Evaluation of bridge decks using non-destructive evaluation (NDE) at near highway speeds for effective asset management-implementation for routine inspection (Phase III)

This project focused on implementing the 3DOBS technology (developed under Phase I and Phase II) for successful detection, quantification, and visualization of concrete bridge deck distress features at near-highway speeds for routine MDOT inspections. The integration and further re-defining of the 3DOBS methods into MDOT practices was accomplished by assessing 11 bridge decks with an average size of 10,350 square feet. Distress features were categorized according to the Bridge Element Inspection Manual and compared to traditional (visual) element level inspection results. The Great Lakes Engineering Group, LLC worked with the research team to inspect, interpret, report results, and advise on current condition state reporting requirements. The project team also trained MDOT bridge inspectors in the use of the remote sensing equipment, data collection, data processing, and reporting through multiple different training sessions. A cost comparison between 3DOBS and traditional inspection methods was conducted, with 3DOBS costing an average of $92 per bridge, as compared to$39 for traditional methods. For producing standard element level condition state tables, 3DOBS cost more than a traditional inspector, but is still estimated to be less than $100 for an average bridge in this study

Evaluation of Comparative Repair Methods for Stone

Stone masonry, once popular in 19th and early 20th century America, was gradually replaced by concrete and other modern building materials. Many Pennsylvania quarries produced prized local stone such as Pennsylvania Blue Marble, Hummelstown Brownstone, and Chester County Serpentine, all no longer quarried. These materials were used to construct numerous historically significant architecture in the Mid-Atlantic Region. While material authenticity is one of the guiding philosophies for conservation design, oftentimes compromises must be made for many reasons—cost, availability, compatibility with other materials or structure, schedule, skilled labor, aesthetics and an important one which will be the focus of this thesis—durability. Using serpentine as a model, this paper explores alternative methods of non-in-kind repair for buildings constructed with stones no longer quarried in the United States. Two methods are evaluated in detail: Creating a new face or patching using Lithomex, a composite repair material applied directly onto a substrate such as stone or brick. Creating a new face or unit replacement with an available stone such as sandstone, colored with Colorwash Stain, a potassium silicate mineral stain for masonry. An evaluation of repair durability is assessed by comparing surface erosion and color change before and after accelerated weathering. Profile change (profilometry) is assessed through digital models of the samples created with a structural light 3D scanner and color change is analyzed by comparative spectrophotometry. Three case studies of past serpentine repair act as additional discussion of repair methods not evaluated through testing

A Framework for Risk Analysis and Vulnerability Assessment of the Rubble Masonry at Tuzigoot National Monument

Located on the summit of a sandstone and limestone ridge overlooking the Verde River in Clarkdale, Arizona lies a cluster of two to three story masonry Native American ruins known as Tuzigoot National Monument. This thesis focused on Group III, which contains the first pueblo rooms built on the site, still containing historical stabilization material. Despite partial collapse, burial and excavation, these walls have endured. Since excavation in 1933, Tuzigoot has been continuously stabilized reflecting changing attitudes in materials and methods. In light of past and current preservation management, this thesis studied the construction and performance of the rubble wall masonry at Tuzigoot National Monument in order to develop a risk and vulnerability analysis of the walls. It resulted in the development of a Historic Preservation Guide that included a phased methodology consisting of a comprehensive development and preservation history, the development of a rapid assessment survey to identify wall vulnerability and priority, and a detailed comprehensive condition assessment for the most at-risk walls to identify monitoring and/or remedial interventions

Pavement Surface Distress Detection, Assessment, and Modeling Using Geospatial Techniques

Roadway pavement surface distress information is essential for effective pavement asset management, and subsequently, transportation agencies at all levels dedicate a large amount of time and money to routinely collect data on pavement surface distress conditions as the core of their asset management programs. These data are used by these agencies to make maintenance and repair decisions. Current methods for pavement surface distress evaluation are time-consuming and expensive. Geospatial technologies provide new methods for evaluating pavement surface distress condition that can supplement or substitute for currently-adopted evaluation methods. However, few previous studies have explored the utility of geospatial technologies for pavement surface distress evaluation. The primary scope of this research is to evaluate the potential of three geospatial techniques to improve the efficiency of pavement surface distress evaluation, including empirical analysis of high-spatial resolution natural color digital aerial photography (HiSR-DAP), empirical analysis of hyper-spatial resolution natural color digital aerial photography (HySR-DAP), and inferential geospatial modeling based on traffic volume, environmental conditions, and topographic factors. Pavement surface distress rates estimated from the aforementioned geospatial technologies are validated against distress data manually collected using standard protocols. Research results reveal that straightforward analysis of the spectral response extracted from HiSR-DAP can permit assessment of overall pavement surface conditions. In addition, HySR-DAP acquired from S-UAS can provide accurate and reliable information to characterize detailed pavement surface distress conditions. Research results also show that overall pavement surface distress condition can be effectively estimated based on the extent of geospatial data and inferential modeling techniques. In the near term, these proposed methods could be used to rapidly and cost-effectively evaluate pavement surface distress condition for roadway sections where field inspectors or survey vehicles cannot gain access. In the long term, these proposed methods are capable of being automated to routinely evaluate pavement surface distress condition and, ultimately, to provide a cost-effective, rapid, and safer alternative to currently-adopted evaluation methods with substantially reduced sampling density

Developing Guidelines for Two-Dimensional Model Review and Acceptance

Two independent modelers ran two hydraulic models, SRH-2D and HEC-RAS 2D. The models were applied to the Lakina River (MP 44 McCarthy Road) and to Quartz Creek (MP 0.7 Quartz Creek Road), which approximately represent straight and bend flow conditions, respectively. We compared the results, including water depth, depth averaged velocity, and bed shear stress, from the two models for both modelers. We found that the extent and density of survey data were insufficient for Quartz Creek. Neither model was calibrated due to the lack of basic field data (i.e., discharge, water surface elevation, and sediment characteristics). Consequently, we were unable to draw any conclusion about the accuracy of the models. Concerning the time step and the equations used (simplified or full) to solve the momentum equation in the HEC-RAS 2D model, we found that the minimum time step allowed by the model must be used if the diffusion wave equation is used in the simulations. A greater time step can be used if the full momentum equation is used in the simulations. We developed a set of guidelines for reviewing model results, and developed and provided a two-day training workshop on the two models for ADOT&PF hydraulic engineers

Effect of surface roughness on the efficiency of self-healing polymers

A shape memory polymer (SMP) is a smart material capable of maintaining two distinct shapes depending on its temperature. A SMP is soft at temperatures above its glass transition temperature but hard below it. When copolyester thermoplastic additives are dispersed in a SMP, it becomes a SMP-based particulate composite capable of self-healing at both the molecular level and the structural level. This makes it very desirable for industrial applications. Upon damage to the composite, the surfaces at the damage interface have to come into contact for efficient healing; the shape memory effect, coupled with a confined recovery (healing) process, ensures this. This study examined the effect of the surface roughness at the damage interface on the efficiency of the healing process. Also studied was the effect of the compressive stress at the point of contact during the healing process on the healing efficiency. The particulate composite (CP-PSMP) consisted of polystyrene shape memory polymer (PSMP) as the matrix and copolyester thermoplastic additives (CP) as the reinforcement. Compressive programming at 10 % pre-strain was performed on the CP-PSMP, which was then tested for its pre-flexural strength. Next, the surfaces were varied using sandpapers of different embedded particle diameters, and the CP-PSMP was healed at 10 MPa using the close-then-heal (CTH) self-healing mechanism. The recovered flexural strength was then obtained and the healing efficiency computed as a fraction of the recovered flexural strength to the pre-healing flexural strength. Healing efficiencies were found to be higher for CP-PSMP with smoother surfaces. The highest healing efficiency of 39 % was found in CP-PSMP with average and root-mean-squared roughness profile parameters, Ra and Rq, of 0.425 and 0.617 μm respectively. Another set of tests revealed that healing was more efficient at higher compressive stresses. Efficiencies at higher compressive stresses (20 – 80 MPa) ranged from 78 % to 118 %. Next, the effects of sanding on healing efficiency was examined by comparing the healing efficiencies of two sets of CP-PSMP with similar Ra and Rq values—one of which was treated with sandpaper. The sanded CP-PSMP samples were 24 % more efficient in healing

Experimental Study of a Cascade of Low Pressure Turbine Blades with Upstream Periodic Stator Wakes

The objective of this study is to experimentally study film cooling flows. A closed-loop wind tunnel with a four passage linear cascade of US Air Force Research Laboratory (AFRL) ultra-high-lift L1A low pressure turbine (LPT) blades and upstream wake generator is used in conjunction with Particle Image Velocimetry (PIV) flow visualization technique to study turbulent film cooling flows due to the interaction between vanes and blades. Further post-processing in the form of Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) modal analyses is performed to determine the relevant modes that characterize the coherent structures in the flow. An image patching algorithm is also implemented. The results obtained are used to characterize the periodic wake on the cascade flow. The periodic wake has been studied in detail near the leading edge of the suction side. The velocity data led to the mean velocity profile and maximum velocity deficit in the wake. The POD identified the most energetic modes representing the vortex shedding wavelength, and its harmonics, of the wake generator plates. The DMD confirmed the wake passage frequency. Implementation of the image patching algorithm with four domains was presented. The technique was successful in computing the average vector field. Further downstream of the leading edge, the POD modes are shown to become more chaotic and less energetic. The leading order mode pair loses close to half of their energy to lower order modes due to the cascading of turbulent kinetic energy to lower spatial scales and to viscous dissipation losses. When the wake is impinging on the leading edge, the boundary layer separates near the transition point. The boundary layer remains completely attached to the trailing edge when the wake is not impinging on the leading edge