor that should be carefully considered when designing a concrete structure. If allowed to become excessively wide, cracks can create a poor impression of construction quality, cause durability problems, and may also indicate unacceptably large vertical deflections of floor members. Important new design provisions, incl...
Columns are an important structural element in reinforced concrete structures. They are usually cast integrally with the framing concrete beams and slabs although precast columns can be used in appropriate situations. They have to provide resistance to both axial forces and bending moments generally resulting from load applied to the floor beams an...
Thin walled steel tubes have been used extensively in structural applications particularly for axially loaded members. When used as flexural members the effects of both local buckling become significant in the determination of the flexural capacity. A number of numerical studies have been carried out to determine the significance of initial imperfe...
The load carrying behaviour of cylindrical thin-walled shell structures under axial load is strongly dependent on imperfections invariably caused by various manufacturing processes. Axisymmetric imperfections have been known to result in particularly severe reductions in strength. Imperfections in the vicinity of circumferential welds in steel silo...
Current Australian design methods for reinforced concrete columns allow for a simplified approach, which makes a number of assumptions regarding the material properties of the steel and concrete. The introduction of 500 MPa reinforcing steel has pushed the material properties beyond the current assumptions thus requiring some changes to the current...
Architectural steel structures with visible tension and compression members are becoming more prevalent as a popular form of construction that reflects the nature of the resistance to the applied loads. These members require the use of structural steel pins at their ends to ensure either axial tension or axial compression in the members. Structural...
Architectural steel structures with visible tension and compression members are becoming more prevalent as a popular form of construction that reflects the nature of the resistance to the applied loads. These members require the use of structural steel pins at their ends to ensure either axial tension or axial compression in the members. Structural...
In this paper several design methods have been developed that can be used to conservatively estimate the strength of circular thin-walled concrete filled steel tubes under different loading conditions. The loading conditions examined include axial loading of the steel only, axial loading of the concrete only, and simultaneous lending of the concret...
The behavior of thin cylindrical shells under axial compression is very sensitive to imperfections in the initial geometry. Local axisymmetric imperfections are among the most detrimental and have been shown to be a regular feature of circumferentially welded joints in civil engineering shell structures such as steel silos and tanks. Many of the ex...
Thin-walled members may be subject to performance limitations arising through local or distortional buckling of slender elements comprising the cross-section of the member, or overall buckling of the member. The effects of structural instability may be aggravated by the presence of geometric imperfections in these elements. An investigation is pres...
In this paper a comprehensive series of tests is described and presented. The tests were performed to examine the behaviour under axial load of short, thin-walled, square steel tubes with or without internal restraint. The influence of specimen length on the local buckling strength was also investigated. The specimens had width-to-thickness ratios...
The increasing sophistication of standards for the design of steel structures is not matched by traditional methods of analysis. Thus, the new standards may fail to deliver the precision implied, while making it difficult to carry out manual design. The methods of advanced analysis rectify these problems by providing more accurate methods of predic...
This report presents the results from an experimental study performed to investigate the behaviour of thin-walled box sections with internal lateral restraint. Two series of tests were conducted examining the influence of the width to thickness ratio and the length to thickness ratio on the buckling strength of the tube. The material properties, re...
In this paper, a comprehensive series of tests is described and presented. The tests were performed to examine the behavior of short thin-walled circular steel tubes with or without internal restraint. The tubes had diameter-to-thickness ratios of between 55 and 200 and a length-to-diameter ratio of 3.5. The tests included bare steel tubes loaded b...
The measurement of imperfections in multi-storey steel structures is described. The measured imperfection data is categorized which includes individual members, plane frames in two orthogonal directions and imperfections relative to center of rotation of structure in plan view. The three types of imperfections which arise from fabrication and erect...
Thin-walled cold formed profiled steel decking panels with intermediate stiffeners may exhibit distortional buckling involving transverse flexure of the stiffener. Local buckling in the flat plate elements between the flanges and webs may also occur. Varying degrees of post-buckled strength reserve may be encountered in sections undergoing local an...
The occurrence and magnitude of flange curling deflections in profiled cold-formed steel decking panels is investigated experimentally. The test panels examined were a roll-formed standing seam panel, and a brake-pressed trapezoidal panel. The test specimens were loaded in pure flexure and the load-response characteristics, and differential deflect...
The tests described in this paper are the second in a program carried out to determine the effectiveness of intermediate stiffeners in controlling the buckling modes of profiled steel decks. A series of specimens with ''flat-hat'' intermediate stiffeners were brake-pressed to designs that were chosen to ensure that the primary buckling mode took pl...
A new partial shear connection strength model has been developed which considers the equilibrium of a segment of a simply-supported composite slab under any loading condition. The model incorporates shear connection performance derived from a new test called the slip block test. This small-scale test shows that shear connection performance is affec...
The size and position of intermediate stiffeners in the compression flanges of thin-walled profiled steel decks exert a strong influence on the dominant buckling mode of the flange. The ability of the deck to provide both high load-carrying capacity before the onset of elastic buckling and a high ultimate-load capacity may therefore be affected. A...
The paper describes advanced analysis as defined in the Australian limit states design specification, AS 4100-1990. Advanced analysis may be used for the second-order inealstic analysis and design of frames in which the members are compact and have full lateral restraint. Some aspects of the inclusion of residual stresses, geometrical imperfections...
The role of imperfections in the design of columns and beam-columns were investigated. The concept of a physically imperfect beam-column, where the member out-of-straightness and out-of-plumbness imperfections relate to the independent specification of fabrication and erection tolerances in design codes, was introduced. It was found that while the...
The present changes from the Working Stress Design Method (WSD) to the Limit States Design Method (LSD) for designing steel building frames have begun a trend in which progressively more accurate estimates are formed of the moment and axial force distributions in the frame, and simpler methods are used to design its members.
Despite the proliferation of computer hardware and software, there is still a role for simple hand-calculation methods. This paper is a contribution to that philosophy with respect to the buckling loads of stepped crane columns within rigid frame buildings. Graphs of three factors are presented which enable the design engineer to calculate the buck...
A method is presented for the determination of the in-plane buckling loads of any three-member frame composed of prismatic members. The method is general requiring the solution of a compact 3 multiplied by 3 stiffness matrix. Its application is ideally suited to computers with small storage.
The draft limit state 'Steel Structures Code' recently published by the SAA includes a new section on methods of structural analysis, and a significantly changed section on the section and member capacities of beam-columns in in-plane bending, out-of-plane buckling, and biaxial bending. This paper summarizes the background of these new and changed...
Beam-columns are structural members which support loads causing both bending and axial compression. The beam-column strength is defined by an interaction curve, i. e. a plot of pairs of axial force (N) and moment (M) that will cause failure. This technical note presents the computation of the safety indices for reinforced concrete beam-columns desi...
The probabilistic models of steel beams and columns used in the calibration of the proposed limit states design (LSD) rules for these members are presented. Safety indices are computed for members designed to the existing AS 1250 rules and the proposed LSD rules. The components considered are beam segments with and without lateral support including...
Design specifications for columns include nomographs for calculating effective length factors. The method, which is simple to use, requires the designer to evaluate G at each end of the column, but only positive G-factors result, and in the case of sway-prevented structures, effective length factors are always less than one. In practice, some colum...
A statistical analysis of hot-rolled steel beams and columns designed according to Australian Standard AS 1250-1981 is presented. Estimates of various components of variability are given based on available experimental data. From the analysis of braced beams, of beams in elastic and inelastic buckling ranges and of axially loaded columns, the range...
The concept of concrete origami has wide-ranging possibilities for the concrete industry, according to the authors. This article describes the original concept, its refinement in two earlier canoes, and the construction of an entry for an international concrete canoe competition in Stockholm, Sweden.
The stress-ribbon structure is a prestressed concrete tension member which hangs in a catenary shape. It might be thought of as a degenerate suspension bridge in the sense that the deck and the suspension cables have the same profile in elevation. Stress-ribbon structures offer considerable advantages in sites where the anchorage of the large tensi...
The results are presented of an investigation into the influence of creep and shrinkage on the sustained load behavior of pin-ended composite columns. Tests were performed on built-up composite columns containing two steel channels without battens and encased in unreinforced concrete. The loads were sustained for periods up to 4 yr. Basic creep and...
A numerical method is described for the second order, in-plane analysis of portal-type, steel, industrial frames accounting for both non-linear geometrical and material responses. Although primarily designed for determining the ultimate strength of frames, the same method can be used to predict the critical elastic frame buckling loads for any axia...
The results are presented of an investigation into the behavior of pin-ended composite columns containing more than one steel component. A series of tests was performed on built-up composite columns containing two steel channels with and without battens and encased in unreinforced concrete. Comparative tests were made on similar unencased columns....
Composite slabs consisting of steel decking combined with concrete have been used in building applications for several years. Some advantages of such a system are fast construction, elimination of formwork and ease of providing services. A new type of steel decking is described which has additional features. These include the ability of the slab to...
The results are presented of a theoretical and experimental investigation at the University of Sydney into the behavior of pin-ended concrete filled square steel tubes eccentrically loaded to bend about any required axis. The principal variables examined are eccentricity of loading, slenderness and inclination of the loading axis, i. e. biaxial ben...
In contemporary practice continuously reinforced concrete pavements (CRCP) are terminated and anchored at each bridge approach. An approach slab, jointed at each end, provides the CRCP to bridge abutment link. This transition is not always smooth as the provision of transverse joints can lead to discontinuities in the carriageway profile, particula...
SYNOPSIS Concrete filled tubes are likely to be economical with the use of very high strength concretes and thin-walled steel tubes. The strength of the steel tube is affected by local buckling effects which may also influehce the confinement to the concrete infill. Very high strength concretes exhibit rapid unloading in the post-ultimate region. T...
