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Taking the Dengkou Bridge on the Yellow River for Baotou -Yinchuan high -speed railway for example, the changing of the waterfronts and sand banks in the wandering reaches, where the bridge is located, and the changing of the cross sections of the river bed are analyzed. Measures to build multiple spans over the changing width of the main channel and reasonably arrange the bridge spans were proposed as the selection of the bridge site could not meet the requirements speculated in Navigation standard of inland waterways and the selection cannot be adjusted. Through the study of the channel layout under the existing conditions, the bridge span plan was optimized and adjusted so that the 4伊178mmain span in the current main channel can meet the requirements of the two-way navigation for representative ships, and the right side span and the side span on the left side of the banks can meet the requirements of one-way navigation for representative ships. The navigable multiple spans of the bridge have covered the changing range of the main channel. The navigable conditions of the channel are satisfied without implementing sand bank and channel protection and channel regulation, and the harmonious and win-win situation of bridge construction and channel protection is realized, which provides certain reference for the bridge design of the same type of project. [ABSTRACT FROM AUTHOR]

Railway bridge construction is long and complex in its process with low visualization, involving a variety of professionals, resulting in low efficiency and low refinement. In view of this development status, BIM technology is used to refine the railway swivel bridge construction to solve the problems of scheme feasibility, structural collision, schedule control and collaborative management in traditional construction modes. Based on the swivel bridge on the Beijing -Harbin Railway Line and the BIM technology, refined management of the construction is realized, the visual interactive analysis of bridge and site information is completed, and a collaborative management platform is independently developed for the project management, which accelerates the speed of the construction works and improves the efficiency. It has practical significance for promoting intelligent construction of bridge works. [ABSTRACT FROM AUTHOR]

Taking the reach of the Yellow River in the Sanshenggong reservoir reach as an example, the method for determining the design navigable water level in the upstream reach of the hydro-junction on the Yellow River is studied so as to provide a basis for the design of bridges on the reach and the evaluation of the impact of navigable conditions. The target reach of this study is the reach of the Yellow River with sluice dams in the plain low head reservoir reach, where the incoming flow at all levels and the peak discharge in the design return period differs greatly. The paper first analyzes the measured large-section data near the bridge site after the flood seasons in 1998, 2012 and 2018, calculates the backwater of the reservoir reach, and selects appropriate calculation sections from the perspective of safety. The maximum navigable water level is determined by analyzing the combination of a 10 -year flood with the water level before the dam in the corresponding flood season and the combination of normal pool level before the dam with the corresponding inflow flow at all levels, and the minimum navigable water level is determined by the combination of incoming flow with multi-year guarantee rate with the corresponding draw down water level before the dam and the combination of minimum operating water level before the dam with the corresponding incoming flow at all levels. [ABSTRACT FROM AUTHOR]

Based on the construction of the Heishui River Bridge during the reconstruction of National Highway G353 in Ningnan County, a supporting project of Baihetan Hydropower Station, the paper presents the research on the bridge construction technology to convert land-based construction to over-water construction of piers for the continuous rigid frame bridge located in a mountainous reservoir. After comparison of pontoon bridges with cable cranes and catwalks, the "pontoon bridge" proposal was selected and accepted, with the pontoon bridge made up of fabricated polythelene pontoons together with a floating platform, a transfer construction elevator and tower cranes. The results show that the "pontoon bridge" proposal had advantages in construction under such special working conditions, and may provide reference for similar projects. [ABSTRACT FROM AUTHOR]

Sea-crossing bridge has bad weather, inconvenient sea traffic, low construction efficiency of cap and difficult construction control, in order to reasonably select the cofferdam structure of the high pile cap of sea-crossing bridge, based on the foundation construction of sea-crossing bridge cap of the DSSG02 bid section of Ningbo Zhoushan Port main passage, this paper compares and selects the schemes of using different structure types of hanging box cofferdam for high pile cap of sea-crossing bridge from the aspects of project cost, structure dead weight, construction efficiency and safety risk, etc., and studies the assembly design, construction and finite element analysis of the new type of composite hanging box cofferdam. The results show that the new type of composite hanging box cofferdam used in this project has the characteristics of relatively low engineering cost, convenient disassembly and installation, clear force and good structural integrity, the maximum displacement and stress of cofferdam and bottom-sealing concrete structure meet the requirements of structural safety and functional use under various working conditions. The research results have a good reference for the subsequent construction of the same type of high pile cap. [ABSTRACT FROM AUTHOR]

Relying on the construction of Zhoudai Bridge in the main passage of Ningbo Zhoushan Port, an exposure test station was carried out simultaneously during bridge construction to evaluate the durability of the bridge's concrete structure. In view of the severe natural conditions such as strong wind, big waves, and high flow velocity, the design and construction technology of the exposure test station were elaborated, the key points of the design and construction technology control of the exposure test station under severe sea conditions were discussed, and a new prefabricated platform construction technology were proposed. The construction of the prefabricated exposure test station is smooth and efficient, which can reduce construction risks, ensure construction quality, and provide a reference for the same type of construction under severe sea conditions. [ABSTRACT FROM AUTHOR]

The main bridge of the Chibi Yangtze River Highway Bridge is designed as a cable-stayed bridge with double tower and double cable plane. In order to optimize the mix proportions of the bridge tower concrete and understand the performance characteristics of the bridge tower concrete, the effects of single addition of fly ash (FA), and the compound of FA and ground blast furnace slag (GBFS) on the performance of the bridge tower C50 grade concrete were investigated, and the influence of mineral admixtures on the microstructure of the bridge tower concrete was analyzed by mercury porosimeter (MIP) and scanning electron microscope (SEM). The results show that the workability and strength of the bridge tower C50 concrete prepared with FA and GBFS composite admixtures meet the design and construction requirements, and its drying shrinkage value is low. Meanwhile, the bridge tower concrete prepared with FA and GBFS composite admixtures are better than the concrete with single addition of FA in early strength and strength development, elastic modulus, resistance to chloride ion permeability and anticarbonation of C50 concrete. Compared with single addition of FA, the composite additions of FA and GBFS had a better action on the refinement of pore structure and the improvement of microstructure of concrete. [ABSTRACT FROM AUTHOR]

Due to low accuracy of the traditional impedance admeasuring apparatus, a portable impedance admeasuring apparatus based on an automatic balance bridge is designed. In the apparatus, a test signal source is obtained by filtering a square wave signal and an I/V conversion circuit is constructed by using a high input-impedance operational amplifier, which leads to accurately measuring the current via a tested unit. After amplitude and initial phase angle of both voltage and current signals of the tested unit are acquired by using the pulse phase discriminating circuit, the impedance parameters of the tested unit are calculated in the single-chip microcomputer system. The experimental results demonstrate that the impedance admeasuring apparatus is of high accuracy and its maximum error is only 0.052% when measuring resistors or resistance-capacitance series-connection networks. [ABSTRACT FROM AUTHOR]

To optimize the design of girder bridge, the proper cell number of the two-lane CSWs PC box girder was investigated. Based on the two-lane CSWs PC box girder bridge design parameter, the mechanical behaviors of single-room girder box with single cell to five cells were analyzed under four different load conditions by finite element analysis (FEA).The mid-span displacement in the bottom flange, the von-Mises shear stress in both corrugated web sides, the normal warping stress and the natural frequency of the box girders were obtained. The results show that multiplying cell numbers can increase the prestressing efficiency and decrease the von-Mises shear stress in both corrugated web sides in some cases. However, with the cell number increasing, the normal warping stress under eccentric load and the dead weight of the girder are increased dramatically. By simple formula method and principal component analysis method, the proper cell number for the two-lane CSWs PC box girder is suggested. [ABSTRACT FROM AUTHOR]

The erection process of the top beam section of the steel concrete composite beam pier is greatly affected by the environment and resource allocation, it is necessary to choose a reasonable erection process according to the actual situation on site. Taking Zhuhai Honghe Bridge Modaomen Waterway main channel bridge project as an example, the erection process of the pier top beam section of the main tower area was discussed and researched, two kinds of erection processes, traditional erection method and innovative erection method, were proposed. The advantages and disadvantages of the two construction processes were analyzed and summarized. According to the actual situation of the bridge site, different erection processes were selected for the two main piers to the construction of the top beam section of the pier, both have achieved good results in the project implementation, provide reference for subsequent similar bridge construction. [ABSTRACT FROM AUTHOR]

In order to verify the dynamic response amplitude and the corresponding structural safety of the single tower and double cable plane cable-stayed concrete bridge structure design scheme under the specific seismic excitation of the project site, based on the relevant theory of bridge structure seismic resistance, relying on the single tower and double cable plane cable-stayed bridge project of Youshui Third Bridge, the internal force response of the main tower single structure and the typical section of the main beam structure in the bridge design scheme was calculated and analyzed by using MIDAS bridge professional finite element software. In the analysis and calculation, in combination with the requirements of the design code, two methods based on the response spectrum analysis and the linear time history analysis were used for independent verification, and the differences between the response spectrum and the linear time history calculation results are evaluated respectively, as well as the similarities and differences with the seismic code. The results show that the dynamic response parameters of the bridge under the seismic action in the code are consistent with the results of linear time history analysis based on the finite element model, and the reasonable value according to the code can simplify the design calculation completely, which has important reference value for the actual engineering design. [ABSTRACT FROM AUTHOR]

The main span of Zhungeer Yellow River Bridge on Rongwu expressway is 440 m double tower and double cable plane concrete cable-stayed bridge. The main beam is more than 120 m away from the ground. The cast-in-place construction of No.0-1 beam section adopts the structure of erecting inclined support on the tower + suction and insertion grouting corbel, which reduces the welding workload between corbel and embedded parts, and reduces the risk of installation and construction of tall support. A series of new technologies and innovative technologies have been adopted in hanging basket automatic control, cable force conversion of stay cable and winter construction in the main girder cantilever construction, which can safely and efficiently complete the main girder construction tasks, and provide experience and reference for similar bridge construction in the future. [ABSTRACT FROM AUTHOR]

Based on the technical guide of highway bridge construction monitoring, the deformation laws of arch ribs of steel bridges were investigated through monitoring the displacement and the internal stress of arch rib at each construction stage in real time. The results show that the variation interval of vertical displacement of steel bridge arch rib at L／4 and 3L／4 is from 0.30 to 13.50 mm under different working conditions, and the vertical displacement range of L／2 is from 0.25 to 11.40 mm under different working conditions. The direction of displacement is vertical downward. The stress range of the arch legs at both ends of the steel arch ribs varies from 6.79 to 26.53 MPa under various working conditions, and the variation range of stress at L／4 and 3L／4 is from 1.60 to 27.93 MPa under various working conditions. The stress variation range at L／2 is from 0.21 to 11.49 MPa under various working conditions, and the stress change is compressive stress. The stress deformation change trend of the symmetrical position for the full span arch rib is consistent, and the whole arch rib produces the maximum displacement change and the internal stress change after the suspender is tensioned under the working condition 2.The construction phase can be used as the key monitoring condition of forced deformation. [ABSTRACT FROM AUTHOR]

Wave and current loads on pile foundation of sea-crossing bridges have always been given priority in the design of sea-crossing bridges. The wave-current force in practical projects is usually obtained by the computing method of wave-current force for single pile foundation recommended in the Code of Hydrology for Harbour and Waterway ( JTS145—2015), without reasonable consideration of the influence of local scour shape. In this study. Hong Kong-Zhuhai-Macao Bridge has been taken as an example. Based on physical model test results, a calculation method of wave-current force for pile foundation considering local scour patterns is proposed by modifying the selection of such parameters as velocity, CD and 6'M in the calculation model. The proposed method, which guarantees the project safety and can be cost-effective as well, has been successfully applied to the design of pile foundation of Hong Kong-Zhu-hai- Macao Bridge. [ABSTRACT FROM AUTHOR]

The Hainan Puqian Bridge designed with a novel structural style, its main pier is supported by two separated independent cap each has 16 steel-concrete composite piles with 4.3 m maximum diameter. The large diameter of pile foundation and steel casing and the complex construction environment will lead to a series of problems in the construction process, such as processing, transportation, subsidence and testing of steel pipe piles. In this paper, the design theory, construction technology and quality control of pile foundation are systematically studied, and a set of oversize diameter steelconcrete composite piles construction methods in meizoseismal area of marine environment is put forward. On one hand, it provides important design and construction technology assurance for the Puqian Bridge pile foundation project, and on the other hand, it improves and enriches the bridge pile foundation design and construction theory in meizoseismal area of marine environment. It has accumulated valuable experience for the similar project design and construction in the future. [ABSTRACT FROM AUTHOR]

To investigate the dynamic response of bridges under non-uniform excitation, a 1/20 reduced-scale continuous beam bridge was designed and fabricated. The seismic simulation shaking table test with non-uniform excitation input was carried out. The extension table was set for the single small vibration table, and the table input excitation was changed to improve the shaking table equipment. The El-Centro and Taft waves suitable for the class Ⅱ field were selected, and the macroscopic failure modes and the time history displacement curve of main parts were analyzed under different seismic intensities. The experimental results show that the bridge damage is increased with the increasing of seismic intensity, and the difference of seismic excitation input between original table and extended table becomes obvious after improving the shaking table equipment. The improved equipment can be used for non-uniform seismic excitation shaking table test of large span bridge structure, and the dynamic response of bridges under seismic effect can also be obtained. [ABSTRACT FROM AUTHOR]

Due to the long-term chloride corrosion, the prestressed concrete box girder in the marine condition is often destroyed, so it cannot meet the requirement of the durability of 100 years. This paper puts forward a series of technical measures, namely, improving the durability of concrete, increasing the concrete cover thickness, painting silane in the surface, using the stainless steel, and adding the corrosion inhibitor. Moreover, based on the reliability theory, the corrosion probability of the main girder in the first rank of the prestressed concrete box girder by different measures is analyzed and compared. And then, some probable technical methods for the prestressed concrete box girder are obtained to meet the requirement of long service life, which can provide a valuable reference for the practical engineering. [ABSTRACT FROM AUTHOR]

The being built Hongkong-Zhuhai-Macao Bridge is about 50 km, and the major project of bridge and tunnel in the sea is 35.6 km, with a design life of 120 years and 6 years long construction period. This project has the longest mileage, largest investment and the biggest difficulty in construction in China construction history of sea-crossing bridge. In order to accelerate the progress and improve the quality, the technology of the integration of precast and aquatic installation is used in the pile caps and piers of the non -navigable bridges. Deep water pier is divided into two/three prefabrication, and prestressed rolling continuous external thread bars are settled in the pier, with a diameter of 75 mm, yield strength of 830 MPa, and tensile strength of 1 030 MPa. All the installation of steel bar and part of the tensioning of the bottom section pier are completed in the pier precasting yard. The rest of the connection, tensioning, and grouting of the prestressed steel bar are conducted in the water conservancy project site. We emphatically expounded the technical process of the installation of CB03 in pier precast yard and tensioning prestressed steel bars in Hongkong-Zhuhai-Macao Bridge project , which has certain reference value to similar construction engineering projects. [ABSTRACT FROM AUTHOR]

Based on the finite element (FE) method and Duhamel integration, a numerical-analytical combined method for the dynamic response problem of an FE bridge under moving loads was proposed, and the conditions of resonance and cancellation for the bridge subjected to multiple moving loads were derived. The FE modes of the bridge structure were first computed and then converted into an analytical form constructed over all the elements of the bridge deck with the element shape functions. The analytical dynamic responses of the bridge were derived from Duhamel integration, and transformed into a simple integration and a summation of the previous results through elimination of the time variable from the integration, which enables the computation process more efficient. The proposed approach has the versatility of the FE method in dealing with structures of arbitrary configurations and the special efficiency and convenience of the analytical method in dealing with moving loads. In the numerical examples, the present method is verified with the Newmark method and the traditional analytical method based on a simply supported beam bridge and a 3-span continuous beam bridge. The results show that the accurate solution of the FE structures subjected to moving loads is obtained with the present method, and no approximation is introduced during the computation process. The conditions of resonance and cancellation are discussed for the problems with multiple moving load, and the influence of the load distances on the responses of the bridge is also revealed. [ABSTRACT FROM AUTHOR]

Field measurement of wind characteristics at site of long-span bridges is one of the basic research areas on bridge wind engineering. The wind characteristics parameters based on field measurement can provide a basis for the verification and modification for wind tunnel testing and simulation technology. A long term and continuous field measurement was carried out with the ultrasonic anemometers and propeller anemometers installed at site of Xi-hou-men Bridge. Based on the data of field measurement, this paper presents the field measurement results of natural wind characteristics of strong monsoon at site of Xi-hou-men Bridge, including turbulent intensities, gust factors, turbulence integral length scales, power spectral density, the profiles of mean wind speed and spatial correlation of gusty wind, and so on. These field measurement results can provide detailed wind characteristics of coastal areas which can be taken as a reference for the design and construction of other similar long span bridges. [ABSTRACT FROM AUTHOR]

The three influencing factors of wind-rain-induced static forces were analyzed aiming at the phenomenon of simultaneous actions of wind and rain for long-span bridge decks, based on the analysis of static load on the bridge deck section. The test method of the increment of wind-rain-induced static forces in joint wind and rain comparing to wind-induced static forces in single wind is given. The wind-rain-induced static characteristics test was carried out in the surroundings of simultaneous actions of wind and rain built in the atmospheric boundary layer wind tunnel, taking a twin-separated box girder as research object. The influencing rule of rainfall on the wind-induced static forces of bridge deck sections was obtained. Experimental results display the effect of impact force of rain on the wind induced drag force of bridge deck sections is dominant in the large negative angle of attack of circumstances. The effect of change of flow field and water film on the surface of bridges on the wind-induced drag force of bridge deck sections is dominant in the small negative and positive angle of attack of circumstances. The gravity of raindrops, impact force of rain, change of flow field and water film on the surface of bridges all have certain contribution on the wind-induced lift force of bridge deck sections. The change of flow field and water film on the surface of bridges play the most important role on the wind-induced pitching moment of bridge deck sections, followed by the gravity of raindrops, finally is the impact force of rain. The result shows that the effect of rainfall on the wind-induced static forces of bridge deck sections is mainly depended on the change of flow field and water film on the surface of bridges. [ABSTRACT FROM AUTHOR]

Based on the three positioning principles for installation in bridge engineering, the fourth positioning principle for installation which is suitable for the construction engineering is put forward. Based on the characteristics and applicability of a few existing analysis methods of construction mechanics for structure and according to the positioning principles of components of structure in actual projects, an improved nonlinear analysis method named element birth and death of local configuration constraint is put forward to solve the problem of death element's 'floating' in this paper. This method was applied in the mechanical emulation and analysis of the Heshi Stupa of Famen Temple during the construction process. The computation results by the improved method agreed with the measured values well in the project. This indicates that the improved method is an effective analysis method of construction mechanics for structure. [ABSTRACT FROM AUTHOR]