In this paper, the authors present the most recent results from their on-going study for a practical combined analysis and load test methodology. For bridge analysis purposes, it is often desirable to have full 3D finite element models. However, development of such models may not be feasible since these 3D models require considerable time, effort and expertise. Therefore, the American Association of State Highway and Transportation Officials (AASHTO) specifications provide practical methods for the analysis of the bridges. The basic approach, which is commonly used by design offices, department of transportation (DOT) engineers and other practitioners, is the beam line analysis using distribution factor (DF) formulations. In the current codes, the DFs are defined as a function of span length, beam spacing, beam stiffness and slab thickness. In this study, the researchers explore the use of simply measurable quantities to obtain DFs more reliably, and then analyze the bridge condition efficiency quickly and easily. The authors aim to investigate obtaining the moment and shear DFs of single span T-beam bridges by using modal frequency w, flexibility coefficient ofand skew angle teta which can be determined by means of simple field tests. First, Finite Element (FE) models of 40 single span T-beam bridges are analyzed to obtain modal frequency and flexibility coefficient. Second, the moment and shear values are collected for all models under HL-93 truckload. Third, a multiple regression analysis is conducted to generate an equation to determine the DFs using modal frequency, flexibility and skew angle. Finally, the new approach is verified by using extra FE models and validated by using experimental data coming from a real life bridge.
Abstract