A Novel Statistical Model for Link Overstrength

  • Jaya Prakash VemuriEmail author
Conference paper


The Eccentrically Braced Frame (EBF) has both high ductility and high stiffness characteristics. The key member of the EBF is the link, which acts as a sacrificial fuse by dissipating seismic energy. Steel design codes prescribe a constant overstrength factor for links, but experimental results have shown that such assumption can lead to either conservative or unsafe designs. In this paper, a statistical model to estimate overstrength due to strain hardening in steel EBF links is presented. The analysis involves a new parameter, “peak rotation”, a quantity which is not known a priori by the designer, but corresponds to the link rotation observed at maximum shear resisted by the link. A regression analysis is performed on experimental link data obtained from literature. The normalized link length, peak link rotation and the ratio of ultimate strength to yield strength are observed to affect link overstrength. A good fit is obtained between the calculated values from the model and the actual experimental values. The parameter estimates and their errors are tabulated and are found to be statistically significant. The residual analysis carried out on the independent parameters shows no trends.


Eccentrically braced frame Link Strain hardening Peak rotation Overstrength 


  1. 1.
    American Institute of Steel Construction (AISC) (2010) AISC seismic provisions for structural steel buildings. ANSI/AISC 341-10, American Institute of Steel Construction, Chicago, Illinois, 309 pGoogle Scholar
  2. 2.
    Arce G, Engelhardt MD (2003) Experimental behaviour of shear and flexural yielding links of ASTM 992 steel. In: STESSA 2003: proceedings of the conference on behaviour of steel structures, pp 107–114Google Scholar
  3. 3.
    Barecchia E, Corte DG, Mazzolani FM (2006) Plastic overstrength of short and intermediate links. In: Fifth international conference on the behaviour of steel structures in seismic areas (STESSA), Yokohoma, JapanGoogle Scholar
  4. 4.
    Byfield MP, Davies JM, Dhanalakshmi M (2005) Calculation of the strain hardening behaviour of steel structures based on mill tests. J Constr Steel Res 61:133–150CrossRefGoogle Scholar
  5. 5.
    Canadian Standards Association (CSA) (2009) Design of steel structures (CSA S16-09). Canadian Standards Association, TorontoGoogle Scholar
  6. 6.
    Engelhardt MD, Popov EP (1987) Advances in design of eccentrically braced frames. Earthq Spectra 3:43–55CrossRefGoogle Scholar
  7. 7.
    Engelhardt MD, Popov EP (1989) Behaviour of long links in eccentrically braced frames. Report No. UCB/EERC-89/01, Earthquake Engineering Research Center, University of California at Berkeley, Richmond, CAGoogle Scholar
  8. 8.
    Engelhardt MD, Popov EP (1992) Experimental performance of long links in eccentrically braced frames. J Struct Eng ASCE 118:3067–3088CrossRefGoogle Scholar
  9. 9.
    Fujimoto M, Aoyagi T, Ukai K, Wada A, Saito K (1972) Structural characteristics of eccentric K-braced frames. Trans AIJ 195:39–49Google Scholar
  10. 10.
    Hjelmstad KD, Popov EP (1984) Characteristics of eccentrically braced frames. J Struct Eng 110(2):340–353CrossRefGoogle Scholar
  11. 11.
    Jain AK, Koboevic S, Redwood R (1996) Design and behavior of eccentrically braced frame with flexural links. In: Conference proceedings of advances in steel structures (ICASS-96), vol 1, pp 233–238Google Scholar
  12. 12.
    Kasai K, Popov EP (1986) Cyclic web buckling control for shear link beams. J Struct Eng ASCE 112(3):505–523CrossRefGoogle Scholar
  13. 13.
    Kasai K, Popov EP (1986) General behavior of WF steel shear link beams. J Struct Eng 112(3):362–382CrossRefGoogle Scholar
  14. 14.
    Krawlinker H (1978) Shear in beam-column joints in seismic design of steel frames. AISC Eng J 15(3):82–91Google Scholar
  15. 15.
    Malley JO, Popov EP (1984) Shear links in eccentrically braced frames. J Struct Eng ASCE 110(9):2275–2295CrossRefGoogle Scholar
  16. 16.
    Popov EP, Kasai K, Engelhardt MD (1987) Advances in design of eccentrically braced frames. Earthq Spectra 3(1):43–55CrossRefGoogle Scholar
  17. 17.
    Richards PW (2004) Cyclic stability and capacity design of steel eccentrically braced frames. PhD dissertation, University of California, San DiegoGoogle Scholar
  18. 18.
    Richards PW, Uang CM (2005) Effect of flange width-thickness ratio on eccentrically braced frames link cyclic rotation capacity. J Struct Eng 131(10):1546–1552Google Scholar
  19. 19.
    Ricles J, Popov EP (1987) Dynamic analysis of seismically resistant EBFs. Report No. UCB/EERC-87/07, Earthquake Engineering Research Center, BerkeleyGoogle Scholar

Copyright information

© Springer India 2015

Authors and Affiliations

  1. 1.Department of Civil EngineeringIndian Institute of Technology (IIT) HyderabadHyderabadIndia

Personalised recommendations