The size and shape of the elements vary due to the geometry of each part from irregular dimension element for the gusset-less connections to the biggest elements for beams and cross braces to minimize the analysis time. 3, 128–133. (2017). The structural response data in Table 1 illustrates that the detailed multi-scale model produces lower strain responses indicating a stiffer connection, as expected with more beam elements, when compared to the multi-scale and shell element models. Consequently, the acquired fatigue damage response may lead to overestimating the remaining life of the component. This protocol could be functional via the monitoring data collected through a long term SHM system to predict the bridge structural behavior in the presence of damage. Aygül et al.
(2017). Prediction of strain values in reinforcements and concrete of a RC frame using neural networks. 17, 130–138. The original Memorial Bridge, constructed in 1923, was a through truss vertical lift bridge. Figure 11 illustrates the results of the mean stress histograms at the hot-spot location of the weld toe and the nominal stress at the instrumented locations of the gusset-less connections. Yes, the bridge will go completely vertical, so room access is easy. In order to create the multi-scale models (see Figures 6B,C), different dimensions of elements were connected by defining the appropriate constraint equations at the interface point to ensure the uniformity of the stress distributions and displacements (Mashayekhi and Santini-Bell, 2019). This is a vertical lift bridge like the Cape Cod Railroad Bridge in Massachusetts. The Railroad Bridge is a vertical lift bridge. Structural Response Monitoring of a Vertical Lift Truss Bridge. The central government is working at full throttle to complete the construction of India’s first vertical lift railway sea bridge in Rameswaram, Tamil Nadu. 124, 817–829. The bridge is also the only pedestrian link between the two communities, who value this bridge as much for its function as a transportation link as for its beauty and the access to the water views. The third model is the multi-scale model (see Figure 6C), at which the gusset-less connections and the deck of the bridge were modeled with beam elements. While the peaks of the output spectrum show the natural frequencies of the system, the first singular vector estimates the corresponding mode shape. IIW (2000). Becoming a Patron or a subscriber for as little as Rs 999/year is the best way you can support our efforts. The top chord web plates are 24 inches tall and the bottom chord web plates are 36 inches tall. The proposed damage detection criterion is based on performing a control chart analysis on the wavelet packet averaged data for feature classification between different states. This selective application of sensors can contribute to the goal of managing an aging bridge inventory with high maintenance and replacement costs. Struct. However, with the hundreds of movable bridges in the US, which are typically located in coastal environments that are typically highly susceptible to extreme weather events, there are few long term monitoring programs for these bridges subjected to vertical operations in addition to traffic and environmental loads (Catbas et al., 2014). 30, 91–105. Mashayekhi, M., and Santini-Bell, E. (2019). If the bridge experiences a vessel collision causing a significant reduction in the overall capacity of the target members as modeled in this work, ≥90% of the member capacity, deliberate actions should be taken immediately to reduce demand or replace the damaged members. MMa created the multi-scale finite element models, performed the static model calibration, and conducted the fatigue assessment included in this manuscript. Each run of the load test included a series of individual truck passes to ensure collection of high-quality data with the least measurement errors due to uncertainty and variability in the field testing. The deck of the models at both the northbound and southbound stop locations during the load test was re-meshed to consider an accurate path to account for the truck applying loads. Prior to the long term monitoring program design, it is beneficial to get an overview of the bridge's behavior thorough some short term monitoring. The SCF for the location of the strain rosette C is computed using a perpendicular path starting from the strain rosette location to the weld toe, as shown in Figure 8C. Figure 8. This approach not only provides bridge owners with additional time and flexibility for maintenance and rehabilitation of deteriorated bridges, but it also can facilitate a better resource allocation to repair or replace damaged components. The nominal stress ranges are multiplied by the measured SCF to achieve the hot-spot stress ranges.  The counterweights in a vertical lift are only required to be equal to the weight of the deck, whereas bascule bridge counterweights must weigh several times as much as the span being lifted. Figure 10B shows the output spectrum in which the peaks represent the first three natural frequencies of the bridge. The bridge is instrumented by a series of SHM sensors including accelerometers, uniaxial strain gauges, strain rosettes, and tiltmeters. Therefore, prior to embarking on a lengthy multi-purpose modeling program, a preliminary analysis was performed by creating a three-dimensional wire-frame structural model of the Portsmouth-side horizontal span and lift tower in SAP2000® (see Figure 2). Truck accident is the third leading cause of bridge failure or collapse in the United States. The radiused filet welds at the gusset-less connection of the Memorial Bridge connecting the cold bent flanges to the web of the connection (as shown in Figure 8) can make the weld toe of the connection a hot-spot location. Virtual Bridge Co. The representing analytical responses belong to the horizontal strain gauges (Ex) for the bottom connection under the truck load corresponding to the second stop during the load test. Appl. J.
Cambridge: Woodhead Publishing. Performance Construct. Frequency-domain decomposition analysis of the bridge, (A) the acceleration time history captured by the specified sensor during a lift event, (B) the output spectrum peaks representing the natural frequencies of the Memorial Bridge, and (C) the first three mode shapes derived from the structural model in SAP2000®.
Int. Analyzing Prerepair and Postrepair vibration data from the Sarah Mildred Long Bridge after Ship Collision. These objectives were developed through collaboration with the bridge owners and the bridge designer. The 544 foot span weighs 2,050 tons and provides 136 feet of vertical clearance when in the raised position at mean high water. After each step of a scale-reduction, the optimum location of the interface point was determined by minimizing the difference between the structural responses of the two models.