Influence of Member Length Imperfection on the Capacity of Spatial Structures

Mehrdad Gordini, Mohammad Reza Habibi*, Mohammad Hadi Tavana, Moslem Amiri, Mehrzad Tahamouli Roudsari
Department of Civil Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran



Load bearing capacity of Double Layer Grid Spatial Trusses (DLGST) majorly depend on the structures' imperfections. It is important to analyze the systems with consideration of the influences of uncertainties to ensure the safety of DLGST.


The variation of imperfect members’ positions and initial size of length imperfections (being longer or shorter than the ideal size) were selected as the parameters of the current research. Member length imperfections for both long and short members were randomly taken into account according to the randomly generated numbers. These random numbers were generated using a normal distribution.

Results and Conclusion:

The effect of imperfection is investigated by repeating the analyses simulations on structures with a stochastic dispersion of the imperfect member position and initial length imperfection. It has been demonstrated that the length imperfections might significantly decrease safety of the structure and also shown that the position of imperfect members has effect on the structural performance.

Keywords: Space frame systems, Imperfections, Safety, Steel structures, Double-layer grid spatial truss.

Abstract Information

Identifiers and Pagination:

Year: 2018
Volume: 12
Publisher Item Identifier: EA-TOCIEJ-2018-43

Article History:

Received Date: 20/7/2018
Revision Received Date: 2/11/2018
Acceptance Date: 5/11/2018
Electronic publication date: 22/11/2018
Collection year: 2018

© 2018 Gordini et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Civil Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran, Tel: 00989187393590; Fax: 0098-833-8432879; E-mail: