mb-po

There are several types of natural disasters, such as earthquakes, floods, tsunamis and landslides. Japan has a long history of devastating disasters which have killed thousands of people and severely destroyed the infrastructure. In 1995, the Great Hanshin Awaji earthquake occurred, destroying numerous buildings and infrastructure. Portions of the country are still recovering from the Tohoku earthquake and tsunami of 2011. In recent years, several massive bridges have been damaged by various typhoons in local areas of Japan such as Hokkaido, Tohoku, and Kagoshima.

Natural disasters can occur anywhere in the world and pose a threat to our lives. In the aftermath of a natural disaster, among the infrastructure, the rapid recovery of bridges is required. Repairing the damaged infrastructure is of utmost importance, because this not only aids evacuation but also allows relief to be provided to local communities. However, numerous risks and restrictions are present within the disaster zones. Even if a prefabricated bridge is used in an emergency, it takes a week or more until it is in a usable state. Because heavy machinery and emergency vehicles may be unable to access the site, recovery work may be delayed. In certain situations, an emergency bridge could be needed even in locations where professional engineers are not available to construct them. Furthermore, secondary hazards caused by localized damage could probably impede any rescue operations. These situations raise the question, “which useful activities can be performed in the immediate aftermath of a natural disaster?".

In this study, basic mechanisms for the buckling of a thin cylindrical shell under torsional loading are reviewed from a post-buckling perspective. Deflections are considered extensively into the large-deflection range to the point that the shell is allowed to fold to a flat two-dimensional form, in a mechanism reminiscent of a deployable structure. Herein, critical and initial post-buckling effects are explored through concepts of energy minimization and hidden symmetries. For its comparison with the final large-deflection folded shape, a truss element program is employed. It is shown that, as buckling develops, the mode shape must change to accommodate both the symmetry-breaking aspects of the predominately inward deflection and the rotation of peak and valley lines of the buckle pattern necessary to accommodate the geometry of the final folded shape. The concept behind the structure has been inspired from two different forms of structural design techniques, namely, Origami which is the art of paper folding, and scissor mechanism, which is a principle using linked, folding supports in a criss cross 'X' shaped pattern as a basic unit in the structural system. A novel structural system is proposed which has the advantages of both the techniques and simultaneously serves the specific purpose of providing relief for displaced people in times of need and in emergency situations. A scissor structure is employed an Origami-inspired foldable and/or deployable and movable bridge is used as a Mobile bridge. This implies that it is useful to create a bridge construction using a folding mechanism based on the academic science of Origami skills. It might be significant to discover the essential core of an ``Origami-inspired more useful industrial deployable bridge".

In the field of bridge engineering, several studies have discussed the merits of modular bridges [1] and the use of lightweight materials, such as fiber-reinforced plastic (FRP) [2] or air tubes [3]. Although these propositions allow the rapid construction of bridges, there remain various problems regarding the creation of large construction yards and use of heavy industrial machinery. However, any rescue technology should have a low level of complexity and high degree of resilience, to enable its deployment even by unqualified personnel. Hence, we propose a new type of foldable and deployable bridge traded as Mobile Bridge (hereinafter referred to as “MB”) (Japan Patent No.2006-037668 [4], PCT WO2015/193930A1 [5] including European Patents. The MB can be deployed and folded quickly owing to a scissor mechanism which allows for a highly efficient construction and easy transportation. The idea for this new bridge is based on the academic studies on post-buckling using Origami fundamentals [6] and [7].

In previous studies of the MB [8]-[10], the mechanism and design concept were evaluated via numerical finite element analysis followed by a fundamental static-loading test using a small experimental bridge. The current research reviews the field testing of the latest MB in a real river and its fundamental experimental and numerical results using a full-scale experimental MB. Experimental testing includes strain and acceleration measurements in free and forced loading conditions. From these results, it is possible to estimate the basic dynamic characteristics of the bridge. In addition, in order to provide the basis for development of new methods for structural reinforcement and suppression of vibrations, various numerical models are designed. The conducted research allows for a better and safer MB to be designed.