cold-formed steel structures: advances in research and design - apcmr

5. FURTHER DEVELOPMENTSFurther studies representing the natural extension of the current research activities onthe behaviour of CFS structures have been planned at the University of Naples.The preliminary calibration study on the numerical modelling of CFS memberspresented in Section 2 will be used as a basis for a wide numerical study of the bendingbehaviour of C-sections. In particular, the reliability of the codified analysis methodologieswill be investigated, with systematic variation of the size of the edge-stiffening lip. Theultimate objective is to gain an insight into current available design methodologies andpossibly improve them. In fact, as discussed in Section 4, current codified provisions oftenpresent systematic error in prediction the load bearing capacity of such type of sectionsbecause the web-flange interaction in the distortional failure mode is neglected.The complex behaviour of CFS lightweight low-rise buildings laterally braced bypanels under seismic actions requires the setting-up of an additional research activity aimingat the development of useful and practical analysis and design methodologies. Consequently,on the basis of the results coming from the experimental studies illustrated in Section 3, thenext research activity will be articulated in the following two main phases: (1) developmentof reliable mechanical models, in order to capture the complex hysteresis response of shearwalls stud-panels systems; (2) evaluation of the deformation demand for stud shear wallssystems, on the basis of a realistic and sufficiently wide database of acceleration records.The development of the first phase of the research will benefit of the long experiencethat has been matured [56,57,58] in both the modelling of the hysteresis behaviour of singlestructural components and studying its influence on the global response of the structure. Thedefinition of the deformation demand to small buildings made of the stick-built constructionsystem represents the scope of the second phase of this research. It will be carried outaccording to the suggestions given in the document FEMA 350 [59]. It is deemed important toemphasise the need to perform an analytical-numerical study aiming at evaluating thedeformation demand to steel stud shear walls systems. In fact, such a structural systemexhibits a peculiar hysteresis behaviour, with a strong pinching of hysteresis loops, whichreduces the energy absorption capacity.6. REFERENCES[1] Pekoz, T., Possible future developments in the design and application of cold-formedsteel. Keynote lecture. In Proceedings of the 4 th International conference Light-weightsteel and aluminium structures (ICSAS’99), Espoo, Finland, 1999.[2] Yu, W.W., Cold Formed Design (3rd Edition). John Wiley & Sons. New York, 2000.[3] Schuster, R.M., Residential applications of cold-formed steel members in NorthAmerica. In Proceedings of the 5 th International Structural Stability ResearchConcilium – SSRC. Chicago, 1996.[4] Gad, E.F., Chandler, A.M., Duffield and C.F., Stark, G., Lateral behaviour ofplasterboard-clad residential steel frames. Journal of Structural Engineering, ASCE,No.125(1): 32-39, 1999.[5] Burstrand, H., Ligth-gauge steel framing leads the way to an increased productivity forresidential housing. Journal of constructional steel research, Elsevier, No.46(1-3):Paper No.213, 1998.[6] Davies, J.M., Light gauge steel framing for housing construction. In Proceedings ofthe 2 nd International conference on thin-walled structures, Singapore, 1998.