Cold-Formed Steel Research Consortium (CFSRC)
http://jhir.library.jhu.edu/handle/1774.2/40427
2017-09-25T17:09:11ZSDII Building Archetype Design v1.0
http://jhir.library.jhu.edu/handle/1774.2/40638
SDII Building Archetype Design v1.0
Torabian, S.; Eatherton, M.R.; Easterling, W.S.; Hajjar, J.F.; Schafer, B.W.
Building archetypes are fundamental to exploring and demonstrating the seismic behavior of modern structures. No suitable archetypes or prototypes exist in the open literature that focus on steel deck diaphragms for conventional steel buildings. Three dimensional building analysis, with meaningful contributions from the diaphragm in terms of behavior, has not formed the basis for modern seismic standards in steel at this time. The objectives for the SDII building archetypes include the following. Develop a series of 3D steel-framed archetype buildings that explore and document the design of horizontal lateral force resisting systems (LFRSs) with steel deck-based diaphragms as well as vertical LFRSs and the inter-relationship between the two. Provide a series of buildings that form a common basis of comparison for diaphragms in steel-framed buildings much the same way the SAC buildings did for the vertical LFRS. Explicitly explore the impact of the ASCE 7-16 standard, and ASCE 7-16 alternate diaphragm design with Rs=1 and Rs=3 in designs. Inform areas for needed experimentation, and create targets for advancing nonlinear analysis within the full SDII effort. Version 1.0 of this archetype effort includes: (1) a complete slide deck explaining the design of a 12 story steel building archetype using buckling restrained braced (BRB) frames for the vertical LFRS and steel deck with fill for the diaphragm/horizontal LFRS detailed to the ASCE7-16 standard as well as the ASCE7-16 alternate diaphragm provisions with Rs=1 and Rs=3, (2) a series of spreadsheets that provide the complete design calculations for the gravity and lateral systems, (3) a series of computer models (using the SAP structural analysis program), and (4) a literature review of other related building archetypes and justification for developing new building archetypes.
2017-07-01T00:00:00ZSteel Deck Diaphragm Test Database V1.0
http://jhir.library.jhu.edu/handle/1774.2/40634
Steel Deck Diaphragm Test Database V1.0
O'Brien, P.; Eatherton, M.R.; Easterling, W.S.; Schafer, B.W.; Hajjar, J.F.
From the 1950’s to the present, a substantial number of large-scale tests have been conducted on steel deck diaphragms or concrete on metal deck diaphragms. The data, papers and reports for these tests are located in scattered references and many are not publically available. As part of the Steel Diaphragm Innovation Initiative (SDII), a database of over 750 past experiments on metal deck diaphragms was created. The information contained in this database can be useful for several applications including evaluating strength and stiffness prediction equations, assessing resistance and safety factors, and investigating ductility of diaphragms. The database contains fields related to 1) specimen identification and reference, 2) the test setup including information about the geometry, loading type, deck orientation, beam sizes, steel deck geometry, and concrete slab information if applicable, 3) fastener information including sidelap fasteners, structural fasteners, and shear studs, 4) information about materials including deck material and concrete fill material, and 5) test results for selected specimens including stiffness, strength, and ductility.
Front material and Excel database of test results.
2017-07-01T00:00:00ZCharacterizing the load-deformation behavior of steel deck diaphragms using past test data
http://jhir.library.jhu.edu/handle/1774.2/40633
Characterizing the load-deformation behavior of steel deck diaphragms using past test data
O'Brien, P.; Eatherton, M.R.; Easterling, W.S.
Recent research has identified that current code level seismic demands used for diaphragm design are considerably lower than demands in real structures during a seismic event. However, historical data has shown that steel deck diaphragms, common to steel framed buildings, perform exceptionally well during earthquake events. A new alternative diaphragm design procedure in ASCE 7-16 increases diaphragm seismic demand to better represent expected demands. The resulting elastic design forces from this method are reduced by a diaphragm design force reduction factor, Rs, to account for the ductility of the diaphragm system. Currently, there exist no provisions for Rs factors for steel deck diaphragms. This research was therefore initiated to understand inelastic steel deck diaphragm behavior and calculate Rs factors. A review of the literature showed that a large number of experimental programs have been performed to obtain the in-plane load-deformation behavior of steel deck diaphragms. To unify review of these diaphragm tests and their relevant results, a database of over 750 tested specimens was created. A subset of 108 specimens with post-peak, inelastic behavior was identified for the characterization of diaphragm behavior and ductility. A new recommended method for predicting shear strength and stiffness for steel deck diaphragms with structural concrete fill is proposed along with an appropriate resistance factor. Diaphragm system level ductility and overstrength are estimated based on subassemblage test results and Rs factors are then calculated based on these parameters. The effects of certain variables such as deck thickness and fastener spacing on diaphragm ductility are explored.
2017-06-01T00:00:00ZIn-plane shear stiffness of bare steel deck through shell finite element models
http://jhir.library.jhu.edu/handle/1774.2/40632
In-plane shear stiffness of bare steel deck through shell finite element models
Bian, G; Schafer, B.W.
The objective of this report is to explore the in-plane elastic shear stiffness of bare steel deck diaphragms through high fidelity shell finite element modeling. Profiled steel panels, i.e, metal deck, often serve as a key distribution element in building lateral force resisting systems. Acting largely as an in-plane shear diaphragm, metal deck as employed in walls, roofs, and floors plays a key role in creating and driving three-dimensional building response. Accurate prediction of shear stiffness is needed to better understand the shear behavior of bare steel deck. According to the shear stiffness expression in AISI S310 or SDI’s Diaphragm Design Manual (DDM), total shear deformation can be separated into three parts: pure shear deformation, warping deformation, and connection slip. In this report, bare deck finite element models were built with typical fastener layouts from DDM. The shear condition was performed on the models by imposing deformations at the perimeter. By changing boundary conditions, these shear deformation terms can be separated and the values of shear stiffness were compared with DDM expressions. The results showed that the prediction of shear stiffness from pure shear deformation and connection slip from finite element modeling agree well with the DDM prediction; however, the warping stiffness predicted from DDM is smaller than shell finite element predictions. DDM uses a simplified model to predict warping deformation and this model may need to be revised in the future.
2017-06-01T00:00:00Z