Cost Impact of Increasing Heavy Vehicle Loads on Bridges

This study aimed to investigate the cost impact of meeting the increase in freight demand by doubling the truck weight （AS 1 ）, doubling the traffic volume （AS2）, or legalizing a new-proposed-truck of 97-kip weight instead of the currently legal 80-kip truck （AS3）. The State of Michigan＇s average daily traffic database of year 2001 has been used as a case study. The study was applied only on the very common US Bridge with RC （reinforced concrete） deck over steel girder. Sampling criteria also includes the age of the bridges. The study covered the four-cost-impact categories provided by the NCHRP （National Cooperative Research Program）. The current truck weight and double traffic volume （AS2） show the best scenario to meet the increase in freight demand. However, doubling the truck weight with the current traffic volume （AS 1） was the worst scenario. The use of the proposed 97-kip truck with the current traffic volume （AS3） compromises both, meeting the increase in freight demand and the cost impact.

Assessment of Long-Time Behavior for Bridge Girders Retrofitted with Fiber Reinforced Polymer

Maintaining both the safety and serviceability of deteriorating highway bridge networks necessitates suitable BMS （bridge maintenance system） tools that can maximize cost effectiveness. Numerous experiments have been conducted to detect the long-term mechanical properties of the epoxy resin materials used in FRP （fiber reinforced polymers） strengthening and maintenance technique. Experiments were used to develop a short-term test and construct a model that can reliably predict the long-term behavior of epoxy resin. Furthermore, FEA （finite element analysis） models were developed, using the ANSYS software, to simulate three unstrengthened and FRP strengthened prestressed concrete girder bridges of different configurations. Models simulate the original and aged properties of construction and retrofitting materials under the application of AASHTO （American Association of State Highway and Transportation Officials） fatigue truck and a site-specific fatigue truck in different scenarios. These models were used to develop the bridge performance chart for the capacity of the bridge, with and without strengthening interventions, as a BMS tool. The results show an immediate significant improvement in the concrete tensile stress with the intervention of FRP strengthening.