STR-862: APPLICATION OF 4D AND 5D BIM IN COLD-FORMED STEEL RESIDENTIAL BUILDINGS

Traditional residential building systems are not sufficient to produce the required number of housing units needed every year to solve the current housing problem in many countries. To meet such a challenge, it is necessary to explore the latest construction technologies, and to create innovative building systems that have the potential to bring high-performance affordable housing within reach of new markets. Light (cold-formed) steel (CFS) framing systems have proven to be a worthy alternative to traditional systems. Recent advances in the application of Building Information Modeling (BIM) into the Architecture-Engineering-Construction industries present an additional mean to further enhance the efficiency of CFS projects. This paper presents a BIM based integrated approach for project scheduling and cost estimating of cold formed steel residential buildings. The approach integrates the basic 3D BIM model with the construction management tools used for project scheduling and cost estimation to produce a 4D BIM and 5D BIM models that can be used to enhance the project efficiency in both the design and construction phases. The developed models facilitate communication among all project participants and support project management in effectively planning on-site construction activities. A case study is presented to demonstrate the methodology

Buckling strength of tapered bridge girders under combined shear and bending

This paper represents the finite element results for the local buckling of tapered plate girders subjected to combine pure bending and shear stresses. An idealized model is developed representing the loading of the tapered panel that generates uniform normal stresses due to flexure, or uniform and constant shear stresses in the case of shear. Eigen-value analysis was performed for several tapered web plate girders that have different geometric parameters. A parametric study is made to reduce the FE model size showing the effect of decreasing the tapered panel adjacent straight panels, maintaining the same result accuracy as a complete girder model. The combined buckling capacity of bending and shear is determined by applying all possible load pattern combinations, together with different interaction ratios. An analysis study is presented to investigate the effect of the tapering angle on the combined bending–shear capacity of the girder. The study also includes the effect of the flange and web slenderness on the local buckling of the girder. Considering residual stresses as part of the loading stresses, the analysis procedure is repeated for some cases, and the effect of combining of the residual stresses together with the external loads is found. Empirical approximate formulae are given to estimate the combined flexure–shear buckling resistance of the tapered girder safely

Computational Study of Cold-Formed-Steel X-Braced Shear Walls

The aim of this paper was to present a verified finite element method that represents the full-scale-braced shear walls under seismic loads and to study their ductility. The models account for different types of material and geometric nonlinearities. The screws that connect the cold-formed-steel (CFS) studs, tracks, gusset plates, and braces are considered explicitly in the model. The deformation of the hold-downs under the horizontal load is considered. The finite element program ANSYS (2012) is used to model and analyze the case studies. A parametric study is performed to investigate the response modification factor (R) of the CFS-braced shear walls. The parametric study showed that the North American Specification is about 20% conservative in estimating the (R) factor

Buckling strength of axially loaded cold formed built-up I-sections with and without stiffened web

This paper presents a numerical procedure using finite element analysis for the calculation of axial strength of cold formed steel built-up I-sections composed of two back-to-back channels or stiffened web sigma (Σ). The material nonlinearity of the plane and curved parts of the section were considered in the model. The effects of initial local and global geometric imperfections as well as the membrane residual stresses have been taken into consideration in the FE model. The results of the nonlinear FEA were compared with the available experimental data, and with the calculated theoretical buckling capacities based on the AISI design provisions. A parametric study was performed using the developed FE model to investigate the effects of member and geometries and imperfection values on the capacity of CFS built-up I-columns. A comparison is performed between the member’s axial capacities results from the parametric study and the design capacities calculated using the AISI. The results of the parametric study state that the design specification noted in the AISI are generally conservative for long and medium length columns, but may give un-conservative estimates for some of the short columns. Keywords: Cold-formed-steel, Nonlinear parametric columns, Finite-element, Bucklin