Abheetha Peiris

Carbon fiber–reinforced polymer rod panels for strengthening concrete bridges:

The practice of using fiber-reinforced polymer laminates and fabric to repair and strengthen concrete structures is well established. What limits the application of fiber-reinforced polymer materials, especially in flexural strengthening, is the equipment and man power needed for continuous application when retrofits take place over waterways or multilane roadways. A carbon fiber–reinforced polymer rod panel system consisting of 1220-mm (48-in) panels made continuous through a finger joint/splice was developed to overcome these limitations. The system’s performance hinges on whether forces can be transferred from one panel to another. This study investigated the bond characteristics of carbon fiber–reinforced polymer rods, as well as the flexural behavior of concrete members strengthened with carbon fiber–reinforced polymer rod panels, to improve knowledge of the finger joint’s behavior. Bond tests were conducted using double-lap shear specimens on individual rods with both steel and concrete substrates. Further bond tests were performed on small carbon fiber–reinforced polymer rod panels on steel substrate. Flexural tests were carried out under four-point bending on small-scale reinforced concrete beams that were strengthened using continuous carbon fiber–reinforced polymer rod panels and carbon fiber–reinforced polymer rod panels spliced using a finger joint. Case studies of four field applications are presented to provide a better understanding of the system. The new carbon fiber–reinforced polymer rod panels effectively reduce labor and equipment costs for work conducted on bridges with limited access, as they enabled the performance of repair/retrofit operations by a small crew working out of a single work platform.

Seismic Evaluation of Bridges on and over the Parkways in Western Kentucky – Summary Report

This report (KTC-07-02/SPR246-02-1F) provides an overall summary on the seismic investigative study performed on bridges on/over the five parkways in Western Kentucky. The comprehensive study was further divided into the followings tasks, each reported separately as follows: (1) The first report of this study (KTC-07-03/SRP246-02-2F) involved data collection and field inspection of bridges on/over the parkways. The resulting inventory contains data of three hundred fifty-one (351) bridges on/over the parkways, detailing their construction type, soil profile, present condition, etc. (2) In KTC-07-04/SPR246-02-3F, a preliminary seismic evaluation and ranking was performed on all bridges within the inventory. Details of the evaluation and ranking procedure are outlined. In this task seventeen (17) bridges, that are deemed susceptible to major earthquakes, were identified. (3) Detailed seismic evaluations of the seventeen (17) bridges were subsequently carried out using time-history analysis for a projected 250-year seismic event. The results of the analysis are presented in KTC-07-05/SPR246-02-4F. (4) KTC-07-06/SPR246-02-5F presents the preliminary evaluation and ranking of bridge embankments along the parkways. (5) The last report, numbered KTC-07-07/SPR246-02-6F, provides the latest seismic hazard maps for the expected earthquake (EE), probable earthquake (PE), and maximum credible earthquake (MCE), which will be used in seismic analysis and design of highway infrastructures in Kentucky.

Repair Using Steel Fiber Reinforced Polymer on US 150 Bridges

This report details the pre-construction monitoring, planning and design, and construction of the retrofit measures on the US150 bridge over Beech Fork River in Nelson County, Kentucky (KY) and Cartwright Creek bridge on the border of Washington-Nelson County, KY. All reinforced concrete girders of the five-span Beech Fork River bridge and three-span Cartwright Creek bridge of deck-girder construction had developed diagonal cracks near or at the transition of the variable-and-constant depth regions. To remedy the problem steel fiber reinforced polymer (SFRP) sheets were selected as the means of retrofit due to their strength and stiffness, as well as conformability and flexibility. Repair to the reinforced concrete girders was done by attaching the SFRP sheets to the vertical and bottom faces. Application of SFRP was quickly executed with the use of specialty epoxy designed for use with the steel wire sheets. Construction of the retrofit was completed in May of 2007.

Development and Deployment of Aluminum Bridge Decks

This report contains the analysis and retrofit of a steel truss bridge on KY 974 over Howard Creek in Clark County, Kentucky. The bridge had major corrosion and damage to the steel stringers, along with cracking and leaching occurring in the concrete bridge deck. The retrofit involves the replacement of the corroded steel stringers and the damaged concrete bridge deck. The original concrete deck was removed and replaced by light-weight high-strength aluminum deck panels. The aluminum deck panels, each 2-m wide, were assembled at the site and connected to each other and to the bottom steel stringers using special clamps and connectors. Following the new deck installation, the top surface was waterproofed and a new asphalt overlay was placed. The new bridge deck constructed of aluminum material significantly reduces the deck weight, while it also allows rapid construction due to prefabricated components. In addition, the new deck can now carry a HS20-44 truck weight, which the old concrete deck was not designed to carry.

Implementation of Remote Sensing Technology on the I-64 Bridge over US60

Remote sensing devices have been implemented on the I-64 Bridges over US60 in Franklin County, KY. One of the girders in the westbound bridge has been previously repaired due to unexpected fatigue cracking. The exterior girder in the eastbound bridge has shown signs of impacts due to the traversing trucks on US60. Sensing and recording devices such as strain and temperature gauges, infrared sensors, ultrasonic height detectors, and an accelerometer have been installed. Specifically, eleven strain gauges are used on the repaired girder, impacted girders, and girders adjacent to them. Two sets of infrared sensors, ultrasonic detectors, and video cameras are placed to capture the impacting truck(s). Overall structural responses will be studied through data collected from the strain and temperature gauges, and accelerometer. Data are stored on-site, but the investigator has the flexibility of transmitting or viewing the data, live or stored, via an internet connection.

Seismic-Hazard Maps and Time Histories for the Commonwealth of Kentucky

The ground-motion hazard maps and time histories for three earthquake scenarios, expected earthquakes, probable earthquakes, and maximum credible earthquakes on the free surface in hard rock (shear-wave velocity >1,500 m/s), were derived using the deterministic seismic hazard analysis. The results are based on (1) historical observations, (2) instrumental records, and (3) current understanding of the earthquake source, recurrence, and ground-motion attenuation relationship in the central United States. It is well understood that there are uncertainties in the groundmotion hazard maps because of the uncertainties inherent in parameters such as earthquake location, magnitude, and frequency used in the study. This study emphasizes the earthquakes that would have maximum impacts on humans and structures. The ground-motion parameters, including time histories, are intended for use in the recommended zone (not site-specific) where the structure is assumed to be situated at the top of a bedrock foundation. For sites underlain by soils, and in particular for sites underlain by poorly consolidated soils, it is recommended that site-specific investigations be conducted by qualified professionals in order to determine the possibilities of amplification, liquefaction, slope failure, and other considerations when subjected to the ground motions.