Ichiro Konishi

Reducing the Bandwidth of Structural Stiffness Matrices

Abstract A new diagrammatic procedure for reducing the bandwidth of a structural stiffness matrix is proposed. The minimum value of the bandwidth is one of the inherent properties of a structural configuration. It is sought without a node labeling procedure but through a redrawn configuration in a proposed coordinate system (with some restrictions) whose one axis corresponds to the size of the bandwidth. This strategy arises from the fact that the bandwidth reduction problem does not fit the characteristics of digital computers but neccessitates manual treatment in accordance with past experience in node labeling.

Safety assessment of urban expressway bridges based on probabilistic modeling of multiple load environments

Abstract The first part of this paper describes the results of a field measurement and detailed investigations on actual load environments of urban expressway bridges. Based on these results their probabilistic load models are developed. The second part presents the results of critical appraisal of the safety of structures designed under the current Japanese code. The difference in safety margins under various actual loads among typical structural components are studied in detail, and on this basis load factors that distribute the safety uniformly to respective structural members of a bridge subjected to combined loads are quantitatively evaluated.

STOCHASTIC STUDY ON COEFFICIENT OF IMPACT IN DESIGN OF HIGHWAY BRIDGE

Dynamic behaviors of a bridge under the several pulsating forces show the resultant vibration as the results of combination of each individual vibration. In such case, the phase differences of fundamental vibrations from each other have a certain influence upon the resultant oscillation of the bridge. Therefore, in this paper, the authors consider that these phase differences occur at random under the various traffic conditions, and they stochastically clarify that the values of the impact coefficients are reduced successively according to the loading length.