In this study, a new structural system for either retrofitting or design of new structures has been presented that provides more resistance for lateral loading conditions in comparison with the conventional systems. This new structural system can be utilized for a wide range of steel or concrete infrastructure systems from bridges to jackets as offshore structures. In this paper, structural performance of the new systemis compared with conventional system for bridges. The structural response of piers in long- and medium-span bridges has been studied. A comparative study is carried out through static pushover analysis of four medium-span bridge piers and reveals the new system has a higher load-carrying capacity compared with the conventional system, whilst no significant changes are observed for period-based ductility. A probabilistic analysis of the structural collapse is carried out through incremental dynamic analysis (IDA). The results from IDA analyses show higher seismic safety for the new system compared to the conventional system. Besides, a time history analyses for far-field earthquake ground motions to evaluate structural response of a long span bridge was conducted. The results indicate that the stiffness degradation observed in the conventional system caused more damage than the stiffness degradation observed in the new system.

Hydraulic bridges are critical components in infrastructure network. One of the major causes of its collapse is due to local scouring of its foundations. Hence in this study, the mechanism and various factors affecting local scour around bridge piers was analyzed. For this, a software platform Hydrologic Engineering Center River Analysis System (HEC-RAS) was used to evaluate local scouring around piers of spillway bridge with radial gates of Telengiri Irrigation Project located in Koraput district of Odisha, India. Soil samples were collected at the site and tested in the laboratory to determine various properties required for model inputs and assess the vulnerability of soil for scouring. Geometric data and design specifications of radial-gated bridge structure along with soil properties of the case study were used to build HEC-RAS model and then steady-state flow profiles were given to calculate local scour depth. Analytical methods such as Kothyari, Richardson, and IRC equations were used to corroborate local scour depth values with the model. The model predicted scouring of 8.29m which is close enough to values predicted by Richardson equation (8.95 m). This small discrepancy was due to not accounting for bed conditions and armoring of bed material. Parameters were varied in the model such as discharge, width and geometry of piers, skew angle of bridge and piers, angle of attack, and different bed configurations to simulate their effect on local scour depth. The soil was found to be highly erodible as per the soil erodibility factor obtained from the Wischmeier equation.

Bridges are the most useful structures on rivers which floods cause damage to them every year. One of the known factors in bridges destruction is local scouring around the bridge piers. In this study, to investigate the scour depth around the bridge pier in the river bend, experiments were performed in a laboratory flume with a 90-degree bend with  . By placing a cylindrical pier with a diameter of 45 mm at three locations of 30, 45 and 60 degrees along the bend, for three flow Froude numbers, the scouring around the pier under clear water condition was investigated. Natural sand with an average diameter of 0.85 mm is used for the bed materials. The results showed that the maximum scour depth around the bridge pier varies at a different location along the bend. Besides, the flow discharge increase grows the depth and volume of the scour hole at all positions. Additionally, maximum and minimum depth and volume of scouring hole occurs in the second half of the bend at 60- degree position and in the middle of the bend at 45- degree position, respectively. Finally, it was recorded that the development of the sedimentary hill after the pier and its extent in the first half of the bend was higher than the second half of bend. The result also indicated that the maximum and minimum scour depths relative to the pier diameter are equal to 2.24 and 1.22, respectively.

Bridges are the most useful structures on rivers which floods cause damage to them every year. One of the known factors in bridges destruction is local scouring around the bridge piers. In this study, to investigate the scour depth around the bridge pier in the river bend, experiments were performed in a laboratory flume with a 90-degree bend with  . By placing a cylindrical pier with a diameter of 45 mm at three locations of 30, 45 and 60 degrees along the bend, for three flow Froude numbers, the scouring around the pier under clear water condition was investigated. Natural sand with an average diameter of 0.85 mm is used for the bed materials. The results showed that the maximum scour depth around the bridge pier varies at a different location along the bend. Besides, the flow discharge increase grows the depth and volume of the scour hole at all positions. Additionally, maximum and minimum depth and volume of scouring hole occurs in the second half of the bend at 60- degree position and in the middle of the bend at 45- degree position, respectively. Finally, it was recorded that the development of the sedimentary hill after the pier and its extent in the first half of the bend was higher than the second half of bend. The result also indicated that the maximum and minimum scour depths relative to the pier diameter are equal to 2.24 and 1.22, respectively.

In addition to the strength and stability of the bridges, designers and engineers pay much attention to bridge appearance and scenery, which led to build bridges with inclined piers to the flow. Therefore, studying the hydraulic conditions and scour countermeasure of inclined bridge piers is necessary. In this study, the effect of collar on scour reduction at the base of vertical and angled cylindrical piers was investigated. The collar installed at the surface of the sediment bed for vertical and inclined piers. The result of experiments showed that the highest scour depth belongs to the inclined bridge pier toward the upstream direction, which is 15% more than the vertical pier. However, the maximum scour depth in front of the angled pier toward downstream was measured to be about 30% lower than the vertical pier. For the pier inclined toward the upstream direction, the collar reduced the scour in front of the pier about 63%. The collar for the pier inclined toward the downstream direction decreased the scour by about 67%. The result shows that the installation of collars can have a high effect on reducing the scour depth for inclined piers.

The construction of bridges within the river beds often makes changes to the shape and direction of the rivers. These changes take the natural actions of the river, that one of them is the local scouring around the bridges' piers and can cause annually damage. Therefore, many researches have been carried out to control and reduce the scouring. One of the methods presented by researchers is using slot at piers. In present study, the effect of Pier Opening Area on local scouring around the pier with rectangular section is experimentally investigated. For this purpose, piers with square shape slots and different dimensions were used. The piers were tested at three levels (near the water level, on the bed and under the bed) and four Froude numbers. The result showed that the maximum scouring depth and the volume of hole scour had a direct relationship with slot level relative to bed and Froude number and an inverse relationship with Pier Opening Area. The best performance belonged to the slot with greater dimensions which was located under the bed level in the minimum Froude number condition that reduced the depth of scouring about 55. 4 percent.

As a destructive process, scouring exposes bridge foundations to failure and disastrous consequences. Control structures of various arrangements are capable to change and manage the adverse effects. This paper aims to investigate the effect of submerged vanes of a quasi-triangular arrangement (of heights 0, 4, and 6 cm), eppi, and sills (of height 4.5 and 9 cm) on scour development. All tests were executed in a rectangular slope-less flume covered with sediments of D50=1.8 mm. Temporal and equilibrium scour depth were mapped for Froud numbers: 0.15, 0.2, 0.25, and 0.6. Results clarified the aggregate effect of the eppies on the scour depth due to section contraction. Submerged vanes and sill were set up to deteriorate sediment transport. Although the vane of height 4 cm had the most superior performance, but the sill installation of height 4.5 cm greatly increased vane's effect, so that a remarkable reduction of scour was occurred at the first pier foundation.

The main cause of concern about the stability of bridge foundation is the occurrence of scour around the piers. Therefore, there is an interest in finding reliable ways to reduce and control local scour depth. The use of slot through a pier is one of the new proposed methods for controlling and reduction of local scour at bridge piers. This study examines the effect of using rectangular slots through the pier groups at clear water condition. The results of experiments show that in pier groups, reinforcing effect causes that the scour depth at front pier is more than that at a single pier. Also, sheltering effect causes that the scour depth at rear pier is less than that at a single pier. The presence of a slot in a two and three pier groups causes the reinforcing effect increases and sheltering effect decreases. The efficacy of a slot in rear pier is more than that in front pier and single pier for three and two pier groups with S=4b. It was also found that the efficacy of slot for two and three pier groups with S=2b for all piers are almost similar and similar to the single pier. Efficacy of slot in reduction of scour depth, increased with increasing pier spacing.

Piers and abutments cause local contraction in the rivers. As a result of the contraction, the water level increases in the upstream section of the bridge named as afflux. Afflux is one of the key concerns in the design of a bridge construction and the afflux estimation is important when the specific regions in the upstream of the bridge is to be protected against the flood. Hence, estimation of the afflux is required for river training of the upstream sections, before bridge construction. In this research 54 experiments were conducted to investigate the effects of different parameters such as the pier angle with respect to vertical, the Froude number and the contraction ratio on afflux. Design expert software is used to design the experiments and to analyze the results. According to the results, for a downstream inclined and laterally inclined piers, the afflux increased. However, the afflux decreases due to an upstream inclined pier. Also, the effect of inclination angle on the afflux is smaller for inclined piers towards upstream than inclined pier to the downstream or laterally inclined piers. By increasing the pier angle from zero to 24 degrees, toward channel side walls and toward downstream the afflux increases by 20 and 15 percent, respectively. While in the same situation by increasing the pier angle from zero to 24 degrees toward upstream, the afflux decreases by about 5 percent. The higher affluxes were observed in larger Froude numbers and contraction ratios. The analysis showed that the Froude number and contraction ratio have more effects on the afflux as compare to other parameters. Finally, appropriate equations are presented to estimate the afflux.

Introduction: One of the main factors in the collapse of the bridge piers in rivers is local scouring. By placing the piers in the direction of the streams, a complex three-dimensional flow is formed around the pier that has been the popular subject of research by many researchers. Methods of reducing the depth of local scouring are divided into two systems: 1. increasing the strength of bed materials around the piers by using more resistant materials, such as riprap, collar and gabion in the riverbed. 2. Reducing the strength of the main factors such as downward flow and horseshoe vortex by the deflector, blade and submerged Vane or changing the geometric shape. In the present study, the effect of the deflector shapes such as triangles and curved surface on the maximum scour depth around the pier under clear water conditions were considered. General factors of bridge pier scour include down-flows, horseshoe vortex, and wake vortex. In general, the flow impact on the pier and its separation is the main factors that form scour holes around piers. Methodology: The experiments were done in the laboratory of Khuzestan water and power authority laboratory (KWPA), equipped with a flume with a length of 10 meters and a height of 500 mm and a width of 310 mm. The flume is equipped with an electromagnetic flowmeter with an accuracy of ± 0. 1 liters per second and a weir downstream of the flume to adjust the water level. In this study, natural river sand with uniform grain size (δ g = 1. 36), relative density Gs = 2. 64 and the average particle diameter of 0. 95 mm. In all experiments, water depth was considered 100 mm. In this research, three different models of PVC deflector surface (the deflector surface shapes such as triangles, curved and simple surface) with angle's face (θ = 15, 30 and 45-degrees) were adopted. It should be noted that the angle of flow with the deflector head is calculated as α = 90-θ , which used to describe and analyze. The unprotected pier scouring studied to represent a basis for controlling and comparing with the other scour and bed change conditions. A 12-hour control experiment was also conducted on the control pier to determine the experiment time (equilibrium time), and scour depth changes were recorded in the time unit during experiments. Results and Discussion: The horseshoe vortex around the scour hole accelerates digging and transfers the sediments separated from the bed downstream with the main flow. The flow's separation from around the pier also creates perpendicular vortexes on the sedimentary bed known as wake vortexes. These vortexes are active behind the pier, separate the bed particles like a tornado, expose them to the flow, and help move sedimentary particles from the front and sides of piers downstream. The scour hole digging by the horseshoe vortex continues until the water volume inside the scour hole increases and exhausts the vortex energy. In this state, the scour depth changes negligibly over time and reaches equilibrium. The results showed that by reducing the head slope from 40 to 15 degrees, scouring depth decreases. For all deflectors with 15 degrees in the parameter (U/Uc=0. 70), the percentage of the scouring depth reduction is close to 83 to 89 percent. In the parameter U / Uc=0. 96 near inception motion that is the most critical state and the value most comparable to the particle incipient motion, the deflector with triangle surface shows a decrease of 85%, curved surface 77%, and simple 75%. By reducing the angle of the deflector, part of the flow lines didn't deviate towards the bed, which reduced the potential of the high-pressure zone created at the pier. This reduction in compressive potential reduced the flow velocity of the back vortices and, ultimately, reduces their ability to transport sediment downstream. Based on the results, the deflector with a triangle surface shape in all flow conditions had a better and lower scour hole depth than the carved and simple shape. Conclusion: This study used a deflector structure to reduce and control the scour depth around bridge piers. The flow effect was analyzed by implementing these protections and their impact in various relative velocities (𝑈 /𝑈 𝑐 = 0. 97, 0. 83, 0. 70). The scouring pattern and sediment point bar created around the pier with the deflectors protection compared with the control pier (without protection) had less scouring depth due to minor deviation of flow streamlines and reduced disturbances around the pier. Finally, the deflector with a triangle surface shape had a better response to reduce the scouring hole. The results stated that the deflector at the 15-degree angle significantly affects the flow deflection near the bed, corrects the flow pattern around the pier, and reduces scouring depth.