The objective of this thesis is to explore the possibility of a non-destructive method of improving the dependability and economy of timber railroad bridges that have been exposed to environmental and service conditions. With railway companies increasing the load of trains in return for larger profit, maintenance and replacement of timber bridges has risen throughout recent years. Once chosen for its low cost and ease of construction, timber bridges are being replaced by more efficient concrete and steel trestles. The load path of a passing train through the elements of a bridge pier can be affected for several reasons. One focus of this report is how the load is distributed among the piles or supporting elements. Through recent research at Texas A&M University (2003), a relationship between the ultimate test load, Pmax, and the strength parameter, Lambda, was derived from 33 destructively tested specimens. Piles used in the testing were accumulated from three different locations in the United States and subjected to uniaxial compression along the length of the pile in a steel test frame. Instrumentation along the length of the piles provided data for plots of load versus deflection. Analysis of the plots showed that the tendency of the strength parameter, Lambda, to predict the ultimate test load was consistent but a computer generated model representing a typical service train revealed significantly lower loads on the piles than those used in the destructive tests. Further analysis of the test specimens at lower load levels led to a service level strength parameter that was derived with levels comparable to typical train loads. Guidelines for the service strength parameter, Beta, were based upon hypothetical loads from the computer generated model and previous test data. Field testing involved consent from a railroad company to install load cells and string potentiometers on an in-situ timber bridge. While simultaneously taking load and deflection measurements for bridges under the dynamic load of a passing train, the axial stiffness of the piles was determined and used in the calculation of the service level strength parameter,Beta. Future research includes removing the piles that were tested in the field and assessing them in the original method of axial compression in the steel test frame. This method can be used universally in the field to examine load path of passing trains and assess the amount of remaining axial strength of in-situ piles without interrupting daily flow and traffic of the railroad bridge. Ultimately, this research could lead to the railroad industry saving money and time due to the quick and convenient installation process.

Glue laminated wood deck systems are commonly used for bridge decks on girder bridge systems. These decks are usually covered with a hot-mix asphalt wearing surface in conjunction with a bituminized fabric sheet waterproofing membrane. Often cracks occur in the asphalt at the intersection of two adjacent deck panels which limits the useful life of the wear surface, provides a poor riding surface and potentially allows moisture to flow to wooden bridge components. The purpose of this study was to investigate the structural behavior of asphalt/wood/membrane deck systems. This was accomplished experimentally by determining the deflection of bridge deck panels with respect to each other under simulated truck loading. A classical linear analysis model and a finite element analysis model were developed for the deck panel deflections. These analytical results were compared to the experimental results and a value of approximately 0.05 in for the interpanel differential deflection was determined to be a reasonable, conservative value for the typical configuration considered. This deflection was then used to load various asphalt/membrane/ wood configurations to investigate the effectiveness of the arrangement with regards to resisting hot-mix asphalt cracking. It was found that when subjected to repeated deflections of 0.05 in, the following experimental composite bridge deck performed best in terms of reduced cracking: 1) hot-mix asphalt base layer applied directly onto the glulam deck panel; 2) waterproofing membrane placed on the base layer of asphalt; 3) hot-mix asphalt surface layer placed on the waterproofing membrane. / Master of Science

Advanced nondestructive inspection techniques like stress wave timing and resistance microdrilling have been used to successfully inspection timber bridges, but it is most effective on girder style bridges. There is a noted need to develop additional inspection techniques for longitudinal deck/slab timber bridges, which comprise about 20% of the national bridge inventory. One technique that holds potential is ground penetrating radar, a recognized nondestructive testing technique that has been used effectively for many different environmental and transportation applications. It has been utilized successfully to identify buried objects, internal defects and material changes. The objective of this research was to assess the potential for using GPR to identify and assess simulated deterioration in longitudinal timber deck timber bridges. GPR scans were completed in the longitudinal and transverse directions of a screwlaminated timber bridge deck before and after a bituminous layer was added to assess embedded defects that simulated voids, decay, insect damage and horizontal shear splitting. Assessment of the GPR wave energy signal was completed using visualization software that was provided with the commercial GPR unit used for the testing. The radar signal was analyzed in both the longitudinal direction (antenna front to back) and the transverse direction (antenna side to side). Interpretation of the radar signals allowed for the identification of various internal defects present in the deck. Based on the results, GPR has the potential to identify internal defects in timber bridge decks before and after a bituminous layer was added. Large, rectangular void defects (at least 6? by 12? by 5 in. (15.2? by 30.4? by 12.7 cm)) that were hollow, filled with foam, or filled with sawdust/adhesive were most easily identified under all scanning conditions. The addition of a bituminous layer, common to slab bridge construction, damped the signal response and made it more difficult to identify defects. Several smaller defects that were found in the deck without a bituminous layer were not identified in scanning completed after the bituminous layer was added.

The ability to use scientific or engineering advances (new technologies) to meet market needs has become a primary business success factor. New technology is also a major factor influencing growth and productivity within a firm. However, the forces that lead to technological innovation are not always from inside the firm. Often a company receives technology (technology push) from outside sources. However, the transfer process is not always smooth. Public sector research represents an important source of technology. In the major Western industrialized countries, government and university research organizations account for over 40 percent of the national research and development (R&D) expenditures. However, many technology transfer efforts between public (federal government) and private sectors have been disappointing. Like all businesses, government organizations buy, sell, provide, and deliver ideas, services, and goods. Government organizations today face limited funding and personnel, but they must grapple with growing needs for their services. Public organizations often find it necessary to seek help from other organizations and individuals to achieve their objectives. In the case of diffusion of government-sponsored innovations, it is challenging to find parties who can facilitate them, and once the parties are identified, elicit the necessary assistance from them. Numerous research efforts have been conducted on technology transfer efforts between government-sponsored innovation and private sectors. However, when researchers attempt to gain an understanding of the efforts, they primarily look for end results and tend to neglect the information flow and communication process which lead to positive results. The Wood in Transportation Program (WIT), USDA Forest Service, has exerted considerable effort in transferring timber bridge technology to private industry. However, much of this effort has focused upon permanent bridge structures for highway or pedestrian use. Little research has been conducted on how to facilitate technology transfer via an information flow system to the target users. Another potentially large market may exist for portable timber bridges for use in forestry and logging operations. The main goal of this study was to evaluate the information flow through the entire logging system and identify intermediaries who can help the WIT Program, USDA Forest Service facilitate technology transfer. This study utilized a unique backward trace method to gain an understanding of how innovations are diffused. The research consisted of the following steps to attain the final goal of developing strategies to successfully diffuse portable timber bridge technology from public research sectors to private sectors. First, the research evaluated how the final users (loggers) receive information, why they prefer certain channel(s) over others, and how they make decisions to use or not use technology from developers (WIT). Second, intermediaries in the technology transfer process were identified by loggers and they were evaluated on how they receive information from technology developers; how they evaluate the information; how they currently promote and diffuse ideas or innovations. Finally, technology developers were evaluated on how they currently promote and diffuse ideas or innovations. Upon analysis of the network of information flow, a strategic marketing plan for successful transfer of portable timber bridge technology was developed. / Ph. D.

Bridges form a vital link in the physical infrastructure and must be maintained in a "safe working order" at all times. It is estimated that there are currently 20,000 timber road bridges in service throughout Australia. Increasing demands on these bridges due to heavier and faster moving loads, together with deterioration are placing these aging structures at a higher risk of collapse. Unfortunately, many local governments and government departments have neglected the benefits of preventative maintenance and have opted for "just in time" repairs. This is especially true for timber bridges. This past neglect has placed bridge stock in a poor state that is only now being recognised as a significant problem. A key component of this research is to develop improvements to this current situation. This research thesis generates detailed knowledge on the load carrying capacities of timber bridges and new non destructive testing techniques that can be substituted for conventional testing procedures. For the first time guidelines have been developed for undertaking capacity assessment on timber bridges by specifying intervention levels for notched timber and limiting maximum allowable strains in timber members. This newly acquired knowledge will enable Asset Managers to more accurately determine the capacity of sniped timber bridge girders to enable appropriate retrofitting and maintenance while also allowing the safe movement of heavy vehicles. The knowledge generated through destructive testing of timber girders and the analysis of the vast amount of experimental data has enabled the first instance of developing specifications for replacement girders. These specifications detail both functional and performance related targets for three different types of replacement girders. Testing of these replacement girders also demonstrates that through some minor modifications that the specification targets can be met. The outcomes of this thesis provide an innovative approach to accessing the condition and capacity of timber girders and to increasing the safety and life of timber bridges in Queensland. By using new techniques such as Non-destructive testing, species identification and limiting maximum allowable strains, as described in this thesis, the road transport network can be safety used by heavy and permit vehicles. It is only through the effective management of timber bridge maintenance and rehabilitation that Australia can have an efficiently running road transportation network.

Two different asphalt concrete systems were examined in this research study. The existing system, consistent with current timber bridge construction practice, uses a preformed waterproofing membrane placed on a preservative treated wood deck overlaid with a bituminous concrete wearing surface. The second system consists of a treated wood deck overlaid with a base course of bituminous concrete, a waterproofing membrane, and a bituminous concrete wearing surface. The testing regime used in this research to evaluate watertightness and bond performance incorporated three parameters: three waterproofing membranes, two wood preservative treatments, and two environmental degradation conditions induced by temperature cycling in a moisture saturated condition. Control groups were evaluated for each study parameter and duplicate specimens were prepared and tested for each of the study parameters. A total of 160 specimens were constructed and tested. Watertightness of each system was determined by measuring the electrical impedance across a test specimen perpendicular to the direction of bond orientation in the pavement. The bond strength between each material of the paving systems was assessed using a shear test apparatus designed and built for this study. In addition to the laboratory constructed specimens, three drilled cores were taken from a bridge located on Creekside Drive in East Pennsboro Township, Pennsylvania. The deck was constructed using the new design proposed in this research and each core was tested for watertightness and bond strength. Results of watertightness testing indicated that low temperature environments appear to be most detrimental to system integrity in both the existing and proposed paving system configurations examined in this research. In general, each membrane appeared to perform equally well in the proposed paving system configuration as well as with all of the wood preservative treatments used in the existing pavement system. Bond strength between asphalt and wood with no membrane was observed to be nonexistent whether or not any preservative treatment was present. The placement of a membrane between these two layers did, however, result in a significant increase in bond strength because each membrane tested was able to adhere to the wood base better than the asphalt overlay. This gain is strength was significantly offset when petroleum solvent based preservative treatments were present in the wood substrate. Protectowrap M400 membrane performed slightly better than the other membranes when used with untreated wood, but all of the membranes performed equally when preservative treatments were present. The highest interlayer bond strengths (asphalt/asphalt or asphalt/wood) observed in this research occurred when asphalt concrete surface material was placed directly on top of asphalt concrete base material, however the addition of a membrane between the asphalt lifts consistently reduced this strength. The results of bond testing indicate that the proposed system will perform better in terms of shoving in the pavement overlay. Based on bond test results of cores taken from the Creekside Drive bridge, it appears that a shear strength greater than 25 psi after 200 low temperature exposure cycles will provide acceptable paving system performance in a low temperature (0-40ºF) environment. / Master of Science

This essay is a bachelor thesis written for the Degree Program in Constructional Engineering and Design at The Royal Institute of Technology (KTH). This thesis was an assignment given by WSP Sweden and their bridge and water department. The purpose of this report is to conduct an examination on the Life Cycle Cost (LCC) on a prestressed glulam deck bridge and a composite bridge in the early stages of the design phase. This report illuminates the factors that are most crucial in a LCC-calculation for the selected overpasses, and provides an overview regarding which overpass is most efficient from an economic standpoint. The LCC has been calculated based on an 80-year lifespan for the prestressed glulam deck bridge and a 120-year lifespan for the composite bridge. The cost of investment, operating, maintaining and finally the demolition cost was all considered as well. The bridge works that were examined are real life projects in an early stage of the design phase with plans to be built. In the results, the LCC-analysis shows a clear difference in life cycle costs between the prestressed glulam deck bridge and the composite bridge and show that the cost of investment is the most decisive cost during the bridges’ lifespans. The LCC-calculations show that the total life cycle cost for a prestressed glulam deck bridge is higher than the composite bridges’ total life cycle cost.

The aim of this Master’s thesis was to study the dynamic behaviour of a special type ofpedestrian timber bridge with a single diagonal arch - a design proposal made in a previousstudent project. The bridge is intended to be built as a gateway to the Alfred Nobel’s Björkbornin the municipality of Karlskoga. The original plan for this thesis was to build and test adownscaled model in order to verify theoretical investigations. The laboratory testing washowever not possible to be performed, therefore the study was conducted only by means ofanalytical and numerical tools. Both a downscaled model and a full-scale bridge model wereanalysed and compared in order to find proper scale parameters. Different studies wereperformed on the models by means of the finite element method in order to investigate theinfluence of relevant parameters on dynamic behaviour of the bridge. A scale factor wasdetermined which allows for the translation of results from the downscaled model to the fullscale model. Results showed that the dynamic behaviour of this type of bridge is rathercomplicated, and the original design needs to be somewhat modified to meet the comfortcriterion for pedestrians. An increase of the width of the arch, a proper arrangement of thecables, and adoption of longitudinal steel beams under the deck were found to be efficientmethods to improve the dynamic performance of the bridge. Future work should includeexperiments on a downscaled model to validate these theoretical solutions.