Manual for Menshin Design of Highway Bridges: Ministry of Construction, Japan

摘要

The manual presents the seismic design procedures and design details for theconstruction of highway bridges using Menshin Devices (Structures Expecting Reduction of Inertia Force) which is regulated in the Design Specifications for Highway Bridges-Part V Seismic Design. The other regulations, except those presented in this manual, shall conform to the Design Specifications for Highway Bridges. In accordance with the definition of seismic design method, various types of design procedures can be considered in the use of Menshin Devices. In this manual, however, Menshin Design is defined as the seismic design method in which the following three conditions can be satisfied simultaneously: (1) superstructures are required to be supported softly with the use of isolators. Inertia force shall be reduced by elongating the natural period of a bridge when the interia force exceeds a certain limit; (2) elongation of the natural period may cause excessive displacement of decks during an earthquake. With the use of dampers, deck displacement is reduced to an acceptable amount by increasing the energy dissipation capabilities; and (3) for normal loads such as wind loads and centrifugal loads, any vibration which may cause undesirable effects on bridge functions is prevented. Therefore, unless the interia force does not exceed a certain limit, isolators and dampers are required to be stiff enough to prevent vibration.