Effect of Soil and Substructure Properties on Live-Load Distribution in Integral Abutment Bridges

2008 ◽  
Vol 13 (5) ◽  
pp. 527-539 ◽  
Author(s):  
Murat Dicleli ◽  
Semih Erhan
2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Robert W. Fausett ◽  
Paul J. Barr ◽  
Marvin W. Halling

As part of an investigation on the performance of integral abutment bridges, a single-span, integral abutment, prestressed concrete girder bridge near Perry, Utah was instrumented for live-load testing. The live-load test included driving trucks at 2.24 m/s (5 mph) along predetermined load paths and measuring the corresponding strain and deflection. The measured data was used to validate a finite-element model (FEM) of the bridge. The model showed that the integral abutments were behaving as 94% of a fixed-fixed support. Live-load distribution factors were obtained using this validated model and compared to those calculated in accordance to recommended procedures provided in the AASHTO LRFD Bridge Design Specifications (2010). The results indicated that if the bridge was considered simply supported, the AASHTO LRFD Specification distribution factors were conservative (in comparison to the FEM results). These conservative distribution factors, along with the initial simply supported design assumption resulted in a very conservative bridge design. In addition, a parametric study was conducted by modifying various bridge properties of the validated bridge model, one at a time, in order to investigate the influence that individual changes in span length, deck thickness, edge distance, skew, and fixity had on live-load distribution. The results showed that the bridge properties with the largest influence on bridge live-load distribution were fixity, skew, and changes in edge distance.


2021 ◽  
Vol 11 (11) ◽  
pp. 5031
Author(s):  
Wooseok Kim ◽  
Jeffrey A. Laman ◽  
Farzin Zareian ◽  
Geunhyung Min ◽  
Do Hyung Lee

Although integral abutment bridges (IABs) have become a preferred construction choice for short- to medium-length bridges, they still have unclear bridge design guidelines. As IABs are supported by nonlinear boundaries, bridge geometric parameters strongly affect IAB behavior and complicate predicting the bridge response for design and assessment purposes. This study demonstrates the effect of four dominant parameters: (1) girder material, (2) bridge length, (3) backfill height, and (4) construction joint below girder seats on the response of IABs to the rise and fall of AASHTO extreme temperature with time-dependent effects in concrete materials. The effect of factors influencing bridge response, such as (1) bridge construction timeline, (2) concrete thermal expansion coefficient, (3) backfill stiffness, and (4) pile-soil stiffness, are assumed to be constant. To compare girder material and bridge geometry influence, the study evaluates four critical superstructure and substructure response parameters: (1) girder axial force, (2) girder bending moment, (3) pile moment, and (4) pile head displacement. All IAB bridge response values were strongly related to the four considered parameters, while they were not always linearly proportional. Prestressed concrete (PSC) bridge response did not differ significantly from the steel bridge response. Forces and moments in the superstructure and the substructure induced by thermal movements and time-dependent loads were not negligible and should be considered in the design process.


2018 ◽  
Vol 8 (10) ◽  
pp. 1717 ◽  
Author(s):  
Iman Mohseni ◽  
Yong Cho ◽  
Junsuk Kang

Because the methods used to compute the live load distribution for moment and shear force in modern highway bridges subjected to vehicle loading are generally constrained by their range of applicability, refined analysis methods are necessary when this range is exceeded or new materials are used. This study developed a simplified method to calculate the live load distribution factors for skewed composite slab-on-girder bridges with high-performance-steel (HPS) girders whose parameters exceed the range of applicability defined by the American Association of State Highway and Transportation Officials (AASHTO)’s Load and Resistance Factor Design (LRFD) specifications. Bridge databases containing information on actual bridges and prototype bridges constructed from three different types of steel and structural parameters that exceeded the range of applicability were developed and the bridge modeling verified using results reported for field tests of actual bridges. The resulting simplified equations for the live load distribution factors of shear force and bending moment were based on a rigorous statistical analysis of the data. The proposed equations provided comparable results to those obtained using finite element analysis, giving bridge engineers greater flexibility when designing bridges with structural parameters that are outside the range of applicability defined by AASHTO in terms of span length, skewness, and bridge width.


2014 ◽  
Vol 51 (7) ◽  
pp. 713-734 ◽  
Author(s):  
Shelley A. Huntley ◽  
Arun J. Valsangkar

Integral abutment bridges accommodate thermal superstructure movements through flexible foundations rather than expansion joints. While these structures are a common alternative to conventional design, the literature on measured field stresses in piles supporting integral abutments appears to be quite limited. Therefore, field data from strain gauges installed on the abutment foundation piles of a 76 m long; two-span integral abutment bridge are the focus of this paper. Axial load, weak- and strong-axis bending moments of the foundation piles, as well as abutment movement and backfill response, are presented and discussed. Results indicate that the abutment foundation piles are bending in double curvature about the weak axis, as a result of thermal bridge movements, and bending also about the strong axis due to tilting of the abutments. A simple subgrade modulus approach is used to show its applicability in predicting behaviour under lateral loading. In the past, much emphasis has been placed on the lateral displacements of piles and less on variations of axial load. In this paper, a new hypothesis, which offers insight into the mechanisms behind the observed thermal variations in axial load, is proposed and assessed. The data from the field monitoring are also compared with the limited data reported in the literature.


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