IV. BRIDGE ENGINEERING

B. ON GOING PROJECTS
5. Dynamic Response of Prestressed Concrete Bridges
Date of Start

April 2004
Central Road Research Institute, New Delhi (R)

 

Present Status and Progress
Modified the computer program to include the creep and shrinkage prediction model suggested by Muller et al. Based on this inclusion of prediction model in the software, studies were revised to compare the creep and shrinkage in concrete by the following five prediction models:

• ACI-209 recommendation
• B3 model
• CEB-FIP model code 1990
• Muller et al. model
• GL 2000 model

Modified papers, submitted earlier to ASCE and ACI, incorporating the comments of the Reviewers and sent back the revised manuscripts.

Finalized the material model to be incorporated in the software for the study of Dynamic Response of Prestressed Concrete Bridges.

Mathematical modelling of prestressing cable lying inside the concrete 3D element completed.

Developed a software for computation of forces at various nodes of the concrete element due to the prestressing cable.

Integrated this software with the main software being developed for the Dynamic Analysis of PSC Bridges.
 
Findings/Conclusions
Various analytical models to predict the creep of shrinkage have been suggested by the various researchers. These prediction models have been grouped into the following three broad categories:

• Empirical models
• Research based models
• Codal models

These prediction models have been described in the in report No.CRRI/BIE/OLP-0409(01)/2004-05 titled ‘Prediction of creep and shrinkage in concrete’ as well as in the published papers. The predictions obtained by these analytical models have been compared with the experimental results. The results of comparison are also given in the above mentioned interim report. Based on the comparison, GL2000 prediction model has been selected for use in the future study.
 
Recommendations
Development of software for inclusion of stiffness of the prestressing cable

Validation of the software using the data available in the literature / laboratory studies

Case studies for response of prestressed concrete structures under dynamic loading at any time during its service
 
Reports/Publications
1. Goel, R., Kumar, R. and Paul, D.K., ‘A comparative study of various creep and shrinkage prediction models for concrete’, Accepted for publication in ASCE Materials in Civil Engineering.

2. Goel. R., Parkash, S., Kumar, R. and Paul, D.K. (2006), ‘Prediction of creep and shrinkage strains in prestressed concrete bridges’, National conference on Advances in Bridge Engineering, IIT, Roorkee, March 24-25, pp. 543-554.