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In order to overcome the influence of shallow seas, low headroom and existing bridge structure on the construction of jet grouting piles, the construction technology of mobile working platform + jet grouting with connecting rods at sea was studied and put into practical application, based on the contraction practice of the East Artificial Island of Shenzhen-Zhongshan Link. Engineering practice shows that: 1) the construction technology of mobile working platform + jet grouting with connecting rods effectively solves the technical problems in jet grouting pile construction at sea and the working platform has a wider applicable range; 2) the dynamic speed control system based on theoretical calculation formulae can better ensure the quality of jet grouting pile construction, and the deviation rate of cement dosage is only 2.4% ; 3) the impact of the construction process on the existing bridge structure is mainly manifested in horizontal displacement in the down-bridge direction and the deformation value fluctuates in the range of -1.3 ~1.7 mm, which meets the high requirements for deformation control of extremely sensitive buildings (structures). [ABSTRACT FROM AUTHOR]

Scissor-like bridges can quickly build emergency channels after disasters and improve rescue efficiency. In view of the characteristics of poor stiffness and low material utilization of scissor-like elements（SLEs）, a new cable supported scissor-like deployable bridge（CSSDB）for emergency was proposed combined with cable supported system. In order to investigate the behavior of CSSDB, Karamba3D was adopted to establish the finite element model, and parametric analysis was carried out under the action of moving vehicle load, considering the struts’ length and numbers, the SLEs’ cross section, the initial prestress amplitude and the expansion angle. Besides, Galapagos was used to optimize the CSSDB with the minimum structural mass as the optimization objective. The results show that increasing struts’ number, struts’ length and initial prestress can effectively reduce the stress and deflection of SLEs, while the stress and deflection can be increased by increasing expansion angle. Increasing thickeness of SLEs’ cross section reduces stress and increases deflection instead, and the CSSDB’s performance is still dependent on bending of SLEs. The optimization reduces structural mass by 38.89%, and the stress and deflection of CSSDB are 0.25 and 0.2 times than that of the corresponding scissor-like bridge, which proves the superiority of the CSSDB. [ABSTRACT FROM AUTHOR]

：In order to build an island in the sea area of deep silt stratum under the existing expressway bridge and realize the purpose of filling construction to ensure the safety of the bridge, taking the construction of the east artificial island of Shenzhen Zhongshan Link as an example, the backfilling direction and thickness of the island reclamation were determined by numerical analysis method, and the key construction technology method of " constructing isolation steel sheet pile first, then laying sand quilt, and then backfilling sand symmetrically in layers" was proposed. Through the automatic monitoring of the whole process, it is found that the cumulative changes of settlement and displacement of expressway bridge piers are less than1mm, which realizes the safety protection of existing bridges by island reclamation construction in sea area. The results show that the construction technology of island reclamation in the sea area is feasible and the influence on the settlement of adjacent buildings is controllable. The research results can be used for reference for similar projects. [ABSTRACT FROM AUTHOR]

Based on the study of the existing pile driving barge at home and abroad, aiming at the needs of offshore wind turbine and pile foundation construction of sea crossing bridges, the super large pile driving barge with pile frame height of 133 m has been developed, which has made innovations in the optimization selection of main dimensions, the optimization design of pile frame system, and the improvement of hydraulic system. It provides a reference for the designing of similar ships. [ABSTRACT FROM AUTHOR]

Offshore piled wharves are usually connected to land area by approach bridge. The approach bridge structure isgenerally of high pile beam and plate type, and the superstructure forms the bridge deck system by erecting prestressed T beams. Due to the characteristics of a large weight and long span, the T beams are usually installed by crane ships. Therefore,the construction cost and safety risk are high. For Indonesia Shenhua Guohua Java 7 Power Plant Project, the maritime nonrotating synchronous double hoisting technology was applied to install T-beam. During the hoisting process, the lifting distance was adjusted by the ups and downs boom to control the installation position of T -beam, which effectively reduced the construction safety risks. It is the first application in the industry, and has achieved good economic and social benefits, which provides a reference basis for similar engineering construction. [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]

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]

Kelp drying plays an important role in kelp processing and storage. However, there are some challenge issues in the kelp drying, such as high labor cost and high power consumption. In order to solve these issues in kelp drying, reduce the labor intensity, save power consumption, and improve the quality of products, a new type of sea-belt drying system combining the natural drying method with the heat pump drying method has been proposed. The new system is based on a task force and cascading design and consists of 5 parts, namely drying room, heat pump room, palletizing device, bridge part and control room. The automatic control system for the kelp drying includes data communication function, dry rod position tracking function, and environmental parameter measurement function. Without the manual labor, such as transport and tumble the fresh kelp, 50 drying rods hanging 100 kg of fresh kelp are automatically lifted to the drying room, a support frame with a length, width and height of 34.5 m × 6 m × 6.5 m for natural drying. The Siemens programmable logic controller (PLC) is used to communicate with the G120 inverter. The Universal Serial Interface (USS) protocol is employed to achieve long-distance acceleration and deceleration of the target position. The Process Field Bus (PROFIBUS) protocol is utilized to communicate with the Sick barcode positioning sensor to ensure accurate positioning of the drying rod. The rod track is used to synchronize the running motor and position the palletizing equipment. The limit switches are used to generate the trigger signal for kelp transmission from the drying room to the heat pump room, that is, the automatic bridge function. The heat pump drying method is to ensure the moisture content of kelp drying achieving high quality after the natural drying procedure. After completing the design of the automatic control system, several kelps are selected as the experimental samples. The test results showed that the walking motor can be adjusted by frequency conversion. The maximum speed is 20 m/min, the minimum speed is 3 m/min, and the maximum efficiency can be achieved before the target position 50 cm to start the deceleration. The distance between the two drying rods in the drying chamber is 37 cm and can also be precisely located. After the natural drying procedure by the sun-drying and air-drying actually, the moisture content of kelp is about 60 %. When the natural drying level (subject to the sunlight-drying degree and air-drying degree) is insufficient, the kelp should be transfer from the drying room to the heat pump room for further drying. The rails of the drying chamber must be connected to the rails of the heat pump chamber. Then the drying rods hanging the kelp automatically are transferred to the support frame in the heat pump room with a length, width and height of 6.5 m × 6 m × 5.6 m. The distance between the two drying rods is 12 cm, which can be precisely located. The moisture content of kelps are dried to about 15.2% eventually, without sediment, impurity rate of 0%, grade I. The whole operation time is about 5.7 h. The results showed that the novel kelp drying system can achieve high quality products with very low energy consumption and labor cost. In addition, it can be used as a reference in the algae processing industry. [ABSTRACT FROM AUTHOR]

Kelp drying plays an important role in kelp processing and storage. However, there are some challenge issues in the kelp drying, such as high labor cost and high power consumption. In order to solve these issues in kelp drying, reduce the labor intensity, save power consumption, and improve the quality of products, a new type of sea-belt drying system combining the natural drying method with the heat pump drying method has been proposed. The new system is based on a task force and cascading design and consists of 5 parts, namely, drying room, heat pump room, palletizing device, bridge part and control room. The automatic control system for the kelp drying includes data communication function, dry rod position tracking function, and environmental parameter measurement function. Without the manual labor, such as transport and tumble the fresh kelp, 50 drying rods hanging 100 kg of fresh kelp are automatically lifted to the drying room, a support frame with a length, width and height of 34.5 m × 6 m × 6.5 m for natural drying. The Siemens programmable logic controller (PLC) is used to communicate with the G120 inverter. The Universal Serial Interface (USS) protocol is employed to achieve long-distance acceleration and deceleration of the target position. The Process Field Bus (PROFIBUS) protocol is utilized to communicate with the Sick barcode positioning sensor to ensure accurate positioning of the drying rod. The rod track is used to synchronize the running motor and position the palletizing equipment. The limit switches are used to generate the trigger signal for kelp transmission from the drying room to the heat pump room, that is, the automatic bridge function. The heat pump drying method is to ensure the moisture content of kelp drying achieving high quality after the natural drying procedure. After completing the design of the automatic control system, several kelps are selected as the experimental samples. The test results showed that the walking motor can be adjusted by frequency conversion. The maximum speed is 20 m/min, the minimum speed is 3 m/min, and the maximum efficiency can be achieved before the target position 50 cm to start the deceleration. The distance between the two drying rods in the drying chamber is 37 cm and can also can be precisely located. After the natural drying procedure by the sun-drying and air-drying actually, the moisture content of kelp is about 60 %. When the natural drying level (subject to the sunlight-drying degree and air-drying degree) is insufficient, the kelp should be transfer from the drying room to the heat pump room for further drying. The rails of the drying chamber must be connected to the rails of the heat pump chamber. Then the drying rods hanging the kelp automatically are transferred to the support frame in the heat pump room with a length, width and height of 6.5 m × 6 m × 5.6 m. The distance between the two drying rods is 12 cm, which can be precisely located. The moisture content of kelps are dried to about 15.2% eventually, without sediment, impurity rate of 0%, grade I. The whole operation time is about 5.7 h. The results showed that the novel kelp drying system can achieve high quality products with very low energy consumption and labor cost. In addition, it can be used as a reference in the algae processing industry. [ABSTRACT FROM AUTHOR]

To solve the problem that the vehicle bridge coupling method could not directly solve the long-gauge strain of bridge, the solution method for the dynamic long-gauge strain time history of bridges was investigated under the moving vehicle loads. Considering the influence of road surface irregularity, the dynamic solution equation of the long-gauge strain of bridge in the vehicle bridge coupling system is solved by MATLAB software. The dynamic long-gauge strains in the middle of bridge span at different speeds were solved and compared with the traditional point strain time history. The results show that the long-gauge strain and the point strain time history are generally close. When the vehicle speed exceeds 20 m·s-1, the difference between them is slight. Under different vehicle speed conditions, the long gauge dynamic strain time history and the point strain time history have the same change regularity with vehicle speed. The variation regularity of long-gauge strain with vehicle speed and the accuracy of theoretical test are verified. [ABSTRACT FROM AUTHOR]

In the construction of the pile foundation of the bridge over water, the steel casing is often used as the retaining structure. After the steel casing is sunk in place, the steel casing must be removed and then sunk again because of construction deviation or design change. In order to develop a safe, economical and efficient steel casing removing process, relying on the Jinfeng Bridge in Zhangzhou, we studied the steel casing removing process of "gas cap method + vibrating hammer" through the comparison of schemes and theoretical analysis, summarized the construction key points of the technology, verified its economic rationality and safety reliability, which can be popularized in similar projects. [ABSTRACT FROM AUTHOR]

In view of the low efficiency of bridge maintenance decision-making， insufficient maintenance funds and unreasonable fund allocation， a multi-objective decision-making method for bridge deck maintenance scheme of highway was proposed. Firstly， a database was established to collect quantitative data of maintenance methods. Secondly， entropy-weight TOPSIS and analytic hierarchy process (AHP) were used to determine the maintenance priority coefficients of bridge decks in highway networks and the weights of maintenance objectives respectively. Thirdly， a multi-objective decision-making model based on 0-1 knapsack problems was established. Finally， five bridges on Raocheng Highway (G1501) located in Shenyang city in Liaoning Province， China were taken as a case study to demonstrate the validity and the effectiveness of the proposed method. The results showed that the proposed method considers the maintenance priorities of bridge decks during the maintenance decision-making process and can give reasonable and feasible maintenance solutions， thus it can be an effective support for the maintenance decision-making management of highway bridges. [ABSTRACT FROM AUTHOR]

Deformation data feature extraction and analysis is a key issue to be solved in building deforma⁃ tion prediction, early warning and mechanism interpretation. For this reason, An improved variational mode decomposition algorithm （IVMD） is established to construct a new method of feature extraction and analysis of deformation data. The K value of variational mode decomposition is determined by sample entro⁃ py, center frequency ratio and correlation coefficient to establish improved variational mode decomposi⁃ tion , and the new algorithm is tested by simulation signal and bridge deformation monitoring data. The re⁃ sults show that IVMD can accurately extract the component signals contained in the simulation signals, and its correlation coefficient (R) and root mean square error （RMSE） indexes are superior to empirical mode decomposition （EMD） and wavelet transform methods. The reliability of IVMD algorithm is verified theoretically. Based on IVMD, the natural frequency and damping characteristic parameters of the bridge can be extracted accurately, and the deformation characteristic information of the bridge caused by tempera⁃ ture change, multi⁃path effect and other environmental impacts can be extracted well, which confirms the validity of IVMD in feature extraction and analysis of deformation monitoring data. [ABSTRACT FROM AUTHOR]

Waterfront resources in the middle reaches of the Yangtze River are abundant, with quite high value of development and utilization. This paper establishes, based on sufficient analysis on characteristics of waterfront resources and geological environmental conditions in the middle reaches of the Yangtze River, the evaluation model for construction appropriateness of major projects such as port and wharf, river-crossing bridge and river-crossing tunnel etc. in the perspective of geology; classifies various project types into four levels i.e. appropriate for development, relatively appropriate for development, generally appropriate for development, and non- priority development by analytic hierarchy process (AHP) and conducts zoning evaluation. According to the results, the port terminal in the middle reaches of the Yangtze River is dominated by non-priority development areas, with a length of 931.47 km, accounting for 46.71% of the total length of the coastline; cross-river tunnels and cross-river bridges are mainly suitable for development and generally suitable for development areas, with the lengths being 1550.75 km and 1224.18 km, respectively, or 77.77% and 61.39% of the total length of the coastline. Finally, we put forward suggestions and rectification measures according to characteristics of each project level, so as to privide a theoretical basis for construction and deployment of major projects in terms of geology, promote the scientifically reasonable development and utilization as well as the effective protection of waterfront resources in the middle reaches of the Yangtze River, and further facilitate the development of Yangtze River Economic Zone and national spatial planning, and protect the sustainable and sound development of Yangtze River. [ABSTRACT FROM AUTHOR]

Taking the single tower cable-stayed bridge of Youshui Third Bridge as the background, based on the finite element program Midas Civil, the overall numerical analysis of the single tower cable-stayed bridge structure system was carried out. The influence of single load and load combination condition on the stress and deflection of main beam, internal forces and horizontal displacement of main tower, and internal force and stress of stayed cable of single tower cable-stayed bridge in the stage of completion and operation were studied. The results show that the secondary adjustment in the bridge stage makes the cable tower pre-biased to the side span. The pre-bias magnitude is the horizontal displacement induced by the maximum influence of the car on the cable tower, indicating a reasonable bridge state; the influence of the system temperature and temperature gradient on the deflection and cable force of the main beam is not significant; the stress amplitude of the side cable force does not vary notably and the stress amplitude of the main span cable reaches to the maximum magnitude under the combined load condition. [ABSTRACT FROM AUTHOR]

Taking a continuously curved box girder bridge on ramp as example, the coupling vibration response and the impact coefficient of space vehicle-bridge of the bridge were analyzed. Considering the influence of bridge damping ratio and bridge deck irregularity, the general software of ANSYS was used to simulate the bridge. The vehicle was simplified to 16-degree-of-freedom model. The coupled vibration response MATLAB program of highway curved box girder bridge was compiled by modal synthesis method, and the dynamic response of continuously curved box girder bridge was investigated under multi-vehicle loading. The results show that the impact coefficient of the vertical deflection of main girder is less affected by the number of transversely loaded vehicles, and the dynamic response of the outer web of the mid-span section is the largest. It is suggested that the impact coefficient at the outer web should be used for the design. When the longitudinal vehicle spacing is fixed with the vehicle speed less than 22 m·s-1, the impact coefficient is the maximum under the single-vehicle condition and is decreased significantly with the increasing of the number of vehicle loading at the longitudinal direction. When the vehicle speed is more than 22 m·s-1, the impact coefficient of the main girder under the longitudinal two-vehicle and three-vehicle conditions fluctuates up and down the impact coefficient curve under the single-vehicle condition. The longitudinal vehicle spacing has little influence on the impact coefficient in the design. [ABSTRACT FROM AUTHOR]

In order to further improve the detection accuracy of the sensor， a systematic theoretical investigation on the vibration characteristics of a nanomechanical sensor with a micro-particle adsorbed at various positions was carried out. Taking the typical micro-suspended bridge structure as the research object， considering the influence of the particle’s own mass， and using the perturbation theory， the expression of the exact mode shape and the corresponding resonant frequency of the loaded micro-suspended bridge was obtained. By this method， the relationship between the mass of the adsorbed particles and the dynamic characteristics of the micro-suspended bridge can be easily determined. The results show that the particle with larger mass has a great influence on the performance of the micro-suspended bridge. With the increase of the mass of the particle to be tested， the change of the mode shape of the micro-suspended bridge cannot be ignored. Finally， the accuracy of the result was verified by finite element simulation. [ABSTRACT FROM AUTHOR]

The No.4 main pier of Zhuankou Yangtze River Highway Bridge is located in the deep shoal area of the Yangtze River. The construction water area has no overburden and the rock lace is inclined. Through the analysis and comparison of various widely used steel cofferdam positioning systems, the positioning system construction technology of reinforced concrete comb anchor + single positioning ship can minimize the impact of cofferdams construction on the passage of the channel vessels, and provide effective anchoring forces to ensure the fine positioning requirements of the cofferdams in waters without overburden. At the same time, through the method of setting the back pressure bracket at the foot of the steel cofferdam and installing the steel support pier support after the cofferdam sinks the bed, the problem of the plugging of the inclined rock face cofferdam can be effectively solved, compared with the traditional blasting construction and the design scheme of the special shaped steel cofferdam, this scheme has low safety risks, saves construction time and creates good economic benefits. [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 No.4 main pier of Zhuankou Yangtze River Highway Bridge is located in the deep shoal area of the Yangtze River. The construction water area has no overburden and the rock face is inclined. Through the analysis and comparison of various widely used steel cofferdam positioning systems, the positioning system construction technology of reinforced concrete comb anchor + single positioning ship can minimize the impact of cofferdams construction on the passage of the channel vessels, and provide effective anchoring forces to ensure the fine positioning requirements of the cofferdams in waters without overburden. At the same time, through the method of setting the back pressure bracket at the foot of the steel cofferdam and installing the steel support pier support after the cofferdam sinks the bed, the problem of the plugging of the inclined rock face cofferdam can be effectively solved, compared with the traditional blasting construction and the design scheme of the special shaped steel cofferdam, this scheme has low safety risks, saves construction time and creates good economic benefits. [ABSTRACT FROM AUTHOR]

Dynamic load test is an effective method to analyze the dynamic characteristics of bridges. Firstly, through TST5926 EV large scale structure dynamic characteristic test and analysis system, taking Yu-Quan Bridge of Jiangsu Normal University as the research object, the field test was carried out. Based on environmental incentives, the first two order natural frequencies, damping and vibration patterns of the bridge were determined by the basic frequency modal test. Secondly, through the running car test and brake test under different speed, the maximum and minimum dynamic deformation of the bridge was measured by using TST5925 EV wireless telemetry dynamic strain measurement and analysis system. Using the relationship between the dynamic amplification coefficient and the impact coefficient, the impact coefficient of the bridge was calculated. As the speed of the sports car increases, the impact coefficient presents an approximate sine curve. [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]

To assess bridge risk of terrorist attacks，this paper proposed a simulation model of risk assessment based on analytic network process (ANP). Through building bridge terrorism attacks risk assessment index system，adopted Delphi consulting method and the Saaty scale method to quantify some qualitative assessment indicators，used validity coefficient method to verify the scientificity and consistency. Five bridges in one region could as potential targets for modeling and simulation and risk assessment，it used the SD software，ANP and AHP method to calculate the evaluation judgment matrix，the weighted matrix ，limit the super matrix，and the consistency check. Simulation results show that the ANP method can improve the shortage of AHP risk assessment model，and the evaluation results can provide decision-making reference for the relevant departments. [ABSTRACT FROM AUTHOR]

In order to solve the information redundancy problem in the optimal sensor placement (OSP), the information redundancy function β(R) was proposed, and then the triaxial modal assurance criteria considering the redundancy of information was established by combining g (R) with the triaxial modal assurance criterion (TMAC), which can ensure both the observability and discriminability of the modal shape. Furthermore, to improve the solution efficiency, a novel hierarchic wolf algorithm (HWA) was put forward. First, the dual-structure coding method was used to overcome that the original wolf algorithm (WA) can only solve the optimization of continuous variables, and the artificial uniform distribution method was raised for the initialization of the wolf population to ensure the uniformity of the initial data. Then, the hierarchic method was adopted to avoid that any individual wolf has the similar grade with the wolf king, which may enhance the diversity of the wolf population and improve the searching efficiency of the algorithm. Finally, the parametric sensitivity analysis and the OSP selection were performed on the benchmark of Highway Bridge. The results indicate that the searching ability of the HWA greatly increases compared with the original WA, which can better solve the OSP problem. [ABSTRACT FROM AUTHOR]

Important buildings may be subjected to accidental loads, such as explosions or impacts, during their service life. For reinforced concrete ( RC ) frame structures, columns on the first floor are more prone to failure, compared with other components. The performances of the newly formed two-bay beams above the failed columns were determined the resistance capacity against progressive collapse of the structure. In order to investigate the mechanical characteristics and failure mechanism of the two-bay beams, tests of three 1/4-scaled RC rectangle beam-column subassemblies were carried out. It was observed that the compressive arch action was activated and the peak value of the vertical load was improved due to the compressive arch action. Based on the test results, the method to determine the vertical bearing capacity of RC two-bay beams was proposed. According to the equilibrium equations of the internal forces at the key sections of the beam, the compatibility equations of deformation, the relation between the vertical load and the deflection of the middle joint of the two-bay beam were derived. By increasing the deflection of the beam step by step, the vertical bearing capacity of the two-bay beam considering the compressive arch action can be yielded, which is taken as the maximum vertical load of the beam in the calculation. The proposed method was verified to be effective by comparing the calculated and test results. [ABSTRACT FROM AUTHOR]

To obtain the shrinkage and creep development law of high strength concrete in bridge engineering, reinforced concrete cross beams were used as creep samples for biaxial creep test. Normal stress condition( 14 MPa plus 2 MPa,6 MPa plus 2 MPa) with two combinations were considered. The comparison between creep with single stress and biaxial stress were analyzed. It is indicated that the creep of high strength concrete is highly affected by stress combination. Creep coefficient of biaxial stress is 75 % of that of single stress. Accuracy of exiting creep prediction models is unsatisfactory to predict the development of concrete creep with biaxial stress status. Exponential function creep model has higher prediction accuracy. Since vertical stress distribution in box beam is highly effected on concrete creep, it is suggested that vertical prestressing for web plate must be controlled during designing and construction. [ABSTRACT FROM AUTHOR]