In order to quantify the influence of temperature changes on integral abutment bridge movements, thirty-two Sokkia RS30N reflective targets were strategically attached to a bridge along its length. These targets were surveyed every month for twelve consecutive months. These changes in length coincided with restraint conditions between purely fixed and simply supported. Movement of expansion joints was also recorded. The movements of the expansion gaps at opposite corners appear to exhibit similar movements. This behavior indicates a type of twisting motion occurring within the bridge as a result of unequal movements at the east and west sides of each abutment. This motion suggests that the bridge abutments experience forces that incite weak axis bending in the abutments, especially in the north abutment. These quantitative bridge movements were compared to predicted behavior from a finite-element model. A detailed finite-element model of the bridge was created using SAP2000 (Computers and Structures, Inc.) software. The detailed model was developed using solid elements for all components of the bridge except piles and bents. Longitudinal surface springs were placed at the abutment elements in order to simulate the soil-abutment interaction. A typical temperature load was assigned to the bridge deck and girder elements to compare the calculated stress concentrations in the model with the observed cracking on the abutment. The model produced high stress concentrations in the abutment adjacent to the bottom girder flange. This corresponded to the same location of observed cracking. The finite-element model also showed lateral movement of the north abutment. This lateral abutment contributed to the unequal movements of the bridge spans. Once the comparison between the measured bridge behavior of the survey and the findings of the detailed finite element model was completed, a simplified model was used to evaluate the bending moment and stresses in the abutment of the 400 South Street Bridge. The simplified model was also used to perform a parametric study on the influence of skew, span length, and temperature gradient on weak-axis abutment moments.

This study presents the behavior of a precast skewed integral abutment bridge (IAB) using the recently developed NEXT-F Beam section in particular. In order to understand the bridge response, a 3-dimensional finite element model of a bridge (Brimfield Bridge) was developed to examine the thermal effect on the response of the bridge structural components. Eighteen months of field monitoring including abutments displacements, abutment rotations, deck strains, and beam strains was conducted utilizing 136 strain gauges, 6 crackmeters, and 2 tiltmeters. The behavior of the NEXT beams during construction was examined by conducting hand calculation considering all factors that could affect strain readings captured by strain gauges embedded in the 6 beams. Parametric analysis and model validation were conducted considering the effect of soil conditions, distribution of thermal loads, and the coefficient of thermal expansion used for the analyses. Using the validated model, the effect pile orientation was investigated. All the results and illustration plots are presented in detail in this study. As a result of this study, the behavior of the NEXT beams during construction was explained. Long term behavior of the bridge was also explained using field data and FE model. Furthermore, it was concluded that the coefficient of thermal expansion of concrete and temperature variation along the bridge depth and transverse direction can have a significant effect on the strain readings and calculated response, respectively. Lastly, it was found that orienting piles with their web perpendicular on the bridge centerline or with their web perpendicular to the abutment centerline will result in small ratio of moment demand to moment capacity.

No description available.

Integral abutment bridges are jointless bridges in which the deck is continuous and connected monolithically with the abutment walls supported typically by a single row of piles. This thesis focuses on the effects of two major parameters on the seismic behavior of an integral abutment bridge in Tennessee by considering soil-structure interaction around the piles and in back of the abutments: (1) clay stiffness (medium vs. hard) around the piles, and (2) level of sand compaction (loose vs. dense) of the abutment wall backfilling. Modal and nonlinear time history analyses are performed on a three dimensional detailed bridge model using the commercial software SAP2000, which clearly show that (1) compacting the backfilling of the abutment wall will increase the bridge dominant longitudinal natural frequency considerably more than increasing the clay stiffness around the piles; (2) the maximum deflection and bending moment in the piles under seismic loading will happen at the pile-abutment interface; (3) under seismic loading, densely-compacted backfilling of the abutment wall is generally recommended since it will reduce the pile deflection, the abutment displacement, the moments in the steel girder, and particularly the pile moments; (4) under seismic loading, when the piles are located in firmer clay, although the pile deflection, the abutment displacement, and the maximum girder moment at the pier and the mid-span will decrease, the maximum pile moment and the maximum girder moment at the abutment will increase.

Vibration-based damage detection (VBDD) comprises a family of non-destructive testing methods in which changes to dynamic characteristics are used to track the condition of a structure. Although VBDD methods have been successfully applied to various mechanical systems and to simple beam-like structures, significant challenges remain in extending this technology to complex, spatially distributed structures such as bridges. <p> In the present study, numerical simulations using a calibrated finite element model were used to investigate the use of VBDD methods to detect small-scale damage on a two-span, integral abutment overpass structure located in Saskatoon, Saskatchewan. The small scale damage was defined in this study as the removal of a concrete element from the top surface of the bridge deck, resembling the spalled clear cover of concrete deck of the overpass. Five different VBDD techniques were evaluated, including the Change in Mode Shape, Change in Flexibility, Change in Mode Shape Curvature, Change in Uniform Flexibility Curvature and Damage index methods. In addition, the influence of the size of damage, the orientation of damage geometry, sensor spacing (3 m, 5 m and 7.5 m), the approach used for mode shape normalization, and uncertainty in the measured mode shapes was investigated. <p> It was found that localized damage could be reliably detected and located if the sensors were located within 3 m of the damage (the distance between adjacent girders) and if uncertainty in the mode shapes was attenuated through the use of a sufficient number of repeated trials. Furthermore, studies using a limited sensor installation that could be achieved without interrupting the flow of traffic indicated that small scale damage could be detected and potentially located using sensors that are placed well away from the damaged area, provided uncertainty in mode shape was attenuated.

Vibration-based damage detection (VBDD) comprises a family of non-destructive testing methods in which changes to dynamic characteristics are used to track the condition of a structure. Although VBDD methods have been successfully applied to various mechanical systems and to simple beam-like structures, significant challenges remain in extending this technology to complex, spatially distributed structures such as bridges. <p> In the present study, numerical simulations using a calibrated finite element model were used to investigate the use of VBDD methods to detect small-scale damage on a two-span, integral abutment overpass structure located in Saskatoon, Saskatchewan. The small scale damage was defined in this study as the removal of a concrete element from the top surface of the bridge deck, resembling the spalled clear cover of concrete deck of the overpass. Five different VBDD techniques were evaluated, including the Change in Mode Shape, Change in Flexibility, Change in Mode Shape Curvature, Change in Uniform Flexibility Curvature and Damage index methods. In addition, the influence of the size of damage, the orientation of damage geometry, sensor spacing (3 m, 5 m and 7.5 m), the approach used for mode shape normalization, and uncertainty in the measured mode shapes was investigated. <p> It was found that localized damage could be reliably detected and located if the sensors were located within 3 m of the damage (the distance between adjacent girders) and if uncertainty in the mode shapes was attenuated through the use of a sufficient number of repeated trials. Furthermore, studies using a limited sensor installation that could be achieved without interrupting the flow of traffic indicated that small scale damage could be detected and potentially located using sensors that are placed well away from the damaged area, provided uncertainty in mode shape was attenuated.

Master of Science / Department of Civil Engineering / Dunja Peric / Integral Abutment Bridges (IABs) are Jointless Bridges whereby the deck is continuous and monolithic with abutment walls. IABs are outperforming their non-integral counterparts in economy and safety. Their principal advantages are derived from the absence of expansion joints and sliding bearings in the deck, making them the most cost-effective system in terms of construction, maintenance, and longevity. The main purpose of constructing IABs is to prevent the corrosion of structure due to water seepage through joints. The simple and rapid construction provides smooth, uninterrupted deck that is aesthetically pleasing and safer for riding. The single structural unit increases the degree of redundancy enabling higher resistance to extreme events. However, the design of IABs not being an exact science poses certain critical issues. The continuity achieved by this construction results in thermally induced deformations. These in turn introduce a significantly complex and nonlinear soil-structure interaction into the response of abutment walls and piles of the IAB. The unknown soil response and its effect on the stresses in the bridge, creates uncertainties in the design. To gain a better understanding of the mechanism of load transfer due to thermal expansion, which is also dependent on the type of the soil adjacent to the abutment walls and piles, a 3D finite element analysis is carried out on a representative IAB using state-of-the-art finite element code ABAQUS/Standard 6.5-1. A literature review focusing on past numerical models of IABs is presented followed by details of the numerical model developed in this study using the interactive environment ABAQUS/CAE 6.5-1 along with the analysis details. A discussion of results for the analysis of the IAB with three different soil conditions and each experiencing three different temperature change scenarios is presented. Conclusions of the study and recommendations for future research wrap up the thesis. The advancement of knowledge enabled by this research will provide a basis for introduction of new guidelines in Kansas Bridge Design Manual.

A parametric study of single-span integral abutment bridge (IAB) was conducted using finite element analysis to explore the effects of various load conditions, bridge geometries, and soil properties. This study investigated the difference between the live load distribution of traditional jointed bridges and integral abutment bridges (IABs) under HL-93 truck component load. The results showed that AASHTO live load distribution factors (LLDFs) were overly conservative by up to 50% to use for IABs. LLDFs for IABs proposed by Dicleli and Erhan (2008) matched well for interior girder moment, but they were unconservative for exterior girder moment by up to 20% for the bridges studied. The study further investigated the effects of various parameters on the IAB responses under dead, live, and thermal loads and load combinations specified by AASHTO. The results of this study are limited to short to moderate single-span straight bridges under dead, live, and thermal loads. Due to a fixity of superstructure and abutments in IABs, the bridge response to each loading is influenced by the relative stiffness of superstructure to substructure. Under combined loads, the amount of each load effect varied depending on superstructure and substructure stiffness, but the critical load combination for each bridge response was determined in this study. Yielding of piles seems unavoidable for IABs built on sand under combined loads even after the change of pile size or pile orientation, but replacing the soil around top 3m (10ft) of piles with softer material is effective to reduce the significant amount of pile moment for IABs built on sand foundation soil. This thesis includes some design recommendations based on the findings of this study.

No description available.

The United States Department of Transportation (US-DOT) Federal Highway Administration (FHWA) initiated in 2009 the Long-Term Bridge Performance (LTBP) program to gather high-quality data on a representative sample of bridges over a twenty-year period of time. The goal of this program is to quantify how bridges behave during their service life while being exposed to different types of loadings and deterioration due to corrosion, fatigue and various climate conditions along with their corresponding maintenances. The data gathered will result in the creation of databases of high quality data, acquired through long-term instrumentation, to be used for improved design practices and effective management of infrastructures by employing best practices for maintenance. As part of the LTBP Program two integral abutment bridges, a California Bridge near Sacramento, CA and a Utah Bridge near Perry, UT, were selected to be monitored for temperature changes as well as to undergo periodic live-load testing. Live-load testing included slowly driving a truck over the bridges. The bridges were instrumented to collect test data and use it to calibrate a finite-element model. This finite-element model was used to determine the actual bridge behavior and compare it with the AASHTO LRFD Specifications. This thesis also examined how different parameters such as thermal gradients, mean temperature, and end-rotation affect these two integral abutment bridges.