Delft University of Technology
Van Reekum, R.B.
Structural behavior of pressure locked gratings:.
Degree: 2015, Delft University of Technology
Pressure locked gratings have many uses, both on land and at sea. This is mainly due to the high degree of flexibility in dimensions and load bearing capacity. Despite the many uses in our surroundings, the term pressure locked grating is unknown to many. This term refers to the way in which the most important connection in pressure locked gratings is manufactured.
Pressure locked gratings are galvanized and/or coated to prevent corrosion, galvanization is almost always used. This thesis is primarily focused on the behavior of galvanized pressure locked gratings. A pressure locked grating is made up of three type of bars: load bearing bars, cross bars and support bars. The connections between the load bearing bars and the cross bars are realized by pressing the cross bar into premade notch in the load bearing bar. The bars will deform plastically, which results in a connection based only on friction. This connection is called a pressure locked connection.
The load bearing bars serve primarily for load transfer in one direction. The pressure locked connection weakens the load bearing bars. The cross bars redistribute a local load over the load bearing bars outside of the loading area and reduce the buckling length of the individual load bearing bar. The support bars are spot-welded to both the load bearing and cross bars.
Pressure locked gratings are calculated according to RAL-GZ-638, a standard published by the Deutsches Institut für Gütesicherung und Kennzeichnung e.V. In this standard, pressure locked gratings are calculated on the basis of linear elasticity theory. A calculation according to the EN 1993-1-1 is not possible because it is not suited for pressure locked gratings.
The main objective of this thesis is to determine if a calculation based on the plasticity theory is possible for pressure locked gratings. Through the application of this theory the design strength can be greatly increased, which has a large economic potential. This research is divided up into four parts that are stated below.
• Analytical study
• Experimental study
• FEM validation
• Parametric study
The vast diversity in size and properties and the complex functioning of the pressure locked connection make pressure locked gratings a difficult product to research. The pressure locked connection also has a big influence on the strength and stiffness. In this galvanizing has a big influence.
The analytical study shows that pressure locked gratings fail through: local lateral torsional buckling of one of the load bearing bars, global lateral torsional buckling for the entire pressure locked grating or by a mechanism due to a plastic hinge in de load bearing bars.
To research the behavior, numerical models were developed in the FEM-package ABAQUS. To determine the accuracy of these models, experiments were carried out on a number of pressure locked grating geometries. The results of the tests were compared with FEM simulations which made it possible to validate the FEM-models. The validation has taken place on the basis of four test…
Advisors/Committee Members: Abspoel, R., Feijen, M..
Subjects/Keywords: steel; pressure locked gratings; FEM; experiments
to Zotero / EndNote / Reference
APA (6th Edition):
Van Reekum, R. B. (2015). Structural behavior of pressure locked gratings:. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:d10408ea-eeb9-45dd-83e5-bc7139457990
Chicago Manual of Style (16th Edition):
Van Reekum, R B. “Structural behavior of pressure locked gratings:.” 2015. Masters Thesis, Delft University of Technology. Accessed December 12, 2019.
MLA Handbook (7th Edition):
Van Reekum, R B. “Structural behavior of pressure locked gratings:.” 2015. Web. 12 Dec 2019.
Van Reekum RB. Structural behavior of pressure locked gratings:. [Internet] [Masters thesis]. Delft University of Technology; 2015. [cited 2019 Dec 12].
Available from: http://resolver.tudelft.nl/uuid:d10408ea-eeb9-45dd-83e5-bc7139457990.
Council of Science Editors:
Van Reekum RB. Structural behavior of pressure locked gratings:. [Masters Thesis]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:d10408ea-eeb9-45dd-83e5-bc7139457990