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Life Cycle Assessment for Civil Engineering Structures of Railway Bridges
Published in Nigel Powers, Dan M. Frangopol, Riadh Al-Mahaidi, Colin Caprani, Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2018
G. Lener, J. Schmid, A. Strauss
Figure 5 shows as example the cost-optimized chloride performance group evaluation, in this case the abutment A of the bridge object 1062 on the line 33.003, for two different maintenance strategies (strategy I “process delay due to coating” and strategy II “concrete replacement”. From figure 5 it can be seen that an intervention is required for the abutment wall only and not for the abutment wing wall. The LeCIE WEB tool also allows the combination between the processes. Based on this capability, the most cost-effective intervention strategy can be determined.
Erosion and deposition
Published in Arved J. Raudkivi, Loose Boundary Hydraulics, 2020
The common shapes of abutments are the wing-wall and spill-through abutment, Figure 9.20. Some laboratory studies have simulated the abutment by vertical plates with either a rectangular or semi-cylindrical vertical end. Guide banks are used to guide or deflect the flow away from an eroding bank or ‘fix’ the width of the flow. Guide banks have been used extensively in India at the heads of abutments to restrict bridge waterway and prevent outflanking of the bridge. The trend is to give the guide bank an elliptical plan form aimed at prevention of flow separation.
Numerical 3D analysis of masonry arch bridge cracks using jointed rock model
Published in António S. Cardoso, José L. Borges, Pedro A. Costa, António T. Gomes, José C. Marques, Castorina S. Vieira, Numerical Methods in Geotechnical Engineering IX, 2018
Balint Penzes, Hoe-Chian Yeow, Peter Harris, Christopher Heap
Figure 3. shows the analyzed abutment behind the wing wall. Which comprised 1 m of Fill material, overlying 1.6 m grey mudstone (Mudstone 1) over 0.3 m thick Limestone layer at a depth 2.6 m below the road surface. Based on the site inspection below the bridge structure the mudstone at depth was assumed slightly stiffer (Mudstone 2). Furthermore, it was observed during the site inspection work that at the arch structure stiffer fill material was used above the crown and behind the pilaster.
Turbulence approach for predicting scour at abutments
Published in Journal of Hydraulic Research, 2022
Gijs Hoffmans, Frans Buschman, Maarten Van der Wal
According to Breusers et al. (1977), the equilibrium scour depth at abutments and bridge piers, if the width of the structure is larger than the flow depth, is: where KB ranges from 0.75 (wing wall abutment streamlined) to 3.0 (vertical wall abutment). To determine the unknowns in Eq. (24), the following assumptions have been made: KB = 1.5 for 45° wing wall abutments (the ratio between the transverse and streamwise length is 0.33) and uniform and hydraulic rough conditions exist upstream of the scour hole, i.e. r0 = 0.10 and r0,m= 0.25 based on experimental data (Dey & Barbhuiya, 2006), providing the geometry abutment factor: αga = 1.426 (χe = 1.753). Therefore, with αga ≈ 1.4, it follows that ℓy ≈ 6.5 h (Eq. 23).
Seismic reliability and limit state risk evaluation of plain concrete arch bridges
Published in Structure and Infrastructure Engineering, 2021
Vahid Jahangiri, Mahdi Yazdani
In this part, the description and finite element models of the two considered bridges are presented. For more details, please refer to the work of Marefat, Yazdani, and Jafari (2019). The bridges are placed at 23 and 24 km of the old railway of Tehran-Qom. The first bridge, which is named 2L20, comprises two arches with equal spans of 20 m, and the second bridge, which is named 5L06, comprises five arches with equal spans of 6 m. All the structural portions of the bridges, such as the spandrel wall, arch, wing wall, abutment, foundation, and pier, are constructed with plain concrete. The outer surface of the arches is filled with a thin layer of concrete. Profiles of 2L20 and 5L06 models are displayed in more detail in Figures 1 and 2, respectively. Furthermore, their geometric features are shown in Table 1. It can be seen from Table 1 that the geometric characteristics of the bridges, especially such as the number of spans and the span lengths, are quite different. Concrete quality determination of the bridges is done using cylindrical core sampling from various portions of the bridges, and the obtained results are shown in Table 2.
Abutment scour depth modeling using neuro-fuzzy-embedded techniques
Published in Marine Georesources & Geotechnology, 2019
Fatemeh Moradi, Hossein Bonakdari, Ozgur Kisi, Isa Ebtehaj, Jalal Shiri, Bahram Gharabaghi
Putting abutment made of Perspex with different geometric shapes, including vertical wall, and 45° wing wall abutment semicircular with varying sizes in the flume examined the scour processes around the abutments (Figure 1). The ratio of b/l for semicircular and vertical wall abutments is 2 and for the 45° wing wall abutment is 3. At this point, b and l are abutment length in the stream direction and abutment length perpendicular to the approaching stream. Flow depth is adjusted using the tailgate and through vernier point scale with a validity of ±0.1 mm is measured. The flow rate using inlet valve is controlled and recorded by weir-calibrated V-notch. Due to sheet flow activity with insufficient flow depth, scour process encounters a problem. Thus, to prevent undesirable scour, the flume is loaded with water withdrawn from a tube with low velocity. Uniform grading of bed material distribution using the geometric standard deviation is defined and for uniform sediments, (Dey, Bose, and Sastry 1995). In all experiments, there is a clear water condition, and the ratio of average stream velocity (U) to the critical velocity for the movement of the particle (Uc) is less than 1 (). Also, the stream characteristic range, sediment, and geometric shape are presented in Table 1.