Syed Naveed, Raza Shah (2016) Behavior of steel pallet rack beam to column connections at ambient and elevated temperatures / Syed Naveed Raza Shah. PhD thesis, University of Malaya.
Abstract
Steel pallet racks (SPRs) are designed to be readily demountable and capable of re- assembly depending upon the volume of storage goods. Therefore, semi-rigid boltless beam-to-column connections (BCCs) are used in these structures which govern the stability of SPRs in the unbraced down-aisle direction. The performance of SPR BCCs relies upon the behavior of the connection device, namely, ‘beam end connector’ (BEC). The structural behavior of the BEC varies with its configuration and hampers the development of a common analytical model to predict the behavior of all types of SPR BCCs. The behavior of the SPR BCCs becomes more complicated in case of fire. However, the literature completely lacks the studies on the behavior of SPR BCCs subjected to elevated temperatures. This research examines the experimental and numerical behavior of SPR BCCs at ambient and elevated temperatures and consists of two main types of investigation. In the first phase, the experimental testing of SPR BCCs at ambient temperature was performed using double cantilever test setup. Thirty-two tests were performed based on the variation in column thickness, beam depth and number of tabs in the beam end connector to examine the behavior of SPR BCCs. The moment-rotation (M-θ) behavior, load-strain relationship, major failure modes and the influence of selected parameters on the connection performance were investigated. A comparative study to calculate the connection stiffness was carried out by comparing various stiffness design methods available in the literature and the appropriate method is determined. A 3D non-linear finite element (FE) model that simulates the testing protocol was generated using ABAQUS FE software and its accuracy was validated against experimental results. After achieving a good overall agreement between the FE analysis and experimental results, the FE model was further extended to perform parametric analysis. In the second phase, experimental and numerical testing of SPR BCCs subjected to fire were performed. Three different temperature ranges (450 °C, 550 °C and 700 °C) were selected to test twenty-four connections. For experimental testing at elevated temperatures, the details of specimens and the type of test setup for mechanical loading were same as those used for experimental testing at ambient temperature. The 3D non- linear FE model developed for ambient temperature testing was modified to validate the elevated temperature testing results. The findings showed that the connection performance significantly relies on the sizes of the members constituting the connection. Furthermore, at ambient temperature, the major failure modes were the deformation of tabs, distortion of the BEC and tearing of the column web. Similar failure modes were observed up to the temperature range of 550 °C. However, at 700° C, the out of plane buckling of column web was observed as an additional and dominant failure mode. At ambient temperature testing, the variation in the geometrical features of connection parameters considerably affected the stiffness as compared to the strength of the connection, whereas at elevated temperature testing, variation in material properties exhibited a noticeable degradation in the strength as compared to the stiffness of the connection
Actions (For repository staff only : Login required)
![[img]](http://studentsrepo.um.edu.my/style/images/fileicons/application_pdf.png)
