Report

Report
Author:
Publisher:
Total Pages: 764
Release: 2006
Genre: Highway research
ISBN:

Annual Report

Annual Report
Author: Missouri. Department of Transportation. Research, Development and Technology Division
Publisher:
Total Pages: 80
Release: 2003
Genre: Transportation
ISBN:

Response of No-Name Creek FRP Bridge to Local Weather

Response of No-Name Creek FRP Bridge to Local Weather
Author: Wenjie Liu
Publisher:
Total Pages: 73
Release: 2012
Genre:
ISBN:

Since 1996, over 30 Fiber Reinforced Polymer (FRP) composite bridges have been installed in the United States. Bridge locations are in Kansas, Missouri, New York, Iowa, Colorado, West Virginia, Ohio, California, Idaho, Washington, Pennsylvania, Illinois, Maryland, Oregon, North Carolina and South Carolina. Compared to traditional steel and concrete bridge structures, the FRP panel shows several significant advantages: reduced weight, higher strength, better corrosion resistance and quicker installation. However, FRP materials exhibit different physical properties. As such, a composite bridge would demonstrate different deformation and failure patterns than a traditional bridge. During the past years, much experimental research has been conducted to investigate FRP bridge deck performance. Most experiments divide into two types: 1) static and fatigue tests in the laboratory and 2) real traffic load tests in the field. These experimental results, as well as FEM analytical results, have served as baseline data for FRP bridge deck design. A long-term remote monitoring system was designed to investigate the response of the No-Name Creek composite bridge to the local weather. The characteristics of the bridge temperatures, the temperature differences of the two panel surfaces and the relationship between the temperature difference and the deflection were investigated with respect to the different weather patterns. Twelve thermal sensors were embedded into the FRP bridge panels. In addition, 3 laser sensors were installed to measure bridge thermal deflection. Between October 2004 and September 2005, bridge temperature and deflection were measured at 20 minute intervals. Relations between weather condition, temperature distribution and bridge thermal deflection for that bridge were analyzed. From the analysis of the experimental and FE methods, the responses of the composite bridge to weather are summarized as follows: (1) The temperatures of the upper and bottom panel surfaces and their differences greatly change with time of day and season. The extreme temp usually appears in the early afternoon and the minimum temp usually appears in the early morning or in the night. The bottom surface temperature is near the climatic temperature. (2) The bridge deflections are approximately proportional to the temperature differences. (3) The bridge had a significant upward deflection on a sunny day during the summer with the maximum often occurring between 3:00-5:00PM. The bridge has a downward deflection during the night with it being the most severe in the winter. (4) Comparing climate induced deflection to traffic load induced deflection, the climate induced deflection is at least on the same order of deflection as allowable traffic load. Therefore, it should be considered in the FRP bridge design process. (5) Thermal load and deflection usually are larger on clear days than on unclear, rainy, and snowy days. (6) Distributions of thermal load in the panel can form a larger amount of deflection in the hot season than in the cold season.

Field Test and Analysis of Two Prestressed Concrete Bridges After Deck Replacement with Frp Panels

Field Test and Analysis of Two Prestressed Concrete Bridges After Deck Replacement with Frp Panels
Author: Madhan Kumar Kantha Samy
Publisher:
Total Pages: 124
Release: 2007
Genre:
ISBN:

Bridges B-0071 and B-0171 in Hamilton County, Ohio have been in service for about fifty years. They are short span bridges with prestressed concrete girders. Until late 2001, they had conventional reinforced concrete decks, which have been replaced with fiber reinforced polymer (FRP) decks. Two girders in bridge B-0171 were replaced with new prestressed girders. These bridges are significant as there are few instances of FRP decks on concrete girders. The Hamilton County Engineers Office contracted with the Civil Engineering Department at the University of Cincinnati to perform load testing on the bridges. Information gained from this research will seek to confirm the safety of the new technology, evaluate construction and design techniques with reference to the FRP deck, and determine overall performance of the bridge to provide understanding of the system. The two short span prestressed concrete bridges with fiber reinforced polymer decks were subjected to four sets of nondestructive truckload testing. Strain gauges were placed along the height of the girder cross-section, and longitudinally and transversely across the bottom of the deck. Displacement transducers were placed to measure overall girder displacement, relative deck displacement, deck panel separation, and deck-girder connection separation. A three-dimensional finite element analysis model was created to replicate the performance of each bridge. The two new prestressed girders in bridge B-0171 strengthened the bridge considerably and increased its load carrying capacity. But the old prestressed girders in bridge B-0071 and bridge B-0171 did not show any sign of deterioration. The four sets of test data collected over a two-year period show that the age effect on structural behavior is very small for both the bridges. The deck had very little influence on the distribution of loads in the structure for these bridges. Due to low deck stiffness and incomplete connectivity, the FRP deck did little to strengthen the girders. The long term monitoring of the deck result complied with the short term testing as reported by Eder8. The finite element model closely matched with the structural components of the original bridge. The new improved model is a better representation as it was calibrated with four sets of field data collected over a period of two years. The field test data from both tests shows that the girders are simply supported on the abutment. But the girders in the model are designed as fixed end beams to have a reasonable value for the modulus of concrete used in the model. In reality it can be assumed that the support condition is between fixed and simply supported. It was also demonstrated that the deck had very little influence on the distribution of loads in the structure for these bridges. The majority of the load transfer between girders was most likely due to the diaphragms. The Impact Factor based on one set of experimental results was 1.217. However, for analysis the LRFD value of 1.33 was used. The Load Rating Factor for bridge B-0071 was 1.66 and for bridge B-0171 was 2.48 with the governing truck loading being the Design load Type Tandem. These rating factors were based on girder performance only due to insufficient deck information.