Types Of Piers Research Articles

Shaking Table Test Study on the Earthquake Behavior of High‐Speed Railway Bridge Pier with Rounded Rectangular Cross Section

Rounded rectangular cross section piers were widely used for high‐speed railway (HSR) bridges in China. However, the performance of such piers under seismic scenarios has not been well studied. To study the earthquake behavior and damage of rounded rectangular cross section piers under different intensities of earthquake excitation, nine scaled pier specimens were constructed and tested on the shaking table. Experimental results show that the specimen remains elastic (no or slight damaged) for all experimental earthquake scenarios (from 0.45 g to 0.96 g). Finite element (FE) models were developed and validated by the experimental results. Using this FE model, the damage levels of these specimens under severe earthquake excitations (from 1.05 g to 1.95 g) were quantified. Numerical results show that the specimen in transverse direction shows no or slight damage, while repairable damage can be seen in longitudinal direction as the earthquake intensity increases from 1.05 g to 1.65 g. Repairable and unrepairable damage can be seen in transverse and longitudinal direction, respectively, as the earthquake intensity increases to 1.95 g. Researchers can make good use of these findings for better earthquake design or protection of this type of HSR piers in the future.

Earthquake Resistance Optimization and Evaluation of Bridge Piers Structural Form and Dimensions Based on Demand to Capacity Ratio and Yielding Points of Force-Displacement

The evaluation of structural safety must be taken after each earthquake. The importance losses of life and materials carries the significance of the works in the field of earthquake engineering. The purpose of this study was to optimize and evaluate the earthquake resistance of bridge piers by adopting different cross-section forms and dimensions for bridge supports under earthquake action. Two methods of seismic design were used in the optimization and evaluation process. These methods were demand to capacity ratio (DCR) and yielding point. The results of demand to capacity ratio shown that the values of DCR for all piers forms models were increased when the dimension of pier cross section were increased and the values of DCR became less than 1.0, indicating that the increasing in dimensions leading to rise the capacity of bridge supports to carry the earthquake loads in transverse and longitudinal direction. Comparing with models, solid wall pier form had the lower value of DCR, indicating that solid wall piers were suitable in the design of bridge supports to resist the lateral loads of earthquake and it has enough stiffness and capacity under earthquake action. The results of performance points shown that the yielding points were increased when the dimensions of piers were increased for all piers form in transverse and longitudinal direction. The maximum values were appeared within support No. 1 and support No. 4. Solid wall form of pier had the higher values of yielding points, meaning that this type of piers form had higher seismic capacity and it will resist the earthquake action more than others piers form. This study recommended that to use third model for each pier form in the design of bridges structures to resist the earthquake load. Also this study was recommended to use solid wall piers as supports in construction of bridge structure within areas had earthquake action.

Vehicular impact resistance of highway bridge with seismically-designed UHPC pier

This study strives to numerically explore the performance of highway bridge supported by seismically-designed ultra-high performance concrete (UHPC) piers in resisting heavy truck impact. Firstly, six types of bridge piers are designed with considering two different concrete types (i.e., normal strength concrete (NSC) and UHPC) and three various seismic hazard levels (i.e., earthquake intensities (EI) of 7, 8, and 9) according to Chinese seismic design specifications, and the corresponding refined finite element (FE) models are established and validated by reproducing the tests of drop hammer impacting on reinforced NSC and UHPC members. Based on the well-verified FE models of simply-supported double-pier bent highway bridge and heavy truck, total 54 collision scenarios are carefully designed by referring to the actual accidents, and the vehicle-pier collision analyses are numerically performed by using the nonlinear FE analysis program LS-DYNA. Then, the effects of seismic fortification level and concrete type of impacted pier on the vehicular impact force and dynamic responses of entire bridge structure, as well as the damage and failure modes of both impacted pier and entire bridge are studied. It demonstrates the effectiveness of seismically-designed UHPC pier on improving the vehicle-impact resistance of bridge structure. Besides, more attentions should be paid to the safety of NSC-EI7 and UHPC-EI7 piers and the brittle shear failure in NSC-EI8 piers. Finally, aiming to quantitatively compare the anti-collision performances of entire bridge structure supported by NSC and UHPC piers under the identical seismic fortification intensity, a performance evaluation method of entire bridge structure is proposed based on the residual lateral displacement of the impacted pier. The present work can provide helpful references for the practical applications of UHPC in bridge piers and the on-site feasible evaluation of the residual performance of the post-collision bridge structure.

Analisa Kapasitas Struktur Intake Rumah Pompa Karang Anyar, Pulokerto

Intake Building Structure is a Pier Type Structure that is used as a building for the distribution of clean water. This structure stands on a stake that stands on the edge of the river, as a pier-type building that accepts the load of river currents and pump vibration loads, it is necessary to analyze the maximum capacity, economical and also sturdy. There are several important aspects that must be reviewed to get the maximum design, including water current load, soil load, pump vibration load and also earthquake load in the form of spketrum response based on Palembang area. The design reference used is SNI1727-2013 and SNI 1726-2002. Based on the analysis, the intake structure was obtained in the form of reinforced concrete structures on the floor area and pilecap while for the foundation of the stake in the form of composite steel, columns and beams because it supports a heavy enough load, the profile steel is used.

Experimental and numerical study on seismic behavior of a self-centering railway bridge pier

This study mainly focuses on experimental and numerical investigation of the isolation mechanism and seismic performance of a self-centering railway bridge pier. To begin, a 1/25 scale typical self-centering railway pier model was designed and constructed, which consisted of a gravity pier, a spread foundation and a pedestal. The gravity pier was rigidly connected to the spread foundation, which was then directly seated at the top of the pile cap to allow the uplift of the pier during strong earthquakes. The model was tested in a pseudo-static manner under constant axial load and cyclic lateral load to characterize its seismic performance. It was found that the lateral load, the bending moment at the pier bottom, and the width of compression zone at the bottom of pier remained essentially constant when the uplift reached a certain extent. The hysteretic curves were in inverse 'Z' shape with narrow loops indicating good self-centering effect but poor energy dissipation. This means that the lateral force-displacement relationship of this type of piers can be simplified as an elasto-plastic curve and they should be used along with additional energy-dissipation devices. Upon the test results, a two-spring model was proposed and developed in the OpenSees platform to represent the test model, which was analyzed using the test load history. The results indicate that the two-spring model can simulate the pseudo-static test with high precision. This modeling technique hence can be employed to analyze seismic response of this type of bridge piers.

Numerical investigation of seismic performance of bridge piers with spread footings considering pier plastic hinging and footing rocking, sliding, and settlement

In this study, we conducted numerical parametric analyses to investigate the seismic performance of a bridge pier with a spread footing on dense sandy ground. For the numerical model, we considered plastic hinging in the pier and foundation rocking, sliding, settlement, and embedment. The investigated parameters included pier height, footing width, excitation intensity and type, and footing embedment. With an increase in the pier height-to-foundation width ratio, the rocking response became more pronounced. The direction of the foundation’s permanent tilt was highly dependent on that of the maximum foundation rotation. Near-fault pulse-like ground motions destabilized a system easily. In addition, the maximum drift ratio of the pier and the maximum rotation and settlement of the footing were highly dependent on the minimum contact area. Thus, the ratio of minimum contact area to footing base area (minimum contact area ratio) is an important index for evaluating the performance and stability of the model. When the minimum contact area ratio exceeded 30%, the overall performance of the pier-footing system was suitable; by contrast, when it was below 30%, the drift ratio of the pier and rotation of footing dramatically increased, influencing the system stability.

The impact of cables on local scouring of bridge piers using experimental study and ANN, ANFIS algorithms

Abstract The main purpose of this study was to analyze and predict scour depth and hydraulic performance of piers using soft computing methods and to estimate scour depths using artificial neural networks and ANFIS methods. In the present study, three situations were studied: a rectangular pier without a cable (type I), a rectangular pier with a cable that has a diameter equal to 10% of the pier diameter, and a cable twist angle of 15 degrees (type II), and a rectangular pier with a cable 15% of the pier diameter and an angle of twist of 12 degrees (type III). Tests were carried out with different flow-approach angles: zero, 5, 10, and 15 degrees. Dimensional analysis based on the π Buckingham method was performed. Then, the effect of different parameters, and their importance for estimating scour depth was investigated. Piers with an angle of 15 degrees with respect to the direction of flow had the greatest depth of scouring. Cables can reduce scour depths at this angle; for the second and third classes of piers, the scouring is 10 and 22% compared to the first pier classification. For the second type of pier, angles of 5, 10, and 15 degrees led to increases in scouring depths of 3, 21, and 37% compared to the zero-angle situation.

Experimental and computational assessment of shear beams as earthquake resilient measure for double-column piers supported by pile-group

The double-column pier with energy dissipation members is an effective way for achieving the seismic resilience of bridges. However, there is short of shaking table tests to assess the impacts of the energy dissipation member on the seismic response and soil-foundation-structure interaction (SFSI) of the double-column pier. Therefore, this paper aims to evaluate the effects of the shear beams on the seismic response of the double-column pier supported by the pile-group in the mixed soil, rather than the cable-stayed bridge model. Two types of double-column piers-one is a conventional double-column pier, and the other is a new double-column pier with shear beams-were built and studied in a 1/70-scale cable-stayed bridge model using shaking table tests. The dynamic characteristics, seismic responses, and SFSI effects between two types of double-column piers were compared under different earthquake waves. Test results revealed that the shear beams significantly decreased the reinforcement strain and the bending moment of the double-column pier. The SFSI effects on the double-column pier with shear beams are more significant than the double-column pier. Also, the computational model developed in OpenSees could reproduce the seismic responses of the double-column piers with and without shear beams and detect the seismic response variations induced by the shear beams. The shear beam was earlier yielding than the column and dissipated the earthquake input energy so that the column could remain elastic under the El Centro with 1.4 g. Consequently, the effects of the shear beam on mitigating the seismic damage and enhancing the seismic resilience of the double-column pier were validated.

Experiments and numerical simulation on the influence of pier scour on pipeline safety: a case study of Hang-Yong high-speed line

ABSTRACT Changes in the water flow field will occur around bridge piers, leading to local scouring. When pipelines intersect bridge piers, this kind of scour may cause pipeline exposure or even suspension, thereby influencing the safety of pipelines. Experiments and numerical simulations were conducted to calculate the local scour depth around piers. This paper focuses on the influence of scour around the bridge piers and its hazards to the downstream submarine pipelines. The scour elevation could be used to estimate the influence of bridge piers on the safety of submarine pipelines. Three types of bridge piers were included in this numerical model. In order to ensure the safety of submarine pipelines, it is necessary to arrange the bridge piers and pipelines reasonably, and to monitor the scour at pipelines.

Seismic performance evaluation of a steel tubular bridge pier in a five-span continuous girder bridge system

The seismic performance of a steel tubular bridge pier in a five-span continuous girder bridge system was evaluated through dynamic non-linear time-history analysis under strong ground motions. The seismic performance of the hollow steel tubular (HST) and partially concrete-filled steel tubular (PCFST) bridge piers was assessed with different eccentricities of superstructure. Considering the variation of ground classification under rare earthquakes, six seismic waves were input. The analytical results indicate that the eccentricity of superstructure has little effect on the maximum displacement response of the HST bridge piers and the PCFST bridge piers under ground motion excitations in the longitudinal (LG) direction; however, under the ground motion excitations in the transverse (TR) direction, the maximum displacement response of the bridge piers increases when the eccentricity (e/H) increases from 0 to 0.2, which implies that eccentricity affects the seismic response of the two types of piers. Both in the LG direction and TR direction, the HST piers have reached their yield strengths; stress concentration and local buckling were observed around the plastic hinge zone and the load bearing capacity decreases. Although the PCFST piers entered the elasto-plastic range, the expansion of local buckling deformation of the steel tubular column has been restrained by the concrete in-fill. According to the simulated results, the PCFST pier exhibits high ductility and bearing capacity, which can improve the seismic performance of the bridge system.

Research on the Green Development of Space Defense System and Construction Technology of Great Walls in Shahukou

To study the characteristics of green development of the ancient Great Walls, this paper studies the space defense system in Ming and Qing dynasties and construction technology of Shahukou by means of literature review and on-the-spot investigation. The conclusions are as follows. The ancient Great Walls in Shahukou is a large and deep spatial structure which composes of Shahukou pass of Great Walls, Shahu fortress, and different types of piers. The attackers need to occupy city towers over city gates in Shahu Fortress and corner tower over Mamian pier, while the defenders need to carry out fire prevention and anti-collision work for the gate and gate hole in Shahu Fortress. Rammed materials has experienced many stages, such as ginger stone and yellow mud, grass mud, tabia, glutinous grain pulp tabia, and glutinous grain pulp mortar. Timber construction, timber component, and timber formwork were existed timber in the construction process in ancient Great Walls. The reason why large area of covered bricks lost was that a through joint was formed between the brick layer and the rammed soil.

Seismic performance of grouted sleeve connected precast pier based on steel hysteretic model

The static and quasi-static behaviors of cast-in-place pier and grouted sleeve connected precast pier are simulated by ABAQUS, which are based on the steel hysteretic constitutive model. The accuracy of the finite element simulation is verified by comparing with the existing experimental results. Then the simulation results of the two types of piers are compared and analyzed. The results show that: the seismic performance of precast pier connected with grouting sleeve is similar to that of cast-in-place pier, they both have good plastic deformation capacity. When the displacement is large, grouting sleeve connected pier has higher hysteretic energy dissipation than that of cast-in-place pier, it’s suitable in high earthquake region; The steel hysteretic model can better simulate the seismic performance of reinforced concrete structure under cycle load.

A Numerical Case Study on Pier Shape Coefficient of Seismic Hydrodynamic Pressure in Design Codes

To study the pier shape coefficient of seismic hydrodynamic pressure, three waterpier coupling finite element models of piers with circular, rectangular and elliptical sections are built. The results numerically calculated with the same input ground motion show that the horizontally distributions of the hydrodynamic pressures from the vertical central lines to the edges of the three types of piers at a given depth are almost the same, the difference among the pressures on the three piers is mainly from the decreasing rate from the central line to the edge. The pressures decrease with the input direction from perpendicular to parallel. The result values of shape coefficients are close to the provisions in Japanese code, and those for circular and elliptical piers are slightly less than that stipulated in the code; and the coefficient values for rectangular pier are less than that in Euro code 8 and those for elliptical pier are in the range of the code.

A Hybrid Particle Swarm Optimization and Genetic Algorithm for Model Updating of A Pier-Type Structure Using Experimental Modal Analysis

Conventional design of pier structures is based on the assumption of fully rigid joints. In practice, the real connections are semi-rigid that cause changes in dynamic characteristics. In this study, quality of the joints is investigated by considering changes in natural frequencies. For this purpose, numerical and experimental modal analyses are carried out on related physical model of a pier type structure. When numerical results are evaluated, natural frequencies generally do not match the expected experimental results. Uncertainties in different aspects of engineering problems are always a challenge for researchers. The numerical models which are constructed on the basis of highly idealized scheme may not be able to represent all of the physical aspects of the physical one. For this study, determination of percentage of semi-rigid joints is considered as an optimization problem based on the numerical and experimental frequencies. Probabilistic sensitivity analysis is also used to determine the search space. A new technique of optimization problem is solved by a combination of smart particle swarm optimization (PSO) and genetic algorithms, and a complicated and efficient system for model updating process is introduced. It is observed that the hybrid PSO-Genetic algorithm is applicable and appropriate in model updating process. It performs better than PSO algorithm, considering the good agreement between theoretical frequencies and experimental ones, before and after model updating.

Seismic fragility analysis of reinforced concrete piers of steel box girder bridges: A parametric study

The purpose of this paper is to investigate the influence of typical parameters on seismic fragility curves of reinforced concrete (RC) piers of continuous steel box girder bridges. Typical parameters considered include the pier heights, pier section types, and total length of bridges. Twenty recorded ground motions from historic seismic events are randomly selected for fragility analyses. The finite element analysis program, OpenSees, is employed to perform nonlinear dynamic analyses of the bridges. A set of damage states of bridge piers is proposed based on the damage index, which is based on the drift ratio of the pier. Fragility curves of piers are eventually generated using maximum likelihood estimation. The numerical analysis results show that the bridges with shorter piers are less vulnerable to earthquakes than those with higher piers. Moreover, the wall pier types have significantly improved seismic performance compared with the other types. The fragility analysis results also reveal that the total bridge length has notably affected to seismic response of bridges.

Application of Improved GMDH Models to Predict Local Scour Depth at Complex Bridge Piers

Scour depth prediction is a vital issue in bridge pier design. Recently, good progress has been made in the development of artificial intelligence (AI) to predict scour depth around hydraulic structures base such as bridge piers. In this study, two hybrid intelligence models based on combination of group method of data handling (GMDH) with harmony search algorithm (HS) and shuffled complex evolution (SCE) have been developed to predict local scour depth around complex bridge piers using 82 laboratory data measured by authors and 615 data points from published literature. The results were compared to conventional GMDH models with two kinds of transfer functions called GMDH1 and GMDH2. Based upon the pile cap location, data points were divided into three categories. The performance of all utilized models was evaluated by the statistical criteria of R, RMSE, MAPE, BIAS, and SI. Performances of developed models were evaluated by experimental data points collected in laboratory experiments, together with commonly empirical equations. The results showed that GMDH2SCE was the superior model in terms of all statistical criteria in training when the pile cap was above the initial bed level and completely buried pile cap. For a partially-buried pile cap, GMDH1SCE offered the best performance. Among empirical equations, HEC-18 produced relatively good performances for different types of complex piers. This study recommends hybrid GMDH models, as powerful tools in complex bridge pier scour depth prediction.

Numerical modeling of the effect of pile geometry and pile cap leveling on the local scour under inclined pier group

When the bridge piers are located in front of the water flow, vortices are formed against it and due to their activity, the materials of the river bed are eroded around the bridge piers and the scouring hole is created. If the foundation depth and bridge pier piles are insufficient, the bridge will fail. Now, due to the importance of identifying the mechanisms affecting the scouring on this types of bridge piers, the effect of the geometric shape of the piles that installed under the inclined piers and also the effect of the pile cap leveling in the sedimentary bed have been investigated and the properties of the scouring around the inclined pier group was studied numerically and using the Flow-3D software. The study of total shear stress in the flow bed at different leveling of the pile caps shows that of the highest shear stress was created when the pile cap position is at the same level with the river bed and by installing the pile cap at a lower level than the river bed, the maximum shear stress decreases. This may be due to the fact that in this case the distance between the pier group increases and the presence of the second pier decreases the flow rate in the pier group and different pier in the one pier group act as the two Independent piers in the formation of flow pattern. By comparing the final longitudinal sections of the scouring at different leveling of the pile cap, it is concluded that the largest reduction in scouring depth occurs in aerofoil-shaped pile caps and pile caps with the sharper nose and better aerodynamic shapes are good options to control the horseshoe vortices and will reduce the scouring depth around the inclined pier group.

The shear pin strength of friction pendulum bearings (FPB) in simply supported railway bridges

The friction pendulum bearings (FPB) begin to be used in railway bridges in China. In one earthquake region in China, the shear pins of FPB are required to be well to provide the enough shear force and stiffness under service loads (such as the vehicle forces being less than 170 kN in the longitudinal direction and 40 kN in the transverse direction) or small earthquake loads with a peak ground acceleration (PGA) being less than 0.1 g, however, are cut off to isolate seismic energy under large earthquake loads with a PGA being larger than 0.2 g. It is necessary to identify the appropriate strength of FPB shear pin to satisfy the above requirements. This paper selected the simply supported bridges on a single-line railway in the above earthquake region as the study object, which had a span length of 32 m and two height types of piers (8 m and 25 m). A prototype finite element model (FEM) and a scaled FEM were numerically analyzed, and a scaled experimental model was tested on shake table for each bridge. The results of them were compared with each other to validate the rationality of all models and to achieve the appropriate strength of FPB shear pin. The results show that the appropriate strengths of FPB shear pins are 540 kN in the longitudinal direction and 300 kN in the transverse direction for the bridge with the pier height of 8 m. Likewise, 350 kN and 270 kN are determined as the appropriate strengths of FPB shear pins for the bridge with the pier height of 25 m in the longitudinal and transverse directions, respectively. The numerical method of FEM is correct based on the experimental validation, and can be used to identify the appropriate strengths of FPB shear pins for other railway bridges.

Experimental verification of functionality of fibre-reinforced concrete submersible piers

Low capacity of river banks is a problem of many world cities. Extension can be realised in many ways. One of the ways is to use a system of floating piers. Usual types of piers are filled with floating material, which supports the pier for the whole lifetime. The system of piers described in this article is innovative, because it is supported by an air bag, which can be deflated and then the whole system sinks down to the bottom of the river. This can be helpful in case of danger of floods, because there will be no need to transport the piers to a secure dock. Piers are designed for easy modular connection in various groups. The main types of groups are linear and areal. This article briefly describes the design of fibre reinforced concrete pier and other support constructions which are necessary for the right function of the system. The design of the pier was verified by hydraulic experiments on models in scale 1:10 to real pier. The article contains the description and results of the experiments that have proven the system to be feasible.

Local Scour at Complex Bridge Piers in Close Proximity under Clear-Water and Live-Bed Flow Regime

In this study, we investigated the characteristics of scour at complex bridge piers in close proximity. The experiments were performed under both clear-water and live-bed flow regimes. We compare our results with those for a single complex pier. Further, the performance of existing predictors is discussed. In this study, four typical pier arrangements were adopted, including side-by-side with aligned or 30° skewed flow, staggered, and tandem. The results show that the skew angle for a side-by-side arrangement significantly accelerates the clear-water scour development at all the vertical piles as well as between the piers, and the most scoured pile shifts from the upstream end to the downstream end of the upstream pier flank. The staggered and tandem pier arrangement show significant protection to the downstream pier for both the developing rate and the equilibrium scour depth. When the flow velocity exceeds the threshold for general bed motion, the clear-water scour pattern for all the pier arrangements may be altered significantly due to the upstream sediment supply, the weakened protection effect, and the enhanced flow contraction. The bed-forms migrate via the bridge opening and are damped gradually by the flow, and thus the response of the bed morphology under live-bed conditions is quite unsteady.