Lightweight wood construction is one of the most common forms of residential construction in the United States. Unprotected lightweight wood structural members are extremely sensitive to elevated temperatures often experienced in fire conditions. Residential fires are a commonly occurring incident across the globe and consequently make up a large percentage of residential property loss and damage. In the United States, building code provisions limit lightweight construction to particular building types. These building codes prescribe protected lightweight wood assemblies in building types for which they are allowed. Although many components of lightweight wood buildings are required to be protected in some form, there are still many parts of the building that are not necessarily required to be protected, especially in private residential structures. A fire may start in an area of a building that is protected, but may propagate into areas that are not. This leaves portions of the unprotected structure vulnerable to rapid fire damage. Lightweight wood members can quickly lose load resistance due to a loss of cross-section as a result of charring. Analytical models currently exist and are generally accepted for heavy timber elements, but the applications of these models do not extend to lightweight wood members. As a result, this thesis investigated the application of an analytical model to lightweight wood elements. In developing this model, the finite element method and finite difference models were used to investigate the phenomenon of wood char in fire conditions. Finite difference models were explored as an alternative to finite element models because finite difference formulations did not require specialty programs. Following the development of analytical char models, mechanics-based analyses were conducted to evaluate the performance of lightweight beams and columns exposed to fire conditions.

What if Light was used to emphasis the Lightness of a Lightweight structure. In this project I set out to explorer the way in which we visually and emotionally experience “Lightweight”. I feel that car companies are beginning to see previous mistakes and engineer for a future in which physically lighter cars are requisite. This leads me to the question; how do we as designers communicate this in a positive way and sell a future efficient, lightweight lifestyle? I began the project by considering “What is Lightweight” especially in its visual and emotional forms. This thought process lead me to the use of abstract photography of light itself to help me to create a new lightweight BMW design language. The final result is a mixture of lightweight, twisting, structural forms that flow around the user to create a floating interior architecture. This will allow for, in a future autonomous world, the exposure of a fully lightweight transportation experience.

This thesis presents a tool for the mechanical validation of formal software specifications. The tool is based on a novel approach to incremental validation. In this approach, small-scale aspects of a specification are validated, as part of the stepwise refinement of a formal model. The incremental validation technique can be considered a form of "lightweight" model checking. This is in contrast to a "heavyweight" approach, wherein an entire large-scale model is validated en masse. The validation tool is part of a formal modeling and specification language (FMSL), used in software engineering instruction. A lightweight, incremental approach to validation is beneficial in this context. Such an approach can be used to elucidate specification concepts in a step-by-step manner. A heavy-weight approach to model checking is more difficult to use in this way. The FMSL model checker has itself been validated by evaluating portions of a medium-scale specification example. The example has been used in software engineering courses for a number of years, but has heretofore been validated only by human inspection. Evidence for the utility of the validation tool is provided by its performance during the example validation. In particular, use of the tool led to the discovery of a specification flaw that had gone undiscovered by manual validation alone.

No description available.

Ultra high performance concrete, specifically Ductal® concrete, has begun to revolutionize the bridge design industry. This extremely high strength material has given smaller composite sections the ability to carry larger loads. As the forces being transferred through composite members are increasing in magnitude, it is vital that the equations being used for design are applicable for use with the new materials. Of particular importance is the design of the horizontal shear reinforcement connecting the bridge deck to the top flange of the beams. Without adequate shear transfer, the flexural and shearing capacities will be greatly diminished. The current design equations from ACI and AASHTO were not developed for use in designing sections composed of Ductal® and Lightweight concrete. Twenty-four push-off tests were performed to determine if the current horizontal shear design equations could accurately predict the horizontal shear strength of composite Ductal® and Lightweight concrete sections. Effects from various surface treatments, reinforcement ratios, and aspect ratios, were determined. The results predicted by the current design equations were compared to the actual results found during testing. The current design equations were all found to be conservative. For its ability to incorporate various cohesion and friction factors, it is recommended that the equation from AASHTO LRFD Specification (2004) be used for design. / Master of Science

Although design codes have accepted lightweight concrete as a suitable structural material for nearly 50 years, there is still a good deal of uncertainty as to how to calculate the strength of this material when designing for shear in beams.  Design codes tend to penalize lightweight concrete due to its lower tensile strength and smoother interface along the shear cracks.  In this study, there were twelve tests on six full-scale, prestressed girders with composite decks designed to provide answers to some of those uncertainties.  The variables considered were concrete density, concrete compressive strength, effective shear depth, shear span-to-effective depth ratio, the amount of shear reinforcement, and the composite cross-sectional area.  Results show that the sand-lightweight concrete girders exceeded the expected shear strength according to the 2010 AASHTO LRFD Bridge Specifications.  Compared to normal weight concrete, sand-lightweight concrete performed reasonably well, and therefore, does not need a lightweight modifier when designing for shear.  However, a reliability analysis of the sand-lightweight girders in this study as well as twelve previous experiments indicate that there should be two different strength reduction factors for the shear design of sand-lightweight concrete depending on which shear design procedures are used in the 2010 AASHTO LRFD Bridge Design Specifications.  For the General Procedure as well as the guidelines outline in Appendix B5, the strength reduction factor should be increased from 0.70 to 1.00.  For the Simplified Procedure, that factor should be 0.75. / Ph. D.

This research focused on designing a grout mixture using lightweight aggregate that achieves the minimum 28-day compressive strength required for normal-weight grout, 2000 psi. This research specifically studied the effects of aggregate proportion, slump, and aggregate soaking on the compressive strength of the mixture. The variable ranges investigated were 3-4.75 parts aggregate to cement volumetrically, 8-11 in. slump, and 0 and 2 cycles of soaking. The statistical model developed to analyze the significance of variable effects included a three-way interaction between the explanatory variables. All three explanatory variables had a statistically significant effect on the grout compressive strength, but the effect of soaking was minimal and decreased as aggregate proportion decreased. This research also showed that lightweight grout, when prepared using aggregate proportion and slumps within the ranges suggested in American Society for Testing and Materials C476, reaches the required minimum 28-day compressive strength with a factor of safety of at least 2.7.

Master of Science / Department of Civil Engineering / Mustaque A. Hossain / Pavement preservation by adopting low-cost maintenance techniques is increasing among transportation agencies day by day. Chip seal, also known as seal coat, is widely used as a low-cost, thin surface treatment in preventive maintenance of asphalt pavements in many states, including Kansas. Loosening of aggregate particles from chip-sealed pavement and associated windshield damage to vehicles is a common problem. Thus the Kansas Department of Transportation (KDOT) uses lightweight aggregates as cover materials for chip seals. Although this has decreased windshield damage problems extensive chip loss on seal-coated pavements in the state has been reported. In this study, lightweight aggregates along with polymer-modified asphalt emulsion were used to determine proper aggregate and emulsion application rates to minimize chip loss in chip seals. Again, lightweight aggregates were studied in the laboratory to determine the effect of moisture content and electrical charge on chip loss. Evaluation of chip seal was performed by statistical analysis based on rutting potential, chip embedment, and retention. Results show that aggregate retention and embedment depth depend on aggregate-emulsion interaction, whereas rutting depends on the type of aggregate. Proper selection of aggregate and asphalt emulsion is important to maximize aggregate retention in chip seal. Chip loss also results from a lack of compatibility between the aggregate and asphalt emulsion. Results indicate that retention of aggregate depends on the prevailing charges of aggregate and emulsion particles. Moisture condition of the aggregate does not have any effect on chip loss. A new sweep test machine has been developed to assess chip loss, and it was found to be better than the sweep test currently recommended by the American Society for Testing and Materials (ASTM).

Within the framework of this Final Year Project in Mechanical Engineering an investigation is done for a Suitable Bonding Method for a Multi-Material Glove Compartment for Lightweight Design. The industrial partner of this Project is Swedfoam. Decreasing fuel consumption and lowering the carbon foot print for automobiles, lightweight construction is one of the key factors to achieve these regulations and more crucial these aims as future needs. Often a simple idea already has a great potential, such as replacing conventional materials with lighter ones in certain applications. Exactly this is done for the lid of a glove compartment; a metal plate, used as a core of the application beforehand is disposed and replaced with a composite, which decreases the weight of the lid significantly. A problem is faced with the new design of the inner lid of a glove compartment, because due to the lighter material the joining method is changed to bonding. Previously the bonding failed mainly due to temperature changes. A literature survey on the material data is done, as well as lab experiments on the used composite in order to characterize crucial material parameters required for the occurred problems when using bonding as joining method. The results from the experiments and literature survey are used to simulate different bonding methods with the commercial software Abaqus. Results from the simulation are presented using adhesive and tape as bonding methods. Finally it is shown, that it is most important for a successful bonding, where or respectively on which surfaces the bonding is done.

Problem Area With the introduction of the Bugatti Veyron in 2005, a new breed of sportscars was born: the hypercar. It was celebrated as a technological masterpiece, its todays hybrid counterparts, the McLaren P1, Ferrari LaFerrari and Porsche 918 Spyder were named the ‘holy trinity’ of sportscars. However, only a few hundreds of these cars will ever be built, and most enthusiasts will only be able to experience their performance in the virtual world in a racing simulator. The few lucky owners though face a similar problem: These machines are so fast and their traction limit is so high that they can hardly be driven flat-out on open roads, which turns many of them into a track-only toys or garage queens. Design process The design process used is fairly traditional, starting with a research phase, an ideation phase which is being followed by a refinement phase and ultimately the execution of the design in form of a physical scale model and digital renderings. However it needs to be stated that the availability of VR reviews already has a very positive impact on the design workflow. Many design solutions, ergonomics and proportions were modeled directly in 3D and immediately tested in VR, similar to a continously updated 1:1 clay model in the industry. Final result The final result is a lightweight sportscar that makes most out of its limited power resources. Not only does it use state-of-the art technologies and materials to be as efficient as possible, it also boosts the driving experience with several innovative design solutions. The styling is modern and in line with Porsche’s carefully developed current design DNA, but also links to the past. Connaisseurs of the Porsche heritage will find several references to models from the past, yet all these elements are respectfully interpreted in a contemporary yet timeless way. Other, more high-volume manufacturers also produce versions of their models with ridiculously powerful engines - similar to the era of the muscle cars in the late 60ies. In some cases, it seems that this is more of an engineers game of numbers, a marketing strategy or a method to please the ego of the companies’ board members. The fun of sportscar driving however is where the driver and or the machine reach their physical limits - in speed, revs, reaction time, grip and g-forces. Finding and riding along on this edge is the challenge of driving a sportscar, and this project claims that this can be brought back to a level that is far below that of hypercars. The challenge of this project is therefore to develop a car that can deliver an exciting, memorable driving experience with less financial, energy and material resources. At the same time, in an age of Uber, Lyft and the advent of autonomous vehicles, this car should attract younger customers to keep the following generations interested in the driving aspect of cars, a key factor in the emotionality that ultimately leads to higher profits for the manufacturer and above all, an exciting leisure time experience for the customer. Design process The design process used is fairly traditional, starting with a research phase, an ideation phase which is being followed by a refinement phase and ultimately the execution of the design in form of a physical scale model and digital renderings. However it needs to be stated that the availability of VR reviews already has a very positive impact on the design workflow. Many design solutions, ergonomics and proportions were modeled directly in 3D and immediately tested in VR, similar to a continously updated 1:1 clay model in the industry. Final result The final result is a lightweight sportscar that makes most out of its limited power resources. Not only does it use state-of-the art technologies and materials to be as efficient as possible, it also boosts the driving experience with several innovative design solutions. The styling is modern and in line with Porsche’s carefully developed current design DNA, but also links to the past. Connaisseurs of the Porsche heritage will find several references to models from the past, yet all these elements are respectfully interpreted in a contemporary yet timeless way.