Software for the Analysis of Bridges Including Vertical and Angular Deformations by Utilizing Direct Integration Techniques
3. International Conference on Civil and Environmental Engineering (ICOCEE), İzmir, Turkey, 24 - 27 April 2018, vol.2, pp.511, (Summary Text)
- Publication Type: Conference Paper / Summary Text
- Volume: 2
- City: İzmir
- Country: Turkey
- Page Numbers: pp.511
- Istanbul University Affiliated: Yes
Abstract
It is well-known that bridges, viaducts, and similar structures have been damaged and even destroyed under earthquake excitation; however, reliable reasons have not been determined yet. It is observed that, generally, only horizontal seismic effects are included in the current studies and vertical motion is neglected for the investigation of the behavior of bridge-type structures subjected to earthquakes. Likewise, only the horizontal impact is taken into account by important prevailing international specifications/codes. One of the main reasons for excluding vertical behavior is the possibility for the system to become mechanism if the vertical loads are small compared to the potential tension forces during the earthquake since the solution will become practically impossible. Recently; a general purpose computer program, that can perform the conventional static and modal analyses of a structural system including the vertical effects has been developed, and was presented by the authors in XX. Uludag Mechanical Congress. By using this software, the mode shapes and dynamic characteristics of an example bridge model have been obtained. Since the dimensions of the mass matrix and the stiffness matrix of the structural system are the same, the program included a mass component corresponding to each degree of freedom, including angular components. Moreover, accounting distributed mass and taking angular components into consideration were possible options. At this stage of the study, by implementing Direct Integration Techniques to the aforementioned code for time history analysis of the structural system; obtaining acceleration, velocity, displacement and force components at each nodal point has become possible. By making use of this program, a horizontal earthquake acceleration record has been applied to all horizontal degrees of freedom, and 30% of the horizontal acceleration has been applied to the vertical degrees of freedom together with the rotational ones. As it stands, the program is capable of performing analysis for a large number (millions) of unknowns that push the limits of extant general purpose finite element programs. Initial findings based on the analyzed bridge model reveal that taking vertical motion under consideration may be crucial since vertical reaction forces, reaching 1/3 of the own weight of the bridge, may come into scene.