Hysteresis Model Based Prediction of Integral Abutment Bridge Behavior

Open Access
- Author:
- Pugasap, Kongsak
- Graduate Program:
- Civil Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- February 28, 2006
- Committee Members:
- Jeffrey A Laman, Committee Chair/Co-Chair
Andrea J Schokker, Committee Member
Daniel G Linzell, Committee Member
Mian C Wang, Committee Member
Thomas E Boothby, Committee Member
Andrew Scanlon, Committee Member - Keywords:
- Bridge Abutments
Hysteresis
Numerical Models
Monitoring
Integrals
Predictions - Abstract:
- Integral abutment (IA) bridge construction has become more common due to desirable performance, however, many design uncertainties still exist, particularly long-term behavior prediction. In order to better understand these design uncertainties, a study of IA bridge behavior through long-term monitoring and numerical modeling has been undertaken. Monitoring and instrumentation consists of three prestressed concrete IA bridges located on I99 in central Pennsylvania. Evaluation of field data reveals hysteretic behavior of IA bridges that may be a significant influence on long-term behavior in addition to creep and shrinkage effects. On the basis of field data and two different problem types; geotechnical and structural, two major sources influencing long-term hysteretic behavior of IA bridges, including soil-structure interaction and yielding of structural connections, are identified. These two hysteretic sources were incorporated in finite element (FE) models using hysteresis elements derived from selected hysteresis models available in the literature for all three instrumented bridges. Also proposed is an alternative condensed hysteresis model in which two selected degrees of freedom at the pile head location are required. Similar types of hysteresis elements employed in the FE models were implemented in the condensed hysteresis models. Equivalent temperature loads to incorporate creep and shrinkage effects by using the AAEM method, ambient temperature loads, and earth pressures were applied to the FE and condensed hysteresis models. Predicted results from all models are compared against field data to evaluate model accuracy. Eight load cases were analyzed with a simulation period of 100 years to determine the relative magnitudes of hysteretic behavior and effects of creep and shrinkage. It is determined from predicted response at the end of the simulation period that the ratios of condensed hysteresis model to 2-D predicted abutment displacements range from 0.81 to 1.08. The ratios of long-term to short-term predicted abutment displacements range from 1.5 to 2.3. The ratios of predicted abutment displacement influenced by hysteretic behavior to short-term predicted abutment displacement are from 1.1 to 1.2 for an elevation near girders, and are from 1.3 to 1.6 for an elevation near abutment bases. These predicted ratios indicate the validity of the condensed hysteresis models and the importance of hysteretic behavior and effects of creep and shrinkage on long-term behavior of IA bridges.