ABSTRACT SCOUR AND SCOUR PROTECTION AT BRIDGE ABUTMENTS Kayat&uuml / rk, Serife Yurdag&uuml / l Ph. D., Department of Civil Engineering Supervisor: Prof. Dr. Mustafa G&ouml / g&uuml / S Co-Supervisor: Dr. Mehmet Ali K&ouml / kpinar January 2005, 213 pages Bridge failures are mainly caused by scouring the bed material around bridge foundations during flood. In this study, scour phenomenon around bridge abutments is experimentally studied. Effect of abutment size, location and size of the collars placed around the abutments, time evaluation of scour hole around the abutment, scour characteristics of abutment and pier interaction were experimentally investigated. Scour measurements were conducted in a rectangular channel of 30 m long and 1.5 m wide filled with erodable uniform sediment. In the first part of the study, in order to investigate the size effect of the abutment on the maximum scour depth, abutments of nine different sizes were tested for three different water depths. It was found that the length of the abutment is more important parameter than the width of it. Secondly, efficiency of various sizes of collars, which are used to reduce the local scour depth, located at different elevations around the abutments was determined. It was noticed that when the collar width was increased and placed at or below the bed level, the reduction in scour depth increases considerably. Some tests for partial-collar arrangements around the abutments were conducted and it was shown that instead of full-collar one can use partial-collar arrangements around the abutments to achieve the same efficiency as the full-collar. Time development of scour holes around the abutments with and without collar cases were recorded. It was observed considerable reductions in scour depths around the abutments can be obtained with collars compared to the cases in which there are no collars over the same time period. Finally, a series of experiments were carried out to investigate the interaction between bridge abutments and piers related to the local scour around them. Based on the experiments conducted with two different abutment lengths and pier diameters varying the lateral distances between them it was observed that scour depth reduction capacities of collars vary significantly while comparing a single abutment or pier.

Darbe, remiantis archyvine ir ikonografine medžiaga atskleidžiama Lietuvos tiltų statybos raida ir jų architektūros bruožai. Darbe analizuojamas tiltų ir aplinkos santykis, tiltų tipologija, išryškinami reikšmingiausi tiltai - kultūros paveldo objektai. Lietuvos tiltų ikonografija nagrinėjama dokumentiškumo aspektu, remiantis senaisiais atvaizdais ir rašytiniais šaltiniais. Iki šiol Lietuvos tiltų istorija tyrinėta labai fragmentiškai. Tiltai - sudėtingi specifiniai inžineriniai statiniai. Visa tiltų statybos istorija byloja apie kiekvieno laikotarpio kultūrą, statybos meną, mokslo ir technikos pažangą. Šie statiniai turi istorinę, techninę, architektūrinę vertes ir yra neatsiejamas kelių plėtros atributas. Mūsų dienomis, kai kelių ir tiltų tinklas yra labai platus, tiltai tapo tarsi nepastebimi ir jų svarba šiandien iki galo nebesuvokiama. Inžinieriai visais laikais siekė statyti tvirtus, ilgaamžius ir grakščius tiltus. Dabartiniame pasaulyje vyrauja tradicija, kur tiltų architektūrai suteikiamas ypač svarbus vaidmuo. Darbe pristatomi senieji Lietuvos tiltai (XIII-XVIII a.); apžvelgiami ankstyvieji geležinkelių tiltai; aptariama tiltų statyba bei jų architektūriniai bruožai XX a. (nepriklausomoje Lietuvoje, Sovietmečiu bei dabartiniais laikais). / The final paper presents a review of the development of bridge construction technology and architectural design. The review is based on the materials obtained from historical archives and iconographic resources. The paper analyzes the impact of bridges on the environment and their typology, and highlights the most important bridges which are the objects of cultural heritage. The iconography of Lithuanian bridges is analyzed in terms of documentation. The study is based on the historical images and literature sources. Until the present day, the history of Lithuanian bridges has not been devoted consistent attention. Bridges are complex and exceptional engineering structures. The history of bridge construction narrates an exciting story about the culture, the art of construction, and the scientific and technological progress of the particular historical period. These structures have indisputable historical, technological and architectural value. Moreover, they are a major integral part of road construction. Nowadays, the infrastructure of roads and bridges has expanded to the extent where people no longer realize the utmost importance of bridges. The engineers of all times attempted to design strong, durable and elegant bridges. The contemporary architects tend to devote an especially great deal of attention to the design of bridges. The paper presents the old Lithuanian bridges (from the 13th -18th centuries) and reviews the early railroad bridges. The development of the... [to full text]