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The Dalian Bay Subsea Tunnel is constructed using the immersed tube method, where 18 sections of immersed tubes are prefabricated using a fixed dry-dock. The dock entrance serves as a protective barrier between the dry-dock and the sea, playing a crucial role in ensuring dock safety by preventing water ingress and providing wave protection. On the premise of safety and economy, it is necessary to take into account the convenience of construction and the ease of use. On the basis of summarizing the typical dock gate types for prefabrication of immersed tubes both domestically and internationally, this project adopts the fixed dry dock method, gravity-type dock entrances, and large floating caisson gate system. The dock entrance system incorporates curtain grouting, water stop strips, steel gates, and concrete structure water stop system, and is equipped with the energy dissipation self-flowing water dock gate pier structure. The caisson of floating dock gate adopts cast-in-situ scheme, which can provide reference for similar projects. [ABSTRACT FROM AUTHOR]

In order to promote the industrialization development of reinforcement in pier towers, three kinds of structural optimization design of reinforcement parts were proposed. Taking the connection mode of main reinforcement and stirrup, stirrup structure and stiffness skeleton as parameters, the four-point bending test of two reinforced concrete beams was carried out (the new reinforced concrete beam was referred to as the new beam, and the traditional tied reinforced concrete beam was referred to as the traditional beam), and the bending mechanical properties of the optimized design structure of the new pier tower reinforcement parts were studied. The test results show that the crack distribution of the traditional beam is denser than that of the new beam, the peak load of the traditional beam is about 5% higher than that of the new beam, and the ductility of the traditional beam is slightly higher than that of the new beam. The reinforcement strain of the two specimens is basically consistent with the variation load. Under the same load, the stirrup strain of the new beam is about 50% (500 με) larger than that of the traditional beam, and the stirrup restraint capacity and load sharing ratio of the new beam are higher. In general, the bending resistance mechanical properties of the new beam are basically the same as those of the traditional beam. The welded connection of the main stirrups of the pier tower and the new stirrup structure can be used in practical engineering. [ABSTRACT FROM AUTHOR]

Pile-pier structures in water level fluctuation zone are very common in the current construction of wharves, trestles, bridges and other structures, and their construction is greatly affected by water level changes, the difficulties and costs are high. Based on the project of a heavy loading wharf in Daya Bay Petrochemical Zone of Huizhou City, a widely applicable method for the construction of partially submerged piers, the reverse lifting base mould construction method, has been proposed. This method can create dryland construction conditions without cofferdam work, which has the advantages of low cost, high construction efficiency and low construction difficulty. Through scheme design and load calculation, it is verified that there verse lifting base mould construction method is feasible theorectially, and finally good results were achieved in the construction of the partially submerged pier of the project involved. [ABSTRACT FROM AUTHOR]

An existing mooring pier, as a reserved structure, needs to be evaluated for its bearing capacity when the dock is put into use during the upgrading and renovation. A spatial model is established using finite element software SAP2000, and the ultimate bearing capacity of the mooring pier is calculated based on the actual operating conditions and structure of the mooring pier. To verify the reliability of numerical calculations, a prototype test of the mooring pier was designed and implemented. The test used tugboat graded loading, with displacement as the experimental control parameter, effectively solving the problems of reaction force and difficulty in building the observation system. The numerical calculation results are in good agreement with the experimental results, proving that the method for determining the bearing capacity of the mooring pier is reasonable, and the evaluation results meet the requirements of upgrading and renovation. This provides a reference example for the bearing capacity evaluation methods of similar structures. [ABSTRACT FROM AUTHOR]

The liquid bulk cargo berths No.1 and No.2 of East Second Port Pool in Jida Port Area of Maoming Port are independent pier type cylinder caisson gravity wharf. This paper focuses on the precision control of round caisson installation. Under the influence of uncovered conditions and long period waves in the open sea, compared with traditional caisson installation, this project excavates and optimizes from the aspects of ship machinery equipment, selection of lifting point sling, hoisting mode, and takes effective control measures, which greatly improves the accuracy and efficiency of caisson installation, reduces project cost and safety risks of offshore lifting, and provides valuable experience and reference for the installation of independent pier caissons in similar LPG wharves in the future. [ABSTRACT FROM AUTHOR]

It is difficult to build cofferdams in deep waters with shallow overburden and with high risks. Based on the construction of pier No.31 of Xiangluzhou Bridge, a notching+locking steel pipe pile process is proposed to build the cofferdam. Finite element software was used to analyze the cofferdam structure in various construction stages and the calculation results showed that the strength, stiffness and stability of the cofferdam in each construction stage met the design objectives specified in the design criteria. The key technologies for notching in the cofferdam, sand filling in the notched groove, concrete water stop wall and 义pre-shoring method义 are studied to ensure the smooth implementation of the cofferdam. The result of field practice shows that the process is safe and reliable in construction of pile caps in deep waters with shallow overburden and the risk is controllable. [ABSTRACT FROM AUTHOR]

Xiamen Second East Passage project is a large fabricated prefabricated bridge project similar to the Hongkong- Zhuhai-Macao Bridge (HZMB) in structure and construction technology. In the construction of post-pouring holes for the piers of the HZMB, the circular steel formwork and wood formwork are used to assemble the formwork, and the process of penetrating the whole rebar after the completion of straight thread sleeves connection is adopted for the rebar. This process has low efficiency, serious damage of epoxy rebar coating when penetrating, and low installation accuracy. In order to improve the construction efficiency and quality, the construction technology of pier prefabrication of Xiamen Second East Passage was improved. In the new technology of post-pouring hole construction, the whole supported and disassembled formwork was adopted for the formwork, and the rebar was adopted for the process of laying rebar. Through the analysis of the key technology of the process, it provides experience for similar project construction in the future. [ABSTRACT FROM AUTHOR]

The foundation of the No.5 pier of the Changtai Yangtze River Bridge is designed as a flat round-end type and a stepped -faced open caisson structure. Its dimensions are 95.0 m in length, 57.8 min width and 64min height, which is currently considered the largest underwater steel open caisson in the world. During the second borrowing and sinking construction process, due to the large difference in the stratum distribution, uneven stress on the bottom of the caisson, and strong sensitivity of the long side and short side tilt attitude, the "stepped" method of borrowing was adopted in the construction, following the principles of symmetry, synchronicity and uniformity. Through a series of active control and dynamic correction measures, the caisson sinks efficiently and smoothly. Through inversion analysis, the subsidence coefficient is positively correlated with the subsidence rate. When the subsidence coefficient is less than 1, the caisson will hardly sink; when the subsidence coefficient exceeds 1.1, the sinking rate of the caisson can be further accelerated. Finally, after sinking the open caisson in place, the stress state, support state and geometric attitude are kept in good condition. [ABSTRACT FROM AUTHOR]

In the open sea terminal, the trestle pier generally adopts the high -pile pier platform structure. It has good permeability, small wave reflection, and small resistance to waves and currents. The upper pier platform often adopts the cast in -situ reinforced concrete structure. For the unprotected offshore water transportation project, the construction sea area conditions are harsh, steel casing or concrete casing is usually used as the temporary construction formwork of pier and abutment, and the main structure is poured inside the casing, but the formwork still needs to be removed after the construction is completed. Taking the actual project as an example, this paper proposes a prefabricated shell structure of trestle pier, which is a part of the permanent structure. It can save most of the procedures of erecting and dismantling formwork, reduce the water operation time of constructors and ensure the construction progress. [ABSTRACT FROM AUTHOR]

In order to effectively promote the energy conservation and emission reduction in the water transportation industry and boost the green and low -carbon development, the systematical research of LNG bunkering in the water transportation industry was carried out. Based on the present situation of LNG bunkering wharfs, the paper systematically analyzes the advantages, disadvantages and adaptability of inland river sloping LNG bunkering wharfs and floating LNG bunkering wharfs. In view of the lack of research on vertical LNG bunkering wharfs, a new type of vertical pier LNG bunkering wharf is proposed based on the characteristics of contiguous and conventional pier wharfs. Based on engineering projects, the plan layout and process flow of floating LNG bunkering wharfs and vertical pier LNG bunkering wharfs are compared. The analysis shows that: the new vertical pier LNG bunkering wharf has stronger adaptability, better durability and safety, and less investment. It has good application value and promotion prospect. [ABSTRACT FROM AUTHOR]

A simplified bilateral trigonometric leveling was used to survey the differences of elevations of the top of the piers for the non-navigable span of Hongkong-Zhuhai-Macao Bridge under Contract CB03, which could quickly obtain precise and accurate measurements. Equal-height centering rods and prisms of the same specifications and models, instead of surveying rods, were placed on the benchmarks at the top of different piers and two total stations were employed to survey respectively the elevation differences of the same shore and the elevation differences between the calculated benchmarks of the opposite shore vertical angle and the opposite shore horizontal distances to increase the checking conditions for the loop closure errors in the segments of survey, but the total station was not positioned alternately on the survey station and the benchmarks. The paper introduces the simplified bilateral trigonometric leveling method, the conditions in the surveyed area, and the scheme for bilateral trigonometric leveling. The number of surveying indicators and statistic data distributed in the intervals between the observed values of elevation difference in the 96 surveying segments and 24 loop closures was established according to the observed values of elevation difference and loop closures formed during the construction of Hongkong-Zhuhai-Macao Bridge and precision calculations and analyses were made with the results showing that the presented method can meet the requirement of second order leveling accuracy. [ABSTRACT FROM AUTHOR]

The single segment grouting sleeve prefabricated pier has been applied in practical engineering. In this paper, the model of single segment grouting sleeve prefabricated pier was established by finite element analysis software, and the calculation accuracy of the established finite element model was verified by comparing with the test data. Considering the influence of traffic flow of urban bridges, the influence of urban road height limit and the lifting capacity of lifting equipment, multi-segment prefabricated piers are bound to be a trend. Therefore, a new type of two segment grouting sleeve prefabricatedpier was proposed and the parameter expansion analysis was carried out. Through the change of the parameters such asslenderness ratio, eccentricity and reinforcement ratio, the key parameters affecting the ultimate bearing capacity of the two segment reinforced concrete pier under compression were obtained. The results show that the ultimate bearing capacity of two segment grouting sleeve prefabricated piers (the upper end is hinged and the lower end is consolidated) decreases with the increase of slenderness ratio and eccentricity. The calculation of bearing capacity of two segment grouting sleeve prefabricatedpiers can be referred to the current code of integral pier column. Concrete and steel constitutive structure in GB 50010—2010 Code for design of concrete structure can simulate single or two segment grouting sleeve prefabricated pier better. At the same time, the reasonable connection part of the pier columns of the two segments is located at the length of 0.35~0.45 times the pier column length above the bearing platform. [ABSTRACT FROM AUTHOR]

As a kind of surface protection block, the fence board has good wave dissipation effect, economic project cost, clear lines and certain aesthetic feeling after being connected into one piece. Therefore, it is widely used in the slope protection structure of breakwater, revetment and shore connection structure. At present, the process of "binding and clamping bottom" or" pier bottom" is widely used in the prefabrication of fence plates in China, the bottom formwork shall be cast-in-situ concrete floor or steel formwork. After the cast-in-situ concrete reaches the design elevation, the surface shall be finished manually to complete the prefabrication. Therefore, the appearance quality of the top surface is greatly affected by human subjective factors, and cracks are easy to appear, which affects the quality and service durability of components. By adopting the "reverse" prefabrication process, this problem will be fundamentally solved and provide reference for similar projects. [ABSTRACT FROM AUTHOR]

Relying on the Xiang'an Bridge (the second east passage in Xiamen) project, we introduced a high -precision installation and construction technology for prefabricated piers based on wet operation at sea, mainly aiming at many problems such as difficult water stop and high installation accuracy of offshore piers. The pallet water stop and the steel box water stop ensure the dry working conditions in the piers, and the high -precision installation of the pier is realized by the top three - dimensional jack and the underwater jack. During the hoisting process, the spreader is monitored in real time to ensure the safety of the spreader structure during the hoisting process. [ABSTRACT FROM AUTHOR]

Based on the research background of the approach bridge on the north side of Jinan Fenghuang Road with the main span of 245 m, which is the continuous composite beam with the largest span in China, we analyzed the high sensitivity of beam falling of temporary piers in side span and middle span, and discussed the problem of synchronous beam falling of temporary pier. Two feasible beam falling technical schemes were proposed, i.e., first synchronous falling beam with middle span and then falling beam with side span (scheme 1) and first falling beam with side span and then synchronous falling beam with middle span (scheme 2). Taking the small jacking force or large lifting force and large beam falling amount of temporary pier as the operability principle, the jacking force, equipment and beam falling amount of each temporary pier of the two beam falling technical schemes were compared and analyzed. The results show that the scheme 1 has the characteristics of small jacking force of 630 t for side span temporary pier, small beam falling height of 5.7 cm and good implementation controllability, while the scheme 2 has large pier jacking force of 3 356 t for side span temporary, beam falling height of 29 cm, and poor implementation controllability. Finally, the scheme 1 is adopted as the optimal beam falling technical scheme, which provides reference for the beam falling operation of similar light continuous composite beam bridge projects. [ABSTRACT FROM AUTHOR]

The steel caisson usually needs to be floated to the bridge location with the aid of the floating structure for subsequent construction due to its heavy weight. The current capped floating-aid structure has high requirements for airtightness, and the integral closed bottom floating-aid structure has significant shortcomings such as difficulty in overall removal. In order to solve these problems, a sub-tank bottom-closing floating-aid sealing board structure with convenient disassembly, high processing precision and adjustable draft was proposed. Relying on the No.5 pier caisson project of Changtai Yangtze River Bridge, the structure and construction plan of the sub -tank bottom -closing floating -aid sealing boards were introduced in detail. On this basis, the finite element analysis method was used to simulate the strength and stiffness of the sealing board under different working conditions, which had verified the feasibility and rationality of this structure. The application of this structure successfully completed the floating task of the No.5 pier caisson of Changtai Yangtze River Bridge, and was used as a construction platform after demolition, which successfully saved costs and construction period. It provides anew idea of the optimal design for floating transportation construction technology of steel caisson. [ABSTRACT FROM AUTHOR]

Sluice is one of the main structures in navigation power junction, which mainly plays the role of blocking river water storage and regulating water level. Taking Huzuishan sluice of Xinjiang navigation power junction in Jiangxi as an example, the construction technology of A-type open hump weir was introduced. Through repeated tests on site, it is determined that using the sluice pier fixed with "bailey like frame" as a slip form traction system, it can ensure that the wire surface is formed at one time, the pouring speed is fast, the pouring surface thickness is uniform, the construction period is effectively reduced. Some good engineering results have been obtained.Sluice is one of the main structures in navigation power junction, which mainly plays the role of blocking river water storage and regulating water level. Taking Huzuishan sluice of Xinjiang navigation power junction in Jiangxi as an example, the construction technology of A-type open hump weir was introduced. Through repeated tests on site, it is determined that using the sluice pier fixed with "bailey like frame" as a slip form traction system, it can ensure that the wire surface is formed at one time, the pouring speed is fast, the pouring surface thickness is uniform, the construction period is effectively reduced. Some good engineering results have been obtained. [ABSTRACT FROM AUTHOR]

In the project of height difference measurement between the top of piers with 110 m span in Hongkong-ZhuhaiMacao Bridge CB03 segment, by analyzing the principle of trigonometric leveling, the requirements of specifications and the conditions of survey area, a set of trigonometric leveling scheme for bilateral observation of total station was proposed, to clear observation methods, to determine the technical index, to simplify the operation flows. The height measurement experiment on No.21—No.31 piers was carried out, and the measurement accuracy was calculated, which proves that the scheme meets the requirements [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]

Based on complex and harsh offshore construction conditions and special requirements, the Hongkong-Zhuhai- Macao Bridge non-navigable hole bridge pier adopts factory prefabrication and on-site installation process. The pier platform installation adopts three construction schemes, namely the double -locking steel box cofferdam without internal support structure, the separate capsule flexible water stop structure and the large cylinder dry method are used for the overall installation of the pier. The three schemes are studied and analyzed from the aspects of construction scheme, ergonomics and engineering cost. The characteristics and applicability of the three schemes are proposed, which provides basis for the subsequent installation decision of the sea-crossing bridge piers in China. [ABSTRACT FROM AUTHOR]

The south approach bridge of Shacheng Bay Bridge of Fujian Shacheng Bay cross-sea passage project adopts the steel-concrete composite beam bridge with a standard span of 80 m. The length of the bridge is 928 m, the height difference between the two sides of the bridge is more than 20 m, and the average height of the bridge water pier is close to 50 m, the maximum longitudinal slop is 2.5 %, the curvature of the flat curve is 1/1 730, and there are few information to follow for the top push construction of the large span curvature and high pier groove type beam at home and abroad. By comparing the transfer scheme of the beam section to the field, the risk of high place work is avoided. The joint design optimizes the main structure pier and the groove beam, and realizes the top push construction without support. The design and transformation of the top push system ensure the synchronization of the top push construction, and then put forward a safe and reliable top push and correction construction method. It has high practicability and economy, and can provide some reference for similar bridge top push construction. [ABSTRACT FROM AUTHOR]

The support method has been widely used in the construction of the main beam between the auxiliary pier and the transition pier of the concrete cable -stayed bridge. Concrete cable -stayed bridges in canyon areas limited by complex geographical and geological conditions, there arc many problems in the construction of support method, such as high risk of safety and quality and high cost. In view of the shortcomings of the support construction method, a construction technology of main girder of " mid-span counterweight + post-installation of auxiliary pier installation" is proposed, full cantilever pouring construction of side span beam section of super high pier has been realized, and the cast-in-place bracket adapted to the temperature effect of large cantilever is designed, the construction of cast-in-place section of side span in non-closure section has been realized. This technology is convenient in construction and has good economic benefits, which can be used for reference in similar projects. [ABSTRACT FROM AUTHOR]

In order to ensure the structural safety of the anti-fouling device in the water intake open channel of nuclear power plants and further ensure the safety of water intake from nuclear power plants, through a wave physical model test, the stress of the main cable and the anchor pier of the anti-fouling device under different water level, different wave and different blocking rate is obtained, the structural strength of the main cable of the anti-fouling net is analyzed, and the change rule of the internal force of the pier structure of the anti-fouling net with the blocking rate is studied, which provides the input parameters for the structure design. The research can provide reference for other anti-fouling facilities. [ABSTRACT FROM AUTHOR]