Concrete Continuous Rigid Frame Research Articles

Control Technology on Jacking Closure Construction of Liangjiang Great Bridge

Prestressed concrete continuous rigid frame bridge is widely used in bridge engineering. Its closure is one of very important working procedure in the bridge construction. In this paper, taking Liangjiang Great Bridge in Xinxu Highway as an example, the methods for determining the Jacking force and displacement are discussed. The implementation of the process and construction technology of closure jacking scheme is introduced in detail. Through the finite element simulation, the stress state of on the structural pusher is analyzed. And the maximum stress of the pier bottom and the displacement of the pier top are obtained. They can verify the feasibility of the scheme. Monitoring results from the site construction verify the safety of the scheme. The method has a certain reference value on jacking closure construction for the similar bridge.

Influence of Tensioning Stress to Web Cracking of Rigid Frame Bridge in Cantilever Construction

Cantilever construction is main mode for prestressed concrete continuous rigid frame box-girder bridges, but the diagonal cracks on web are often appeared in construction. The prestressed tension is an important part of the construction beyond doubt. This article takes a bridge under construction as the background to analyze the variation of stressed in the process of construction by MIDAS FEA. The result shows that the vertical steel stretch-drawn in advance has to be a consensus in future.

Study on the Reasonable Alignment of the Steel Truss Concrete Composite Continuous Rigid Frame Bridge

The alignment of steel truss concrete composite continuous rigid frame bridge (STCR in short) has a significant influence on the distribution of internal bending force, the research concerning the reasonable alignment, however, is very limited. In the negative bending moment section of STCR, the bottom chords are in compression state, in addition, the secondary moment caused by the joint stiffness of STCR is too significant to be neglected, therefore, these bottom chords are compression and bending members, which mechanical characteristics are somehow similar to that of the main arch of the open spandrel arch bridge, with the difference lies in that the bottom chord of STCR in the mid-span is in tension while the arch in the mid-span of open spandrel arch bridge is still in compression. On the basis of the method that determine the reasonable alignment of open spandrel arch bridge, a segmental pressure line method is proposed to determine the reasonable alignment of STCR: (1) Select an initial approximate reasonable axis for the bottom chord and a specific load condition, and calculate the internal force of members through finite element model analysis; (2) Select the compressed bottom chord as the research object, make the internal force of the adjacent members as external force to the research object and apply them to the corresponding position, repeat the iterative calculation, and get the discrete node coordinates that approximate the real pressure line; (3) Take the discrete nodes and the bottom chord node in the mid-span as the controlling nodes, using the curve fitting method to get the parabola alignment that can be applied to practical engineering. To validate this method, a detailed engineering application was introduced. Results of the example show that the proposed method is simple and efficient, it can significantly reduce the internal bending force of each member, and improve the internal force distribution state of STCR.

Analysis on Seismic Performance of Corrugated Steel Web Continuous Rigid Frame Bridge

Corrugated steel web continuous rigid frame bridge is a new form of bridge. Using the finite element analysis software Midas Civil to analyze dynamic characteristics of the corrugated steel web continuous rigid frame bridge in a method of subspace iron and the nonlinear dynamic time history analysis method is used to analyze the seismic performance of the bridge, then compared with the ordinary concrete web continuous rigid frame bridge. The results show that the natural frequency of the corrugated steel web continuous rigid frame bridge is smaller than that of the concrete web continuous rigid frame bridge, and the seismic performance of the corrugated steel web continuous rigid frame bridge is superior to that of concrete web continuous rigid frame bridge, the improvement of the seismic performance of piers is most significant.

Research on Ultimate Load of Highway Prestressed Concrete U-Shaped Continuous Rigid Frame Bridge Based on Nonlinear Finite Method

Prestressed concrete U-shaped continuous rigid frame bridge is a kind of highway concrete bridge which consists of deck plate, edge beam and side beam and other parts. Based on solid degenerate shell element and with the help of layered shell element to simulate the concrete and steel, the spatial prestressed effect can be implemented. At the same time, the cracking, yielding and crushing performance of concrete nonlinear change can be described through appropriate criteria. Research results have shown that the calculated data are of good stability and convergence compared with using SOLID65 element in ANSYS. Early load of the prestressed steel has a smaller increase in linear stage and a rapid increase in the later nonlinear stage. The results provide a reliable calculation method of the ultimate bearing capacity of the highway U-shaped prestressed concrete structures.

Effect Evaluation of Web Reinforcement of Continuous Rigid Frame Bridge

Based on a prestressed concrete continuous rigid frame bridge reinforcement project, the finite element model of the bridge was established, which includes two kinds of work condition of before and after bridge reinforcement. The finite element model had analyzed the change of natural frequency, deflection and bending stiffness after the web reinforcement of a prestressed concrete continuous rigid frame bridge, in which we have got analysis results that web reinforcement bridge deflection is less than before reinforcement, and the changing law is obvious as inversely proportional relationship, at the same time, the changing law of natural vibration frequency of web reinforcement bridge and original bridge is not obvious, so only deflection but natural vibration frequency can effect evaluation of web reinforcement of continuous rigid frame bridge.

Optimization of Prestress Reinforcement Design in Large-Span Prestressed Concrete Continuous Rigid Frame Bridges

As the span became longer and the accumulation of service period of bridges, the problem that deflection of main span has also clearly emerged. To reduce long term deflection of large-span prestressed concrete continuous rigid frame bridges, tendon group-additional bending moment influence matrix method is proposed to optimize the design of prestressed reinforcement. Based on elasticity assumption, an optimum prestressed tendon arrangement can be derived by least square method. The new design is tested to be effective considering shrink and creep effect which fulfills the practical application.

Design and Test Analysis of Mid-and-Long Term Monitoring System for External Prestressed Continuous Rigid Frame Bridge

Study and design a set of economical and practical mid-and-long term monitoring system for long-span prestressed concrete continuous rigid frame bridge relying on the engineering of Xintan Qijiang Bridge in Chongqing. Master the static characteristics of such parameters as displacement, stress and external cable force during operation process of bridge through finite element model and make a comparative analysis of the relevant data after running for two years to test the feasibility and practicability of mid-and-long term monitoring system for continuous rigid frame bridge suggested in the paper.

Crack Detection and Analysis of Long-Span Continuous Rigid Frame Bridges

As more and more large-span prestressed concrete continuous rigid frame bridges have been constructed, different types of cracks have appeared on box girder, which not only spoils the beauty, but also reduces the safety and durability of these bridges. This paper sees one rigid frame bridge on the highway as the research background, and then detects and analyzes the cracks appeared on the web plates of the long-span prestressed concrete rigid frame bridge in construction phase. In the last, it discusses the major causes of the cracks on the web plates with ANSYS simulation analysis results.

Asymmetric of Continuous Rigid Frame Bridge Precamber and Construction

Prestressed concrete continuous rigid frame bridge has the advantages of no expansion joints, smooth driving the advantages,however, due to cross under serious scratch,seriously affect the service life of the bridge.Take a Large span asymmetric continuous rigid frame bridge of Guizhou as engineering background,use finite element Program Midas/Civil modeling,carried out Analysis of the construction process,And select a reasonable way to Set the bridge pre-camber,and provide reasonable data for the construction of control,to ensure the bridge structure linear reasonable.

Investigation on Closure Temperature of Long-Span Pre-Stressed Concrete Continuous Rigid-Frame Bridge

Based on a long-span pre-stressed concrete continuous rigid frame bridge, the Chaoyangsi bridge, the influence on stress and deformation of the girder caused by different closure temperature was analyzed. With the aided platform Midas/Civil, comparative analysis of three different closure temperatures was carried on to determine the reasonable one. It is concluded that different closure temperature has important influence on girder stress, but the most dangerous stress combination of girder under serviceability limit state could be taken as remain the same. Though different closure temperature has little influence on the displacement of girder, it is recommended to pay highly attention to the influence on the mid-span vertical displacement when doing the formwork. And finally this article puts forward some effective measures to prevent and reduce the temperature effect.

Analysis of Effective Pre-Stress and Stiffness of the Continuous Rigid Frame Bridge in Service Based on Inversion Theory

Due to the shrinkage, creep, friction and other factors, the pre-stress applied to the beam is not a constant. It is important to obtain the information of the pre-stress in order to ensure security of the bridge in service. To solve the problem mentioned above, the paper puts forward a new way to analyze the effective pre-stress using the displacement inversion method based on the inversion theory according to the measured vertical deflection of the bridge in service at different time. The method is a feasible way to predict the effective pre-stress of the bridge in service. Lastly, taking the pre-stressed concrete continuous rigid frame bridge for example, the effective pre-stress and stiffness are analyzed by establishing the finite element model.

Analysis of Effective Pre-Stress of Continuous Rigid Frame Bridge in Service Based on Inversion Theory

Due to the environment, climate, loads and other factors, the pre-stress applied to the beam is not a constant. It is important for engineers to track the state of the pre-stress in order to ensure security of the bridge in service. To solve the problem mentioned above, the paper puts forward a new way to analyze the effective pre-stress using the displacement inversion method based on the inversion theory according to the measured vertical deflection of the bridge in service at different time. The method is a feasible way to predict the effective pre-stress of the bridge in service. Lastly, taking the pre-stressed concrete continuous rigid frame bridge for example, the effective pre-stress is analyzed by establishing the finite element model.

Test and Research of Long-Term Stress Variation of High-Pier & Long-Span Continuous Rigid-Frame Bridge

Pre-stressed concrete continuous rigid frame bridges have been widely used for modern long-span bridges due to its advantages, such as comfortable for travelling, easy to be constructed and maintained etc. However, cracks and excessive mid-span sag of box girders generally exist in many built bridges of this kind during service, and because of its large size and the complex natural environment, it is particularly important to study the long-term performance based on the long-term field measurements. In this paper, a high-pier & long-span pre-stressed concrete continuous rigid-frame bridges, with five-spans (106m+3×200m+106m), was taken as the research object, by pre-embedding strain sensors in mid-span sections and root sections on box girders, field-tests for stress variation were conducted in extreme weather conditions (ie, the hottest and coldest in one year) after its completion in two years, providing tested data for studying long-term performance of bridges similar to the same kind.

连续刚构高性能混凝土配合比设计

连续刚构高性能混凝土配合比设计

Design of Prestressed Concrete Continuous Rigid Frame Bridge with V-Shape Piers

This paper introduces the design of a prestressed concrete continuous rigid frame bridge with V-shape piers built in Shijiazhuang city, China. The model and structural shape of this bridge were stated considering the factors such as hydrology, environment, artistic display and construction technology. The V-shape piers in main elevations combining the changed sections and larger hanged roof of box-girder gave out the lively and attractive views of whole bridge. The design software MIDAS/Civil was applied to build the numerical model for analyzing the static properties of the bridge structure. The results show that the loading performances of the bridge meet the specifications of current Chinese design codes. The bridge has been constructed and operated since Jan. 2010, which is becoming a main linkage between city and outskirts, and a landscape of the Taiping River Park of the city.

The Detection Research of Tension about Vertical Prestressed Fine Rolled Twisted Bar in Box-Girders Construction of Civil Engineering

At present, vertical prestress detection is almost blank during box-girders construction of civil engineering . In order to effectively detect the effective tension at box-girder construction process in civil engineering based on the theory of structural dynamics, scene detection means, the relationship of box-girder vertical prestressing tensile force and dynamic characteristics of the exsertion segment reinforced was established. Vertical prestress of part of the box beam segments of a three-span prestressed concrete continuous rigid frame was detected , the shortcomings of the current vertical prestressing tensile force was analyzed . The results show that: the proposed method is direct, effective and able to effectively monitor the vertical prestressing tensile force. The research has important theoretical and engineering applications for crack prevention of box-girders.

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.

Statistics and probability analysis of vehicle overloads on a rigid frame bridge from long-term monitored strains

It is well known that overloaded vehicles may cause severe damages to bridges, and how to estimate and evaluate the status of the overloaded vehicles passing through bridges become a challenging problem. Therefore, based on the monitored strain data from a structural health monitoring system (SHM) installed on a bridge, a method is recommended to identify and analyze the probability of overloaded vehicles. Overloaded vehicle loads can cause abnormity in the monitored strains, though the abnormal strains may be small in a concrete continuous rigid frame bridge. Firstly, the abnormal strains are identified from the abundant strains in time sequence by taking the advantage of wavelet transform in abnormal signal identification; secondly, the abnormal strains induced by heavy vehicles are picked up by the comparison between the identified abnormal strains and the strain threshold gotten by finite element analysis of the normal heavy vehicle; finally, according to the determined abnormal strains induced by overloaded vehicles, the statistics of the overloaded vehicles passing through the bridge are summarized and the whole probability of the overloaded vehicles is analyzed. The research shows the feasibility of using the monitored strains from a long-term SHM to identify the information of overloaded vehicles passing through a bridge, which can help the traffic department to master the heavy truck information and do the damage analysis of bridges further.

Construction Monitoring Techniques for JU-MA River NO.3 Bridge

Construction monitoring is a system, especially for long-span pre-stressed concrete continuous rigid frame bridge. Based on the construction control of the right bridge Ju-ma River NO.3 Bridge, this paper has made comprehensive conclusion and detailed discussion in the aspects of construction control method, the basic process of construction control, and bridge construction control survey methods. The findings described herein will provide considerable reference for the construction control of other similar long-span bridges.