High Piers Research Articles

Seismic Response on the Mangjiedu Long-Span PC Continuous Rigid Frame Bridge with High Piers

The selected high-span continuous rigid frame bridge for studying is Mangjiedu Bridge in this paper. Based on the principle of structure dynamics and the method of seismic response analysis, the finite element model of the main bridge in Mangjiedu Bridge under Midas-civil was built according to the structural features, site conditions and seismic fortification intensity of the bridge. Then the characteristics of main bridge structure were studied using Lanzcos modal analysis method, and the seismic responses of main bridge are studied by earthquake response spectrum analysis and time history analysis respectively. The results show that the fundamental frequency of the main bridge is 0.1943Hz, and the transverse vibration mode shapes are most remarkable in the former 10 ordered types of vibration of main bridge. The main bridge is in the conditions of elastic range and does not failure under E1 earthquake. Both response spectrum analysis and time history analysis show that the largest displacement along the main bridge appears at the top of pier and the largest transverse displacement appears in the central position of main span. It also shows that the maximum shear and maximum moment occur at the bottom of main pier.

Effect of Wind Load on the Track Structure of Bridge with High Pier and Large Span

The high pier and large-span bridge is high, soft, and have large contact area with the outside world, under the action of wind load, it will occur large vertical and horizontal displacement .This displacement effect on the track structure and will cause rail additional force, lateral displacement and create initial track irregularities, and then reduce the lateral stability of track structure. In this paper, through the large finite element software, we build pier-beam-track model to simulate and analyse the influence on the track structure under the vertical and horizontal wind load, it reached the following conclusion: horizontal wind load basic does not cause rail additional force, but reduce the rail lateral stability; longitudinal wind load can make rail produce certain vertical additional force, but compared to the telescopic additional force, the force basic can be ignored.

Analysis of the lateral dynamic response of high pier viaducts under high-speed train travel

With the development of high-speed railways in the last decade, the dynamic behaviour of trains and bridges has been studied more thoroughly. However, it is difficult to find papers in the scientific literature about the lateral response of high-speed trains travel over long viaducts with high piers. In order to evaluate the riding comfort or vehicle dynamic response of a train over this kind of bridges, an efficient nonlinear dynamic interaction model of the train–track–bridge system was developed and checked. In that model, a three-dimensional multi-body train and a finite element bridge and track system are considered. Ballast stiffness and rail flexibility are taken into account in the finite element model. For reproducing the interaction between wheel and rail, a simplified nonlinear creep contact model has been included. In this study, track irregularities and wheel-hunting movement are considered as the system lateral excitation. The influence of pier height on the response of train and bridge is also studied. Continuous bridges, straight and constant section deck viaducts with variable height and tapered piers are the structures which have been considered. The height of the tested viaduct ranges between 60 and 120m. The results of this study show that train behaviour is in accordance with riding comfort standards. And, although some bridge response values obtained are not allowed in the currently recognized train traffic safety standards of bridges, they can be easily improved.

Vibration of Long-Span & High Pier Continuous Rigid-Frame Bridge due to Traffic Load

The bridge vibration problem would be highlighted due to flexibility of bridge when traffic is run on the long-span & high-tower continuous rigid-frame bridge. The finite-element (FE) software of bridge-vehicles coupling vibration theory was utilized to analyze traffic load influence on bridge vibration. It is found that the vehicle accelerations are varied greatly in the middle of mid-span and edge of side-span and vehicle bodies are plunged. According to the evaluating indicator of comfort level, people feel sea-sickness when vehicles run in design speed with fundamental frequency. Due to fundamental frequency of body in different speed, the sea-sickness feel will be stronger with lower speed. The impact action can be decreased by the increase number of vehicle-line load, and it is affected by the distance of vehicle-line load.

Millau viaduct geotechnical studies and foundations

The Millau viaduct over the Tarn River is an exceptional bridge considering the height under the deck and the 2.5km total length. Each of the seven high piers is founded on a thick raft setting on four large piles of 5m in diameter and 10–15m deep. The ground schematically consists of limestone in the north and of marls in the south. As the bridge is very sensitive to foundation settlements, the concessionary company decided to use the observational method for controlling the displacements and if necessary stabilize the foundations. The measurements show that the movements have remained small and admissible, particularly in terms of the rotations. The settlements have not occurred continuously under the load, but by steps.

Based on the Theory of Reliability High Piers Short Towers Cable-Stayed Bridge Characteristic Parameter Analysis

In view of high pier extradosed cable-stayed bridge structure characteristics, Yunnan Nanpangjiang River Bridge is taken as an example. This paper studies the influence of parameter change on the structure of the main girder by adjusting the girder height, cable tower height, bending stiffness and the cable tower pier stiffness. It can help us understand mechanical properties of the structure so as to estimate safety evaluation when the structure parameters are changed. Furthermore, it can provide the reference for economic and reasonable structure form design in the bridge of safety evaluation. It also can evaluate the safety of girder and tower through reliability theory. The result shows that the application of reliability theory is reliable and practical to evaluate the high pier extradosed cable-stayed bridge safety performance.

Eigenvalues and modes of distributed-mass symmetric multispan bridges with restrained ends for seismic response analysis

Closed-form solutions are developed for the elastic response of symmetric bridges, continuous over two, three or four spans, for unidirectional earthquake perpendicular to the deck, i.e., in the transverse or the vertical direction. The ends of the deck are restrained along the earthquake component, but free to rotate within the plane of bending. The mass and flexural rigidity of the deck are uniform along its length and modelled as continuous. The piers may support the deck through flexible bearings or are rigidly connected to it, in which case a lumped mass is considered at the connection. For each bridge geometry a nonlinear transcendental equation is derived for the modal circular frequency and solved numerically. Closed formulas are given for participation factors, participating masses, the curvature and end slope of the deck and the end reactions. The frequency and cumulative participating mass of the important modes are plotted as a function of the dimensionless total stiffness of the piers. Parametric analyses are presented for the mass of the piers, the location of the intermediate piers and their relative stiffness. They suggest that the eigenvalues are close to those of a simply supported beam with uniformized transverse restraint and mass, except for relatively high pier stiffness and for a single pier of medium stiffness. Even if this approximation is made, modal shapes and elastic forces or deformations of the deck may differ significantly from those of a simply supported beam with uniformized parameters and should be calculated with the closed-form expressions presented. The analytical first-mode frequency and the one from the single-mode method of the AASHTO code in general agree very well, but the first mode participating masses from the two methods may differ.

Research on the Traveling Wave Effect of a Rigid-Continuous Girder Bridge with High Piers Based on Multi-Support Excitation

This paper, aiming at rigid-continuous girder bridge with high piers, uses the large mass method (LMM) to analyze the seismic response of such special structure under a series of different phase differences by considering both rigid foundation and elastic foundation models. In addition, this paper discusses the influence rules for extreme response of different parts of structure due to traveling wave effect. The result shows that traveling wave effect greatly affects the rigid-continuous girder bridge with high piers. When considering the traveling wave effect, the internal force of bridge piers presents increasing trend, and the displacement of pier top reduces with increasing phase differences. The internal force and extreme displacement response of bridge structure present cyclical variations with phase differences, and that cycle is consistent with the characteristic period of bridge.

大跨度连续梁桥的地震碰撞模拟分析

本文通过对于一座大跨度连续梁桥地震碰撞过程的模拟分析和数据显微处理，首次发现并提出了碰撞群的概念，认为碰撞群中高频高强的加载卸载过程(可称之为冲击钻效应)是导致碰撞破坏的原因。在此基础上，本文提出了一种梁端碰撞损伤度评估方法，并针对本文的研究对象给出了碰撞损伤度评估结果。本文还通过对比大桥不同模型(不同墩高、不同基础类型)中所发生的地震碰撞，提出：1) 为减轻多跨连续梁桥地震碰撞、降低边跨落梁概率，应合理设置和设计制动墩；2) 在建模时，梁墩基础的模拟方式应谨慎、合理；3) 在高烈度区进行高墩大跨度连续梁的桥台设计时，应考虑碰撞中的冲击钻效应所。 In this paper, with a large span continuous girder bridge as the research object, the simulation analysis of seismic collision and the data microprocessing is carried out. based on this, a new the concept of the collision group was first discovered and put forward. Just because of the loading and unloading process in high-frequency and high-strength happened in a collision group (can also called impact drill effect), the collision damage is resulted. On this basis, we propose a beam end collision damage evaluation method and by applying the evaluation method on to the large span continuous girder bridge, the results of the assessment of the degree of collision damage is given. In this paper, by contrast seismic collision occurred in different models of bridge (with different pier, different base types) , the following suggestions should be pay attention: 1) To mitigate multi-span continuous girder bridge seismic collision, reducing side span girder falling probability, the setting and the design of a brake pier should be reasonable; 2) When set up the model of a bridge, how to simulating the base of pier should be cautious and reasonable; 3) When designing a long span continuous beam bridge with high pier in the high-intensity area, the impact drill effect should be considered.

The Mechanical Property of High Bridge Pier

As for those high piers of bridge that constructed crossing sea and clough, the p-delta effect is evident; Looking upon present situation over the domestic and foreign research, stipulated laws on p-delta effect are various. Research shows that computing upper pier displacement by energy method was simple and versatile for different load case in comparing with other methods, and neglecting p-delta effect often underestimated the disadvantageous state when the pier is high; also, lateral loads like wind and seismic force further aggravate the pier state.

Experimental Research on the Temperature Field of High and Hollow-Thin Pier

To study the temperature field changing regulation of hydration heat and control concrete cracks caused by great temperature difference in the construction of hollow-thin pier, testing the temperature field of the high and hollow-thin pier of Cha Jiugou Bridge and it got changing regulation of the temperature. The finite element analysis on the pier was also carried out and the temperature stress contours and curves of the hydration heat of the concrete are obtained. It can be seen that the outer surface and the center of the pier are compressive within 10 hours in the pouring early. With the temperature difference, the center generates the compressive stress, the surface generates tensile stress.

Seismic response analysis of road vehicle-bridge system for continuous rigid frame bridges with high piers

The objective of this study is to investigate the effects of earthquakes on road vehicle-bridge coupling vibration systems. A two-axle highway freight vehicle is treated as a 13 degree-of-freedom system composed of several rigid bodies, which are connected by a series of springs and dampers. The framework of the earthquake-vehicle-bridge dynamic analysis system is then established using an earthquake as the external excitation. The equivalent lateral contact force serves as the judgment criteria for sideslip accidents according to reliability theory. The entire process of the vehicle crossing the bridge is considered for a very high pier continuous rigid frame bridge. The response characteristics of the vehicle and the bridge are discussed in terms of various parameters such as earthquake ground motion, PGA value of the earthquake, incident angle, pier height, vehicle speed and mass. It is found that seismic excitation is the most influential factor in the responses of the vehicle-bridge system and that the safety of vehicles crossing the bridge is seriously impacted by the dual excitations of earthquake and bridge vibration.

Plastic Hinge Analysis of Seismic Performance of High Bridge Pier

To analyze the second plastic hinge of high bridge pier formed in the earthquake and study the pier seismic performance, this paper takes the Kunming Slope Railway Bridge as an example. The simulation model was built by the elastic-plastic finite element ANSYS software. The buckling load of piers was calculated by buckling analysis capabilities of ANSYS software, a small enough initial offset given to the model, then the buckling load of piers put into the model. The deformation of non-linear model under the loads was calculated, the process was recorded that the reinforced concrete bridge piers initially yielding on the cross-section, continuously rotating around the neutral axis, and finally forming the eventually plastic hinges in certain parts of pier. The location of the plastic hinges can be inferred by final data of analysis software. By analyzing the calculated results, the seismic performance of the second plastic hinge in high bridge is studied.

Analysis of the Temperature Effect of Piers with Concrete-filled Steel Tubes under Cold Currents

AbstractThe temperature distribution of high piers with concrete-filled steel tubes (CFST) is investigated by continuously observing the temperature distribution of Labajin Bridge in Ya’an-Lugu expressway. Mathematical statistical methods are used to study the temperature gradient of the cooling mode. Results show that the closer the distance between the measurement point and the pier center, the wider the gap between the pier temperature and atmospheric temperature, as indicated by the temperature variations along the radius of the CFST section. Under the cold current effect, the direction of the temperature gradient along the radius of the CFST section can be demonstrated by the cubic polynomial. An exponential function is used to describe the temperature difference in the webs. The temperature difference of the cooling mode results in tensile stress on the surface of the pier. This stress is offset at the top of the pier, significantly influencing the internal force in the structure.

Effect of Local Concrete Strength Decline on High Piers' Nonlinear Stability

The nonlinear stability of three main piers of Xiniu bridge was analysed with RM Bridge V8i in this paper. The change of high pier’s nonlinear stability with the strength decline of high pier’s local concrete and variation of high pier’s height were also respectively researched.The results show that nonlinear stability coefficients will be lower if one segment of high pier’s concrete strength declines. It also indicate that the nonlinear stability coefficients drop is related to the decrease of the concrete strength, the distance between the segment at the bottom of pier, and the height of pier.

The Kinetic Performance of High Pier under Seismic Load

With the rapid development of national transportation, many bridges with higher and higher piers crossing sea and clough are constructed. The p-delta effect of tall piers in bridge is so evident that can not be ignored to assure the absolute safety of bridge. Research shows that, in comparison with other ways, energy analysis was simple and versatile for different load combinations in computing upper pier displacement, and neglecting p-delta effect often underestimated the disadvantageous state when the pier is high.

Construction Risk Assessment Research of Continual Rigid Frame Bridge with Concrete-Filled Steel High Piers

Engineering bridge construction is a very complicated system work. The potential risk would occur frequently in the process from construction preparation to completion. The bridgework has fundamental features in huge investment, complex technology, broad engineering, long project life cycle and big impact if an accident happened. Compared to other highway construction process,there are more risks in the process of the bridgework. According to the method of steel tube concrete composite column bridge pier construction on bridge engineering, this thesis identifies the bigger risk factors in the procedure with the analytic hierarchy process. Combined with the technology of the MIDAS/CIVIL and imitating upper structure construction of actual construction process, it quantificationally analyses the construction risk. This could be for the reference to risk analysis on bridge project construction.

Seismic Response Analysis of High Pier and Long Span Rigid Framed Bridge under Non Uniform Excitation

Taking the Longtan River Bridge as the engineering background , the seismic response analysis of high-pier and long-span continuous rigid-framed bridge considering travelling wave effect is simulated by means of the great mass method . Conclusions are drawn under asynchronous and synchronous excitation respectively , between which comparison indicates that the seismic responses for the main beams of continuous rigid-framed bridge are decreased at various degrees , such as the longitudinal horizontal displacement . The travelling wave effects on the piers are also related to the characteristics and locations of the bridge piers and so on .

Dynamic Buffeting Response Analysis of High Pier and Long Span Continuous Rigid Frame Bridge with Stochastic Wind Field

The fluctuating wind field is simulated for digital by using the stationary Gauss processes, which Kaimal spectrum and Panofsky spectrum is used to the simulation of wind target spectrum with different direction and speed. According to Davenport quasi-steady buffeting force model formula, the time-history of wind velocity is converted to Buffeting force time history, which are applied to the Structure model node, combined with ANSYS for long-span continuous rigid frame bridge buffeting response analysis dynamic simulation.Taking a high pier and long span continuous rigid frame bridge as an example, analyzes dynamic buffeting response of the bridge under the action of the stochastic wind field, which as the guidance of high pier and long span continuous rigid frame bridge design work, practice has proved that the method is simple, reliable, also can be a way that dynamic analysis of buffeting response of large span bridge or tower structure under the action of stochastic wind field.

Research on Design and Construction of Continuous Rigid Frame Bridge in Canyon Area

One high piers and long-span bridge in mountainous area is designed as three-span which is 106+200+106 meters. The superstructure is pre-stressed concrete continuous rigid frame, and the sub-structure is hollow thin wall piers among which the highest is 167 meters. Under the background of this bridge, this paper mainly introduces the designing and construction methods of high piers and long-span continuous rigid frame bridge in canyon area, with the expectation to be served as reference to design the similar bridges in the future.