I-35W Mississippi River Bridge Research Articles

Failure in concrete and methods to improve the performance

This scientific article presents a comparative analysis of two engineering failures caused by concrete deterioration: the collapse of the Champlain Towers South apartment complex in Surfside, Florida, and the failure of the I-35W Mississippi River bridge in Minneapolis. By examining these catastrophic events, this study aims to identify the underlying causes of the concrete failures and draw valuable lessons to prevent similar incidents in the future.

Measuring winners and losers from the new I-35W Mississippi River Bridge

The opening of the replacement for the I-35W Mississippi River Bridge on September 18th, 2008 provides a unique opportunity to evaluate the impacts generated by this additional link on network performance. Using detailed GPS data to estimate travel times on links and for origin-destination pairs, this research finds that while on average travel time improved with the reopening of the bridge, the subsequent restoration of parts of the rest of the network to their pre-collapse configuration worsened travel times significantly on average. In all cases, the distribution of winners and losers indicates clear spatial patterns associated with these network changes.

Overview of Structural Health Monitoring for Steel Bridges

Because of the unpredictable nature of mechanical and environmental loads, steel bridges do not necessarily behave as anticipated in design. Moreover, such loads cause the deterioration of the bridge with respect to time. In the United States, there are many highway bridges classified as structurally deficient because of aging and/or insufficient design. Also, considering the catastrophe of the I-35W Mississippi River Bridge, it is critical to implement a system to monitor the health of bridges and report when and where maintenance operations are needed. Through successful health monitoring, the life of a deteriorating bridge can be extended, and catastrophic failure events can be prevented. Therefore, it is important to have a systematic approach to monitor the health of a bridge. Despite its promising benefits, structural health monitoring (SHM) is infrequently used in bridge applications. This paper will present the basic concepts of SHM and the conventional and new sensors applied for monitoring various structural parameters in steel bridges, which is beneficial to practitioners on bridge inspection and retrofitting.

Stochastic failure analysis of the gusset plates in the Mississippi River Bridge

The I-35W Mississippi River Bridge over Minneapolis, Minnesota, collapsed suddenly on August 1, 2007. Previous studies showed that the demand-to-capacity ratio for one of the gusset plates had become extremely high after about 40 years of service of the bridge and therefore, the failure of the gusset plate caused the failure of the whole bridge. A forensic assessment using stochastic reliability analysis is carried out in this research to check whether the collapse of the bridge could have been predicted at the design stage. For this purpose, the probabilities of failure for different types of stresses in the gusset plate are estimated. To consider the uncertainties involved in dead load and live load increments with time, the gamma process concept is employed to model stress increments. It is shown that the probability of failure in the year 2007 was higher than the recommended value. Therefore, it can be concluded that if the results of this study had been available at the design stage, the lack of reliability in 2007 could have been predicted and the collapse of the bridge and its disastrous consequences could have been prevented. It is also concluded that stochastic reliability analysis can be used as a rational tool for failure analysis and reliability assessment of bridges to prevent the risk of collapse.

Modeling the day-to-day traffic evolution process after an unexpected network disruption

Although various approaches have been proposed for modeling day-to-day traffic flow evolution, none of them, to the best of our knowledge, have been validated for disrupted networks due to the lack of empirical observations. By carefully studying the driving behavioral changes after the collapse of I-35W Mississippi River Bridge in Minneapolis, Minnesota, we found that most of the existing day-to-day traffic assignment models would not be suitable for modeling the traffic evolution under network disruption, because they assume that drivers’ travel cost perception depends solely on their experiences from previous days. When a significant network change occurs unexpectedly, travelers’ past experience on a traffic network may not be entirely useful because the unexpected network change could disturb the traffic greatly. To remedy this, in this paper, we propose a prediction–correction model to describe the traffic equilibration process. A “predicted” flow pattern is constructed inside the model to accommodate the imperfect perception of congestion that is gradually corrected by actual travel experiences. We also prove rigorously that, under mild assumptions, the proposed prediction–correction process has the user equilibrium flow as a globally attractive point. The proposed model is calibrated and validated with the field data collected after the collapse of I-35W Bridge. This study bridges the gap between theoretical modeling and practical applications of day-to-day traffic equilibration approaches and furthers the understanding of traffic equilibration process after network disruption.

Why Choose the New I-35W Mississippi River Bridge?

On September 18th 2008, a replacement for the previously collapsed I-35W bridge opened to the public. Consequently, travelers were once again confronted with the opportunity to find better alternatives. The traffic pattern of the Minneapolis road network was likely to readjust, because of the new link addition. However, questions arise about the possible reasons (or components in the route choice process) that are likely to influence travelers crossing the Mississippi, who had to choose among the bridge options, includingthe new I-35W bridge. Using GPS data and web-based survey collected both before and after the replacement bridge opened, a bridge choice model is estimated using weighted-least squares logit. In this way the proportion of I-35W trips can be estimated depending on the assigned values of the explanatory variables, which include: statistical measures of the travel time distribution experienced by the subjects, alternative diversity, and others. The results showed that travel time savings and reliability were the main reasons for choosing the new I-35W bridge.

The traffic and behavioral effects of the I-35W Mississippi River bridge collapse

On August 1, 2007, the collapse of the I-35W bridge over the Mississippi River in Minneapolis abruptly interrupted the usual route of about 140,000 daily vehicle trips, which substantially disturbed regular traffic flow patterns on the network. It took several weeks for the network to re-equilibrate, during which period travelers continued to learn and adjust their travel decisions. A good understanding of this process is crucial for traffic management and the design of mitigation schemes. Data from loop-detectors, bus ridership statistics, and a survey are analyzed and compared, revealing the evolving traffic reactions to the bridge collapse and how individual choices could help to explain such dynamics. Findings on short-term traffic dynamics and behavioral reactions to this major network disruption have important implications for traffic management in response to future scenarios.

Learning From the Media in the Aftermath of a Crisis: Findings from the Minneapolis Bridge Collapse

This study builds on previous examinations of social and mediated learning, expanding the scope to the context of crises. We argue that mediated learning might be particularly important during crisis both to ameliorate the negative emotional consequences of such events as well as to prompt the learning of information that might be important in future emergencies. Using data collected from Minneapolis, Minn., residents after the collapse of the I-35W Mississippi River bridge, we demonstrate that individuals might have the capacity to learn from the media in the midst of a crisis and that women report learning more than men from crisis media coverage. Finally, we discuss implications for future crisis learning research and recommendations for the media.

Measuring Winners and Losers from the New I-35w Mississippi River Bridge

The opening of the replacement for the I-35W Mississippi River Bridge bridge on September 18th, 2008 provides a unique opportunity to evaluate the impacts generated by this additional link on network performance, and thus empirically test whether a Braess Paradox occurred. Using detailed GPS data to estimate travel times on links and for origin-destination pairs, this research finds that while on average travel time improved with the reopening of the bridge, the subsequent restoration of parts of the rest of the network to their pre-collapse configuration worsened travel times significantly on average. In all cases, the distribution of winners and losers indicates clear spatial patterns associated with these network changes. While no Braess paradox was found in this case, the research provides a method for measuring such phenomena.