Advanced Steel Construction

Vol. 13, No. 4, pp. 412-426 (2017)


EFFECTIVE LENGTH FACTOR OF COLUMNS IN

NON-SWAY MODULAR STEEL BUILDINGS

 

Guo-Qiang Li1,2, Ke Cao1, Ye Lu1,2,* and Jian Jiang1

1College of Civil Engineering, Tongji University, Shanghai 200092, PR China

2State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, PR China

*(Corresponding author: E-mail:This email address is being protected from spambots. You need JavaScript enabled to view it.)

Received: 8 February 2016; Revised: 27 January 2017; Accepted: 25 February 2017

  

DOI:10.18057/IJASC.2017.13.4.6

 

ABSTRACT:

Prefabrication by off-site manufacturing (OSM) leads to faster construction, improved quality, and reduced resources and waste. As a specific type of off-site structure, modular steel buildings consisting of volumetric modular units is a relatively new structural form in comparison with traditional steel frames with fixed or flexible beam-to-column connections. For multi-strorey modular steel buildings, additional lateral force-resisting systems are commonly used to prevent the structural side sway. In order to rationally evaluate the stability of columns in the non-sway modular steel buildings, the governing equations for determining the effective length factor (K-factor) of columns are derived using the three-column sub-assemblage model. A simplified method based on the French rule is proposed to determine K-factors. Its accuracy and effectiveness are verified against governing equations (maximum error within 6%) and finite element simulation of a six-storey modular steel frame (maximum error within 9%). The influencing factors on the K-factor are studied. The results show that the available methods such as the alignment chart and French rule cannot be directly applied to determine K-factors for the modular steel buildings. It is found that the boundary restraint parameters and their relative values affect the K-factor. The assumption of pinned connections between modular units is found to be non-conservative. It is recommended to check and strengthen the flexible connections for the design of modular steel buildings with too small or too large relative stiffness of the connections between modules.

 

Keywords:

Effective length factor, column buckling, semi-rigid connection, non-sway modular steel building, simplified method

 

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