Search

The traditional approach to formulating building codes often is slow and labor-intensive, and may struggle to keep pace with the rapid evolution of technology and domain findings. Overcoming such challenges necessitates a methodology that streamlines the modernization of codal provisions. This paper proposes a machine learning (ML) approach to append a variety of codal provisions, including those of empirical, statistical, and theoretical natures. In this approach, a codal provision (i.e., equation) is analyzed to trace its properties (e.g., engineering intuition and causal logic). Then a ML model is tailored to preserve the same properties and satisfy a collection of similarity and performance measures until declared equivalent to the provision at hand. The resulting ML model harnesses the predictive capabilities of ML while arriving at predictions similar to the codal provision used to train the ML model, and hence it becomes possible to use in lieu of the codal expression. This approach was examined successfully for seven structural engineering phenomena contained within various building codes, including those in North America and Australia. The findings suggest that the proposed approach could lay the groundwork for implementing ML in the development of future building codes. [ABSTRACT FROM AUTHOR]

The paper summarizes the main new design provisions included in the recently revised Australian standard for steel storage racks. The standard features multitiered analysis provisions ranging from basic linear-elastic analysis-based provisions to highly advanced integrated design-analysis [geometric and material nonlinear analysis with imperfections (GMNIA)] provisions that allow the analysis and design to be completed in one step. The GMNIA provisions distinguish between beam element-based and shell element-based analysis according to cross section slenderness and provide rules for the imperfections to use for the two types of analysis, including imperfections in the local and distortional buckling modes for the shell element-based analysis. The selection of the system-based reliability (resistance) factor () is discussed. The standard is seen as the most advanced design code of its type currently available for frame-type steel structures. The paper also provides an in-depth discussion about the use of linear and nonlinear elastic analysis methods for the design of steel storage racks and how torsion may be considered in determining design capacities while not in the structural analysis. [ABSTRACT FROM AUTHOR]

In roof systems, a high strength steel profiled sheeting fastened to high strength steel cold-formed purlins of a lipped C- or Z-section is commonly used throughout the world. The design of such systems is performed according to the provisions of the limit states Australia/New Zealand Standard for Cold-Formed Steel Structures in Australia and the North American Specification for the Design of Cold-Formed Steel Structural Members in the United States. In both standards, which include the newly developed direct strength method of design (DSM), the method presented is limited to pure compression and pure bending. The situations of pure shear and combined bending and shear as occurs in a continuous purlin system are not considered. In order to extend the DSM to purlin systems, three different test series on high strength cold-formed C-section purlins have been performed at the University of Sydney. The test series include predominantly shear, combined bending and shear, and bending only test series. Two different section depths and three different thicknesses of the lipped channel section were tested in this study. Further, tests with and without torsion/distortion restraint straps screwed on the top flanges adjacent to the loading points were also considered. This paper summarizes the test results and formulas developed from the effective width method and the DSM. Proposals for design are included in this paper. Comparisons with the Australian Steel Structures Standard are also included to take account of the tension field action. [ABSTRACT FROM AUTHOR]

Prestressed concrete sleepers (or railroad ties) are the crosstie beam support in railway track systems. They are designed and constructed under flexural constraints in order to carry and transfer the dynamic wheel loads from the rails to the ground. Under perfect wheel and rail conditions, the dynamic loading on railway tracks could be treated as a quasi-static load using a dynamic impact factor. The current design method for the prestressed concrete sleepers taking into account the quasi-static effect is based on allowable stress where crack initiation is not permitted. In reality, the impact events are often detected due to the uncertainties of wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration. Over the design life span of the prestressed concrete sleepers, there exists the feasibility of extreme and repeated impact loading events. These have led to two proposed limit states for the consideration of structural engineers: ultimate limit states and fatigue limit states. Prestressing techniques have been long used to maintain the high endurance of the sleepers under repeated impact cycles. In spite of the most common use of the prestressed concrete sleepers, their impact behavior and capacity under the repetitions of severe impact loads are unclear. This paper presents the experimental investigation aimed at understanding the dynamic crack propagations in prestressed concrete sleepers in railway track structures under repeated impact loading. The impact forces have been correlated against the probabilistic track force distribution obtained from an Australian heavy haul rail network. The effects of track environment including soft and hard tracks are highlighted in this paper. [ABSTRACT FROM AUTHOR]

A series of tests on cold-formed high-strength stainless steel square and rectangular hollow sections subjected to web crippling is presented in this paper. The types of stainless steel investigated in this study were high strength austenitic and duplex material. The measured web slenderness value of the hollow sections ranged from 16.5 to 49.7. The tests were carried out under four loading conditions considered in the American Specification and Australian/New Zealand Standard for cold-formed stainless steel structures, namely end-one-flange, interior-one-flange, end-two-flange, and interior-two-flange loading conditions. The web crippling test strengths were compared with the design strengths obtained using the American, Australian/New Zealand, and European Specifications for stainless steel structures. In addition, the North American Specification for cold-formed carbon steel structural members was also used to predict the web crippling strengths and compared with the test results. It is shown that the design strengths predicted by the specifications are either unconservative or very conservative. Hence, a unified web crippling equation with new coefficients for cold-formed high strength stainless steel square and rectangular hollow sections is proposed in this paper. It is shown that the proposed web crippling equation is safe and reliable. [ABSTRACT FROM AUTHOR]

An experimental investigation of cold-formed stainless steel hollow sections subjected to web crippling is presented in this paper. Tests were conducted on square and rectangular hollow sections of austenitic stainless steel type 304. Tensile and compression coupon tests were performed to obtain the longitudinal tension and transverse compression material properties. The web crippling tests were conducted under two loading conditions for end-two-flange and interior-two-flange specified in the current American Specification and Australian/New Zealand Standard for cold-formed stainless steel structures. The test strengths obtained from this study and the test strengths of stainless steel lipped channel sections under end-one-flange and interior-one-flange loading conditions conducted by other researchers are compared with the design strengths obtained using the current American Specification, Australian/New Zealand Standard and European Code for cold-formed stainless steel structures. In addition, the test strengths are also compared with the design strengths obtained using the unified web crippling equation as specified in the North American Specification for cold-formed carbon steel structural members. A unified web crippling equation for cold-formed stainless steel sections with single web is proposed in this paper. [ABSTRACT FROM AUTHOR]

This paper describes a series of compression tests performed on long columns fabricated from cold-formed high strength steel plates with nominal yield stress of 550 MPa. The steel is classified as G550 to Australia Standard AS1397. The test results presented in this paper are the second stage of an Australian Research Council research project entitled “Compression stability of high strength steel sections with low strain-hardening.” A total of 28 long columns, which were made from two thicknesses of sheet steel (0.42 and 0.6 mm), were tested. A box shaped section was tested between pinned ends over a range of lengths. This paper shows the comparison of loads obtained experimentally with those predicted on the basis of AS/NZS 4600 and the AISI specification including Supplement No. 1, 1999. The finite element program, ABAQUS, was also used to simulate the column behavior. For sections which undergo local instability at loads significantly less than the ultimate loads, the column design rules in AS/NZS 4600 and the AISI Specification are unconservative if used in their current form for G550 steel. Proposals for improved column design of high strength slender sections are proposed in this paper. A first companion paper (Part I) describes a series of compassion tests on stub columns. [ABSTRACT FROM AUTHOR]

This paper describes a series of compression tests performed on stub columns fabricated from cold-formed high strength steel plates with nominal yield stress of 550 MPa. The steel is classified as G550 to Australia Standard AS1397. The test results presented in this paper are the first stage of an Australian Research Council research project entitled “Compression stability of high strength steel sections with low strain-hardening.” The tests include lipped-square and hexagonal sections, including 94 box-shaped fix-ended stub columns. The purpose of these tests was to determine the influence of low strain hardening of G550 steel on the compressive section capacities of the column members. The results of the successful stub column tests have been compared with the design procedures in the Australian/New Zealand Standard for Cold-Formed Steel Structures and recent (1999) amendments to the American Iron and Steel Institute Specification. As expected, the greatest effect of low strain hardening was for the stockier sections where material properties play an important role. For the more slender sections where elastic local buckling and postlocal buckling are more important, the effect of low strain hardening does not appear to be as significant. This is contrary to recent design proposals in the USA where it was proposed that the more slender sections would be more greatly influenced by low strain hardening. A simple proposal for improved design capacity is given in the paper. A second companion paper (Part II) describes a series of compression tests on long columns made from the same material. [ABSTRACT FROM AUTHOR]

Cold-formed C channel sections have been used in portal frame construction for agricultural and light industrial sheds for many years in Australia. The knee joint designs have been copied from hot-rolled portal frames, regardless of the fact that many designers believe this is not realistic. Earlier testing conducted at the Univ. of South Australia demonstrated that these concerns were justified and that the joint designs widely used in practice do not match the moment capacity of the sections and fail prematurely. An alternative joint design has been developed using self-drilling screws. The joint demonstrates excellent moment capacity and rigidity, and is simple to design. A similar joint has also been examined for the ridge connections, which are at a lower angle than the knee joints. This paper describes the development and testing of the self-drilling screw joints, as well as summarizing testing of the conventional joints. [ABSTRACT FROM AUTHOR]

The Australian Residential Timber-Framed Construction standard (AS1684:1999) has recently been revised to explicitly define the bracing contribution of nominally fixed plasterboard clad walls as 0.45 kN/m for cladding on one side and 0.75 kN/m for cladding on two sides. These values clarify the allowance, which designers may rely upon for the presence of plasterboard and their inclusion in the standard infers a necessity for plasterboard products to at least meet these requirements. A review of the relevant Australian, ISO, and ASTM standards, as well as plasterboard manufacturers’ in-house quality control tests has established that these tests mainly focus on serviceability aspect of plasterboard (e.g., storage, transportation, and installation) rather than that of structural bracing performance. It has also been determined that there are no direct correlations between serviceability conditions and structural bracing performance of plasterboard. In fact, a limited set of data provided by the plasterboard manufacturers shows that almost no correlation exists between the current quality control tests and the most commonly measured parameter, the density of plasterboard. It has been concluded that current tests are inadequate to serve as control measures for bracing performance of plasterboard. Nonetheless, it must be noted that density is not the only parameter that may influence the bracing performance of plasterboard; other parameters such as linerboard strength and bonding between gypsum and linerboard may also affect the bracing capacity. This paper details a new test, termed fastener bearing test, which provides a method to evaluate the bracing capacity of plasterboard. The results of this test show a very high correlation with shear connection tests. The proposed test is practical and simple to perform as part of the manufacturing process, in addition to the current tests, without severe cost and time penalty to the plasterboard manufacturers. [ABSTRACT FROM AUTHOR]

The article discusses the effects of dead and live loads on shores in response to a paper on reliability-based load requirements for reinforced concrete building structures on shores in Sydney, Australia. The factors considered include the Australian and American building codes, the literature on the shore system behavior, and variations in the ambient temperature and its effect on slabs gain resistance. A description on the shoring and striking of consecutive floors is offered.