Development Of Precast Barrier Wall System For Bridge Decks

As Ontario transportation infrastructure enters the era of maintenance, rehabilitation and replacement, it needs more use of prefabricated elements and systems, which can quickly assembled to overcome relatively longer time to open bridge to the traffic. This thesis reports on both analytical and experimental investigations conducted on various aspects of precast bridge barrier, including design loads, structural design, sequence of construction, connection details between the barriers and bridge, joints between barrier segments and water leakage control. In this study, thru post-tensioned bolted connection system was developed to connect the precast barrier wall with bridge deck. The primary intension behind these connections is to expedite construction cycle simulataneously with minimizing traffic disruption, improve work-zone safety, quality and constructible and lower down lifecycle cost of bridges. A total of five experimental tests on full-scale specimens of the developed system were conducted to verify and substantiate the design procedure used to develop the barrier wall system. Good correlation between theoretical ultimate loads, in the form of bending, shear and punching shear resistance, and the experimental findings was achieved.

Development Of Precast Barrier Wall System For Bridge Decks

As Ontario transportation infrastructure enters the era of maintenance, rehabilitation and replacement, it needs more use of prefabricated elements and systems, which can quickly assembled to overcome relatively longer time to open bridge to the traffic. This thesis reports on both analytical and experimental investigations conducted on various aspects of precast bridge barrier, including design loads, structural design, sequence of construction, connection details between the barriers and bridge, joints between barrier segments and water leakage control. In this study, thru post-tensioned bolted connection system was developed to connect the precast barrier wall with bridge deck. The primary intension behind these connections is to expedite construction cycle simulataneously with minimizing traffic disruption, improve work-zone safety, quality and constructible and lower down lifecycle cost of bridges. A total of five experimental tests on full-scale specimens of the developed system were conducted to verify and substantiate the design procedure used to develop the barrier wall system. Good correlation between theoretical ultimate loads, in the form of bending, shear and punching shear resistance, and the experimental findings was achieved.

Cooperative Highway Work Zone Merge Control Based on Reinforcement Learning in a Connected and Automated Environment

Given the aging infrastructure and the anticipated growing number of highway work zones in the U.S.A., it is important to investigate work zone merge control, which is critical for improving work zone safety and capacity. This paper proposes and evaluates a novel highway work zone merge control strategy based on cooperative driving behavior enabled by artificial intelligence. The proposed method assumes that all vehicles are fully automated, connected, and cooperative. It inserts two metering zones in the open lane to make space for merging vehicles in the closed lane. In addition, each vehicle in the closed lane learns how to adjust its longitudinal position optimally to find a safe gap in the open lane using an off-policy soft actor critic reinforcement learning (RL) algorithm, considering its surrounding traffic conditions. The learning results are captured in convolutional neural networks and used to control individual vehicles in the testing phase. By adding the metering zones and taking the locations, speeds, and accelerations of surrounding vehicles into account, cooperation among vehicles is implicitly considered. This RL-based model is trained and evaluated using a microscopic traffic simulator. The results show that this cooperative RL-based merge control significantly outperforms popular strategies such as late merge and early merge in terms of both mobility and safety measures. It also performs better than a strategy assuming all vehicles are equipped with cooperative adaptive cruise control.