Outstanding Paper Award
The International Association for Bridge and Structural Engineering (IABSE) presents the Outstanding Paper Award to the author(s) of a paper published in the preceding year’s issues of the IABSE quarterly Journal Structural Engineering International (SEI), encouraging and rewarding contributions of the highest quality. The award will be presented in the categories ‘Scientific Paper’ and ‘Technical Report’ by Prof. Fernando Branco, President of IABSE, on September 21, 2017, on occasion of the 39th IABSE Symposium in Vancouver (Sept. 21-23, 2017).
Category ‘Scientific Paper’: “Post-Tensioned Glass Beams for a 9 m Spannglass Bridge” by Michael Engelmann, Bernhard Weller, Germany, SEI 2/2016 (May), pp. 103-113.
Glass beams may be reinforced to allow for a fail-safe behaviour and to avoid brittle and total collapse. This approach from reinforced concrete design is applied to glass and extended by post-tensioning the reinforcement by using Spannglass beams. A high-grade steel cable relieves the brittle material from unbeneficial tensile stress and accommodates permanent dead-load deflection. A structural concept was evolved that led to the development of Spannglass beams, which were tested for a span of 2 m. This concept was extended to larger spans in order to consider size effects and to provide this option to a broader field of application. To verify this, a 9 m pedestrian glass bridge with post-tensioned reinforcement was designed and tested experimentally. Three full-size glass specimens were utilised with adhesive connectors and two reinforcement designs. A post-tensioning concept was finalised and put into practice. Finally, four-point bending tests were performed to yield the maximum loads. This paper explains the experimental design, presents the results and provides conclusions of how to design workable structural glass beams with post-tensioned reinforcement. The paper also presents the design process and the construction of a 9 m Spannglass Bridge used by pedestrians at Glasstec 2014 in Düsseldorf, Germany.
Category ‘Technical Report’: “Construction of a Large Composite Gridshell Structure: A Lightweight Structure Made with Pultruded Glass Fibre Reinforced Polymer Tubes” by Lionel du Peloux; Frédéric Tayeb; Olivier Baverel, and Jean-François Caron, France, SEI 2/2016, (May.) pp. 160-167.
The Ephemeral Cathedral of Créteil at Paris, France, is a gridshell structure made of composite materials. Built in 2013, this 350 m2 religious edifice is a temporary church meant to gather the parishioners during the two year renovation of their permanent cathedral. This large-scale prototype represents a first in the building industry which still shows excessive apprehension for the use of non-traditional materials such as composites, especially when it comes to structural applications.
After a brief description of the structure, this paper gives an insight into the field of elastic gridshells and discusses the benefits of composite materials in such structures. The overall design process employed, from the three dimensional (3D) shape designed by the architect to a full structural shell, is then explained. Finally, complexities due to the connections are highlighted and solutions are presented.