M.S. - Civil and Environmental Engineering

Permanent URI for this collectionhttps://hdl.handle.net/10125/20031

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Random Parameter-Enabled Discrete Choice Model Development to Identify the Impact and Unobserved Heterogeneity among Contributing Factors to Animal-vehicle Collisions
(University of Hawaii at Manoa, 2022) Yu, Wanxin; Zhang, Guohui; Civil Engineering
Safety is one of the most important characteristics of transportation networks. It can be simply defined as arriving at the destination with no injuries, injuries and fatality. Analysis of the severity and the risk factors are used for influencing highway and vehicle designs, safety management on major roads of the transport network, and directing and implementing a wide variety of regulatory policies on injury prevention. Vehicle- animal collisions account for a large proportion of traffic accidents that occur every year. An estimated 1 million to 2 million crashes between motor vehicles and large animals such as deer occur every year in the U.S., causing approximately 200 human deaths, 26,000 injuries, and at least $8 billion in property damage and other costs. In rural states such as Wyoming, wildlife-vehicle crashes represent almost 20% of reported collisions. Therefore, the study of vehicle-animal accidents is of great significance to the analysis of traffic safety. There are many different models that we can use when analyzing traffic safety data. In this article, I used the multinomial logit (MNL) model for the analysis, and then I used the Mixed MNL method to get another result. The two results are analyzed and compared, and the final conclusion is drawn.
Numerical Load Testing of a Geosynthetic Reinforced Soil
(University of Hawaii at Manoa, 2016-12) Kaya, Landon
Geosynthetic reinforced soil (GRS) abutments have been increasingly used due to several advantages over traditional concrete abutment walls. Two notable advantages include: (1) Fast and cost-efficient method of construction due to the elimination of cast-in-place reinforced concrete abutments; and (2) Reduced carbon footprint due to less use of cement since cement production produces an enormous amount of carbon dioxide. GRS abutments have to be designed for settlement and bearing capacity. Available design procedures are often based on large scale load tests on GRS columns which is expensive and not routinely performed. Therefore, using a numerical model to simulate these load or performance tests would offer a more economical alternative. The FEMtij program was used for analyzing GRS load tests in 2-D and 3-D. In 2-D , the ideal constitutive models for the soil, CMU blocks, geotextile, and footing were the subloading tij, Drucker-Prager, linear elastic with post-yield softening, and linear elastic, respectively. Three factors that greatly affect the GRS capacity were investigated by performing a sensitivity analysis. These factors were the effects of soil-footing friction angle, the constitutive model of the CMU (Drucker Prager vs linear elastic), and the constitutive model of the geotextile (linear elastic with post-yield softening vs linear elastic). The 3D analyses were less successful, details of which can be found in the thesis. From the calculated 2D load-settlement and lateral displacement curves, and heat maps of shear strain, the following observations and conclusions were made: (1) The capacity of the GRS increased with increasing soil-footing friction angle. (2) Using a Drucker-Prager model for the CMUs caused the GRS to have a smaller capacity than if they were linear elastic. (3) Modelling CMU blocks with an elasto-plastic model is important due to some of the CMUs crushing during the performance tests. (4) By allowing the geotextiles to soften after exceeding its tensile strength, the GRS capacity was less than if the geotextiles were linear elastic. (5) It is important to model a softening geotextile because of the observed ripping of the geotextiles during the performance tests. (6) Shear bands were observed in the GRS columns. They are inclined at 45° and 50° to the horizontal for GRS columns without and with CMU blocks, respectively.
Design Guidelines for Impact Mechanical Frequency Up-Conversion Piezoelectric Energy Harvesters
(University of Hawaii at Manoa, 2016-12) Corr, Lawrence
Vibration energy harvesters based on the impact mechanical frequency up-conversion technique utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems tuned to efficiently convert mechanical energy to electrical energy. In order to design energy harvesters to take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the mechanisms of energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. The purpose of this work is to develop design guidelines for impact mechanical frequency up-conversion piezoelectric energy harvesters. The specific objectives are to develop guidelines for: • Maximum energy transfer from the impactor to high frequency system • High frequency system design to maximize energy generation from piezoelectric device • Impactor size and placement of high frequency system to maximize impactor / high frequency system interaction for a given excitation spectrum
Unconfined Compression Tests on Basalt Rocks from Hawaii
(University of Hawaii at Manoa, 2016-05) Yamada, Miles
Unconfined compression tests were performed on 66 basalt samples to obtain index properties and elastic constants. The samples were obtained from a boring drilled at the University of Hawaii at Manoa. These values were compared to results obtained from other studies to determine correlations and observe vertical trends at the site. Properties obtained from nondestructive tests on the basalt rocks included unit weight (oven-dried, saturated-surface-dry, and apparent), unit weight through the use of a CoreLok machine, absorption, RQD, and percent recovered. Properties obtained from compression tests included unconfined compressive strength, Young’s Modulus, axial strain at failure or at 50% of ultimate load, failure type, and failure plane angle to horizontal. The results indicate that there appears to be two different layers of rock at the location of the boring. There is an upper layer of rock characterized by lower unit weights, higher absorption and lower strength and stiffness, compared to the lower layer of rock. This points to significantly different rock types, probably from different lava flows with somewhat different original magma composition and viscosity. It is worth noting that RQD, percent recovery and axial strain do not show discernible distinctions between these two rock units and thus appear to be less useful as indicators of distinct rock units, at least as encountered at the site. Strong correlations were observed between absorption and unit weight, as expected. Strong correlations were also noted between the various unit weights and the results of the unconfined compression tests. In particular, there are reasonably strong correlations between index properties in terms of unit weight and absorption, and test results in terms of unconfined compression strength and stiffness. No discernible correspondence was observed between field parameters in terms of RQD, percent recovery or axial strain versus index parameters and strength test results.
Evaluation of GSSHA for Simulating Sediment Concentrations in Steep Hawaiian Watersheds
(University of Hawaii at Manoa, 2016-05) Nielson, Jeffrey
Physics-based hydrological models, like GSSHA, potentially have an accuracy advantage over empirical or semi-empirical models, when simulating processes in steep Hawaiian watersheds, which can be very dissimilar to lands (or field plot experiments) where the empirical relationships were developed. GSSHA, therefore, could potentially be a valuable tool for hydrology projects in Hawaii, but is seldom used in Hawaii. In this study, GSSHA was evaluated and used to predict streamflow and sediment concentrations in the upper region of Halawa watershed on leeward Oahu—a watershed with an average overland basin slope of 0.65—during single-event storms. Single-event simulations were the focus here, because of the importance of single-event storms to Hawaii’s sediment issues (other studies claim that a large portion of annual sediment flux occurs during low-frequency, high-magnitude storms). Streamflow and sediment concentration data collected at 15-minute intervals were used to calibrate and validate the simulations. Several case studies were developed to test findings from past studies, including the finding that GSSHA tends to over predict sediment for low-frequency, high-magnitude storms, when calibrated with only high-frequency, low-magnitude storms (as stated in the GSSHA manual). It was found that GSSHA becomes less accurate in sediment concentration predictions for low-frequency storms (>2-year recurrence interval) when calibrated with only high-frequency storms (<2-year recurrence interval). It is shown that the degradation in accuracy was likely a result of over prediction in streamflow. It was also found that GSSHA made more accurate predictions of streamflow when the validation storm events were similar to calibration events in rainfall duration, accumulation, and peak intensity, indicating that one set of calibration parameters may not be sufficient for all storm events. Distinctively, however, it is shown that one set of calibration parameters may be sufficient for all storm events for predicting sediment concentrations. GSSHA predicted sediment load with an 8.8% error for a validation storm six times larger (based on streamflow) than calibration. Additionally, in response to studies that have shown that many sediment transport equations over predict sediment flux in steep terrain by orders of magnitude, two sediment transport equations—Engelund-Hansen and Kilinc-Richardson—were tested and compared to determine which equation is better for steep terrain. It was found that the Engelund-Hansen equation consistently outperformed the Kilinc-Richardson equation, indicating that the Engelund-Hansen equation is a better choice for use in steep Hawaiian watersheds.
Designing High Performance Geopolymer Concrete Using Fly Ash and Slag
(University of Hawaii at Manoa, 2015-08) Li, Yanping
A fly ash-based geoploymer was studied as a potential alternative to traditional Portland cement since fly ash has significantly lower CO2 contribution than traditional cement production. The fly ash-based geopolymer was developed using fly ash, slag, and alkali solution, which when combined with aggregate produces a material that has high compressive strength, acceptable workability, and suitable setting time. The compressive strength and setting time of fly ash-based geopolymer paste/mortar were studied by varying the components of the alkali solution, slag replacement content, curing temperature, and liquid to binder ratio (L/B). The workability of the geopolymer paste/mortar was examined by introducing water and super plasticizer. The compressive strength development and cracking phenomenon of the geopolymer concrete were investigated by changing the L/B ratios and curing methods. The microstructural and mineralogical characteristics of geopolymer mortars were characterized using scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and Raman spectroscopy. Due to the complex reactions involved in geopolymer formation, hydroxide concentration and slag replacement percentage on setting time, 7-day and 28-day compressive strength. The results revealed that the compressive strength was dramatically enhanced by introducing slag into the fly ash-based geopolymer due to the formation of C-S-H and a large amount of geopolymer gel. In addition, the compressive strength was controlled by the [OH-] and [Si] concentrations of alkali solution. OH- accelerated the dissolution of glass, while silicate had a more complex role of maintaining the balance of species in solution. Elevated curing temperature resulted in higher compressive strength than room temperature. Higher compressive strength was obtained by using lower L/B ratio. The workability was controlled by L/B ratio and silicate concentration. The setting time was controlled by solution chemistry and slag content. The formation of C-S-H and geopolymer gel was confirmed using SEM/EDS and Raman spectroscopis analyses. The DOE results showed that: for setting time, [OH-], the interaction of [Si] and [OH-], and quadratic (second-order) effect of [Si] were considered significant; for 7-day compressive strength, only [Si], [GGBS/cem] and their interaction were considered significant, while [OH-] was considered not significant; for 28-day compressive strength, all factors appeared to be important.
Physically Distributed Modeling of the Manoa-Palolo Watershed for High Intensity Storms
(University of Hawaii at Manoa, 2015-05) Kumagai, Toru
The Manoa-Palolo watershed of Honoululu, Hawaii is very unique, as it is a small coastal tropical water basin consisting of short streams and steep slopes. There is very limited research that has been done concerning these types of watersheds especially with physically distributed hydrological models. This study was conducted using a physically distributed hydrological model, MIKE SHE, to evaluate the Manoa-Palolo watershed's susceptibility to flash floods and applicability of MIKE SHE for flood forecasting for high intensity short duration rainfall storm events. Modeling of the Manoa-Palolo Watershed was conducted utilizing data that was previously unavailable. The data includes high resolution DEM (10 m grid), high resolution land use data (10 m grid), historical 15 minute interval stream flow data, historical 1-hour rainfall accumulation radar imagery data (2 km x 2 km grid), and historical meteorological data. Calibration and validation of the model was conducted using radar imagery from the Molokai radar station and stream flow data obtained from gauges located within the study site. The model was calibrated and validated using historical storm events including the October 2004 Storm, and the March 2006 Storm. Model generated hydrographs were analyzed and compared to observed hydrographs collected during the storms in order to evaluate the performances of the radar precipitation data to the rain gage data. Additionally, the performances between high and low resolution DEM were compared in order to determine whether the highly variable slopes of the Manoa-Palolo watershed affected the higher resolution DEM model.
Period-one rotating solution of parametric pendulums by iterative harmonic balance
(University of Hawaii at Manoa, 2012-05) Zhang, Hui
In this study, an iterative method based on harmonic balance for the period-one rotation of parametrically excited pendulum is proposed. Based on the characteristics of the period-one rotating orbit, the exact form of the solution is represented using the Fourier series. An iterative harmonic balance process is proposed to estimate the coefficients in the exact solution form. The general formula for each iteration step is presented. The bounds of excitations required for period-one rotations and the convergence of the method are investigated. The method is evaluated using two performance indexes, i.e. system energy error and global residual error. The performance of the proposed method is compared with the existing perturbation method. The numerical results obtained from MATLAB© are used as the baseline of the evaluation.
Generalized processing of FBG/FRP strain data for structural health monitoring
(University of Hawaii at Manoa, 2012-05) Stockdale, Gabriel Lee
In order to promote the widespread application of sensor-based structural health monitoring (SHM) systems, complete and standardized systems need to be developed that are adaptable, can immediately begin to monitor the structure's performance to some degree, and be incorporated into the rehabilitation practices. The combination of fiber reinforced polymer (FRP) laminates and fiber Bragg grating (FBG) strain sensors have the potential to produce such a system for concrete structures. In this work, general processing procedures are developed that efficiently: (1) manage and process the recorded data; (2) ensure the recorded data is accurate and the sensors are working properly; and (3) monitor the limit states of the FRP laminates regardless of their application. The effectiveness of these procedures are then demonstrated through a case study involving the FBG instrumentation of a carbon FRP laminate rehabilitation applied to the Salt Lake Boulevard Bridge for shear strengthening.
Long wave run-up over submerged reef and breakwater
(University of Hawaii at Manoa, 2012-08) Shimabuku, Nathan Takayuki
In this thesis study, joint numerical and experimental studies were carried out to examine the effects that a submerged breakwater's length, distance from the beach and height have on the wave runup. The numerical program was based on a staggered grid leapfrog method on the shallow water equations which is used to simulate runup. Propagation over the reef is simulated with a predictor corrector Boussinesq scheme. We experimentally observed that a trend based on the wave's wavelength, length of the breakwater and lagoon spacing. We see that maximum and minimum runup reduction is observed at half integer and integer values of ζ and γ depending if the wave breaks. We define ζ and γ as the breakwater's lagoon spacing or the breakwater's length in terms of wavelength of the initial wave divided by the breakwater's height in terms of still water depth. We observed that the maximum runup reduction for a non breaking wave and minimum runup reduction for breaking waves were observed at half integer and integer values of γ. We also observed that if a breakwater is present the runup generated by waves can be reduced up to 40% but may be increased by 5%, with the exception of one measurement and that if wave breaking does occur the runup can be reduced by 80% and that it can be increased by 40%.
Prediction of chloride penetration rates in Hawaiian concrete in a marine environment
(University of Hawaii at Manoa, 2012-05) Ropert, Joshua Lee
A study was conducted to evaluate the chloride concentrations of reinforced concrete specimens exposed to a marine environment made with Hawaiian aggregates including various corrosion inhibiting admixtures and pozzolans intended to reduce the chloride penetration rates through the concrete and thus reducing the amount and rate of corrosion of the reinforcing steel therein. Field panels were constructed and placed at Pier 38 in Honolulu Harbor on the island of Oahu in 2002 and 2003 and first sampled for chloride concentrations in 2004 from a previous phase of this overall study. Additional collected samples from 2006 and 2008 were also included in this study. The corrosion inhibiting admixtures included in the field panel mixtures were Darex Corrosion Inhibitor (DCI), Rheocrete CNI, Rheocrete 222+, FerroGard 901, Xypex Admix C-2000, latex modifier, and Kryton KIM. The pozzolanic admixture materials included fly ash and silica fume. The focus on this study was to compare the chloride concentration results from the field panels to that of the computer program Life-365 which is designed to predict chloride concentrations in reinforced concrete. This report limited the analysis of the admixtures to DCI, Rheocrete CNI, Rheocrete 222+, fly ash and silica fume as these are the only admixture options currently available in the Life-365 software. Modified parameters were needed for all of the predicted chloride concentrations of Life-365 as most of the program default parameters overestimated the concentrations through the depth of the specimen when compared to the field panel results. The predicted chloride concentration results were best for the silica fume admixture. In addition, the final half-cell results for the selected admixtures previously listed along with each corresponding visual observation of the field panels were included in this report to provide conclusions to the performances of the concrete constituents included in the field panels. Generally, concrete mixtures with a lower water-cement ratio performed better than those made with higher ratios as concluded from the control panels. The calcium nitrite type admixtures, CNI and Rheocrete CNI, indicated better performance to corrosion resistance with a higher dosage of 4 gal/yd³ compared to the mixtures with 2 gal/yd³. The replacement of 15% fly ash with cementitious materials performed the best and gave the most consistent results. Both the final half-cell readings and visual observations concluded that corrosion was least probable in the field panel. The panels including the remaining admixtures, Rheocrete 222+ and silica fume, exhibited inconsistent results.
Material characterization in support of implementation of the mechanistic-empirical pavement design guide
(University of Hawaii at Manoa, 2012-08) Rayapeddi Kumar, Jayanth Kumar
Use of the Mechanistic-Empirical Pavement Design Guide (MEPDG) and its associated software requires a large number of inputs about traffic loading, environmental conditions, and material characteristics. Except for very important projects, for which many of the material characteristics may be determined directly from laboratory tests, practical implementation of the MEPDG for routine pavement design projects requires the development of a database containing properties for the most commonly used materials within the state. In the analysis of flexible pavements in the MEPDG, the dynamic modulus (|E*|) and resilient modulus (Mr) are the primary input parameters used to characterize the elastic response of Hot Mix Asphalt (HMA) mixtures and base course (unbound granular) materials, respectively. In addition to the elastic properties of the materials used in the mechanistic analysis of the pavement structures, the MEPDG relies on deterioration model parameters to relate empirically the mechanistic pavement responses (strains) on different points of the pavement structure to distresses such as rutting (permanent deformation), cracking, and roughness. This study focuses on measuring in the laboratory the resilient moduli of two types of base course materials and the elastic and permanent deformation characteristics of three types of HMA materials. The continuous demand of aggregates for maintenance and rehabilitation (M&R) of existing pavements and to a lesser degree for construction of new ones as well as the increasing need to reduce the disposal of construction waste is putting pressure on agencies to find ways to increase the recycling of materials such as Recycled Asphalt Pavement (RAP) into the pavement structure. Experiences around the world indicate that Foamed Asphalt (FA) base course mixtures, which are a typically produced by stabilizing Reclaimed Asphalt Pavement (RAP) with foamed (expanded) asphalt, have shown improved performance relative to unbound base materials. Hence in this study, one of the base materials considered is a Foamed Asphalt (FA) base mixture. The other base material studied is a virgin aggregate base course material. The resilient moduli of both materials were studied at different density levels. The results of the study showed that the Mr of FA mixtures is in general between 2.5 and 5 times (corresponding to lowest and highest levels of bulk stress respectively) higher than the Mr of virgin aggregates (Type B) at 98% and 100% of maximum dry density, whereas at 102% of maximum dry density, the Mr of FA mixtures is in general between 2.8 and 1.8 times of maximum dry density (corresponding to lowest and highest levels of bulk stress respectively) higher than the Mr of virgin aggregates. Further, it was observed that the Mr of FA mixtures increased with increases in bulk stress, and the Mr decreased with increases in octahedral shear stress. On the other hand, the Mr of the virgin base course material increase mostly with the octahedral shear stress and to a much lesser degree also increased with the bulk stress. For HMA, this study focuses on comparing the test results of dynamic modulus and permanent deformation tests performed in the laboratory on unmodified, polymer modified asphalt (PMA) mixes (modified with Elvaloy RET©) , and mixes reinforced with FORTA fibers. The laboratory experiments included testing two replicates of HMA specimens of each type at three target air voids. The results of the tests show that the mixes prepared using the PMA binder show relatively better resistance to rutting at high temperatures and low frequencies. For the mixes prepared using fibers, it was observed that the rate of failure in a permanent deformation test remains relatively constant irrespective of the of air voids of the specimen. The effect of the fibers is to hold the coated particles together under these unfavorable conditions, thus providing a level of safety for mixes compacted with high air voids.
Verification of fuse connector performance for hybrid masonry seismic structural systems
(University of Hawaii at Manoa, 2012-05) Mitsuyuki, Steven Satomi
In steel construction, there are various seismic structural systems that have been successfully utilized in the past including eccentric and concentric braced frames and moment frame systems. When these systems are used, the building envelope between structural members is filled with architectural components such as masonry infill walls, which are only expected to carry out of plane loads, such as wind, on each individual wall panel. Hybrid masonry is a relatively new type of structural system which incorporates the masonry infill walls within steel frames into the structural system to resist lateral loads imposed on the structure. This research represents the third phase of testing at the University of Hawaii at Manoa (UHM) and is part of an ongoing project funded by the National Science Foundation (NSF) and Network for Earthquake Engineering Simulation Research (NEESR) to investigate the applicability of hybrid masonry as an adequate structural system. In phases I and II of hybrid masonry connector plate development research at UHM, a wide variety of connector designs were explored to determine the positive and negative aspects to different fuse and link connector plate designs and connection methods. Fuse connector tests demonstrated the viability of tapered fuses to dissipate large amounts of energy during cyclic loading. These tests also showed that various practical connector orientations and methods can be applied for hybrid masonry connectors, particularly the straight bolted side plate connection. In addition, during phase I of testing, a series of bolt push out tests were performed to determine the shear strength of post-installed through-bolts in masonry. Observations from the first two phases of testing were used as a guide for selecting 4-inch and 6-inch tapered fuse designs for testing on partially grouted and fully grouted masonry wall specimens. Multiple pairs of both tapered fuse connectors were slip-critically bolted to side plates, which were welded to a steel beam above the masonry wall specimens. These tests were performed to verify that the behavior of multiple pairs of connector plates in series is similar to the behavior of the individual pairs of connector plates. In addition, the tests were performed to observe the interaction between the steel connector plates and masonry wall specimens. Based on numerous observations and results in this phase of testing, the design of Type I hybrid masonry connections was improved. The fuse connector tests showed that the strength and behavior of multiple pairs of fuse connectors can be approximated by designing a single connector plate and multiplying the single plate's capacity by the number of connector plates used. These fuse connectors displayed the capability of dissipating large amounts of seismic energy before failure. Based on the results of these connector subassembly tests, recommended design procedures for connector plates were modified. Both masonry walls failed by means of shear friction at the location of the joint between the masonry and concrete slab. The results from UHM's testing will guide the development of full-scale two-story hybrid masonry test frames which will be tested at the University of Illinois Urbana-Champaign.
Chlordane and dieldrin contamination and biodegradation in Ala Wai Canal sediment
(University of Hawaii at Manoa, 2012-05) Lee, Cindy Mun Yee
The objectives are (1) investigate the contamination levels of chlordane and dieldrin both horizontally (i.e. at different locations of the Ala Wai Canal) and vertically (i.e. at different depth in the sediment) in Ala Wai Canal sediment, and (2) determine whether or not chlordane in Ala Wai Canal sediment can be biodegraded. Objective 1 was accomplished by collecting sediment core samples at various locations along the Ala Wai Canal and the concentrations of chlordane and dieldrin were quantified for each sampling location to formulate a concentration profile. Objective 2 was accomplished by performing laboratory microcosm experiments with Ala Wai Canal sediment spiked with chlordane.
Geometric Effects on Maximum Power Absorption Efficiency for a Single, Two-Dimensional Heaving Body
(University of Hawaii at Manoa, 2012-08) Hager, Rachael Elizabeth
Numerical simulations are carried out to study the effects of body geometry on maximum power absorption efficiency. Diffraction theory is used to study two-dimensional, single, surface-piercing, heaving bodies impinged by regular, harmonic, linear waves. The complex amplitude of the excitation force in the heave direction is calculated numerically using AQWA. Additionally, a wave flume experiment is proposed to measure the complex amplitude of the excitation force in the heave direction, in order to study the maximum power absorption efficiency. From the complex amplitude of the excitation force (Xi), the radiated wave amplitudes at positive infinity (α+) and negative infinity (α-) are calculated using: Xi = 2pAagCgi---------------w The maximum power absorption efficiency for a given frequency is then calculated using: ^ = |a+|2---------|a+|2+|a_|2 The radiated wave amplitude at positive infinity is calculated from the amplitude of the excitation force as a wave impinges the curved face of the body. Rotating the body 180° and measuring the amplitude of the excitation force yields the radiated wave amplitude at negative infinity. Results indicate concave bodies experience the greatest excitation force and convex bodies yield the higher maximum power absorption efficiency, under the condition that the wavelength is relatively short and the draft and waterline cross-sectional area remain constant. For long waves, the geometric effect becomes insignificant.
Assessment of traffic impact studies on Oahu between 1976 and 2002
(University of Hawaii at Manoa, 2012-05) Caroee, Maja
Traffic forecasting is an essential part of project development. The impact that forecast traffic has on infrastructure planning and design is essential for project approval. Since population, employment and tourism are projected to grow by 17%-25% on Oahu over the next 25 years, the need for further development is clear. So the key question is: Can decision makers rely on project traffic forecasts? Previous studies showed large inaccuracy in traffic forecasting, 50% of all megaprojects have inaccuracies larger than ±20%, and 25% of all megaprojects have inaccuracies larger than ±40%. In a U.S. study of roadways the inaccuracies were not as large, 72.4% of all road segments analyzed were within ±0.5% accuracy; the remaining 27.8%% were either over-or underestimated. These studies showed major problems with forecasting accuracy. The analysis herein compared forecasted traffic levels from Traffic Impact Analysis Reports, available through the Hawaii Department of Health, to actual traffic volumes recorded by the Hawaii Department of Transportation to assess traffic forecasting accuracy on Oahu between 1976 and 2002. Information extracted from the EIS and TIAR included: year of EIS, consultant, type of project, location, movement, forecast horizon, forecasted traffic volumes and forecasting method. This study focused on road and residential developments on Oahu and attempted to answer questions such as: Do forecasts show an accurate picture of future traffic demand, both related directly to a specific project and the affected region? Do forecasts provide a "picture perfect" view of future conditions in order to get the projects approved? Is traffic forecasting on Oahu conservative or optimistic? Do forecasts vary by type of development? What is the effect of the forecast horizon? What is the effect of background growth extrapolations? The analysis is split into three components: Illustrative analysis, quantitative analysis, and a three-way comparison among (1) Flyvbjerg's study of more than 200 megaprojects across the world, (2) a study conducted in Minnesota by Parthasarathi and Levinson on post-construction evaluation of traffic forecast accuracy, (3) and the results of this analysis. The analysis of Oahu data shows a tendency towards overestimation of traffic forecasts. The average overestimation is 35% or more than one third of the forecast volume. Fourteen out of the 37 cases, or 38%, were underestimated: nine cases with an error of greater than-20%, two cases with an error of greater than-40% and three cases within the-60% to-40% range. The findings of this study differ greatly from the two studies it is compared to. The study of mega-projects world-wide shows a tendency towards overestimation, the study of traffic accuracy in Minnesota shows very accurate forecasting volumes. There are several reasons for inaccuracy in traffic forecasting, such as inappropriate forecasting models, the assumptions and growth rates used as input into the models, the large uncertainties associated with green field developments, bias for or against projects and lack of an evaluation and adjustment process.
Hybrid masonry connector plate and headed stud small-scale wall testing
(University of Hawaii at Manoa, 2012-12) Aoki, James Mitsunori Katsuki
Hybrid masonry is a new seismic structural system which involves structural steel frames with concrete masonry unit (CMU) walls. The CMU walls serve as shear walls to replace traditional steel bracing. They have different functions depending on the type of hybrid masonry. The CMU walls are either used to transfer only lateral loads through the height of the structure or lateral and gravity loads. Type I Hybrid Masonry uses the CMU walls to resist only in-plane lateral loads. In Type II Hybrid Masonry the CMU walls are also used to support vertical loads. Using the CMU walls as a gravity member, the steel beams in the frames can be reduced resulting in a lower construction cost. In Type III Hybrid Masonry the CMU walls act as the web of a composite shear wall with the steel columns as boundary elements for columns. Drs. Ian Robertson and Gaur Johnson, along with graduate student researchers Seth Goodnight, Reef Ozaki-Train, and Steven Mitsuyuki have designed and tested prospective connector plates to develop connectors that can transfer lateral loads. The first type tested was the ductile fuse connector, which was designed to transfer many cycles of lateral load for Type I Hybrid Masonry. During cycling, the fuse connector plates dissipated energy caused by the simulated seismic activity. The fuse connector possessed the capability to dissipate large amounts of energy and allowed relatively large deflections without damaging the CMU wall. This ductility is an advantage because only the fuse connector plates must be replaced after a seismic event. The second type of connector that was tested was a link plate, which was designed as a uniform plate with no fuse section. These link plates were designed to transfer higher lateral loads than the fuse connector. Rather than allowing large displacements by yielding, this connector plate provided a rigid system that transferred the lateral loads to the CMU infill wall which must be designed for ductile response. In Type I Hybrid Masonry the transfer of in-plane shear from the fuse or link plates to the CMU panel utilizes bolts which pass through the CMU wall and vertical slotted holes in the connector plates on either side of the wall. These through bolts must not be the weak link in the Hybrid Masonry system since failure of the bolts in shear or masonry break-out could represent a non-ductile response that is not suitable for seismic design. This report presents the results of eleven bolt push-out tests were performed on six 8" thick grouted CMU walls to evaluate the performance of the through bolts. Based on these tests a number of conclusions were drawn and recommendations are provided for design of through bolted connections. Type II Hybrid Masonry utilizes headed studs to transfer shear from the steel floor beam to the CMU shear panel below. Type III Hybrid Masonry utilizes headed studs to transfer shear from both the steel floor beam and the columns to the CMU shear panel. Three fully grouted 8" thick CMU walls were tested to evaluate the performance of headed studs at different spacings in these connections. In all cases, the headed studs were ¾" diameter by 6" long, welded to the bottom of the floor beam bottom flange. They were embedded in a 9" high by 7-5/8" thick grout beam on top of the 8" CMU wall. The top course of the CMU wall was a bond beam with one #4 bar and the wall vertical reinforcement consisted of #4 bars at 24" on center. Conclusions and + recommendations are presented based on the results of these tests.
License plate survey for traffic analysis: improving accuracy with correction algorithms
(University of Hawaii at Manoa, 2012-05) Abrishamkar, Alireza
Vehicle tracking methods are widely used for a variety of purposes including collection of travel time and duration of stay data. The collected data are used for planning and management purposes. The type of data depends on the method of data collection. Tracking methods are usually classified into active and passive. In this research they are classified into two categories, discrete and continuous. Among all methods, the discrete method of license plate matching is the most prevalent for data collection. The purpose of this research is to discuss the accuracy of manual license plate matching method for vehicle tracking and travel time data collection, and provide correction algorithms to improve the results. The impacts of recordation style and visual similarities between characters (letters and numbers) on the matching errors are investigated. The correction algorithms are compared and evaluated. The application of correction algorithms--specifically those that are more constrained to filter out false matches--can considerably increase the percentage of matched license plates. To a lesser degree, this processing can improve the statistical values of the license plate datasets such as average, standard deviation and median of travel time and duration of stay in a location. This study also found evidence that a significant portion of mistakenly recorded letters while recording the license plates are visually similar letters, that by itself underlines the human factor in the accuracy of the method. Digits are not significantly probable to be mistaken because of their visual dissimilarity. The workload of recordation is also proved to be significant: more letters to be recorded results in more errors.
Impact of water eutrophication on bacterial indicator organisms occurrence and survival
(University of Hawaii at Manoa, 2014-08) Ferrufino, Alejandra Cecilia
Fecal contamination in water sources is measured and monitored by fecal indicator bacteria (FIBs) put in regulation under the recreational water quality criteria by the Environmental Protection Agency (EPA). This study tests for the extended survival and possible replication of FIBs in marine and freshwater environments and in laboratory microcosms. Three separate studies testing the survival of FIBs were performed in the length of this report. Beach sand and aquatic vegetation were collected from Waialae Beach Park, and were used in beach sand microcosms to test FIB survival and die-off under the influence of nutrient input from aquatic vegetation. The samples collected were divided into different sand microcosms with different vegetation nutrients in order to test their impact on the concentration dynamics of Enterococcus faecalis and Clostridium perfringens. A second study that tested the survival of FIBs in two freshwater ponds was performed at the University of Hawaii Krauss Hall pond and Japanese Garden Pond. The ponds were tested for the trophic level index (phosphorous, nitrogen and algae concentration) and enterococci and Escherichia coli concentrations in the span of five months. In addition to investigating the survival on the FIBs in the ponds, microcosms were set up in a controlled laboratory environment to test for die-off rate of enterococci and E. coli in three different trophic states: oligotrophic, mesotrophic, and eutrophic. All experiments performed during the study show that FIBs have a longer survival rate and replication when aquatic vegetation is present in the environment. The bacterium feed from the nutrients present in aquatic plants and use the vegetation as protective shields from environmental hazards such as UV light.
Evaluating the Effect of Oʻahu Climate Data on MEPDG Distress Predictions
(University of Hawaii at Manoa, 2014-05) Perrett, Matthew Kenneth
The purpose of this project was to create new climatic data files for Oʻahu that represent the variation of conditions found on the island, and determine if the use of these files has any significant impact on distress predictions using the Mechanistic Empirical Pavement Design Guide (MEPDG). The Enhanced Integrated Climatic Model (EICM), used by the MEPDG to predict the climatic effects on material properties, cannot accept missing values in the hourly datasets; therefore, Amelia II was used to perform a multiple imputation analysis on the weather data that was collected. MEPDG runs were conducted with both the default climate file and the new climate files; the impact of these new files on the top-down fatigue cracking, bottom-up fatigue cracking, and rutting predictions was evaluated. It was found that, while most of the stations predicted similar levels of distresses, the climate station using data from Wheeler Army Air Field had consistently slower distress predictions. The primary cause of this was the consistently lower temperatures measured at this station compared to the others. While differences in precipitation amounts had a quantifiable impact on the resilient modulus of the subgrade, the precipitation data from each station were too low to have a significant impact on the final prediction results. Ultimately, it was determined that while Oʻahu's climate is not as variable as most areas in the United States, the climate variation found in different parts of the island can play a significant role in the prediction of pavement distresses; thus, the development of additional climate station files is warranted.

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