Identifying Sensitive Structural and Hydraulic Parameters in a Bridge-Stream Network Under Flood Conditions

The interactions between rivers, surrounding hydrogeological features, and hydraulic structures such as bridges are not wellestablished or understood at the network scale, especially under transient conditions. The cascading effects of local perturbations up- and downstream of hydraulic structures may have significant and far-reaching consequences, and therefore often cause concern among stakeholders. Tropical Storm Irene resulted in hundreds of millions of dollars in losses to infrastructure and property in Vermont, including damage to or failure of over 300 bridges, and considerable stream restoration efforts thereafter. Climate data show that the state is experiencing more frequent and persistent precipitation events, a trend that is predicted to continue. The replacement or re design needed for hundreds of existing bridges to meet the rigorous hydraulic standards imposed by extreme flood events is likely not a viable proposition. Moreover, the up- and downstream impacts of modification of a single structure may extend much farther than anticipated, especially in extreme events. This work presents a framework and methodology to perform such a network-level bridge resiliency analysis beyond detailed characterization of site-specific bridge-stream interactions. The stretch of the Otter Creek from Rutland to Middlebury, VT is used as a test bed for this analysis. A two-dimensional hydraulic model is used to elucidate the impact of individual structures on the bridge-stream network, as well as potential sensitivity to those impacts, during extreme flood events. Depending on their characteristics, bridges and roadways may either attenuate or amplify peak flood flows up- and downstream, or have little to no impact at all. Likewise, bridges may or may not be sensitive to any changes in discharge that result from perturbation of existing structures. Alterations to structures that induce substantial backwaters may result in the most dramatic impacts to the network, which can be either positive or negative. Structures that do not experience relief (e.g., roadway overtopping) may be most sensitive to any network perturbations

Simulation Exploration of the Potential of Connected Vehicles in Mitigating Secondary Crashes

Secondary crashes (SCs) on freeways are a major concern for traffic incident management systems. Studies have shown that their occurrence is significant and can lead to deterioration of traffic flow conditions on freeways in addition to injury and fatalities, albeit their magnitudes are relatively low when compared to primary crashes. Due to the limited nature of crash data in analyzing freeway SCs, surrogate measures provide an alternative for safety analysis for freeway analysis using conflict analysis. Connected Vehicles (CVs) have seen compelling technological advancements since the concept was introduced in the 1990s. In recent years, CVs have emerged as a feasible application with many safety benefits especially in the urban areas, that can be deployed in masses imminently. This study used a freeway model of a road segment in Florida’s Turnpike system in VISSIM microscopic simulation software to generate trajectory files for conflict analysis in SSAM software, to analyze potential benefits of CVs in mitigating SCs. The results showed how SCs could potentially be reduced with traffic conflicts being decreased by up to 90% at full 100% composition of CVs in the traffic stream. The results also portrayed how at only 25% CV composition, there was a significant reduction of conflicts up to 70% in low traffic volumes and up to 50% in higher traffic volumes. The statistical analysis showed that the difference in average time-to-collision surrogate measure used in deriving conflicts was significant at all levels of CV composition

The logistics contribution to the Port of Lisbon competitiveness

Today, maritime freight transport is a keystone on foreign trade between countries as well as in the world economy. This is a main engine of economic activity and in this case, is what allows globalization to arrive in every corner of the planet. A major percentage of world trade is done by sea and the cargo is maneuvered in ports, all around the world which in turn increases the economic and strategic relevance of maritime transport. Portugal is a country with an extraordinary maritime potential, for the development of activities related to sea shipping. Currently, maritime transport is developing faster in other regions of the world, namely in the Pacific (Southeast Asia), which are currently considered to be more competitive than other parts of the world. This research builds a theoretical framework regarding Portuguese ports and focuses on the future of the port of Lisbon. The adopted methodology will consist on a study and analysis, focused on the investigation of the competitive environment, factors of port competitiveness, and an analysis of how on a future we can increase the competitiveness of this port infrastructure. The present work will show that the interests of land and sea stakeholders are different because they have different expectations evidenced by their customers. The relationship between them is not always easy because when one side is affected, the other side will see the impacts, by causing serious imbalances in port activity and in order to prevent that, articulation and integration in terms of supply-chain and logistics is one of the objectives of this dissertation.Na atualidade, o transporte marítimo de mercadorias é uma pedra basilar no comércio externo dos Estados, assim como na economia mundial, caracterizando-se como um dos principais motores da atividade económica e neste caso o que permite a globalização. Um valor significativo do comércio mundial de mercadorias é feito pelo mar e manobrado nos portos de todo o mundo o que por sua vez aumenta a relevância económica e estratégica do transporte marítimo. Portugal é um país rico em potencial económico marítimo, para o desenvolvimento de quaisquer atividades que tenham no mar a sua base. Atualmente, o transporte marítimo está a deslocar-se para outras regiões do mundo, nomeadamente a bacia do pacífico, sendo estas consideradas atualmente como as mais competitivas. A investigação incluirá um enquadramento teórico sobre a temática dos Portos, por forma a ampliar o conhecimento e um estudo aprofundado do ponto de vista da logística, sobre o Porto de Lisboa . A metodologia adotada consistirá no estudo e análise, focado na investigação do ambiente competitivo, fatores de competitividade portuária, e uma análise sobre de que forma futuramente podemos aumentar a competitividade do Porto. O presente trabalho irá demonstrar que os interesses dos Stakeholders do mar e da terra são distintos, porque têm expectativas diferentes face aos resultados evidenciadas pelos seus clientes finais. O relacionamento entre eles nem sempre é fácil porque, quando um lado é afetado, o outro lado sente os impactos, causando sérios desequilíbrios na atividade portuária. A articulação e a integração em termos de logística e cadeia de abastecimento é um dos objetivos da presente dissertação, prevenindo a situação descrita anteriormente

PERFORMANCE ANALYSIS OF UNSIGNALIZED INTERSECTIONS AND ROAD SECTIONS USING VISSIM SOFTWARE

The Kodim intersection is one of the intersections at Jalan Raya Sawangan. Identifying vehicle traffic, performance, and potential remedies at the Kodim intersection and Jalan Raya Sawangan was the goal of this study. The information gathered from the survey results, the research technique employs a strategy from the PKJI (Pedoman Kapasitas Jalan Indonesia) and a simulation utilizing the PTV Vissim program. Based on the results of data analysis and processing, the busiest traffic flow at the Kodim intersection occurred on Weekday at 17.30–18.30 WIB with a degree of saturation value of 1,391 and the LoS value is F. Analysis of the road section also obtained the largest volume of vehicles on Weekday at 17.15–18.15 WIB, the degree of saturation value is 1.49, so the Los value is F. By carrying out several repair solutions, the best service level value is obtained for the repair solution by making a flyover. The solution of making a flyover produces a degree of saturation value of 0.382, so that the Level of Service (Los) value of the intersection is obtained at level B. The resulting degree of saturation value is below 0.85, as required in the PKJI 2014

Populations of Phaeophyscia leana (Tuck.) Essl. within the Ohio River Basin

Phaeophyscia leana (Tuck.) Essl., an endemic North American lichen species presently known to occur only within the Ohio River basin, is state-endangered in Illinois and a potential candidate for the Federal Endangered Species list. Since it utilizes periodically inundated corticolous substrates associated with river channels, oxbow lakes, and sloughs, this imperiled lichen is sensitive to landuse patterns within river floodplains. Surveys for P. leana were conducted to recensus previously documented populations, thereby assessing their stability, and to identify additional populations within the Ohio River Basin. Watercraft surveys were conducted on the Little Wabash River, from Carmi to New Haven, Illinois, and on the Wabash River from Darwin, Illinois, to the terminus at the Ohio River. Watercraft surveys resulted in the discovery of five new populations of P. leana, two in Illinois and three in Indiana, all of which were located south of Illinois State Route 141. Land-based surveys in Illinois identified new populations within the floodplain formed at the confluence of the Wabash and Ohio Rivers in Gallatin County and within the Black Bottom of Massac County. Nine large oxbow lake communities and backwater slough channels were found to support populations of P. leana within the Gallatin Bottoms which is the population center for P. leana in Illinois. Additions to the Illinois core site list include large populations at Fehrer Lake, Big Lake, and Saline Mines, all within the Gallatin Bottoms floodplain. Watercraft reconnaisance of the Wabash River and Ohio River floodplains (the Big Rivers Region) in Indiana led to the discovery of P. leana populations in Posey, Spencer, Perry, Crawford, and Switzerland County, Indiana, as well as a population in Trimble County, Kentucky. The population located at Vevay, Indiana, in Switzerland County is the closest documented population to the type locality near Cincinnati, Ohio. Land-based surveys conducted in the Hoosier National Forest and the Harrison-Crawford State Forest elucidated the only core site in Indiana, the Mano Point population, near Derby. A population was also discovered in Tennessee at the Hartsville boat launch on the Cumberland River (Old Hickory Lake). Core sites in Tennessee include the Hartsville population as well as populations discovered by Loy R. Phillippe on the Caney Fork River near Hell Bend (downstream from Carthage) and below the Center Hill Dam located on Wolf Island. A total of six core sites were located in this survey and eighty-five positions, where P. leana was observed growing, were recorded with UTM coordinates

Populations of Phaeophyscia leana (Tuck.) Essl. within the Ohio River Basin

Phaeophyscia leana (Tuck.) Essl., an endemic North American lichen species presently known to occur only within the Ohio River basin, is state-endangered in Illinois and a potential candidate for the Federal Endangered Species list. Since it utilizes periodically inundated corticolous substrates associated with river channels, oxbow lakes, and sloughs, this imperiled lichen is sensitive to landuse patterns within river floodplains. Surveys for P. leana were conducted to recensus previously documented populations, thereby assessing their stability, and to identify additional populations within the Ohio River Basin. Watercraft surveys were conducted on the Little Wabash River, from Carmi to New Haven, Illinois, and on the Wabash River from Darwin, Illinois, to the terminus at the Ohio River. Watercraft surveys resulted in the discovery of five new populations of P. leana, two in Illinois and three in Indiana, all of which were located south of Illinois State Route 141. Land-based surveys in Illinois identified new populations within the floodplain formed at the confluence of the Wabash and Ohio Rivers in Gallatin County and within the Black Bottom of Massac County. Nine large oxbow lake communities and backwater slough channels were found to support populations of P. leana within the Gallatin Bottoms which is the population center for P. leana in Illinois. Additions to the Illinois core site list include large populations at Fehrer Lake, Big Lake, and Saline Mines, all within the Gallatin Bottoms floodplain. Watercraft reconnaisance of the Wabash River and Ohio River floodplains (the Big Rivers Region) in Indiana led to the discovery of P. leana populations in Posey, Spencer, Perry, Crawford, and Switzerland County, Indiana, as well as a population in Trimble County, Kentucky. The population located at Vevay, Indiana, in Switzerland County is the closest documented population to the type locality near Cincinnati, Ohio. Land-based surveys conducted in the Hoosier National Forest and the Harrison-Crawford State Forest elucidated the only core site in Indiana, the Mano Point population, near Derby. A population was also discovered in Tennessee at the Hartsville boat launch on the Cumberland River (Old Hickory Lake). Core sites in Tennessee include the Hartsville population as well as populations discovered by Loy R. Phillippe on the Caney Fork River near Hell Bend (downstream from Carthage) and below the Center Hill Dam located on Wolf Island. A total of six core sites were located in this survey and eighty-five positions, where P. leana was observed growing, were recorded with UTM coordinates

Simulating hydraulic interdependence between bridges along a river corridor under transient flood conditions

The interactions between rivers, surrounding hydrogeological features, and hydraulic structures such as bridges are not well-established or understood at the network scale, especially under transient conditions. The cascading hydraulic effects of local perturbations up- and downstream of the site of perturbation may have significant, unexpected, and far-reaching consequences, and therefore often cause concern among stakeholders. The up- and downstream hydraulic impacts of a single structural modification may extend much farther than anticipated, especially in extreme events. This work presents a framework and methodology to perform an analysis of interdependent bridge-stream interactions along a river corridor. Such analysis may help prioritize limited resources available for bridge and river rehabilitations, allow better-informed cost/benefit analysis, facilitate holistic design of bridges, and address stakeholder concerns raised in response to planned bridge and infrastructure alterations. The stretch of the Otter Creek from Rutland to Middlebury, VT, is used as a test bed for this analysis. A two-dimensional hydraulic model is used to examine the effects individual structures have on the bridge-stream network, particularly during extreme flood events. Results show that, depending on their characteristics, bridges and roadways may either attenuate or amplify peak flood flows up- and downstream, or have little to no impact at all. Likewise, bridges may or may not be sensitive to any changes in discharge that result from perturbation of existing structures elsewhere within the network. Alterations to structures that induce substantial backwaters may result in the most dramatic impacts to the network, which can be either positive or negative. Structures that do not experience relief (e.g., roadway overtopping) may be most sensitive to network perturbations

Delay-based Performance Analyses Of Four-legged Signalized Intersections: A Case Study

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2014Thesis (M.Sc.) -- İstanbul Technical University, Instıtute of Science and Technology, 2014Önümüzdeki çalışmada ortalama taşıt başına gecikme seç timiz örnek kavşakların çalışma durumunu yansıtmak için kullanılmaktadır.  Gecikme sürücünün arzu ettiği ve gerçekte yaşadığı yolculuk zamanların arasındaki fark olarak tanımlanır. Bu çalışmanın yapılmasında İstanbul’daki Pendik mahallesinde olan iki dört kollu ışıklı kavşak örnek olarak alınmıştır. Biran önce 7:00-10:00, 12:00-14:00 ve 16:30-19:30 Saatlar arasında kamera ile çekim yapılmıştır. Sonra kamera görüntüleri bilgisayar ortamına aktarılıp ve bunlar üzerinden türel ayrımı yaparak 15’r dakikalık zaman dilimleri halinde her yöne giden trafik hacimleri belirlenmiştir. Bu bilgiler ışığında her kol da ve her akım için en fazla taşıt bulunan saat zirve saat olarak tanımlanmıştır. Sonra, zirve saat faktörü (ZSF) zirve saat hacmin akım değerine bölerek her kol için elde edilmişte.  Zirve saat faktörün kullanarak her kol için düzeltilmiş hacim hesaplanmıştır. Sonunda bu akım değerleri VISSIM’e aktarılıp ve oluşturdumuz benzetim model bu verilere göre kalibre edilmiştir. Kalibrasiyon süreci modelin gerçeke yakın çalışmasın sağlar ve sonuçta elde edilmiş sonuçlara daha fazla güvenile bilir. Bu çalışmada kalibrasiyon araç sayısına göre tüm kollarda yapılıp ve benzetim modelin gerçeğe ne kadar yaklaştığı GEH değeri ile ölçülmektedir. Benzetim kalibrasiyonu yapıldıktan sonra elde edilen akım değerleri kayıt edilip ve bu çalışmanın tüm yöntemlerinde akım değeri olarak kullanılmaktadır.  VISSIM’de elde edilen veriler ışığında Amerikan (HCM) ve Avusturalya (Akçelik) yöntemlerin kullanarak seçtimiz kavşakların performansı belirlrnmektedir. Aslında genel Avustralya ve HCM yöntemleri VISSIM’in dinamik yöntem ile karşılaştırılmıştır. Sonunda bu yöntemlerden elde edilen sonuçlar birbiri ile karşılaştırılmış ve olası nedenler tartışılmıştır.For conducting this study, two for-legged signalized intersections in Pendik area of Istanbul city were designated as case studies. Traffic flows obtained using camera recording method at sites between 7:00-10:00, 12:00-14:00 and 16:30-19:30 time periods. Then, all the recordings were transformed to the computer and the frequency of different types of vehicles in 15-min periods were counted and tabulated with respect to their travel directions. Subsequently, on each approach and for each travel direction, the hour during which maximum traffic volume occurs was designated as its peak hour. In continue, peak hour factors (PHF) were calculated for each approach by dividing the peak hour volume to the flow rate of that approach. Using this PHF factor the adjusted flow rate was computed for each lane group.  Finally, these flow rates were transformed to the VISSIM, and the established models were calibrated to replicate the field situation subsequently, and the final volumes yielded by the VISSIM after calibration process were used as this study flow rate inputs in all methods. Employing these data the performance of case studies were estimated applying Australian (Akcelik) and USA (HCM 2000) methods as well as PTV VISSIM software. That is, the conventional methods of Australian and USA were compared with dynamic method of VISSIM. Finally, the results derived from these four methods were analyzed and differences between these methods and possible reasons were discussed.Yüksek LisansM.Sc