There has been no attempt made in this paper to compare the results contained herein to any results secured from previous experimental work. The equations presented are complete in themselves. Development of the equations for the abutments has been independent of the angle of skew. Therefore, they may be used with any solution or this type tor a slab of like material and same length knee, skewed at any angle. As a special case, a right rigid-frame bridge could also be analyzed by this method. / Master of Science

Bridge failures are generally resulted from scour of the bed material around bridge piers and abutments during severe floods. In this study, scour phenomenon around bridge abutments and collars, located at abutments as scour countermeasures, were experimentally studied. The experimental study was carried out under clear-water scour conditions with uniform non-cohesive sediment (having a grain size diameter of d50=0.90 mm). The experimental flume is a rectangular channel of 30 m long and 1.5 m wide filled with this erodible bed material. Based on the results of 97 experiments conducted during the study, the efficiency of various sizes of collars, which were used to reduce the local scour depth, located at different elevations around the abutments was determined. The results obtained were compared with previous studies, and the effect of the sediment grain size on the performance of abutment collars was emphasized. 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. It was also found out that the change of the sediment size did not affect the optimum location of the collar at the abutment, which yields the maximum scour reduction around the abutment.

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.

Extreme rainfall events associated with global warming are likely to produce an increasing number of flooding scenarios. A large magnitude of hydrologic events can often result in submerged orifice flow (also called pressure flow) or embankment and bridge overtopping flow, in which the foundation of a bridge is subjected to severe scour at the sediment bed. This phenomenon can cause bridge failure during large floods. However, current laboratory studies have focused on only cases of free-surface flow conditions, and they do not take bridge submergence into account. In this study, abutment scour experiments were carried out in a compound channel to investigate the characteristics of abutment scour in free-surface flow, submerged orifice flow, and overtopping flow cases. Detailed bed contours and three components of velocities and turbulent intensities were measured by acoustic Doppler velocimeters. The results show that the contracted flow around an abutment because of lateral and/or vertical contraction and local turbulent structures at the downstream region of the bridge are the main features of the flow responsible for the maximum scour depth around an abutment. The effects of local turbulent structures on abutment scour are discussed in terms of turbulent kinetic energy (TKE) profiles measured in a wide range of flow contraction ratios. The experimental results showed that maximum abutment scour can be predicted by a suggested single relationship even in different flow types (i.e., free, submerged orifice, and overtopping flow) if the turbulent kinetic energy and discharge under the bridge can be accurately measured.

ABSTRACT The repair and strengthening of concrete bridge members with CFRP has become increasingly popular over recent years. However, significant research is still needed in order to develop more robust guidelines and specifications. The research project aims to assist with improving design prosedures for damaged concrete members with the use of CFRP. This document summarizes the analysis and testing of full-scale 40’ foot long prestressed concrete (PSC) bridge girders exposed to simulated impact damage and repaired with carbon fiber reinforced polymers (CFRP) materials. A total of five AASHTO type II bridge girders fabricated in the 1960’s were taken from an existing bridge, and tested at the Florida Department of Transportation FDOT structures lab in Tallahassee, Florida. The test specimens were tested under static loading to failure under 4-point bending. Different CFRP configurations were applied to each of the girders. Each of the test girders performed very well as each of them held a higher capacity than the control girder. The repaired girders 5, 6 and 7 surpassed the control girder’s capacity by 10.88%, 15.9% and 11.39%. These results indicate that repairing laterally damaged prestressed concrete bridge girders with CFRP is an effective way to restore the girders flexural capacity.