Edge fairing is often applied to box-girder bridge decks to improve their aerodynamic performance, particularly in long-span bridges. A thorough understanding of the aerodynamic response and flow behavior of bridge decks with edge fairings is essential for optimal design and ensuring wind-induced safety. This study presents a numerical investigation into the influence of the nose position of edge fairings on the aerodynamic behavior of box-girder bridge decks. Two-dimensional unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations were performed using the k-ω-SST turbulence model, supported by appropriate validation studies. Both static and dynamic simulations were conducted for two configurations: edge fairings with nose-up and nose-down positions. The static analysis showed that the nose-down configuration offered superior aerodynamic performance compared to the nose-up configuration. In the nose-down position, the deck experienced reduced static wind forces with smaller fluctuations. Flow features such as leading-edge flow separation and reattachment, as well as trailing-edge flow separation, played critical roles in influencing aerodynamic forces. The dynamic simulations further revealed that the nose-down fairing configuration has improved aerodynamic damping in both torsional and heaving modes. In particular, leading-edge flow reattachment was identified as the primary contributor to enhanced aerodynamic damping in the nose-down configuration. Further, the relatively larger bottom plate slope had better aeroelastic responses in the nose-down position of the edge faring.

Flexural strengthening of reinforced concrete (RC) beams is an important research topic due to its huge practical demand. In the present study, a new flexural strengthening method for RC beams, called the Shear-key Mounted Unbonded Rebar (SMUR) technique, is proposed and its effectiveness is examined through an experimental investigation. A total of 12 RC beams were cast and tested under four-point loading. Ten were strengthened and the remaining two the original or control beams. Before casting the RC beams, their constituent materials, such as cement, aggregate and rebar, were tested to ensure the quality of casting. The beams were strengthened with unbonded rebars attached to their tension faces through shear keys. One of the main advantages of the proposed technique was its speed and ease of application. As well as its effectiveness, the effects of other important aspects, such as the size and location of the rebar, were also examined. It was found that the proposed method noticeably enhanced the flexural capacity of a control beam. The ultimate load capacity of a strengthened beam was 60% higher than that of a control one. The flexural performances of the beams could be further improved by increasing the bar size and its location. The welding and conventional flexure were the dominant modes of failure in the strengthened beams.

Composite structure is becoming prominent for its economy, less time consumption, and higher stiffness-mass ratio. Composite action of the steel-concrete composite structure mainly depends on the connector's geometry and materials. Proper choice of shear connector could make steel beam and concrete slab cross-section minimal. This study carries out push-out tests to evaluate the structural efficiency of channel and angle shear connectors in brick aggregate concrete and stone aggregate concrete. It specifically looks at the failure mode, ductility, load-slip behavior, and energy absorption capacity. In brick aggregate concrete, results show that under monotonic loading, channel connectors have been found to have 15.27% more shear capacity & 28.38% more slip than angle connectors. Similarly, in stone aggregate concrete, channel connectors have been found to have 14% more shear capacity & 12.97% higher slip than angle connectors. On average, stone aggregate concrete has been found to have 34.84% higher shear capacity and 6.7% greater slip than brick aggregate concrete. Strain energy and plastic energy were found 78% and 17.6% less in brick aggregate specimens than those in stone aggregate specimens, respectively. Experimental results were slightly lower for both shear connectors than the empirical values.

This paper explores the potentiality of a proposed strengthening technique named as Far Surface Mounted (FSM) reinforcement for flexural strengthening of RC beam. In this technique the reinforcement is mounted in the tension face of the beam away from the existing beam surface and cast new concrete to increase the flexural capacity of the beam. Results of total 14 tested beams are analysed and presented here in this paper. To evaluate the performance of the new strengthening technique, the load-deflection behaviours of the beams strengthened with new technique are compared with the results of control beam and another beam strengthened with Near Surface Mounted (NSM) reinforcement method. It was found that the beam strengthened with new technique has higher flexural capacity than the control beam and beam strengthened with NSM technique. The influence of shear key spacing and inter-surface locking behaviour are also explored. In most of the cases, it found that the final failure modes are the shear and deboning of the added layer of concrete for the beams strengthened with new technique.

The aim of this study is to investigate the characteristics of Textile ETP and Tannery sludges and strength characteristics of cement-sludge mortar. The textile Effluent Treatment Plant (ETP) and tannery sludges have the potential to become a serious environmental burden for Bangladesh in the future because of their high rate of generation, with a very limited safe disposal option. On the other hand, day by day the demand and price of cement are increasing. This study was devoted to evaluate the technical feasibility of utilizing textile ETP and tannery sludges in cement mortar both as separate and mixed modes. An attempt was taken to replace 5%, 10%, 15% and 20% by weight of cement in mortar with textile ETP and tannery sludges both as a separate and mixed modes. To evaluate the characteristics of the textile ETP and tannery sludges, the pH, moisture content, organic matter content, chemical composition (XRF), TCLP (Heavy Metal) tests were studied. The initial and final setting time, compressive strength, tensile strength, and water absorption of mortar by partial replacement of cement by textile ETP and tannery sludges both as separate and mixed modes were studied to evaluate the properties of cement-sludge mortar. It was found that the textile ETP and tannery sludges both as separate and mixed modes can be a replacement of cement up to 10% in cement mortar and can be used for the purposes of S-type of mortar. The textile ETP sludge as a separate and mixed modes of the sludges can be a replacement of cement up to 20% and can be used for the purposes of N-type of mortar.

The demand for energy has increased tremendously around the whole world due to rapid urbanization and booming industrialization. Energy is the major key to achieving an improved social life, but energy production and utilization processes are the main contributors to environmental pollution and greenhouse gas emissions. Mitigation of the energy crisis and reduction in pollution (water and air) difficulties are the leading research topics nowadays. Carbonaceous materials offer some of the best solutions to minimize these problems in an easy and effective way. It is also advantageous that the sources of carbon-based materials are economical, the synthesis processes are comfortable, and the applications are environmentally friendly. Among carbonaceous materials, activated carbons, graphene, and carbon nanotubes have shown outstanding performance in mitigating the energy crisis and environmental pollution. These three carbonaceous materials exhibit unique adsorption properties for energy storage, water purification, and gas cleansing due to their outstanding electrical conductivity, large specific surface areas, and strong mechanical strength. This paper reviews the synthesis methods for activated carbons, carbon nanotubes, and graphene and their significant applications in energy storage, water treatment, and carbon dioxide gas capture to improve environmental sustainability.

In this paper, an investigation of the effects of inclined corner gaps of varying widths and lengths on the static aerodynamic force coefficients and flow features of a square cylinder at low Reynolds number (Re of 100) by comparing with an unmodified square cylinder is discussed. The width of the corner gap (x/D) was varied between 0.02 and 0.24, with two different lengths of it (l/D), namely, 0.05 and 0.11. The open-source code OpenFOAM was used as a solver. A second-order accuracy level was ensured for both time and space during the numerical set up of the model. Validation and verification studies were conducted to ensure the authenticity of the results. The mean and rms values of the static force coefficients of these cylinders were compared and important flow features were explored. Even at a low Re, the proposed corner modification was found to be effective in improving the static aerodynamic performance. For different gap widths, the static force parameters evidenced some patterns, with an optimum width for which the mean drag value reached the minimum value identified. Furthermore, the mean and fluctuating pressure and velocity contour were analyzed to understand the underlying flow mechanism.

The aim of this study is to investigate the strength characteristics of cement-sludge mortar. The cement content in mortar was replaced by tannery sludge in terms of weight for various quantities. The percentage of cement replaced in mortar by tannery sludge was 5, 10, 15 and 20

Automobile tires are made by vulcanizing natural or synthetic rubber with high-strength steel cords. The scrap tire rubber pad, called the STRP isolator, is made from scrap automobile tires. It is expected to be a low-cost isolator and have mechanical properties similar to widely used elastomeric bearings. This article investigated the seismic protection effectiveness of the STRP base isolation system in comparison with the conventional steel-reinforced elastomeric isolation method. A hypothetical four-story building is modelled with four different sub-structure systems: (i) bonded STRP isolator (B-STRP), (ii) unbonded STRP isolator (U-STRP), (iii) steel-reinforced elastomeric isolator (SREI), and (iv) fixed-base system (FB), and is analyzed under the designed based earthquake (DBE) and maximum considered earthquake (MCE) acceleration. The SREI and STRP isolators are assumed to be geometrically comparable, and their fidelity is verified by comparing the numerical results with the past experimental results. The finding reveals that the seismic performance of the B-STRP base-isolated building is similar to that of the SREI system. The seismic performance of the U-STRP base-isolated building was found to be superior to that of the SREI, B-STRP, and FB base conditions. The U-STRP isolators are stable at the DBE level input while there is slippage at the MCE level input.

Poor quality of construction materials and ineffective design of structural members are primary reasons for fast deterioration of flexural capacity of existing steel reinforced cement concrete (RCC) beam. Beam strengthening methods are applied to prevent further distress in the existing structural element. This article presents the results of an experimental study on the performance of strengthened simply supported 1200 mm long rectangular low strength (low ultimate compressive strength) RCC beams tested in flexure under 4-point bending. The unstrengthened RCC beam (control beam, CB) has been strengthened in this study by attaching additional concrete layer at underside (tension side) of the existing CB. The additional cement concrete layer (FSM layer) is bonded to the existing bottom surface of the CB using epoxy adhesive and steel shear keys. The FSM concrete layer is longitudinally reinforced using steel rebar (FSM steel) to withstand bending stress. This method is regarded as far surface mounted (FSM) reinforcement for flexural strengthening of the existing RCC beam (Strengthened beam, SB). This research investigates the effectiveness of using the FSM technique by performing laboratory tests to observe the expected change in the flexural capacity, deflection and failure mode of the SB relative to the unstrengthened CB. This research also investigates the expected shear transfer between the CB bottom and the FSM concrete layer with consideration for the use of shear keys of different diameters as fasteners, and application of epoxy as a bonding material. The effect of using a 1200 mm long (equal to the length of CB) FSM steel of Ø12 mm in the 62.5 mm thick FSM concrete layer was examined in case A tests. Steel shear key of Ø10 mm and length of 150 mm was used in case A tests for increasing the bond between the CB bottom concrete and the FSM concrete layer. The length of steel shear keys used in the subsequent tests was kept the same. Epoxy and surface roughness at the interface of the CB bottom—FSM layer were used. The mid-span deflection and peak bending moment observed in the SB is compared with those observed in the CB. It is noted that the ratio of the measured deflections SB/CB when beam fails in case A is in the range of 0.4–0.6 and the ratio of peak bending moments SB/CB is in the range of 2.7–3.1. The effect of using a 1200 mm long FSM steel of Ø12 mm (greater than the FSM steel diameter in case A) was investigated in case B tests. Thickness of the FSM concrete layer was of 62.5 mm that is the same as the thickness of the FSM layer in case A. A steel shear key of Ø12 mm (greater than case A tests) and epoxy adhesive were used in case B tests. The ratio of the two deflections SB/CB for case B is 0.5 when beam fails. The ratio of peak bending moments SB/CB for case B is in the range of 2.9–3. The effect of position of the FSM steel in the FSM concrete layer was investigated in case C tests by first decreasing the thickness of the FSM layer from 62.5 mm (the same thickness as in case A) to 37.5 mm. In the next case D tests of the SB specimens, the thickness of the FSM concrete layer was increased from 62.5 mm (case A) to 82.5 mm. For both case C and D tests, the steel shear key of Ø8 mm (smaller diameter than case A, and case B) was used. Epoxy adhesive and the surface roughness were used in both cases. For case C, the ratio of the two observed deflections SB/CB is close to 0.6 when beam fails. The ratio of peak bending moments SB/CB in case C is in the range of 2.4–2.6. The ratio of the observed deflections SB/CB in case D is close to 0.5 when beam fails. The ratio of peak bending moments SB/CB in case D is in the range of 2.8–3.1. The effect of length of the FSM layer was investigated in case E and F tests using a reduced length of the FSM concrete layer. Like case A to D tests, no adhesives were used in case E and case F tests to investigate the variation in deflection and peak bending moment capacity values. For case F tests, the steel shear key of Ø12 mm was used. This diameter of steel shear key is the same as the diameter of shear key used in case B but higher than the diameter of shear key used in case E tests. In case E tests, length of the FSM concrete layer was 700 mm that is shorter than the 1200 mm long CB used in case A to D tests. In the next case F tests, length of the FSM concrete layer was further reduced to 350 mm. This length of the FSM layer is shorter than the 700 mm long FSM layer used in case E. In case F tests, diameter of the FSM steel was 10 mm. The FSM steel was placed in the 62.5 mm thick FSM concrete layer (the same thickness as in case A and case B). The observed SB/CB ratio for deflection in case E tests is in the range of 0.4–0.50. The maximum calculated SB/CB ratio for bending moment capacity in case E is 2.5 when peak moment arises. Debonding of FSM layer in case E was observed when the load carrying capacity of SB specimen was almost zero. The ratio of the two deflections SB/CB for case F is in the range of 0.5–0.6 when beam fails. The ratio of bending moments SB/CB in case F is in the range of 1.8–2.2 when the peak bending moment arises. The experimental results provide evidence that flexural capacity of the SB specimens in comparison with the control beams have increased while mid-span deflection of the SB specimens have decreased due to the increased initial stiffness of the SB specimens. Owing to the ease of the FSM method, and smaller deflection ratio with higher peak moment ratio the FSM method yields, the FSM method is preferred for strengthening the control beams.

Flows over two side-by-side circular cylinders exhibit fascinating flow physics due to complex interactions between the coupled wakes. However, their mutual interference effects have not been elucidated in a quantitative manner thus far. In this paper, we create a mismatch between the two wakes by introducing a size difference in the cylinder pair, such that the effects of one wake on the other can be distinguished. Depending on the size and gap ratios between the two cylinders, the coupled wake exhibits distinct dynamical features including the quasi-periodic flow, synchronized flow, and chaotic flow. Through advanced spectral analysis of lift coefficients and dynamic mode decomposition of the flow fields, we reveal that the quasi-periodic flows are mainly composed of two primary frequencies associated with vortex shedding in the near wakes of the two cylinders. Both wakes impose their own frequencies on the other, resulting in the beating phenomenon in the lift coefficients. The triad interactions between the two wakes generate the sideband frequencies, which are associated with modal structures that are mostly active in the far wake. The transition from quasi-periodicity to synchronization is dominated by the vortex shedding behind the larger cylinder, to which the wake of the smaller cylinder locks in. These results reveal new insights on the coupled wakes of two circular cylinders, and are pivotal for understanding more general wake interaction problems.

Aims: To develop a new cable surface for control rain wind induced cable vibration of stay cable. Background: Stay cables are light and vulnerable structures. Therefore, it can be easily excited by wind or rain wind interaction. Stay cables wrapped with a single helical fillet have been proposed so far. However, these countermeasures could prevent cable vibration well, especially in dry conditions. Objective: Therefore, the objective of this research is to develop a new cable surface to control not only RWIV but also dry galloping of stay cable. Methods: A wind tunnel test will be used to investigate the RWIV characteristics and its new countermeasure. Results: First, a rain wind-induced vibration of circular stay cable was reproduced in a wind tunnel environment. The effect of upper and lower water rivulets was examined to understand their role on RWIV better. A rainfall simulator was employed to generate artificial rainfall for two different wind tunnel experiments. Finally, to control the RWIV of stay cables, novel multiple helical surface fillets were used. The upper and lower rain rivulets can play a significant role in energizing the RWIV. It was also found that the multiple helical surface fillets can suppress the cable vibration well both in wet and dry conditions. Conclusion: Multiple helical fillets cable surface could successfully prevent both the RWIV and dry galloping. To fabricate helical fillet cable to control cable vibration, 04 to 12 fillets with sizes ranging from 3mmx7.5mm to 5mmx7.5mm and a pitch of 2.95D-4.78D (D: cable diameter) are the most influential parameters and suggested herewith for practical application.

Scrap tire rubber pad (STRP) isolators are made from scrap automobile tires, which are expected to be a low-cost material for earthquake-resistant design of low-to-medium-rise buildings in developing countries. This paper describes the seismic vulnerability of a unbonded STRP (U-STRP) base-isolated masonry building using the finite element method. The three-dimensional model of the U-STRP isolators is placed between the foundation and the building without any bonding between them. As a result, the inertia force of the building is transferred to the foundation through the friction. Two alternative versions of the U-STRP isolator: strip-shaped and square-shaped, are analyzed, which have comparable geometric and stiffness properties. The fidelity of the U-STRP isolator model is confirmed using the numerical analysis and experimental results. The seismic vulnerability of the masonry base-isolated building is determined using the pushover analysis and the fragility curves and then compared to that of the identical fixed-base building. The findings show that masonry buildings with uniformly distributed square-shaped U-STRP isolators suffer low damage and base shear compared to those of the same size of strip-shaped U-STRP isolators. The U-STRP base-isolated masonry building has superior seismic performance to that of an identical fixed-base building, and a square-shaped U-STRP is more effective than the strip-shaped isolator.

Understanding and predicting the behavior of buildings is a prime engineering interest for better seismic design of building system and this becomes even more important for buildings with planar irregularities. In this study, a detailed numerical investigation was carried out to enhance the understanding of seismic responses of buildings with planar irregularity. Four common and widely visible irregular shapes viz. C, L, I, and T shapes were considered. Two ground excitations with different ranges of dominant frequency were utilized to excite the irregular buildings. Both the modal and time history analyses were carried out and important dynamic features such as modal characteristics, base shear, roof displacement, roof acceleration, and drift of the irregular buildings were predicted. Different irregularity parameters in terms of planar geometry of the buildings were defined to find the most appropriate parameter to represent the seismic responses of the irregular buildings. It was found that among the various irregularity parameters defined, the overall aspect ratio i.e., L/B ratio of buildings are highly correlated with the seismic responses of the buildings. However, the seismic responses of the irregular buildings varied a lot from each other depending on the nature of the earthquake and planar irregularity. It was also found that I and T shapes buildings had the highest seismic responses among the considered buildings.

Stay cables are one of the vital components of a cable-stayed bridge. Due to their flexible nature, stay cables are vulnerable to external excitation and often vibrate with large amplitude under wind action which leads to the fatigue failure of the cables. To suppress such kind of large amplitude vibration by improving the damping ratio of the cable various dampers such as magnetorheological damper, friction damper; oil damper; or high damping rubber (HDR) damper are utilized and gained popularity over time. This paper focuses on improving the damping ratio of stay cables using a combination of two HDR dampers. First, the theoretical model is formulated considering cable bending stiffness to evaluate the damping effect of cable-HDR dampers system. Then, the impact of various design parameters of HDR dampers on cable damping considering the cable stiffness is performed. The comparative analysis of results shows that the considered parameters such as loss factor, spring factor, and installation location of dampers have much effect on the stay cables damping ratio. Finally, the optimal parameters of the two HDR dampers are proposed for damper design.

This study aimed to evaluate the flexural performance of RC beam strengthened with u-shaped ferrocement wrapping and inter-surface locking. Total 12 numbers of RC beams were prepared and tested under third point loading. Three options viz. (i) u-shaped ferrocement wrapping with inherent cementitious bonding, (ii) u-shaped ferrocement wrapping with epoxy bonding and (iii) u-shaped ferrocement wrapping with epoxy and screw bonding were explored for strengthening of RC beam. The first cracking load, load-deflection behaviour, stiffness, energy absorption and the crack patterns were compared between the control and strengthened beams. It was found that the u-shaped ferrocement wrapping with inherent cementitious bonding increases the average flexural capacity up to 19.17% which further increased up to 41.29% by improving the inter-surface locking between the ferrocement layer and the original beam surfaces. The strengthened beam gave up to 35.58% less deformation for the same load compared to the control beam when the inter-surface locking was improved by applying epoxy and screw together. On the other hand, a significant improvement in stiffness and energy absorption capacity was obtained through strengthening with various inter-surface locking. At the maximum test load, all beams showed flexural cracks without any sign of debonding of ferrocement. From this study it could be concluded that u-shaped ferrocement wrapping effectively enhances the flexural capacity of RC beam and this could be further increased by improving the inter-surface locking between ferrocement wrapping and original concrete surface of RC beam.

This study investigates the effectiveness of a new technique to optimize aerodynamic responses of square cylinder by corner modification. The corner of the square cylinder was modified by introducing a small inclined opening which was measured in terms of corner point dislocation. Four specific opening widths (normalized with the depth of the cylinder) viz. 0.02, 0.08, 0.12 and 0.18 were considered. The normalized length of the inclined opening was 0.05 for all cases. The aerodynamic responses of these four modified square cylinders are compared with the unmodified square cylinder. Direct Numerical simulation was utilized to predict the aerodynamic responses and the flow filed. Second order accuracy was maintained both in space and time. The Reynolds number was kept constant at 100. The mean and RMS values of the force coefficients are calculated and compared. The flow filed is analyzed in terms of vorticity filed, mean flow streamlines and after-body wake characteristics. Due to corner modification, a drag reduction of approximately 5% is achieved for square cylinder with corner opening. Along with the separated flow, the corner opening affected the wake of the cylinder as well. Square cylinder with corner opening had different wake characteristics as compared to the unmodified cylinder.

Long-span bridges often exhibit vibration under wind action. Various aerodynamic countermeasures have been developed over the years to enhance the aeroelastic responses of the long-span bridge deck and Separation Interference Method (SIM) is one of these. Engineers should have sound knowledge about the flow mechanism of the aerodynamic countermeasures of the bridge deck for further improvement of the aerodynamic responses and better design of the bridge deck. In the present study, a numerical investigation was carried out to disclose the flow mechanism of SIM on a pentagonal bridge deck. Simulation was conducted by using unsteady RANS for a pentagonal bridge deck with and without SIM techniques and their aerodynamic responses were compared. In the first part performance of unsteady RANS was evaluated to predict the dynamic responses for a pentagonal bridge deck. Then, the steady state responses and flow fields were explored for a bridge deck with and without SIM. Later, the dynamic responses such as flutter derivatives and unsteady pressure characteristics were evaluated and compared. It was found that SIM can improve the aerodynamic responses of the bridge deck. The addition of the curb affected the flow field around the bridge deck and the important flow features noticeably. The leading-edge top and bottom surface separations and the trailing-edge bottom surface separation are the most significant flow features to control both the steady state and dynamics responses of the bridge deck.

Long span bridges exhibit various aeroelastic phenomena. The shape of the deck plays an important role to govern the aerodynamic stability against these aeroelastic phenomena. A pentagonal shaped bridge deck has an improved aerodynamic behavior and thus, this has been applied for a number of practical bridges. The advantage of using this type of deck is that this doesn't require additional devices like fairings. Flow on the top deck is controlled by placing a curb on the top deck each side, which is known as Separation Interference Method (SIM), where flow on the bottom deck is controlled by the bottom plate web slope. In the previous researches, detailed investigations have already been carried out on this kind of deck shape, which show their efficiency against aerodynamic instability of the bridge. Recently, a number of constructed bridges have been shaped as hexagon deck instead of pentagon deck. However, the aerodynamic behavior of the hexagonal shaped bridge decks is not well known. In the current study, we carried out a detailed numerical investigation on the bottom plate web slope effect on flow behavior of a hexagonal bridge deck and the results were compared with a pentagonal bridge deck case. Along with the bottom plate web slope, the width of the bottom horizontal flange plate and the side ratio were also altered to observe their influence on the aerodynamic behavior. A two-dimensional finite volume code with RANS turbulence model is utilized in the present study. The result revealed that the optimum bottom plate web slope shifts to larger slope when the bridge deck is shaped as hexagon instead of pentagon.

Seismic response of a base isolated building is studied for varying properties of Lead rubber bearing. An eight storied educational building is taken into consideration as a structure of interest. Properties of the lead rubber bearing are altered to find the most optimum value of important parameters to obtain a minimum earthquake response of the building. The most important parameters are taken into consideration: initial stiffness (K1), yield strength (Fy/W) and post-to-pre yield stiffness (K2/K1). Three different ground motions are considered in the present analysis and applied in the longitudinal direction of the structure. Base shear, roof acceleration and bearing displacement are utilized to evaluate the performance of the isolated building. It is found that these parameters influence the response of the building significantly and seismic response of the structure reaches to a minimum value for a specific value of the bearing parameter. Finally, some recommendations are made based on the present seismic analysis with different ground motions.