Investigating the Use of In-Place Lateral Pull Off Tests to Determine the Compressive Strength of Structural Concrete

The Kentucky Transportation Cabinet’s current practice for determining the compressive strength of structural concrete consists of two methods. Both methods require that samples be delivered to an off-site facility for testing. Accordingly, affected parties on the project site must wait for the delivery of samples to the off-site facility, the performance of tests and analysis of test data, and the return of test results to the project site. Analysis of existing structural concrete requires core samples to be taken from the structural element in question. As a result, sample locations must be patched and repaired. Sampling can also potentially damage an element’s structural integrity. A quick, on-site method that requires minimal repair is needed to determine the compressive strength of concrete. The lateral pull off test, which is conceptually and methodologically similar to the pull off/pull out test, can be used to determine the compressive strength of in-place concrete. It appears to be an accurate, non-destructive, and reliable method. This method also requires minimal patch work at sample locations. Samples are easily obtained and the test results are quickly determined on-site. Two series of tests — a laboratory test on freshly poured concrete slabs and an in-situ test on ready-to-demolish old bridges — were carried out. Both series of tests run the compressive strength cylindrical concrete test and lateral pull off test simultaneously to validate lateral pull off test as an acceptable and dependable method of determining concrete compressive strength. The test procedure and results look very promising based on the project’s objective

Fill Materials at Integral End Bents

Jointless bridge designs have become increasingly popular due to their low construction and maintenance costs. But this design carries risks. Most notably, integral end bents can be displaced and undergo settlement due to soil movement in embankments and loads carried by the superstructure. In response, the Kentucky Transportation Cabinet (KYTC) devised a novel treatment for end bent and abutment backfills on low- and middle-span concrete bridges in which elasticized geofoam is placed between geosynthetically confined soil and an integral end bent (GCS-IEB). However, this design requires modification where the elasticized geofoam and overlying pavement meet. Using elasticized geofoam is also costly. In response, this study identifies less expensive substitutes for elasticized geofoam that would not be damaged by bridge movements and which would reduce the settlement of integral end bents. Two promising materials were evaluated whose properties are similar to elasticized geofoam but which cost significantly less — shredded tire chips and recycled tire granules. Using a new lab procedure, researchers evaluated the recoverable deformation and maximum resistant stress of different samples, ultimately identifying a recycled tire derivative that is the best low-cost alternative to elasticized geofoam. Step-by-step installation methods are provided to guide the onsite installation of alternative materials. One method applies to recycled tire derivatives delivered in bags, while the other applies to materials that delivered in bulk and placed into baskets onsite

Development of a Laboratory Test for Evaluation of Geogrid Materials

Two test methods have been developed in this project. The first test method is a compression test of a cylinder constructed out of geogrid material and filled with crushed stone. This test is simple and can be easily performed. Only a compression loading machine is needed for this test. The sample preparation is straightforward. However, multiple tests must be run to analyze geogrids with different ultimate tensile strength or different grid aperture size on machine direction and cross machine direction. The second test method is Geogrid Bearing Ratio (GBR) test. This test was developed to measure the effect of geogrids on bearing capacity improvement. The ratio of bearing capacity for the with geogrid treatment to the bearing capacity for the without geogrid treatment is an index that captures a geogrid’s contribution to bearing capacity improvement. The GBR test result is one-parameter, which informs designers of how a geogrid functions in the pavement structure. This test enables comparisons of geogrids with differently aperture shapes. Any difference on grid single string strengths or aperture sizes or shapes are identified by GBR number. GBRs are related to the combined function of string strength, rigidity and integration properties of the geogrid. The optimal geogrid installation position under penetration loading is explored using GBR test. The optimum position is at 4 in. from bottom in 8 in. thick crushed stone configuration under 1.954 in. in diameter piston loading. It is critical to analyze or test particular cases in order to determine a practical, optimal design

Merging Multiple Existing Geotechnical Databases

This report discusses a project undertaken by Kentucky Transportation Center (KTC) researchers to create a comprehensive geotechnical database for highway planning, design, maintenance, and repair. The project consolidated multiple geotechnical data sources into a unified database accessible to Kentucky Transportation Cabinet (KYTC) staff, enabling informed decision making and improving project outcomes. Databases were merged with great attention to detail, ensuring data integrity and coherence. A geotechnical data collector app developed as part of the project supports convenient and efficient data collection in the field, even when phones or tablets lack network connectivity. A rockfall rating app and landslide hazard rating system streamline the collection and assessment of rockfall and landslide data. The report highlights tools used to complete the project, including the ArcGIS suite (i.e., ArcMap, ArcGIS Pro, ArcGIS Online, Collector, Field Maps, Survey123), Microsoft Visual Studio, and Microsoft SQL Server. These tools facilitate geodatabase management, field data collection, and data analysis. Detailed instructions and user manuals are provided for each application. Overall, project deliverables strengthen the Cabinet’s geotechnical data management as well as its geotechnical investigations, risk assessments, and mitigation strategies. It empowers staff by giving them access to valuable tools for data collection, analysis, and visualization, which in turn positively influence the safety and performance of Kentucky\u27s highways

Lessons Learned from Six Different Structural Health Monitoring Systems on Highway Bridges

Structural health monitoring has been utilized in numerous ways to investigate the performance and integrity of highway bridges. This paper highlights the use of six structural health monitoring systems, which were deployed to monitor distinct behaviors on six bridges in Kentucky. The structural health monitoring systems are as follows: (1) Over-height truck impact detection and monitoring on the I-64 over US 60 bridge, (2) Barge impact detection and monitoring on northbound US 41 over the Ohio River, (3) effectiveness of carbon fiber-reinforced polymer retrofit evaluation based on prestressed concrete I-girder crack movement on the I-65 elevated expressway in Louisville, (4) effect of thermal loads on bridge substructure evaluation on KY 100 over Trammel Creek, (5) thermal movement of expansion joints evaluation on eastbound I-24 over the Tennessee River, and (6) crack growth monitoring on steel floor beam on I-275 over the Ohio River. The deployment of the different structural health monitoring systems on Kentucky bridges has provided valuable insights on their planning, implementation, and maintenance, which can be applied on future structural health monitoring projects. While several of the projects have proved immensely successful, with some still being continuously monitored, others, due to numerous complications, have met with only limited success. The best return on investment was realized from structural health monitoring instrumentation that was focused and limited in scope. The successful structural health monitoring systems had continuous communication between all stakeholders during planning, implementation, and monitoring phases of the projects. Following implementation, the availability of contingency funds through the funding source, to replace/upgrade sensors and networking equipment and costs for reprogramming and reinstallation outside of regular maintenance costs, was also important for the structural health monitoring to be successful

Full-Depth Reclamation of Asphaltic Concrete Pavements

The Kentucky Transportation Cabinet (KYTC) has used a full-depth reclamation (FDR) process over the past few years to rehabilitate asphalt pavements exhibiting widespread base failures. FDR transforms existing hot-mix asphalt (HMA) pavement and underlying granular materials into a stabilized base layer. The stabilized layer is then overlaid with a new pavement surface layer. Until now, deciding when and how to use the FDR process has not been well specified in Kentucky — the Cabinet has commonly used a Special Note for Cement Stabilized Roadbed as guidance and relied on the contractor for acceptable materials design. Previous research conducted by the Kentucky Transportation Center (KTC) and funded by KYTC proposed guidelines for FDR pavements and considered various binding compounds including, cement, asphalt emulsion, and foamed asphalt. Guidance also included a process for identifying potential projects for the FDR process and recommendations for examining material sampling, testing, mixture design, structural design parameters, and selection requirements for FDR treatment established through preconstruction planning activities. It also addressed quality control and quality assurance. This report builds on those guidelines by providing a special note for the use of the FDR in Kentucky

Shennan Road and the Modernization of Shenzhen Architecture

Shenzhensetsanexampleforrapiddevelopmentofurbanplanningandconstruction.It was the starting point of the most massive city-construction movement in contemporary China. In less than 40 years, many representative urban space and buildings on the mainmast-west highway—-ShennanRoad,have witnessed the for mation of the banded multi-center structural layout and the miraculous expansion of the city. Many of those iconic buildings are designed by Hong Kong or foreign architects. With the continuous development of the length and width of Shennan road, its broad and prosperous image is not only a symbol of the fruits of reform and opening up in Shenzhen or even China, but also contains the growth history of Shenzhen’s architectural modernization. This paper reviews and summarizes the changes of the urban fabric and the design trend of representative buildings along with the Shennan Road in different periods by the historical research methods. Combined with the transfer path of the city center, this study analyzes what kind of unique role the street and buildings act as in the developmentofurbanstructureinShenzhen,and expound what other urban functions and symbolic meaning they have. In the context of globalization, this article discusses how do the buildings designed by foreign architects change our city,thedrivenfactors behind the phenomenon of the design trend change. This research can make a supplement to the history and theory of the modernization of contemporary Chinese architecture

Effect of Thermal Loads on Substructures: New Trammel Creek Bridge on KY-100 in Allen County, Kentucky

When infrastructure is subjected to temperature changes, structural members that are either partially or fully restrained against motion can develop internal stresses. The phenomenon of temperature-induced internal stress development in superstructure members has prompted the American Association of State Highway and Transportation Officials (AASHTO) to include provisions for determining superstructure temperature load effects. However, little consideration has been given to explicitly quantifying the effect that thermal stresses have on foundation systems such as intermediate bridge piers. The objective of this study is to instrument a multi-span integral abutment bridge with temperature and bridge response monitoring devices, and ultimately, to make a comparative analysis between measurements of temperature-induced soil pressures with pressures derived using the AASHTO design provisions. Accordingly, the New Trammel Creek Bridge (002B00054N) along KY-100 in Allen County, Kentucky has been fitted with temperature and response instrumentation. Data has being continuously collected from the bridge site since May 2011, and can be viewed at: http://www.ktc.uky.edu/kytc/RemoteBridgeMonitoringInKY/ky100Allen.html. Included in the research is a detailed analytical study of the New Trammel Creek Bridge, performed simultaneously with a field-monitoring program. Finite element (FE) modeling and analysis of temperature loadings on the bridge have pointed to AASHTO superstructure temperature provisions as the preferred method. Also called Method B, the AASHTO provisions led to adequate sizing of bridge foundation members

Microstructure and texture analysis of δ-hydride precipitation in Zircaloy-4 materials by electron microscopy and neutron diffraction

This work presents a detailed microstructure and texture study of various hydrided Zircaloy-4 materials by neutron diffraction and microscopy. The results show that the precipitated δ-ZrH1.66 generally follows the δ (111) //α (0001) and δ[]//α[] orientation relationship with the α-Zr matrix. The δ-hydride displays a weak texture that is determined by the texture of the α-Zr matrix, and this dependence essentially originates from the observed orientation correlation between α-Zr and δ-hydride. Neutron diffraction line profile analysis and high-resolution transmission electron microscopy observations reveal a significant number of dislocations present in the δ-hydride, with an estimated average density one order of magnitude higher than that in the α-Zr matrix, which contributes to the accommodation of the substantial misfit strains associated with hydride precipitation in the α-Zr matrix. The present observations provide an insight into the behaviour of δ-hydride precipitation in zirconium alloys and may help with understanding the induced embrittling effect of hydrides.Fil: Wang, Zhiyang. University of Wollongong; Australia. Australian Nuclear Science and Technology Organisation; AustraliaFil: Garbe, Ulf. Australian Nuclear Science and Technology Organisation; AustraliaFil: Li, Huijun. University of Wollongong; AustraliaFil: Wang, Yanbo. University of Sydney; AustraliaFil: Studer, Andrew J.. Australian Nuclear Science and Technology Organisation; AustraliaFil: Sun, Guangai. Institute of Nuclear Physics and Chemistry, CAEP; ChinaFil: Harrison, Robert P.. Australian Nuclear Science and Technology Organisation, Institute of Materials Engineering; AustraliaFil: Liao, Xiaozhou. University of Sydney; AustraliaFil: Vicente Alvarez, Miguel Angel. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Santisteban, Javier Roberto. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kong, Charlie. University of New South Wales; Australi

Non-Nuclear Methods for Compaction Control of Unbound Soil and Granular Layers

In highway construction, the nuclear density gauge (NDG) is the industry standard for measuring soil density and moisture. They are widely used at state transportation agencies, however, because of their reliance on radiation, NDGs are expensive to maintain and have unique storage requirements. Operators must also earn specialized certifications and adhere to rigorous safety protocols. Equipment manufacturers have developed several non-nuclear density gauges which are more user friendly, however, their accuracy has sometimes not equaled NDGs. This comparative study evaluated the performance of the eGauge (a relatively new device) to NDGs. Over 100 soil density and moisture measurements were collected from nine field sites throughout Kentucky. At sites characterized by silt/clay and shale or stabilized clay, NDGs and the soil density eGauge produced statistically similar soil density readings, while significant differences were observed for clays and full depth reclamation (FDR). Across all sites, 82.5% of the NDG and eGauge density readings were within +/- 5% of one another. For soil moisture, readings from NDGs and the eGauge were compared to samples dried in an oven laboratory. At sites characterized by silt/clay and shale, the NDGs, eGauge, and lab samples yielded significantly different measurements, while at sites with clay the eGauge measures differed significantly from those acquired via NDGs and the lab samples. No significant differences were noted for stabilized clays. Based on raw data, 88.2% of NDG and 48.0% of eGauge soil moisture readings were within +/- 5 percentage points of the corresponding lab measurement. For most soil types, the eGauge produces sufficiently accurate readings for field use, although further study of clays and FDR is needed