Steel Bridge Coating Inventory for 2022

The Kentucky Transportation Cabinet (KYTC) has replaced the lead-based coatings on many of its steel bridges over the past 30 years. In the 1980s and 1990s, inorganic zinc primers with vinyl topcoats were the go-to option for coating replacement projects. Since 2000, the typical choice for these projects has been organic zinc primers that are part of a two- or three-coat system. Some of these coatings have localized failures in high-stress areas. KYTC’s current inventory of steel bridges numbers over 1,100 structures. Accounting for expected service lives, to properly maintain protective coatings on these bridges will require the Cabinet to paint at least 50 structures per year. To facilitate the agency’s efforts, Kentucky Transportation Center (KTC) researchers audited the Cabinet’s bridge inventory. KTC used a 10-point qualitative rating scale to evaluate the paint condition of each bridge. This exercise identified 116 bridges as candidates for full removal of the existing coating and recoating. Researchers met with the bridge engineers in each of KYTC’s 12 districts to discuss the rankings and assist with prioritizing projects. An ArcGIS Online map was produced which catalogues key attributes of each bridge, including structure type, location, district, span length, facility carried, feature intersection, paint condition, a brief description, and pictures from the most recent inspection

Safety and Health Concerns for KYTC and Contractor Personnel

This study was initiated to provide a review of safety and health issues related to Kentucky Transportation Cabinet (KYTC) construction activities including both KYTC and contractor personnel. Work included a literature search, interviews with KYTC resident engineers, and both a survey of and subsequent meeting with district construction safety coordinators. Recommendations are provided for implementing changes to improve safety and health regulatory compliance for both KYTC and contractor personnel

Deterioration Modelling of Bridges on BrM 5.2.3

The Kentucky Transportation Cabinet (KYTC) initiated the study KYSPR 17-532, “Deterioration Modelling of Bridges on BrM 5.2.3,” so it could receive assistance identifying and employing bridge deterioration and cost forecast modeling for its bridge maintenance program. The Kentucky Transportation Center (KTC) was to help coordinate KYTC in adapting BrM 5.2.3’s deterioration and cost modelling features and update the existing guide material to reflect all changes for BrM 5.2.3. This study included acquiring access and becoming familiar with AASHTO Bridge Management (BrM 5.2.3) software. It was also to explore opportunities for any training on BrM and BrM 5.2.3’s deterioration and cost modeling capabilities and adapt them to best meet KYTC’s maintenance needs for four National Bridge Elements (NBE) — Reinforced Concrete Deck (12), Steel Open Girder/Beam (107), Strip Seal Expansion Joint (300), and Moveable Bearing (311). But the lack sufficient and reliable data for element-level deterioration modelling has proved a hindrance and impeded the completion of the research. As data points are collected, deterioration rates should be checked occasionally to see if they require calibration

Assessment and Modeling of Stream Mitigation Procedures [2003]

As population increases, so does the need to improve and augment the road network. Construction of new roadways or modification of existing roads often requires diversion or modification of streams. If a stream is disturbed, government regulations require mitigation or compensatory replacement of the affected area in a similar environment. Stream mitigation is of particular importance in Kentucky, as Kentucky ranks second in the United States for having the most miles of waterways. Consequently, stream mitigation has become a significant factor in roadway construction costs. To date, no studies have been made to assess the execution of the mitigation plans or to determine the performance of mitigation projects. In a move to rectify this situation, the Kentucky Transportation Cabinet requested this study

Assessment of Deteriorated Structural Concrete to Provide Durable Repairs

Most of the structural elements on Kentucky bridges are made of reinforced concrete. Many of these elements deteriorate as a result of corrosion of the reinforcing steel caused by carbonation and — primarily — applications of chlorides by the Kentucky Transportation Cabinet (KYTC). Corrosion of reinforcing steel is reviewed along with assessment procedures that leverage nondestructive evaluation (NDE) methods and related laboratory and field tests. Several maintenance procedures are discussed, including the application of sealers and coatings, patch and major concrete repairs, and electrochemical methods. Incorporating NDE and test results into maintenance procedure selection is discussed. Recommendations are provided on expanding application of NDE and tests as this can enable better maintenance decision making related to corrosion of reinforced concrete

Identification of Bridges with Fracture-Prone Details

Welded steel girder bridges can contain details that can high welding and service stresses and are termed constraintinduced fractures (CIF). The Kentucky Transportation Cabinet has steel bridges with weld details known to cause CIFs whose girders have experienced fracture events. The Cabinet’s bridge inventory was reviewed and additional candidate bridges with potential CIF details were identified. A review of bridge plans and pictures along with followup field investigations pinpointed bridges with CIF details that warrant up-close (i.e., arm’s length) inspections. Several uninspected bridges were identified as candidates for inspection to determine if they contain CIF details. Guidance is provided to help the Cabinet prioritize bridge inspections for CIF details and on repair actions for mitigating potentially problematic ones

Proposed Testing of Concrete Sealers

Chlorides, in sufficient concentrations, will cause corrosion of steel reinforcement in bridge decks. Previous studies have shown that de-icing chemicals and practices used by the Kentucky Transportation Cabinet (KYTC) can result in problematic levels of chloride at steel reinforcing depths in a relatively short amount of time. With the advent of liquid applied pre-treatment deicing chemicals, testing performed in Kentucky indicate chloride levels in bridge decks at a depth of two inches have increased significantly. Chlorides, in sufficient concentrations, will cause corrosion of steel reinforcement in bridge decks. Previous studies have shown that de-icing chemicals and practices used by the Kentucky Transportation Cabinet (KYTC) can result in problematic levels of chloride at steel reinforcing depths in a relatively short amount of time. With the advent of liquid applied pre-treatment deicing chemicals testing performed in Kentucky indicate chloride levels in bridge decks at a depth of two inches have increased significantly. Key properties of concrete sealers are resistance to chloride migration into the concrete and good penetration of the sealer into the concrete. Depth of sealer penetration would help offset wheel path wear and enhance the durability of the treatment. However, when a concrete deck has minor cracking, the performance of penetrating sealers will be limited. Recently several products have been promoted by manufacturers for potential use by the KYTC to seal bridge decks. The Kentucky Transportation Center (KTC) was asked to test and evaluate some of these products. For this study KTC focused on four of these products. The process included specimen preparation, application of material, testing, and evaluation

Waterproofing Options for Bridge Decks

Due to the increasing use of deicing chemicals and the subsequent intrusion of chlorides into bridge decks, it is necessary to expand the use of available protective measures, including waterproofing materials. Waterproofing options that fall into three categories; 1) membranes (liquid and sheet systems), 2) friction polymers (laminates), and 3) polymer asphalts. This study assessed the waterproofing characteristics of these products. Prior to this study, no common test had been established to compare the performance of waterproofing products. A test method was developed that closely follows ASTM D5084, “Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter,” for this purpose. This test provided valid information to compare performance of waterproofing options

Investigation of Soluble Salts on Kentucky Bridges

Invisible soluble salts present on steel highway structures can act to promote corrosion even after maintenance painting. Soluble salts include chloride, nitrate and sulfate ions. Soluble salts found on bridge decks and roadways are the result of usage of deicing salts (chlorides), and the deposition of atmospheric pollution (nitrates and sulfates) on exterior surfaces. Typical pollution-related sources of soluble salts are coal-fired power plants, refineries, farming operations, vehicle emissions, and chemical plants. Sites for soluble salt damage on bridges include: Beam ends under open or leaking expansion joints, Flanges and lower portions of webs of overpass structures, Lower chords and connecting members (end posts, portals, vertical posts and diagonals), and guard rails of truss bridges near roadway level, and Outside faces of fascia girders and other bridge elements constantly exposed to the environment. Maximum acceptable concentrations of soluble salts are very low (e.g. 10 μg/cm2 for chlorides)

Experimental Concrete Coating Application on the Median Barrier of I-65 in Louisville

The objectives of this research were to evaluate the experimental protective coating that was applied to approximately 1,200 linear feet of concrete median barrier along the paving project on a section of I 65 between mile points 131.289 and 136.421 in downtown Louisville. The project was completed generally in accordance with the specifications and special notes. This experimental project is the first trial of concrete coatings identified under KYSPR 05-271 Coatings, Sealants and Fillers to Address Bridge Concrete Deterioration and Aesthetics-Phase 1. The coatings systems identified under that study were intended to provide improved protection and aesthetics for reinforced concrete. This project proved that one candidate coatings system could be applied successfully on existing concrete. It is recommended that KYTC further pursue use of this knowledge by conducting more experimental/ prototype projects to further investigate how coatings hold up on new and old concrete barriers