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Steel and Composite Structures
  Volume 29, Number 5, December10 2018 , pages 623-633
DOI: https://doi.org/10.12989/scs.2018.29.5.623
 


Curved-quartic-function elements with end-springs in series for direct analysis of steel frames
Si-Wei Liu, Jake Lok Yan Chan, Rui Bai and Siu-Lai Chan

 
Abstract
    A robust element is essential for successful design of steel frames with Direct analysis (DA) method. To this end, an innovative and efficient curved-quartic-function (CQF) beam-column element using the fourth-order polynomial shape function with end-springs in series is proposed for practical applications of DA. The member initial imperfection is explicitly integrated into the element formulation, and, therefore, the P-δ effect can be directly captured in the analysis. The series of zero-length springs are placed at the element ends to model the effects of semi-rigid joints and material yielding. One-element-per-member model is adopted for design bringing considerable savings in computer expense. The incremental secant stiffness method allowing for large deflections is used to describe the kinematic motion. Finally, several problems are studied in this paper for examining and validating the accuracy of the present formulations. The proposed element is believed to make DA simpler to use than existing elements, which is essential for its successful and widespread adoption by engineers.
 
Key Words
    second-order; steel; imperfection; semi-rigid; design; plastic hinge
 
Address
(1) Si-Wei Liu:
School of Civil Engineering, Sun-Yat-Sen University, China;
(2) Jake Lok Yan Chan:
Department of Civil Engineering, The University of Hong Kong, Hong Kong, China;
(3) Rui Bai, Siu-Lai Chan:
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
 

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