Link to Latest Report : Coming Soon.
Background:
In recent years, several studies have been conducted to evaluate the risk of extreme weather events on bridges. For example, according to Nasr et al. (2019) the increase in global temperature due to changes in weather patterns can have major impacts on bridges as it can create stresses of the same magnitude as traffic loads. Palu and Mahmoud (2019) reported that most of the main load carrying girders in bridges could potentially reach their ultimate capacity when subjected to service loads coupled with extra thermal stresses caused by changes in weather patterns. Khelifa et al. (2013) assessed the probability of bridge failure due to scour based on data from the 2009 U.S. National Bridge Inventory. The analysis showed a range of potential bridge failures and the corresponding economic losses across the United States that could be caused by changes in weather patterns. Guest et al. (2010) found that the lifespan of reinforced concrete bridge decks may be reduced due to heightened exposure to environmental factors. Peters et al. (2006) examined the effect of the change in wind speeds on the structural loads and design methodologies. It was observed that structural failures often occur due to extreme weather-induced loads than standard design values. Similarly, Ghosn (2010) investigated wind load effects on bridge reliability, developing a failure model that demonstrated a decline in reliability as wind speeds increased. Additionally, Bastidas-Arteaga et al. (2014) reported that the increase in temperature could accelerate structural failure and significantly reduce service life of bridges. In another study, Saad et al. (2024) developed a methodology to evaluate the effect of changes in thermal loads in concrete box girders. The results show that the changes in weather patterns could lead to a significant increase in the magnitude of thermal loads on bridges. These findings indicate that the shifting in weather patterns is introducing unforeseen environmental load demands on structures, compromising safety and functionality.
Therefore, it is essential for bridge design standards to be updated to accommodate the evolving demands imposed by changes in weather patterns and extreme weather events. Several challenges must be addressed to achieve this goal, including a lack of expertise among bridge engineers in assessing changes in weather patterns, the unavailability of high-resolution future climate data necessary for such evaluations, the complexity of selecting from numerous climate models and scenarios, and the absence of critical climate variables required for comprehensive analysis. The proposed study will address the eminent challenges and estimate environmental load demands for Oklahoma bridges including consideration of changing weather patterns and weather extremes, and “what if” scenarios.
Objective :
The primary objectives of this research are:
- To understand Global Climate Models (GCMs) and select the most relevant model(s) for predicting future weather patterns in Oklahoma. The selected model(s) will be used for prediction of future weather patterns and estimation of environmental load demands.
- To calculate bridge design loads using historical climate data obtained from Oklahoma Mesonet and other sources and compare with GCMs outputs.
- To conduct a risk analysis to evaluate the impact of weather variables, namely temperatures, precipitation and wind on Oklahoma bridges.
- To develop recommendations to incorporate changes in weather patterns and extreme events in bridge design.
- To conduct impactful workshops and webinars focused on this topic.
Scope :
Task 1 – Document Current Practices:
Working closely with ODOT and through literature review, the team will document the current practices on bridge design. This will include bridge design strategies, consideration of the type of extreme events and likelihood in the bridge design, and bridge risk assessment process. The models and data used by ODOT for determining the bridge design loads or return periods of extreme events will be documented. Also, the risk assessment models used for evaluating the vulnerabilities of bridges to different extreme events will be examined.
Task 2 – Predict Weather Using Climate Models:
In this study, multiple GCMs that provide regional weather projections for Oklahoma will be used for future weather predictions considering changing weather patterns and extreme events. GCMs are physics-based and computationally expensive, solving numerous nonlinear scientific equations in both space and time to simulate the Earth physical climate system. For the purpose of this study, the models from NASA Exchange Global Daily Downscaled Projections Project will be used for predicting future climatic conditions in Oklahoma (NEX-GDDP-CMIP6; Thrasher et al. 2002). The model archive contains over 35 different climate models from the CMIP6 archive which would be ideal for assessment of regional weather patterns across Oklahoma
Task 3 – Compare GCMs Prediction With Historical Climate Data.
Relevant historical climatic data (i.e., temperature, precipitation and wind speed) from the Oklahoma Mesonet and other nearby weather stations will be obtained. The research team plans to selectively co-locate the future weather predictions from GCMs with Oklahoma Mesonet sites. The historical weather data from Oklahoma Mesonet sites will be analyzed to calculate the return period of weather extremes and compare with GCMs predictions.
Task 4 – Conduct Risk Assessment of Bridges Considering Future Weather Conditions.
In this study, a risk assessment of bridge infrastructure subjected to predicted future weather conditions will be conducted using methodologies proposed in the literature. For example, the method proposed by Chang et al. (2020) using Risk Priority Number (RPN) could be used for this purpose.. Future weather predictions using GCMs will be used for this purpose. Severity defines the probability of a bridge to experience damage or failure. Significance, a factor on a 1–10 scale, represents the importance of the bridge to the agency in the network. The Risk Priority Number (RPN) parameter combines these three aspects and is defined as a comparative metric that identifies the bridge at higher risk.For the purpose of risk assessment, selective bridges commonly used in Oklahoma will be considered. The selection of these bridges will be based on the recommendations of the ODOT personnel and the vulnerability to extreme weather events.
Task 5 – Provide Recommendations for Updating Bridge Design Codes and Standards.
The findings of this study will be used to recommend changes in the bridge design codes and standards. Also, the authors will prepare guidelines to perform weather data analysis using advanced models like GCMs. Also, the process of estimating design load or return period from future weather scenarios will be documented. The consideration of future natural hazards and extreme weather events will be important to ensure long-term durability of bridge infrastructure.
Task 6 – Organize Workforce and Webinar.
One workshop and one webinar will be organized as part of this task. The goal is to share the findings of this project and increase awareness of the incorporation of changing weather patterns and extremes events in bridge design. Assistance of the Southern Plains Transportation Center (SPTC) & IBT/ABC-UTC will be sought to make these events successful.
Task 7 – Submit Quaterly Progress Reports and Final Report.
Quarterly progress reports will be submitted to IBT/ABC-UTC. A final report documenting all the data, data analysis, and suggested improvements in bridge design will be submitted to IBT/ABC-UTC materials and involved in research related to nano-synthesis of polymer matrix for FRP enhancement, overlays for bridge decks using polymer concrete, nanomodified polymer concrete for bond enhancement with underlying concretes, manufacturing ductile composites using 3D printing and design strengthening methods for concrete structural elements.
Research Team:
Principal Investigator: Syed Ashik Ali, Ph.D.
Co-Principal Investigator: Dominique Pittenger, Ph.D.,Shreya Vemuganti, Ph.D , Musharraf Zaman, Ph.D., P.E., David Ross Boyd, Ph.D., and Aaron Alexander, Ph.D.