Multimodal Response Spectrum Method Analysis of Integral Abutment Curved Box Girder Bridge
In order to simplify analysis of the dynamic characteristics and seismic response of the integral abutment curved box bridge(IACBB), automatic iteration of the multimode modal response spectrum(MMRS) is realized by APDL language of the structure analysis software ANSYS according to the IACBB's structural characteristics. The realization flow of iterative MMRS in Ansys were presented. and the availability and precision of the iterative MMRS were examined by the time-history analysis. The result shows that 1）the iterative MMRS is a efficient simplify method, and can be used as an estimating method of seismic analysis for the bridge. And the method provides a reference for future similar structures. 2）several conclusions of earthquake response are given. The research results are helpful for the knowledge of mechanics property of the type of the bridges.
BEHAVIOR OF FIBER REINFORCED POLYMER COMPOSITE PILES WITH ELLIPTICAL CROSS SECTIONS IN INTEGRAL ABUTMENT BRIDGE FOUNDATIONS
Title of Document: BEHAVIOR OF FIBER REINFORCED POLYMER COMPOSITE PILES WITH ELLIPTICAL CROSS SECTIONS IN INTEGRAL ABUTMENT BRIDGE FOUNDATIONS Yahya Aliabadizadeh PE, 2016 Directed By: Professor Amde M. Amde , Department of Civil and Environmental Engineering Every year in the US and other cold-climate countries considerable amount of money is spent to restore structural damages in conventional bridges resulting from (or “caused by”) salt corrosion in bridge expansion joints. Frequent usage of deicing salt in conventional bridges with expansion joints results in corrosion and other damages to the expansion joints, steel girders, stiffeners, concrete rebar, and any structural steel members in the abutments. The best way to prevent these damages is to eliminate the expansion joints at the abutment and elsewhere and make the entire bridge abutment and deck a continuous monolithic structural system. This type of bridge is called Integral Abutment Bridge which is now widely used in the US and other cold-climate countries. In order to provide lateral flexibility, the entire abutment is constructed on piles. Piles used in integral abutments should have enough capacity in the perpendicular direction to support the vertical forces. In addition, piles should be able to withstand corrosive environments near the surface of the ground and maintain their performance during the lifespan of the bridge. Fiber Reinforced Polymer (FRP) piles are a new type of pile that can not only accommodate large displacements, but can also resist corrosion significantly better than traditional steel or concrete piles. The use of FRP piles extends the life of the pile which in turn extends the life of the bridge. This dissertation studies FRP piles with elliptical shapes. The elliptical shapes can simultaneously provide flexibility and stiffness in two perpendicular axes. The elliptical shapes can be made using the filament winding method which is a less expensive method of manufacturing compared to the pultrusion or other manufacturing methods. In this dissertation a new way is introduced to construct the desired elliptical shapes with the filament winding method. Pile specifications such as dimensions, number of layers, fiber orientation angles, material, and soil stiffness are defined as parameters and the effects of each parameter on the pile stresses and pile failure have been studied. The ANSYS software has been used to model the composite materials. More than 14,000 nonlinear finite element pile models have been created, each slightly different from the others. The outputs of analyses have been used to draw curves. Optimum values of the parameters have been defined using generated curves. The best approaches to find optimum shape, angle of fibers and types of composite material have been discussed. BEHAVIOR OF FIBER-REINFORCED POLYMER COMPOSITE PILES WITH ELLIPTICAL CROSS SECTIONS IN INTEGRAL ABUTMENT BRIDGE FOUNDATIONS
Stiffnesses of abutments on spread footings with cohesionless backfill
La caracterisation de l'interaction pont-culee-remblai est une composante importante dans les evaluations de la reponse sismique des ponts. Cet article presente une methodologie relativement simple et realiste pour evaluer les rigidites des ressorts non lineaires translationnels (longitudinaux, verticaux et transversaux) pour representer l'interaction pont-culee-remblai. Plusieurs facteurs importants tels que le comportement non lineaire du sol, les dimensions de la culee, les charges de la superstructure, et la difference dans le comportement du sol sous des conditions de poussee et de butee ont ete pris en compte. Seules les proprietes de sol utilisees de facon routiniere sont requises dans le modele. Les resultats predits par l'approche proposee ont ete calibres a partir de rigidites (longitudinales et translationnelles) mesurees dans des essais a grande echelle. La concordance entre les rigidites mesurees et predites est tres bonne. Subsequemment, l'approche a ete utilisee pour developper des relations normalisees pour les rigidites de culees.