cold-formed steel structures: advances in research and design - apcmr
cold-formed steel structures: advances in research and design - apcmr
cold-formed steel structures: advances in research and design - apcmr
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5. FURTHER DEVELOPMENTSFurther studies represent<strong>in</strong>g the natural extension of the current <strong>research</strong> activities onthe behaviour of CFS <strong>structures</strong> have been planned at the University of Naples.The prelim<strong>in</strong>ary calibration study on the numerical modell<strong>in</strong>g of CFS memberspresented <strong>in</strong> Section 2 will be used as a basis for a wide numerical study of the bend<strong>in</strong>gbehaviour of C-sections. In particular, the reliability of the codified analysis methodologieswill be <strong>in</strong>vestigated, with systematic variation of the size of the edge-stiffen<strong>in</strong>g lip. Theultimate objective is to ga<strong>in</strong> an <strong>in</strong>sight <strong>in</strong>to current available <strong>design</strong> methodologies <strong>and</strong>possibly improve them. In fact, as discussed <strong>in</strong> Section 4, current codified provisions oftenpresent systematic error <strong>in</strong> prediction the load bear<strong>in</strong>g capacity of such type of sectionsbecause the web-flange <strong>in</strong>teraction <strong>in</strong> the distortional failure mode is neglected.The complex behaviour of CFS lightweight low-rise build<strong>in</strong>gs laterally braced bypanels under seismic actions requires the sett<strong>in</strong>g-up of an additional <strong>research</strong> activity aim<strong>in</strong>gat the development of useful <strong>and</strong> practical analysis <strong>and</strong> <strong>design</strong> methodologies. Consequently,on the basis of the results com<strong>in</strong>g from the experimental studies illustrated <strong>in</strong> Section 3, thenext <strong>research</strong> activity will be articulated <strong>in</strong> the follow<strong>in</strong>g two ma<strong>in</strong> phases: (1) developmentof reliable mechanical models, <strong>in</strong> order to capture the complex hysteresis response of shearwalls stud-panels systems; (2) evaluation of the deformation dem<strong>and</strong> for stud shear wallssystems, on the basis of a realistic <strong>and</strong> sufficiently wide database of acceleration records.The development of the first phase of the <strong>research</strong> will benefit of the long experiencethat has been matured [56,57,58] <strong>in</strong> both the modell<strong>in</strong>g of the hysteresis behaviour of s<strong>in</strong>glestructural components <strong>and</strong> study<strong>in</strong>g its <strong>in</strong>fluence on the global response of the structure. Thedef<strong>in</strong>ition of the deformation dem<strong>and</strong> to small build<strong>in</strong>gs made of the stick-built constructionsystem represents the scope of the second phase of this <strong>research</strong>. It will be carried outaccord<strong>in</strong>g to the suggestions given <strong>in</strong> the document FEMA 350 [59]. It is deemed important toemphasise the need to perform an analytical-numerical study aim<strong>in</strong>g at evaluat<strong>in</strong>g thedeformation dem<strong>and</strong> to <strong>steel</strong> stud shear walls systems. In fact, such a structural systemexhibits a peculiar hysteresis behaviour, with a strong p<strong>in</strong>ch<strong>in</strong>g of hysteresis loops, whichreduces the energy absorption capacity.6. REFERENCES[1] Pekoz, T., Possible future developments <strong>in</strong> the <strong>design</strong> <strong>and</strong> application of <strong>cold</strong>-<strong>formed</strong><strong>steel</strong>. Keynote lecture. In Proceed<strong>in</strong>gs of the 4 th International conference Light-weight<strong>steel</strong> <strong>and</strong> alum<strong>in</strong>ium <strong>structures</strong> (ICSAS’99), Espoo, F<strong>in</strong>l<strong>and</strong>, 1999.[2] Yu, W.W., Cold Formed Design (3rd Edition). John Wiley & Sons. New York, 2000.[3] Schuster, R.M., Residential applications of <strong>cold</strong>-<strong>formed</strong> <strong>steel</strong> members <strong>in</strong> NorthAmerica. In Proceed<strong>in</strong>gs of the 5 th International Structural Stability ResearchConcilium – SSRC. Chicago, 1996.[4] Gad, E.F., Ch<strong>and</strong>ler, A.M., Duffield <strong>and</strong> C.F., Stark, G., Lateral behaviour ofplasterboard-clad residential <strong>steel</strong> frames. Journal of Structural Eng<strong>in</strong>eer<strong>in</strong>g, ASCE,No.125(1): 32-39, 1999.[5] Burstr<strong>and</strong>, H., Ligth-gauge <strong>steel</strong> fram<strong>in</strong>g leads the way to an <strong>in</strong>creased productivity forresidential hous<strong>in</strong>g. Journal of constructional <strong>steel</strong> <strong>research</strong>, Elsevier, No.46(1-3):Paper No.213, 1998.[6] Davies, J.M., Light gauge <strong>steel</strong> fram<strong>in</strong>g for hous<strong>in</strong>g construction. In Proceed<strong>in</strong>gs ofthe 2 nd International conference on th<strong>in</strong>-walled <strong>structures</strong>, S<strong>in</strong>gapore, 1998.