Modular Expansion Joints and Deck Drains

Inspections were conducted on bridge modular expansion joints and deck drains to assess their performance. Forty-four modular expansion joints were inspected including 38 Wabo-Maurer and 16 Acme joints. Twenty-three elastomeric dams were also inspected for comparative purposes including 21 Transflex dams and 2 Fei-Span units. The joints were rated using a quantitative subjective rating system developed by Penn DOT. Both the modular expansion joints and the newer expansion dams were performing satisfactorily. Both types of joints leaked and experienced a number of minor hardware problems. some of the joints may warrant repairs to restore their complete function. Deck drains and drain outlet piping systems were inspected. The deck drains inspected included those having square and rectangular inlets, pipe drains, and scuppers (edge drains). All types of deck drains appear susceptible to clogging. Large scuppers performed well. Also, simple straight drop pipes were less clog prone than complex piping systems. Recommendations are provided to minimize clogging problems

Performance Survey of Silicone-Sealed Concrete Pavement Joints

This report summarizes field inspections of various silicone-sealed concrete pavement joints. A list of silicone sealant projects was provided by the Kentucky Transportation Cabinet. Observations of performance were subjective and qualitative

Load Indicating Washers

Kentucky Transportation Center (KTC) personnel monitored the installation of load indicating washers (LIWs) on the US 60 bridge at Catlettsburg, KY during construction. On completion of the bridge, KTC personnel performed torque measurements on a number of LIW installations. LIWs previously installed on the Thirteenth Street Bridge over the Ohio River at Ashland, KY were also inspected. The KTC construction inspections revealed no significant problems in installing LIWs. Workers were able to use them to determine proper bolt assembly installation. They also permitted inspectors to rapidly check for proper bolt tension. As with other bolt tensioning methods, LIWs had to be tested prior to installation. The follow-up field torque tests indicated that the LIWs provided consistent bolt tension values. The only potential service problem with LIWs, as discerned on the Thirteenth Street bridge, is related to corrosion. Uncoated LIWs must be hand painted to prevent rusting

Calcium Nitrite as a Corrosion Inhibitor in Reinforced Concrete Bridge Decks

The use of calcium nitrite es a corrosion-inhibiting admixture in reinforced concrete hes been studied on two bridges· the Kentucky 152 Bridge in Washington County and the Gose Road Bridge in Boyle County. Calcium nitrite was added to concrete used in the slabs, diaphragms and barriers of the KY 152 bridge and only in the slab of the Good Road bridge. Construction of both structures was monitored in the fall of 1986. Placement of concrete on both bridges was satisfactory; however, problems were experienced in finishing the concrete. The finishing problems were related to: 1) concrete \u27stickiness\u27, 2) use of spinning-drum screed, 3) use of tyning for deck grooving and, 4) contractor inexperience with the concrete. The finishing problems included; 1) pulled or exposed aggregate, 2) pull cracks, 3) unclosed surface voids and 4) irregular grooves. Compressive strength of the calcium-nitrite admixed concrete for both bridges exceeded 6,000 psi at 28 days. Freeze-thaw tests of specimens from the Gose Road bridge concrete (that incorporated a super water reducer) indicated no deterioration at 360 freeze-thaw cycles. Half-cell, corrosion-potential tests were conducted on both bridge decks in March 1987. Those tests revealed no active corrosion in either bridge. In July 1987, corrosion-potential and polarization-resistance tests were performed using stainless-steel reference electrodes buried in concrete across the deck of the Gose Road bridge. Those tests revealed that reinforcing steel in the bridge was in a passive state and that no active corrosion was occurring. Recommendations are included on remedying concrete-finishing problems. It is recommended that other experimental bridges be constructed using calcium nitrite

Field Inspections of High-Performance Bridge Paints

Paint inspections were performed on 19 steel bridges. Those structures employed various high-performance sacrificial and barrier paints. Those paints were used singly and in combination. The surface preparation varied for some of those paint systems. The inspections included four girder bridges that had original paint and 15 others, mostly trusses that were repainted. Kentucky Transportation Center personnel also monitored several bridges during repainting operations. The inspections revealed that the original paint was in excellent condition. Most of the coatings on the repainted bridges were performing well. Some of those bridges have some spot corrosion. Only one of those bridges showed signs of widespread coating failure. The high-performance coatings were performing well. Most of the corrosion and paint deterioration observed is believed to be related to inadequate surface preparation. Paint inspection provided by the Kentucky Transportation Cabinet is good

Instrumentation of the Twelvemile Bridge

An experimental precast, post-tensioned concrete segmental girder bridge over Twelvemile Creek in Campbell County was instrumented with stress and strain sensors. Those sensors were read during beam fabrication and the initial portion of construction. The work was performed to address Transportation Cabinet questions about structural performance and also to assess the effect of long-term creep. The study and bridge were not completed as originally designed due a beam failure during post-tensioning. A variety of stress, strain, and deflection measuring techniques were to be employed during the study. Several of those including concrete stress and strain meters, and vibrating-wire strain gages were embedded in beams and one pier cap. Those sensors were read during several phases of fabrication and construction. Concrete maturity meters were also employed to determine temperature-time relationships with increases in curing strength for concrete used in the pier caps and in one beam. Compressive strength and modulus tests were also performed on test cylinders obtained from the pier and beam concrete. This report describes the progress of the field instrumentation and laboratory work to the termination of the study. The study was terminated due to the failure of a beam during erection. The bridge was completed using conventional steel girders. Based upon the limited study findings and the beam failure, recommendations are provided that the Transportation Cabinet: 1) conduct further research related to the use of maturity meters, and 2) consider employing nondestructive testing of similar beams in fabrication shops

Summary of Experimental Bridge Features

Experimental bridge features and service problems investigated during this study are reviewed. Those were epoxy-coated reinforcing steel, stay-in-place forms, experimental deck features (rotary compaction and broomed deck finishing), precast segmental bridges, steel-corrosion control methods (weathering steel and hot-dipped galvanizing), microsilica concrete, failures of masonry coatings, and failures of aluminum guardrail-retaining nuts. Several features including latex and low-slump overlays, epoxycoated reinforcing steel, and broomed deck finishes (for state-built bridges), are now in common use. Most of the other experimental bridge features were performing satisfactorily. A corrosion problem was observed on one weathering steel bridge. Analyses of failures of masonry coatings and the aluminum nuts resulted in identification of the probable causes of the failures and remedial recommendations. The report also contains recommendations for further research

Installation and Performance of Portland Cement Concrete Pavement Joint Sealers

Joints are needed in portland cement concrete pavements to control cracking, relieve pavement stresses due to volume change, and to protect immovable structures. However, when the joints are not properly designed, constructed, and maintained, they may become a source of multiple problems. It is the opinion of many pavement management engineers that the most effective way to prevent and/or correct problems with joints is to use a joint sealer material. The purpose of the sealer is to keep surface water and fine, incompressible material from entering the pavement joint. The Kentucky Transportation Center was contracted by the Kentucky Department of Highways to evaluate the installation and short-term performance of four different types of joint sealants used for portland cement concrete pavements. The four cement concrete pavement joint sealers used in the project were: silicone rubber, self-leveling silicone rubber, preformed polychloroprene compression seal, and conventional hot-poured elastic sealant. The silicone sealants were supplied for the project by the DOW Corning Company. The preformed polychloroprene compression seals were supplied by the D. S. Brown Company. The silicone rubber sealant was sticky, difficult to install properly, and subsequently, is displaying evidence of increased wear. The self-leveling silicone rubber sealant was more fluid, less sticky, easier to install, obtained the correct depth in the joint most consistently, and has performed extremely well to date. The preformed polychloroprene compression seals appeared to be easily installed. However, uniformity in depth below the surface of the joint was not achieved and twisting of some seals was observed. A greater amount of incompressible materials are collecting in the pavement joints containing the preformed polychloroprene compression seals. The hot-poured elastic joint sealer was easily installed but installers had difficulties controlling the rate of application. It was concluded that with proper construction techniques, successful applications of silicone rubber joint sealers will result. The silicone sealants provide an effective means of preventing moisture and incompressible fines from entering the pavement joint. Based on this successful initial application and the excellent short-term performance exhibited thus far, it was recommended that self-leveling silicone rubber sealant be used on a number of additional projects so that a more extensive performance data base may be developed by the Department of Highways

Bridge Decks and Overlays

The report presents a historical perspective of the Transportation Cabinet\u27s bridge deck construction and maintenance efforts directed toward increasing bridge deck durability. Bridge decks crack in specific patterns that primarily depend upon bridge designs. Normal deck cracking is due to load-induced and thermal effects. Each type of cracking has a distinct pattern. One-hundred and nineteen experimental bridge deck overlays were inspected. Included were 9 membrane bridges, 87 latex concrete overlays and 23 low-slump overlays. The overlays had been placed originally on both new and existing bridge decks on various routes throughout the state. Most of the overlays were rated in good to excellent condition. None of the overlay methods was discernibly superior to the others. Thirty-four integral abutment bridges were inspected. Nearly all of those bridges are in good to very good condition. Only one bridge had a problem caused by settlement

De Novo VPS4A Mutations Cause Multisystem Disease with Abnormal Neurodevelopment.

The endosomal sorting complexes required for transport (ESCRTs) are essential for multiple membrane modeling and membrane-independent cellular processes. Here we describe six unrelated individuals with de novo missense variants affecting the ATPase domain of VPS4A, a critical enzyme regulating ESCRT function. Probands had structural brain abnormalities, severe neurodevelopmental delay, cataracts, growth impairment, and anemia. In cultured cells, overexpression of VPS4A mutants caused enlarged endosomal vacuoles resembling those induced by expression of known dominant-negative ATPase-defective forms of VPS4A. Proband-derived fibroblasts had enlarged endosomal structures with abnormal accumulation of the ESCRT protein IST1 on the limiting membrane. VPS4A function was also required for normal endosomal morphology and IST1 localization in iPSC-derived human neurons. Mutations affected other ESCRT-dependent cellular processes, including regulation of centrosome number, primary cilium morphology, nuclear membrane morphology, chromosome segregation, mitotic spindle formation, and cell cycle progression. We thus characterize a distinct multisystem disorder caused by mutations affecting VPS4A and demonstrate that its normal function is required for multiple human developmental and cellular processes.This work was supported by: UK Medical Research Council Project Grants [MR/M00046X/1], [MR/R026440/1] and Project grant from National Institute of Health Research Biomedical Research Centre at Addenbrooke's Hospital (to E.R.), Fondazione Bambino Gesù (Vite Coraggiose) and Italian Ministry of Health (CCR-2017-23669081) (to M.T.), National Institute for Health Research (NIHR) for the Cambridge Biomedical Research Centre and NIHR BioResource (Grant Number RG65966) (to F.L.R.), and a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant Number 216370/Z/19/Z) (to J.E.). CIMR was supported by a Wellcome Trust Strategic Award [100140] and Equipment Grant [093026]. This research was made possible through access to the data and findings generated by the 100,000 Genomes Project. The 100,000 Genomes Project is managed by Genomics England Limited (a wholly owned company of the Department of Health and Social Care). The 100,000 Genomes Project is funded by the National Institute for Health Research and NHS England. The Wellcome Trust, Cancer Research UK and the Medical Research Council have also funded research infrastructure. The 100,000 Genomes Project uses data provided by patients and collected by the National Health Service as part of their care and support