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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]

Accurate numerical modeling of structural components is necessary for both performance-based designs of new structures and performance assessments of existing structures. Steel special concentrically braced frames (SCBFs) represent a large portfolio of steel buildings in areas of high seismicity, especially in North America. Therefore, it is necessary to critically study the accuracy of available numerical models for SCBFs and propose improvements to them, if necessary. This requires forming a database of high-fidelity benchmark experimental results for SCBFs against which models can be compared. This paper presents multielement hybrid simulations on a steel SCBF, as a representation of systems with highly unsymmetrical hysteretic response. A representative buckling brace specimen is developed and verified through reversed-cyclic tests to physically capture the response of SCBFs in the experiments. 2-element and 4-element pseudo-dynamic hybrid simulations are carried out on the reference SCBF using the University of Toronto Ten-Element Hybrid Simulation Platform (UT10). The experimental results from the multielement tests are compared with numerical simulations in detail using the available numerical models, which are observed to predict the response well. [ABSTRACT FROM AUTHOR]

This paper examines the accuracy of equations specified by the North American and Australasian steel structures codes for determining the net section tension capacity of a channel brace. It points out that there are three distinct factors affecting the net section efficiency of a cold-formed steel channel brace bolted at the web. These factors include (1) the in-plane shear lag associated with stress concentration around a bolt hole that is also present in flat sheets, (2) the out-of-plane shear lag that is also present in an I-section bolted at the flanges only, and (3) the bending moment arising from the connection eccentricity with respect to the neutral axis. Each of the relevant factors is explicitly incorporated into the equation proposed in this paper for determining the net section tension capacity of a cold-formed steel channel brace bolted at the web. The proposed equation is demonstrated through laboratory tests on low-ductility channel braces having practical aspect ratios that were bolted onto flexible plates, to be more reliable than the code equations and those existing in the literature. [ABSTRACT FROM AUTHOR]

This paper presents shake table test results on two identical 1:0.429 scaled, 8-story moderately ductile RC shear wall specimens under the expected high-frequency ground motion in eastern North America. The walls were designed and detailed according to the seismic provisions of the NBCC 2005 and CSA-A23.3-04 standards. The objectives were to validate and understand the inelastic responses and interaction of shear and flexure and axial loads in the plastic hinge zones of the walls taking into consideration the higher-mode effects. One specimen was tested under incremental ground motion intensities ranging from 40 to 120% of the design level. The intensity range was increased from 100 to 200% for the second specimen. The response of the walls was significantly affected by the second mode, causing an inelastic flexural response to develop at the base as well as at the sixth level. Dynamic amplification of the base shear forces was also observed in both walls. In the second wall, which was tested in the undamaged condition, peak base shear forces occurred prior to significant inelastic rotation and the contribution to concrete of shear resistance exceeded the value used in the design. Once inelastic rotation had developed that contribution corresponded to the value obtained using a value of 0.18 for the reduction factor accounting for concrete cracking. Inelastic rotation in the upper wall region was found to limit the force demand imposed by the higher-mode response. [ABSTRACT FROM AUTHOR]

This paper examines the accuracy of design equations specified in the North American, European and Australasian codes for cold-formed steel structures in determining the net section tension capacity of bolted connections in flat steel sheets. It points out that the shear lag factors embedded in the code equations either yield 'anomalous' results or become irrelevant when they exceed unity. The 'anomaly' was demonstrated through laboratory tests and is explained by using simple calculus. The configurations of specimens tested in the laboratory include single shear- and double-shear connections, with single or double bolts in a line parallel or perpendicular to the force. A proper mathematical expression for the in-plane shear lag factor, which does not suffer from the anomaly of the code equations and never implies shear lag factors greater than unity for any configuration, is presented and shown to yield improved results compared to the current specifications. The resistance factor of 0.8 for the proposed equation is computed with respect to the load and resistance factor design (LRFD) approach specified in the North American specification for the design of cold-formed steel structures. [ABSTRACT FROM AUTHOR]

Ground-motion suite selection for Eastern North America (ENA) is distinguished from suite selection for high seismic regions by uncertainty related to earthquake intensity, spectral shape, and the wide range of relevant periods experienced by low-ductility structures. Whereas trends in high seismic regions point toward developing smaller, more efficient suites for use in practice based on reliable intensity parameters, current research on moderate seismic regions requires the development of ground-motion suites capable of exciting the widest range of structural periods while accounting for uncertainty related to ground-motion intensity. This paper discusses uncertainty related to ENA ground motions in terms of the logic tree in the probabilistic seismic hazard analysis (epistemic uncertainty) and the deaggregation of hazard into magnitude and distance bins (aleatory uncertainty), recommends a suite selection process for addressing this uncertainty without amplitude scaling, and evaluates the effectiveness of a specific suite in the context of reliability-based performance assessment procedures. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental study on the critical buckling load and lateral bracing force of metal plate connected wood truss assemblies. Material property tests—including the modulus of elasticity of dimension lumber, flexural stiffness of plywood panels, and load-slip relationship of nail connection—and full-scale tests of individual trusses and truss assemblies were conducted. The critical buckling load and lateral bracing force were recorded. The continuous lateral bracing, the load sharing and distribution effects, and the residual deformation at the metal plate connections were studied for their influence on the system’s stability performance. The adequacy of the 2% rule of thumb, which is used by some design engineers for lateral bracing system design, was also discussed by comparing to the test results of the lateral bracing forces. The generated database can be used as input parameters and for verification for numerical analysis models and therefore contributes to the improvement of the design methods in the long term. [ABSTRACT FROM AUTHOR]

Formed from a thick layer of polystyrene foam sandwiched between two layers of oriented strand board, structural insulated panels (SIPs) are a viable alternative to traditional wood stud shear walls. Developed in North America, SIPs satisfy building performance criteria while being both sustainable and cost effective. This paper details a comprehensive experimental and parametric study at Napier University examining the structural performance of shear walls constructed of SIPs under the action of both racking loads and combined bending and axial compression. The effects of size and position of openings, for doors and windows, were examined and compared to designs carried out in accordance with BS 5268 and Eurocode 5. The study has demonstrated that SIPs perform as an effective composite material possessing the strength and stiffness necessary to sustain required design loads. [ABSTRACT FROM AUTHOR]

Cold-formed steel roof truss systems that use complex hat shape members for both top and bottom chord elements are a growing trend in the North America steel framing industry. When designing cold-formed steel sections, a structural engineer typically tries to improve the local buckling behavior of the cold-formed steel elements. The complex hat shape has proven to limit the negative influence of local buckling. However, a distortional buckling mode can be the control mode of failure in the design for the chord member with an intermediate unbraced length. The chord member may be subjected to both bending and compressive load because of the continuity of the top and bottom chord members. These members are not typically braced between each panel point in a truss. Numerical analyses using finite strip and finite element procedures were developed to compare with experimental results. A parametric study on geometric imperfection was also conducted to investigate the factors that affect the ultimate strength behavior of a particular complex hat shape. Better understanding of the flexural behavior of these complex hat shapes is necessary to obtain efficient, safe designs of a truss system. The results of these analyses will be presented in the paper. [ABSTRACT FROM AUTHOR]