The Behaviour of Drive-in Storage Structures

The paper describes the behaviour of Drive-in and Drive-thru pallet rack structures. It proposes a number of simplified two-dimensional models for the analysis of such structures. These models are shown to be conservative and take account of the non-linear behaviour of the structures. The paper makes some comparisons between the output from these and a 3-D finite element program. The effects of friction between the pallet and the supporting rail is discussed briefly

The Design of the Pallet Program

This paper describes the procedures underlying the development of the Pallet program which has been produced to design regular pallet racks according to the FEM code. The program determines the buckling load of the equivalent free sway structure and, using stability functions, calculates the axial and shear forces and the bending moments within the structure including the non-linear P - Δ effects. Twelve different combinations of load are analysed and design checks given in the FEM code applied. The paper discusses the different modes of operation of the program. Finally the accuracy of the program is discussed together with future developments

A European Design Code for Pallet Racking

The work leading to a European design code for pallet racking started almost 25 years ago. Many difficulties were encountered in the early days of this work. Notable were the absence of a consistent safety philosophy between the various countries of Europe and the existence of procedures with which the manufacturers were comfortable but which were potentially unsafe. There were also difficulties in defining acceptable standard. test procedures. The emergence of Eurocode 3, especially Part 1.3 dealing with cold formed sections, provided a new impetus to the work because here was a European code which provided the required basis for the design code. Accordingly, Section X of the Federation Europeenne de la Manutention (FEM) commissioned technical experts to draft the new code under the direction of its technical committee. It was a requirement that the code should be, as far as possible, compatible with Eurocode 3. In the early stages of the work, there were a group of these experts but, for most of the drafting period, only the authors of this paper were active. The code was essentially complete in mid 1997 and, since then, it has been subject to trial use by the member companies of FEM and open to consequential comments. However, in May 1997, a significant meeting took place. FEM and the Rack Manufacturers Institute (RMI) of the USA sponsored a meeting between the first author and RMI\u27s own expert , Professor T Pekoz of Cornell University. The intention was to compare the two codes and to report on the potential for possible future harmonisation. It emerged that the two codes were about as different as two codes covering the design of the same structural elements could be! However, the experts took a positive view of the situation and concluding that, from the technical point of view, there was no reason why the two codes could not be brought into convergence and that, in the meantime, we could each learn from the others experience. Consequently, at this late stage in the evolution of the European code, a number of significant changes were made where it was considered that the European code could advantageously be made more compatible with the RMI code without in any way impairing its technical rigour. This paper introduces the new European design code for pallet racking and compares and contrasts it with its American counterpart. As a pallet rack is a particularly demanding application of cold-formed steel sections, it is hoped that the designers of other cold-formed products may also learn from some of the approaches described in this paper

Rotational Stiffnesses of Semi-rigid Baseplates

The paper describes a test procedure to determine the rotational stiffnesses and moment-curvature relationships of semi-rigid baseplates of cold-formed structures. The influence of the modulus of the foundation subgrade on baseplate performance is determined. Increasing the axial load applied to a baseplate is shown to increase the ultimate moment-rotation capacity of a baseplate

Experimental Procedures for Stub Column Tests

In this paper a total of 36 stub columns was tested by two different experimental procedures, namely the FEM and AISI procedures, to investigate the difference in the ultimate load between these procedures. Of these 26 were carried out in the pin-ended condition according to FEM, the rest were in the fixed-end condition according to AlSI specification. It is shown that the failure loads obtained by the two experimental procedures were very close to each other. Both procedures worked well. The AISI procedure is recommended as the standard procedure

Basking shark breaching behaviour observations West of Shetland

This is the author accepted manuscript. The final version is available from BioMed Central via the DOI in this record.This study reports observations of basking sharks (Cetorhinus maximus) sighted during an offshore geophysical survey conducted in July and August 2013, west of Shetland, UK. During the 38-day survey, trained and dedicated marine wildlife observers recorded 19 sightings of basking sharks (n=22 individuals). Of these observations, 17 were of single sharks, with one observation of two sharks and one observation of three sharks. All surface sightings occurred in water with depths between 129 and 199 m, predominantly prior to noon local time (79%), and were mostly of sharks 6-8 m in length, although a young (2 m) individual was also recorded. Breaching behaviour was observed on 14 occasions, by individuals or in small groups. Breaching has been proposed as a male-male competitive behaviour during courtship displays and female basking sharks may breach to signal their readiness for mating. Aggregations of basking sharks at frontal systems are well documented and linked to the occurrence of prey patches; however, these oceanographic features may also be of importance to courtship. The high number of sightings of sharks recorded during a relatively short time frame in addition to breaching behaviour and presence of young individuals, suggest that this area west of Shetland may be an important habitat for the basking shark

Shear Stiffness of Pallet Rack Upright Frames

PaIIet racks, often fabricated using cold-formed steel, are used for the storage of goods. Uprights of these racks are braced in the cross-aisle direction forming a frame, which behaves like a built-up column. Evaluation of the shear stiffness of this frame is needed to determine the buckling load. Currently two approaches prevail in the rack industry to determine the shear stiffness. The RMI code uses a theoretical formula and the FEM code requires testing. There is a considerable difference in the stiffness values determined by two approaches. The present paper describes experimental and numerical studies conducted at Oxford Brookes University to evaluate shear stiffness in an ongoing research project

Cross-aisle Stiffness Tests on Rack Upright Frames

The US Rack Manufacturers Institution (RMI) code uses a theoretical formula derived by Timoshenko and the new Eurocode EN15512 requires testing. There is a considerable difference in the stiffn ess values determined by two approaches. This paper describes the experiments conducted on 80 full sized upright frames at Oxford Brookes University varying upright size, number of panels in the frame, aspect ratio of the panel (panel length/depth), restraints at the intermediate nodes of the frame, loading pattern, lacing pattern (channels back to back or front to front) and bolt tightness. The experimental data reported can be used in proposing revised design procedures