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Village classification is an important foundation for preparing village planning and formulating development strategies. This study takes a typical plateau mountain area-Yulong County, Yunnan Province as the research object. First, the analytical hierarchy process is used to build a “three evaluations” (ecological sensitivity, development potential, and construction suitability)indicator system. Second, spatial correlation analysis of the “three evaluations” was carried out to obtain the initial village classification results. Finally, the state space method was used to calculate the village bearing capacity, which could be used to correct the initial village classification. Thus, the final village classification could be obtained. The results show that a significant plateau mountain space distribution of heterogeneity was shown in the villages of the research area, and the spatial autocorrelation coefficients of the “three evaluations” were 0.343, 0.253, and 0.110, respectively; more than 60% of the villages were in a bearing state and the higher bearing capacity was concentrated in the southeast, northwest, and central regions of the research area. After the comprehensive carrying capacity was calculated and corrected, the special protection category accounted for 23%, the suburban integration category accounted for 4%, the relocation and withdrawal category accounted for 15%, the agglomeration and promotion category accounted for 40%, and the temporary unclear category accounted for 18%. For different types of villages, the layout optimization strategy should be proposed according to the carrying capacity calculation results. The results of this research can provide a reference and basis for the formulation of township(town)-level territorial spatial planning and the implementation of “multi-planning” practical village planning. [ABSTRACT FROM AUTHOR]

Karst caves should be avoided as far as possible during pile foundation construction, but sometimes it is unavoidable. Therefore, research on the bearing characteristics of pile foundations in karst areas is a problem that must be faced. The current status of research on the bearing characteristics of pile foundations in karst areas from three aspects: theoretical research, physical experiments, and numerical simulation was analyzed. The following conclusion was drawn. The existing bearing capacity calculation formulas have insufficient consideration of influencing factors, and subsequent theoretical research should consider the derivation of single pile ultimate bearing capacity calculation formulas under the synergistic influence of multiple factors. The variables in physical model tests are relatively single, and the influence of water on the bearing characteristics of pile foundations is often ignored during the testing process. Subsequent research should focus on the synergistic effect of groundwater and multiple factors. There are few in-situ experiments conducted, and the accuracy of the data obtained through detection needs to be improved. In the future, more in-situ experiments and in-site damage experiments should be carried out to obtain more comprehensive experimental data on the bearing characteristics of pile foundations. Most of the cave models are built with standard size in numerical simulation, which is inconsistent with the three-dimensional geometric size of the actual stratum cave. The establishment of a more realistic Geometric modeling of the cave is a key development direction in the future. [ABSTRACT FROM AUTHOR]

The section K0 +785 -K0 +988 on the north shore of the Dalian Bay immersed tunnel, which is higher than the original seabed surface, is susceptible to ship collision risks and requires anti-collision measures. Taking into account factors such as construction difficulty, environmental protection, and cost, a permeable gravity pier foundation composed of circular caissons, column piles, and cast-in-place piers was proposed as the anti-collision structure, while meeting the requirements of the construction period. Combined with the structural form and main loads of the anti-collision pier, the overall stability of the anti-collision pier structure and the bearing capacity of the column piles were analyzed and calculated using finite element method and specification method. The results show that the permeable gravity pier anti-collision structure can meet the requirements of engineering use in all aspects, and can provide design reference for the construction of similar structures in the future. [ABSTRACT FROM AUTHOR]

Aiming at the problem that it is difficult to ensure the comprehensive improvement of the load capacity and transmission accuracy of the RV reducer during the modification process of the RV reducer, and most of the research on the modification is the single-objective modification. The optimization method with the goal of reducer carrying capacity and backlash was proposed based on the RV,and dynamic experiments were conducted on the modified RV reducer using a comprehensive performance testing platform. Firstly, considering the modified tooth profile equation of the cycloid wheel and the specific parameters of the RV reducer required for the modification, the contact force generated by the standard cycloid wheel was analyzed. Then, according to the position of the maximum contact force, the calculation method of the power of the cycloid gear teeth was obtained. The number of teeth meshing at the same time was judged by comparing the initial meshing gap between the cycloid gear and the pin teeth and the deformation of the cycloid gear and the pin gear. MATLAB iterative calculation method was used to calculate the accurate maximum contact force, and the Hertz formula was used to calculate the leading contact force. Finally, the influence of different modification methods on the return difference was analyzed, and a multi-objective optimization model was established. The improved NSGA-Ⅱ algorithm gamultiobj genetic algorithm was used for optimization, and the optimal modification amount under the minimum fitness was obtained by solving the solution. To verify the accuracy of the modification method, a dynamic experiment was conducted on the modified RV reducer using a comprehensive performance testing platform. The research results show that after optimization, the maximum contact stress between cycloid gear teeth is respectively reduced by 11% and 13%, comparing with median and displacement modification. The optimized return difference is 0.013′, compared with both the equidistant change and the displacement modification, it has been improved. The multi-objective modification with the load capacity and backlash as the optimization target can better solve the problem of improving the comprehensive performance of the RV reducer. [ABSTRACT FROM AUTHOR]

After more than 30 years of development, the foundation calculation system has been updated with the updating of codes and standards. Though the latest version of codes and standards have been released, the corresponding software has not been updated. At the same time, with the expansion of business, the required software should be able to be used in different fields, adaptable to both domestic and foreign codes and standards, and be used more conveniently and efficiently. Therefore, the Foundation Calculation System version 5.0 (FOCAS 5.0) has been developed. The pre-post processing of the new version of the software is compiled with JavaScript. The pre-processing input is convenient, with the function of checking, while the postprocessing displays results in modules and can generate editable calculation sheet. The kernel is developed in the C language, which has kept the calculation modules of 2008 edition, and also expanded the corresponding calculation method. In the module of foundation bearing capacity and slope stability, more calculation methods have been included, which can adapt to codes and standards in different fields and of many countries. It is the richest calculation methods in similar types of software. The new version of the software is a reliable and efficient calculation tool, and also provides reference for similar domestic software. [ABSTRACT FROM AUTHOR]

In order to reveal the mechanism of pile-side grouting reinforcement of existing bridge pile foundations in silty clay stratum, the relationship between grouting pressure and water-cement ratio on the reinforcement effect of pile-side soil was investigated through model tests, and numerical simulations were used to obtain the law of pile-side grouting on the bearing characteristics of existing pile foundations. The research results show that the cement slurry is squeezed and split reinforced in the silty clay, and the diffusion pattern shows linear and radial. The grouting silty clay reinforcement effect is positively related to the grouting pressure, and it shows the trend of increasing and then decreasing with the increase of water-cement ratio. Pile side grouting reinforcement can effectively improve the lateral friction resistance within the reinforcement area, and the deep part of the pile foundation has more obvious improvement of lateral friction resistance compared with the shallow part. [ABSTRACT FROM AUTHOR]

In order to explore the reinforcement effect of wrapped gravel pile on silty clay foundation, based on model test and numerical simulation method, the bearing capacity characteristics of wrapped gravel pile and traditional gravel pile composite foundation were studied, and the effects of gravel modulus, gravel internal friction angle and geogrid stiffness on the bearing capacity and deformation of wrapped gravel pile composite foundation were analyzed. The results show that when the load of traditional gravel pile composite foundation is less than 20 kPa, the settlement increase is not obvious. When the load is greater than 30 kPa, the settlement increases rapidly and the composite foundation is unstable and damaged. Within a certain particle size range, under the same grading, the larger the particle size of the gravel, the smaller the overall deformation of the gravel pile and the higher the bearing capacity. The gravel modulus of wrapped gravel pile has obvious effect on the settlement of composite foundation under high stress. When the pile-soil modulus ratio is greater than 30, its influence on the settlement of composite foundation gradually weakens. Increasing the internal friction angle of gravel can effectively increase the pile-soil stress ratio and improve the stress transfer efficiency of the pile. With the increase of internal friction angle, the settlement of composite foundation decreases gradually, and its effect is more obvious at high load level. The wrapping of geogrid can reduce the settlement of composite foundation, but the influence is limited. When J > 1 000 kN/ m, the influence on the settlement is gradually weakened. [ABSTRACT FROM AUTHOR]

aboratory tests were carried out on the silt solidified by the granulated blast furnace slag (GGBS) alkali-activated by hydrated lime and MgO powder. The optimal mixing amount of hydrated lime and MgO powder used as the alkali activator of GGBS was determined. The bearing capacity of the silt solidified by the GGBS alkali-activated by hydrated lime was studied by using field test. The research shows that the silt solidified by the GGBS alkali-activated by 15% MgO powder and 6% hydrated lime can be used as bridge abutment backfill materials. Considering the economy and reinforcement effect, the silt solidified by the GGBS alkali-activated by 6% hydrated lime can be used as the backfill material of abutment of road-bridge transition section in practice. The present research can be used for controlling differential settlement of road-bridge transition section of expressway. [ABSTRACT FROM AUTHOR]

In order to evaluate the structural performance and working state of the newly built prefabricated bridge, the single girder static load test, the whole bridge static and dynamic load test and the finite element simulation analysis were carried out on the 40 m T beam section of the Jiulinggang bridge of suide expressway. Through the static load test, the strain and deflection of the control section of the single beam and the bridge stage were tested, and the finite element calculation results were compared and analyzed. The natural vibration characteristics of the bridge, the dynamic effect and the impact effect under different driving speeds were obtained by the pulsation test and the driving test. The research results show that, the structural strain and deflection calibration coefficients of single girder and full bridge under static load all meet the requirements of the specification, and the relative residual strain and displacement after unloading are far less than 20% of the specification, and the structural bearing capacity is good. The deflection, strain value and load lateral distribution coefficient of the side beams at all levels of loading are all larger than those of the middle beams, and the overall deformation and stress distribution are relatively uniform, and the torsional stiffness and strength of the structure have a certain safety reserve. The measured damping ratio of the pulsation test is 1. 139%, which is less than 5% specified in the specification, with good dynamic characteristics and good energy dissipation performance during the vibration of the structural system. In the driving test, with the increase of the vehicle speed, the dynamic effect of the structure is more obvious, and the dynamic deflection, dynamic strain and impact coefficient have a tendency to increase obviously, the measured impact coefficients range from 0. 065 to 0. 133, indicating that the bridge deck has good flatness. [ABSTRACT FROM AUTHOR]

Black soil region can serve as the main production area of commodity grain in Northeast China. There is the soil quality decline of cultivated land in recent years, such as the thinner and harder land. Among them, the efficient return of agricultural waste as a carbon source can be an important way to improve soil quality. However, it is still lacking in the regional, agricultural production system model using the regulation of the carbon cycle between plant and animal, in order to promote the return of carbon to the field for the recovery of black land fertility. This study aims to improve the soil organic matter content of black land for recovery. The research object was selected as Qiqihar City located in the hinterland of Songnen Plain in Heilongjiang Province of China. The soil carbon budget of each county was calculated to compare the difference between the soil carbon input and output of different crops. The agricultural carbon balance model was established for plant and animal husbandry using multi-objective linear programming. The least carbon emission and the highest economic benefit were taken as the main targets, while the efficient use of agricultural and waste resources was the secondary target. As such, the balance between soil carbon emission and carbon input was determined, according to the situation of each county. The results showed that the adjustment plan in each county was optimized to reduce the rice planting area, while increasing the cow farming scale and maize planting area with high biomass. There was no decrease in the soil carbon pool of farmland after the full utilization of the waste of cultivation and breeding industry. However, the scale of plant and animal husbandry at the county level should be adjusted, according to the local conditions. Taking Nehe City with a large soil carbon deficit as an example, the maize planting area increased by 46%, while the scale of beef breeding should be reduced by 63%, and the scale of cows, pigs, sheep and poultry breeding increased by 85%, 54%, 76%, and 71%, respectively, in order to balance the carbon input and agricultural economic benefits. Take Longjiang County with a small soil carbon deficit as an example, the rice planting area, and the beef and pigs breeding industry should be reduced, while the corn and soybean planting area increased, and the scale of cows, pigs, and poultry also increased. The organic materials returned to the field were replaced by 33%-49% of the fertilizer nitrogen input after the planting and breeding scale, particularly for the higher soil quality and the soil nitrogen carrying capacity. Moreover, the soil nitrogen-carrying capacity of the three main crops showed an increasing trend, except for the maize planting in Kedong and Keshan County. The agricultural “carbon balance” development model can be expected to serve as the scientific basis for the efficient utilization of agricultural waste resources. The finding can also provide a strong reference to realize the “double carbon” strategy in the black soil area. [ABSTRACT FROM AUTHOR]

Umbilical terminal head is the key hardware equipment of underwater umbilical, which bears complex and harsh loads in deep sea environment, and puts forward higher requirements on the structural capacity of connection system. The deep water umbilical terminal head used in a gas field in the South China Sea was taken as the research object. Based on International Organization for Standardization(ISO)and Der Norske Veritas(DNV) related standards, a finite element model was established for the outer structural components of the umbilical cable terminal according to the elastic-plastic and pure elastic stress analysis methods, and the numerical analysis was carried out. The axial load capacity, shear load capacity, bending moment capacity and torque capacity under production conditions were obtained, and the influence of different lifting methods on the bearing capacity of the deep water umbilical termination head was analyzed. The analysis results show that the bearing capacity calculated under normal production conditions all meet the relevant standard evaluation indicators. Different lifting methods have different effects on the bearing capacity of the deep water umbilical termination head. Compared with the two-point lifting scheme, the four-point lifting scheme is less prone to stress concentration and meets the safety strength requirements. The research results can provide theoretical basis and technical reference for the design and field engineering application of umbilical terminals head. [ABSTRACT FROM AUTHOR]

Offshore floating wind power has developed rapidly in recent years, and the high construction cost is the key factor hindering its development. Drag embedded anchor has become a choice of floating wind power anchor foundation because of its low manufacturing and installation cost. The penetration depth and bearing capacity of drag anchors in clay were calculated by using empirical chart method, theoretical calculation method and finite element method. The results show that the empirical method provided by the manufacturer has low calculation accuracy and is suitable for the initial selection of drag anchor. The results of theoretical calculation method is sensitive to the soil parameters. The finite element analysis shows that the penetration depth of the drag anchor is the key factor to control the bearing capacity. According to the above calculation results, the design process of the drag anchor was proposed. It should be noted that the calculation parameters need to be carefully selected according to the process to ensure the safety and reliability of the project. [ABSTRACT FROM AUTHOR]

As an important connection mode of prefabricated construction, the mechanical properties of grouting sleeve have great influence on the structure safety. As the main mechanical indexes of joint connectors, the ultimate bearing capacity and bond strength are affected by grouting material strength, anchorage length of rebar, eccentricity of specimens, construction disturbance, high temperature, cycle of freezing and thawing, corrosion and other factors. Starting from the components of the grouting sleeve, the grouting material, the sleeve and the connecting steel bar, the influence of different factors on the mechanical properties of specimens was summarized, the existing strength calculation formulas was summarized under different influencing factors. According to the current development situation, the future research direction was put forward, a foundation for the further development of prefabricated buildings was layed. [ABSTRACT FROM AUTHOR]

Hat-shaped steel members are widely used in solar greenhouses, due to their low cost, fast construction, and high material efficiency. This study aims to determine the ultimate bearing capacity of a solar greenhouse with the hat-shaped steel under snow loads. The typical solar greenhouse with an 8 m span and 3.8 m ridge height was selected as the research object. The finite element method (FEM) under ANSYS software was used to analyze the instability mechanism and failure modal of the structure under snow loads (uniform and non-uniform snow loads). An investigation was made to clarify the effects of the longitudinal tie bars, initial geometric imperfections, and sectional dimensions on the ultimate bearing capacity of the structure under non-uniform snow loads. Both the material and geometrical nonlinearity were considered in the finite element model. A bilinear kinematic hardening model was adopted for the steel with a yield strength of 235 MPa, Young’s modulus of 206 GPa, and Poisson’s ratio of 0.3. The geometrical nonlinearity was activated using the ‘NLGEOM’ option. To consider the local buckling, the greenhouse skeletons were then modeled with the Shell181 element suitable for the large strains and rotations. Fixed hinge supports were used for both ends of the skeleton. An arc-length method was utilized to trace the nonlinear load-displacement curve, in order to calculate the ultimate bearing capacity of the structure under snow loads. The ultimate bearing capacity of the solar greenhouse with the hat-shaped steel was slightly higher than that of the hollow rectangular section under the same conditions of net section area, upper flange width, web depth, and wall thickness. The solar greenhouse was more sensitive to the non-uniform snow loads, compared with the uniform ones. The ultimate bearing capacity of the hat-shaped steel solar greenhouse under non-uniform snow loads was about 28% of that under uniform snow loads. Therefore, some suggestions were presented for the non-uniform snow loads in the design stage of the solar greenhouse structure. The roof ridge and north roof end were dangerous sections under non-uniform snow loads, which firstly entered the full section yield state. The longitudinal tie bars were expected to effectively improve the ultimate bearing capacity of the greenhouse structure. The ultimate bearing capacity of the structure with the longitudinal tie bars was about 1.25 times that without tie bars. The ultimate bearing capacity was only reduced by 2%, when the initial geometric imperfections amplitude increased from 5 to 20 mm. It infers that the solar greenhouse was not sensitive to the initial geometric imperfection. The cross-section size of a hat-shaped steel was recommended that the ratio of the upper flange width to the lip width, the upper flange width to the lower flange width, and the web depth to the lower flange width were about 4.17, 3.33, and 4.67, respectively, while, the ratio of the web depth to the lip width, and the lower flange width to lip width were less than 9.25 and 1.7, respectively. These findings can provide a strong reference for the solar greenhouse with the open cold-formed thin-walled steel under snow loads. [ABSTRACT FROM AUTHOR]

The construction of the comprehensive pipe corridor in Xiong’an New Area utilizes the automatic installation of gallery above gallery technology. The subsidence and the bearing capacity of the subcrust under front leg of self-advance large-tonnage installation machine are important to the design of the machine as well as the safe installation. In this paper, the JXSG-6 segment of Jing-Xiong interurban railway in Xiong’an New Area was selected as the field test site to conduct the numerical modeling and the plate loading test to the subcrust under the front leg of the installation machine. Numerical models were developed to investigate the subsidence and stress distribution of the soil under different plate widths and subcrust thickness. The loading test had ten levels of loading and 40 kPa for each level. The results show that: the subsidence of the soil decreases 52.5% when the plate width increases from 1m to 5. The subcrust thickness is optimized at 20 m considering the safety and leveling. The subsidence for each loading stage is around 0.43-0.78 mm, which first decreases, then stabilizes and increases again. The total subsidence after completion of the test is 5.72 mm. At the designed pressure of the front leg, the subsidence is only 1.98 mm. The road surface around the testing area, the sand below the loading plate and the subcrust show good integrity after the loading test. No visible subsidence or any cracks can be observed. The stiffness coefficient of subcrust foundation is calculated as 69.93 MPa/m and the modulus is 58.1 MPa. It can be concluded that the subcrust under the front leg of the installation machine has adequate bearing capacity for the construction of the comprehensive pipe corridor using the pipe gallery installation machine. [ABSTRACT FROM AUTHOR]

Aiming at the problem of inaccurate prediction results of bearing capacity, a bearing capacity prediction method of reinforced concrete members based on immune algorithm is proposed. The bearing capacity prediction objective function of reinforced concrete members is established by static load test, and the ultimate bearing capacity of members is obtained by solving the objective function by immune algorithm. The experimental results show that the prediction result of the bearing capacity prediction method of reinforced concrete members based on immune algorithm is 215 3 kN, which proves the effectiveness of this method. [ABSTRACT FROM AUTHOR]

The self-balanced test pile method is gradually popularized due to its convenience and economy. However, few studies were focused on the conversion coefficient involved in the process of converting this method into the static load-displacement curve. Because the settlement on the pile top is affected by soil continuity, the displacement difference on the pile top of the self-balanced test pile and the static load pile were analyzed using the Mindlin′s formula based on the comparative study of the self-balanced test pile method and the traditional vertical compression static load test method of single pile. An equivalent conversion method to determine the bearing capacity of self-balanced test pile was proposed in order to improve the empirical formula. The rationality of the improved method was verified by indoor simulation test as well as pile foundation engineering test of a super high-rise building in Shenyang. It is found that the self-balance conversion method taking the soil continuity in to account can significantly reduced the fitting error of the load-displacement curve. [ABSTRACT FROM AUTHOR]

In order to study the effect of the replacement rate of recycled coarse aggregate, length-diameter ratio and diameter-thickness ratio on the axial compressive bearing capacity of middle long columns of recycled aggregate concrete with ferronickel slag filled steel tubes (RACFNSFST), the monotonic loading tests were carried out on eight RACFNSFST under axial compression. By comparing the calculation method of axial compressive capacity recommended by the domestic and foreign common concrete-filled steel tube codes, the prediction formula of axial compressive capacity is fitted by regression and compared with the test results. The results show that local buckling occurs at both ends of the medium and long column, which is the failure mode of material, and the long column is the failure mode of whole instability. The medium and long columns with the same reclaimed coarse aggregate substitution rate and section size have better bearing capacity and slower deflection growth than that of the long columns. With the increase of diameter-thickness ratio, the bearing capacity and ductility are reduced, and the hoop effect of steel tube on recycled concrete is obvious. The fitting formula is simple and practical, and it is in good agreement with the measured value. [ABSTRACT FROM AUTHOR]

Based on the model test of the inverted trapezoidal reinforced soil retaining wall under the existing in⁃ door strip foundation, the three dimensional numerical model of the reinforced soil retaining wall was established by FLAC3D finite difference software, and the influence of the foundation offset distance D on the ultimate bearing capacity of the retaining wall, the panel horizontal displacement, tensile stress distribution of reinforcement and potential fracture surface was discussed. The research results show that the ultimate bearing capacity of the foundation first increases and then decreases with the increase of the foundation offset distance D. Through a comprehensive analysis of the ultimate bearing capacity of the foundation, the bearing capacity corresponding to the settlement of 0.1b(b is the width of the foundation) and the final settlement of the foundation, the best offset distance of the foundation is D=0.45H(H is the wall height). When D/H≤0.45,the maximum horizontal displacement of the retaining wall panel appears at the top, when D/H>0.45H,the maximum horizontal displacement of the retaining wall panel appears in the middle of the retaining wall about 0.4H from the toe of the wall. With the increase of D/H, the peak tensile stress of the reinforcement gradually shifts to the inside of the retaining wall, and the distribution is nonlinear in the direction of the length of the reinforcement. The potential rupture surface of the retaining wall is significantly affected by the offset distance D of the foundation, and the position of the rupture surface is overall offset to the load direction, and can be represented by an exponential curve. [ABSTRACT FROM AUTHOR]

Based on rhombic and honeycomb hexagonal non pneumatic tires, a rhombic honeycomb rhombic composite tire was proposed. The load-carrying capacity, grounding performance, fatigue life and rolling state of 10 kinds of composite tires with different proportion of honeycomb and rhombic were analyzed by using finite element simulation software. The simulation results of different tire structures were compared. The results show that the performance of the tire is better when the ratio of rhombic structure to honeycomb structure is even, and when the ratio of rhombic structure to honeycomb structure is 1:4, the comprehensive performance of the tire is the best. [ABSTRACT FROM AUTHOR]

In order to study the influence of joint stiffness on the stability of tubular truss arch, a variable stiffness spring model under reciprocating load was used to replace shell element to consider the semi-rigidity of joints on the basis of the consistency of hysteretic performance of spring element and shell element. The stiffness equation of the spring model was determined by the skeleton curve of the node shell element model under reciprocating load. Taking a tube truss arch with a span of 50 m and a span of 0. 29 as an example, the stability of the joint domain spring model and the common model was analyzed by using material and geometric nonlinear finite element method. The results show that “static instability mode” is the most unfavorable initial defect form of space tube truss arch. The influence degree of joint stiffness on the bearing capacity of tubular truss arch is related to the size, distribution form and load range of initial defects. [ABSTRACT FROM AUTHOR]

With the great development of urban underground space, both the buried depth of the foundation and the buoyancy of the groundwater continue to increase, which may easily cause the foundation pit to float during the construction process or even affect the normal use of the underground structure. Due to the small disturbance to the rock and soil around the pile during construction, the anti-uplift pile has advantages over simple technology, convenient construction, and good anti-floating effect. That is why it is widely used in anti-floating projects. At present, the mechanical properties, bearing capacity and deformation characteristics of uplift piles are the research hotspots of uplift piles in anti-floating engineering at this stage. The action mechanism of the uplift pile, common failure forms and ultimate bearing capacity were mainly summarized and analyzed, some problems of uplift pile in anti-floating engineering were put forward, which provides a new idea for the future development of uplift pile in the field of anti-floating of underground structure. [ABSTRACT FROM AUTHOR]

To improve the bearing capacity of offshore wind turbine foundation, a pile-bucket composite foundation with bucket foundation and steel piles was designed. Based on the limit equilibrium method, the theoretical formula of horizontal bearing capacity of pile-bucket composite foundation was proposed with considering different pile numbers. The finite element analysis model was established to analyze the bearing capacity of pile-bucket composite foundation with different pile numbers, pile diameters and arrangements. The results show that the ultimate bearing capacity of pile-bucket composite foundation can be effectively improved for the same steel amounts of foundation. Compared with single bucket foundation, the bearing capacity of bucket foundation with 1 pile is increased by 44.27%, and the bearing capacity of bucket foundation with 3 piles is increased by 35.76%, while the bearing capacity of bucket foundation with 4 piles is increased by 34.73%. Obvious wedge-shaped equilibrium plastic strain is appeared in the soil foundation of the passive area. The more obvious the equilibrium plastic strain is, the higher the load sharing ratio of foundation soil is, and the higher the bearing capacity of foundation is. The high stress area of foundation is mainly concentrated in the top cover of foundation. [ABSTRACT FROM AUTHOR]

To investigate the reinforcement measures of solar greenhouse structure under extreme wind and snow disasters, the single frame model of solar greenhouse was established by ANSYS finite element analysis software with consideration of material nonlinearity, large geometric deformation and structural nonlinearity conditions. The whole processes of instability and failure for the solar greenhouse structure under four load conditions of wind, snow, wind-led blizzard and snow-led blizzard were respectively simulated. According to the instability mode and load-displacement relationship curve of the structure, the temporary reinforcement methods were proposed. The results show that the wind and snow resistance of the solar greenhouse is significantly improved after temporary reinforcement. The wind load bearing capacity is increased by 154%-300%,and the snow load bearing capacity is increased by 11%-129%. The wind-led blizzard bearing capacity is increased by 245%-273%, and the snow-led blizzard bearing capacity is increased by 203%-264%. [ABSTRACT FROM AUTHOR]

Bridge decks and arch ribs of through arch bridges will produce different deformation along the longitudinal direction of the bridge due to the effect of temperature. Hangers, especially short hangers, will rotate along different axis at ends. This probably makes steel strands in hangers fracture suddenly and further failure of hangers. Therefore, theoretical derivation and finite element analysis were conducted in this paper to analyze the adverse influence of rotation along different axis at ends of hangers. It is found that the bearing capacity of hangers will decrease and the extra bending stress will exist in the lower anchorage zone when hangers rotate along different axis at ends. The maximum bending stress of hangers could reach 56. 5% of the allowable stress in a through arch bridge with a span of 105 m. Furthermore, the mechanical property of steel strands is studied by the finite element analysis and tests. The results show that the breaking force of steel strands rotating along different axis at ends could decrease significantly compared with that of straight steel strands and lead to the decrease of bearing capacity of hangers. Finally, a promoted method to assess the bearing capacity of hangers of half-through or through arch bridges for rotation along different axis at ends is proposed. Jointless bridge decks are suggested to mitigate the adverse influence of rotation along different axis at ends on hangers. [ABSTRACT FROM AUTHOR]

The self-balanced static load test will cause cracks in the pile, in order to ensure that the engineering piles can continue to use normally after the test, the cracks generated at the location of the loadcell should be reinforced by grouting. Combining the relevant specification requirements and engineering experience, the grouting device of the load cell was designed.The key technical points such as the number of grouting pipes, embedding requirements, cement slurry materials, cement slurry preparation, and grouting procedures were given. The calculation of engineering case shows that the bearing capacity of the soil at the side of the pile at the loadcell is increased after grouting, the bearing capacity of the whole pile is increased by more than19%, the compressive strength of the pile body is increased by more than 1.2 times, and the shear strength is significantly improved compared to the conventional pile body after grouting, so that the engineering pile can be used normally. [ABSTRACT FROM AUTHOR]

A new type of circular concrete-filled slotted steel tubular structure was proposed. Monotonic axial compression tests were carried out on six concrete-filled slotted steel tubular columns and six common concrete-filled steel tubular columns. The test results show that the slots can reduce the folding and buckling phenomena when the thickness of steel tube is small. The failure modes of concrete-filled steel tubular columns and concrete-filled slotted steel tubular columns are showed with remarkable dilation in mid-height when the thickness of steel tube is large. The slots of the steel tube have significant effect on the bearing capacity of smaller thickness of steel tube, and the bearing capacity of the concrete-filled slotted steel tubular columns is approximately 1.1 to 1.3 times of that of the common concrete-filled steel tubular columns. With the increasing of steel tube thickness, the ultimate load ratios of concrete-filled slotted steel tubular columns and common concrete-filled steel tubular columns are gradually decreased. The slots provide a local structure for the centralized release of deformation of concrete filled steel tubular columns under axial compression, which can avoid the longitudinal buckling of the steel tube effectively. Considering the influence of confinement efficiency of steel tube, the unified method for calculating the bearing capacity of circular concrete-filled steel tubular under axial compression with different structures is proposed, and the predicted results are more conservative than the experimental values. [ABSTRACT FROM AUTHOR]

A high-humidity environment is one of the main factors that damages wooden structure joints. Therefore, to study the dowel-bearing capacity of laminated veneer lumber in a high-humidity environment, the domestic poplar was used as the study object, and the different diameters of smooth and screw pins were used to carry out monotonic loading tests on the laminated veneer lumber. The influence of the pin types and diameters on the dowel-bearing capacity of the lumber was also studied. The test results showed that the failure modes of the screw pins and the wider smooth pins manifested as tooth-shaped cracks at both ends of the test pieces in perpendicular grain direction, while the fracture pattern showed that the specimen is split longitudinally along the parallel direction. The dowel-bearing capacity, parallel to the direction of the grain in the wood, was greatly affected by the humidity of the environment, particularly when the latter was 95%; bearing strength and initial stiffness decreased obviously, by 25% and 30% respectively. In a high-humidity environment, the screw pin had a lower bearing strength than the smooth pin; the bearing strength decreased and the initial stiffness increased first and then tends to be stable as the diameter of the smooth pin increased perpendicular to the grain. The predicted values of the dowel compressive strength of laminated veneer lumber in high humidity environment should be adopted based on the Eurocode 5 calculation method. [ABSTRACT FROM AUTHOR]

An aerostatic bearing with multi-hole integrated restrictor is designed to reveal the changing law of load-bearing performance of aerostatic bearing with concentrated throttle orifices, and the loadbearing capacity and stiffness of the bearing are studied. The governing equations in polar coordinates are established based on the physical model of aerostatic bearing with multi-hole integrated restrictor. The governing equations were deduced by discrete difference method and solved numerically by finite difference method and flow balance principle, and the pressure distribution of the gas film flow field was obtained. The bearing capacity, stiffness and other performance parameters of aerostatic bearing were analyzed and verified by experiments. The results show that the film pressure of aerostatic bearing increases gradually with the decrease in air clearance. In the case of the same air clearance, the bearing capacity of bearings increases gradually as the number of throttle orifices increases and the orifice diameter increases. In the case of a certain air clearance, the bearing has the optimum stiffness. The bearing stiffness increases first and then decreases gradually with the increase in the number of throttle orifices. As the bearing supply pressure increases, the bearing capacity and optimum stiffness of aerostatic bearing increase significantly. The experimental results are in good agreement with the numerical results, which has verified the feasibility and correctness of numerical calculation and numerical method. [ABSTRACT FROM AUTHOR]

In order to evaluate the actual bearing capacity and condition of a cable-stayed bridge in detail, the static and dynamic load tests of the bridge are carried out to test and analyze the static parameters such as the strain of the main girder control section, the local strain of the bridge deck, the deflection of the main girder, the vertical deviation of the tower top and the strain of the tower root, and the dynamic response of the bridge, such as impact coefficient, natural frequency and mode of vibration. The analysis results show that the measured data of each measuring point are generally in good agreement with the calculation. The check coefficient of some measuring points is greater than 1. 0, and the impact coefficient is greater than the calculated value in the dynamic load test. The damping ratio is 0. 338%-1. 115%, which indicates that the bearing capacity of the structure is low. The research conclusion has certain significance for the analysis of the bearing capacity of similar bridges. [ABSTRACT FROM AUTHOR]

In order to study the mechanical properties of steel tube confined lightweight aggregate concrete short columns under axial compression, 12 square steel tube confined lightweight aggregate concrete short columns with fly ash and ceramisite were designed and tested under static loading. The mechanical behavior, failure modes, and the influences of related parameters on the mechanical behavior of the specimens were analyzed. The test results indicate that the constraint effect of square steel tube on the filling concrete is obvious, which effectively improves the compressive strength of lightweight aggregate concrete and enhances its deformation performance. The specimens still have good load carrying capacity and deformation capacity after reaching the limit load, and the destruction belongs to material damage with potential depletion. The width-thickness ratio of steel tube is the main parameter that affects the behavior of column. With the increase of width-thickness ratio of steel tube, the mechanical behavior of specimen has a tendency of gradual decreasing. Concrete strength and reinforcement ratio belongs to the small effect. [ABSTRACT FROM AUTHOR]

The mechanical behavior of fabricated partially encased composite (PEC) beams was investigated by testing 12 specimens under unidirectional cyclic loads. The main test variables were the shear span ratio, concrete thickness and screw arbors etc. The researching results show that: with the increase of shear span ratio, the failure mode of the specimens changes from shear failure to bending failure. In the later stage of loading, some specimens show asymmetric concrete damage on both sides of the web, which leads to additional torsion on the specimens besides bending and shearing. The screw arbors not only enhance the confining effect of steel on concrete and prevent the local buckling of compressed steel flange, but also play the role of shear connection and ensure the composite action between steel and concrete. The concrete thickness has a great influence on the bearing capacity of specimens with a small shear span ratio, but has only a small effect on specimens with a large shear span ratio as its effect on the flexural capacity of normal section is limited. According to the superposition principle, a formula for calculating the shear capacity of fabricated PEC beams was proposed. On the basis of plane section assumption, a method for calculating the bending capacity of fabricated PEC beams was developed. A three-line model was proposed to reflect the normalized relationship between Vm and Mm. [ABSTRACT FROM AUTHOR]

We analyzed the feasibility of hanging the basement roof of heavy trucks, applied Midas finite element software to assist calculation, checked the concrete roof of basement from two aspects: the ultimate state of floor bearing capacity and the ultimate state of normal use, and explored and summarized a set of reinforcement measures of basement roof to ensure the safety and reliability of the whole hoisting process, and ensure that the main structure of basement roof is intact after heavy load. [ABSTRACT FROM AUTHOR]

In order to study the flexural behavior of reinforced concrete (RC) slab with comer holes, seven RC slabs with different sizes of openings at their corner regions were prepared and tested under static bending load with their four sides being simply supported. The results show that the steel reinforcement at the mid-span yielded first, and then the yielded area propagated towards the comers. At last, the concrete at the top of slab corners crushed along a direction of 45° approximately to the slab sides. Compared with the rectangular slab without holes, the ultimate load of slabs with comer holes decreases； opening coefficients (corresponding to the ratio of length of the corner holes to the span) of 0.0 5, 0. 08, 0. 10, 0. 12, 0. 15 and 0. 20 lead to the decreases of 5. 98%, 10. 35%, 21. 37%, 23. 63%, 38. 50% and 49. 29%, respectively. The cracking load and yield load also decrease correspondingly with the increase of opening coefficients. Based on the plastic hinge line method of plastic limit analysis of RC slabs, four different plastic hinge line patterns were proposed for six different opening sizes of RC slabs with corner holes. The calculation formulas for the bearing capacity of RC slab with comer holes were then established based on the principle of virtual work. The bearing capacity calculated by the proposed calculation formula agrees well with the test value, indicating that the proposed plastic hinge line patterns is reasonable and the adoption of the principle of virtual work is applicable here. The plastic hinge line patterns were simplified by introducing a coefficient which was only related to the opening coefficient. The calculation results of the simplified formula agree well with the test values. [ABSTRACT FROM AUTHOR]

Through on-site CPTU testing, software which interprets CPTU data was used to interpret the test data, and CPTU method was used to classify the site and stratify the soil layer. The physical and mechanical parameters of the soil in the engineering area were calculated, and the applicability of CPTU technology in deep marine soft soil area was proved by comparing the indoor test results. The CPTU method was used to predict the vertical bearing capacity of pile foundation theoretically. The numerical model of rigid pile composite foundation was established, and the field static load test was simulated. The results of single pile vertical ultimate bearing capacity of composite foundation obtained by theoretical formula calculation, numerical simulation and field static load test were compared and analyzed, and the failure forms of composite foundation are discussed. On this basis, the determination of bearing capacity characteristic value of single pile in composite foundation was deeply studied and the interaction mechanism between pile and soil in composite foundation and the working behavior under design load were studied. [ABSTRACT FROM AUTHOR]

In order to study the mechanical properties of prestressed steel reinforced concrete members under the action of eccentric tension, monotonic loading tests were carried out on 15 specimens. The number of prestressed steel tendons, prestressing degree, ratio of longitudinal reinforcement, the amount of steel and eccentricity were design parameters. The load-displacement curve, load-strain curve, bearing capacity, lateral deformation and crack development etc. were obtained by observing stress process and failure modes of prestressed steel reinforced concrete members under eccentric tension. The results show that the eccentric tensile capacity of prestressed steel reinforced concrete members can be improved by increasing the number of prestressed tendons and the amount of steel, improving the prestressing degree and longitudinal reinforcement ratio as well as reducing the eccentricity etc. Eccentricity is the main factor affecting the eccentric tension bearing capacity of prestressed steel reinforced concrete members. The generation and expansion of cracks can be effectively controlled by applying prestressed reinforcement. In accordance with the analysis of theoretical and experimental results, the calculation formula of bearing capacity of eccentrically pulled members of prestressed steel reinforced concrete was proposed. The calculated results agree well with test results. [ABSTRACT FROM AUTHOR]

In order to investigate the influence of different construction exerting on seismic behavior of circular concrete-filled steel tubular (CFST) stub columns, low cyclic loading tests of three large-scale CFST stub columns with different constructions were conducted. The steel components of the specimen was set as steel tube, steel tube with welded horizontal rib, vertical rib and steel cage, and double-skin steel tube, respectively. The latter two specimens had the same amount of steel. The axial force of each specimen was equal. The bearing capacity, stiffness degradation, hysteretic behavior, ductility, energy dissipating capacity and failure characteristics of each specimen were analyzed. The tests results indicate that the setting of vertical ribs can improve the flexural bearing capacity of the member, the horizontal ribs have a significant confining effect on the radial deformation of the steel tube. Inner steel tube has strong confining effect on the core concrete, which enhances the plastic deforming capacity of the outer steel tube. Under the condition of having the same amount of steel, although the bearing capacity of double-skin steel tube is slightly lower than that of steel tube with welded horizontal rib, vertical rib and steel cage, the ductility coefficient and accumulated energy dissipating capacity are significantly improved. The equivalent viscous damping coefficients of each specimen with different constructions are 0.41, 0.53 and 0.58, possessing favorable energy dissipating performances. The test results of CFST column bearing capacity under combination effect of compression, bending and shear are higher than the calculated value according to Chinese code, indicating that the calculated bearing capacity of full-size specimens according to the Chinese code shows a tendency to be rather safe. [ABSTRACT FROM AUTHOR]

A new construction method that strengthens circular steel-tube confined reinforced concrete (RC) column-RC beam knee joint with additional steel rings in the joint area is proposed. A total of 152 finite element (FE) models of circular steel-tube confined RC column-RC beam knee joint stiffened with steel rings in the joint area were established using the ABAQUS software to study the axial compressive behavior of the stiffened joints, after the FE method was validated using results from existing studies. The FE results show that the stiffened joint has a better axial compressive behavior than common joints, due to its higher bearing capacity and better ductility, which proves the effectiveness of the new strengthening method. Based on the parameter analysis results, it is concluded that the bearing capacity of the stiffened joint under compressive loads increases with the axial compressive strength of concrete, the volume fraction of steel rings and the ratio of longitudinal reinforcement in the joint area. The shear forces at the beam end also influences the bearing capacity of the stiffened joints, and the ductility decreases with the shear force. Based on the analysis results, a formula for calculating the bearing capacity of the reinforced joints under compression was established. The formula can be used as a good reference for designing circular steel-tube confined RC column-RC beam knee joints. [ABSTRACT FROM AUTHOR]

Cast steel H-shaped beam to circular tube column joints are formed by using cast-steel stiffener rings that replace the conventional stiffeners in joints. The moment transferring mechanism and bearing capacity of the cast steel joints were analyzed in this paper. A theoretical model for the deformation of the cylindrical shell under normal concentrated forces was proposed. Based on a deformation compatibility condition, the load transferring mechanism was revealed. It is proved that the moment applied to the joint is shared by both the cast steel stiffeners and the circular tube column. A bearing capacity prediction model was proposed based on yield line theory. Four series of nine specimens of the joints were studied by static experimental test and parametric finite element analyses were conducted to verify the load distribution rule and the formula of the bearing-capacity behavior of the joints. It is shown that for the following cases ： the outside diameter of the steel tube column ranges from 203 to 500 mm，the radius-to-thickness ratio of the steel tube column is between 12 and 25，the width of cast steel ring ranges from 20 to 50 mm, and the thickness of cast steel ring ranges from 30 to 120 mm, the bearing capacities of the joints given by the theoretical model agree well with the finite element analysis prediction. The proposed load transferring mechanism and bearing capacity model of the cast steel joints are verified through the experimental and finite element results. [ABSTRACT FROM AUTHOR]

This paper describes a calculation-method investigation on ultimate load-carrying capacities of cold-formed steel columns under axial compression. Based on the existing test data in the literatures, the ultimate load-carrying capacities of 60 steel columns experiencing distortional-global buckling interaction and 50 steel columns experiencing distortional buckling were calculated by using the revised direct strength method in the Chinese code ' Technical code of cold-formed steel structures (exposure draft) ' and the direct strength method in the North American specification or standards of Australia/New Zealand. Comparing the calculated results with the experimental results, it is found that in terms of the ultimate distortional-global buckling interaction resistance, the mean value of the ratios of calculated value to experimental value is close to 1. 0 on the unsafe side when the revised direct strength method in Chinese code is considered. For the ultimate distortional buckling resistance, the calculated values are significantly higher than the experimental results, rendering unsafe design. Based on the above findings, it is recommended that when calculating the ultimate distortional buckling resistance, the formula of the distortional-global buckling interaction and distortional buckling resistance should not be shared. The yield load rather than the global instability resistance should he adopted for calculating the length of half-wave and the distortional buckling resistance. [ABSTRACT FROM AUTHOR]

Bored pile is a widely used pile type of jetty structure, it has good suitability for weak rock strata area with a high content of calcareous sand. As per project experience abroad, the calculation methods of vertical bearing capacity of common used bored pile foundation and horizontal resistance of soil to pile foundation under such geological condition have been analyzed and the results have been compared to domestic industry standard results. Moreover, the major difference between Eurocode and domestic industry standard has been discussed which is Eurocode design approach one applies two sets of combination factors to check the structure separately, while domestic industry standard usually applies one set of combination factors. Meanwhile, common practice in specific area has been introduced which can be a reference for the design of bored pile foundation under similar geological conditions. [ABSTRACT FROM AUTHOR]

Bolted ball-cylinder joints are a new kind of spatial structure joints which can be applied to non-purlin gird structures. This paper first presents observations (failure mode) and results from an experimental program of uniaxial compression tests on five bolted ball-cylinder joints. Finite element (FE) models of the test specimens were established by ABAQUS. The FEA and experimental results agreed well in terms of the failure modes and load-displacement curves, which proved the reliability of the FE models. The bearing capacity of the joints under uniaxial compress in was then defined. Eighty FE models were established to analyze the parameters affecting the uniaxial compressive bearing capacity of the joint. The FE results indicate that the bearing capacity of the joint decreases with the diameter of the cylinder and the length of the chord member, but increases with the thickness of the cylinder wall, the height of the cylinder, and the width of the cross-section of the chord member. The joints with rib stiffeners possess larger stiffness and bearing capacity than ordinary ones. Based on the theoretical analysis, practical calculation formulae for the bearing capacity of bolted ball-cylinder joints under uniaxial compression were proposed. The relative errors between the fitting formulae calculations and the numerical and experimental results are less than 10%, indicating that the formulae are of good engineering value. [ABSTRACT FROM AUTHOR]

The pipe-pile with holes can effectively accelerate the time-space dissipation of excess pore water pressure in the soil around the pile, and reduce the negative effects of sinking-piles. However, the bearing capacity of piles is weakened by opening holes on the pile wall. In order to investigate the reduction of bearing capacity of pipe-piles due to the holes, static tests of single piles and composite foundations of a single pile with a cap were conducted on a pipe-pile without holes and three kinds of pipe-piles with holes in a soft soil foundation. The load-settlement curves, the settlement-log time curves, and axial force of all piles were obtained and their variations with different parameters were investigated. The results show that the reduction of the bearing capacity and the axial force are the least for the pipe-piles with radially-distributed holes. The total settlement and its rebound rate of pipe-piles with holes are smaller than its counterpart without holes for both single-pile tests and the tests of composite foundations of a single pile with a cap. The bearing capacity of composite foundations of pipe-piles with holes and a cap is greater than that of the corresponding composite foundation of a pipe-pile with a cap and without holes. The test results demonstrate that because of the holes, the load taken by the surrounding soil is increased, while the water content of the soil and the total settlement of the composite foundation are both reduced, thereby improving the bearing capacity of the composite foundation. The partial loss of the bearing capacity of pipe piles due to the holes can be made up by the increase of the bearing capacity of the composite foundation using such pipe-piles. [ABSTRACT FROM AUTHOR]

This study presents an investigation on calculating approach of ultimate capacity of FRP-RC columns under eccentric compression. Firstly, a nonlinear finite element model was established using OpenSees for FRP-RC column under eccentric loading. A comparison between experimental and analytical results demonstrates that the presented finite element model could provide good predictions for the responses of FRP-RC columns. Then, a detailed parametric study of 18 000 columns was performed considering various key parameters, such as a material strength, eccentricity ratio, slenderness ratio, type of FRP reinforcement, and longitudinal reinforcement arrangement. The parametric analysis results show that the moment magnification factor for steel RC columns in current Chinese code GB 50010— 2010 underestimates the second-order effect of FRP-RC columns. Based on a regression analysis of the parametric analysis results, a modified design equation of moment magnification factor was derived to determine the second-order bending moments. Subsequently, design equations were derived to determine the strength of cross section with FRP bars based on the strain compatibility, force equilibrium, and constitutive equations. Finally, combing the moment magnification factor method with the cross section strength, a calculating approach for ultimate capacity of FRP-RC columns under eccentric loading was proposed. The predictions obtained from the proposed approach are found in good agreement with experimental results, by comparing the predictions with available experimental results of 43 columns. [ABSTRACT FROM AUTHOR]

The deep-shallow pocket hybrid bearing of spindle assembly of the high precision CNC lathe was taken as the object， the computational fluid dynamics software was used to analyze oil film characteristics of deep and shallow pocket hybrid bearing on the basis of theoretical modeling and analysis. The influence of speed， oil pressure， eccentricity， oil film thickness and angle of deep pocket on the bearing capacity， flow and temperature rise of the oil film were analyzed. The results showed that the flow of the oil inlet hole increases first and then decreases with the increase of the spindle speed， and gradually decreases with the increase of the eccentricity of the spindle. The oil film temperature gradually decreases with the increase of the external oil supply pressure and tends to be gentle. When the oil film thickness is about 0.03mm， the bearing capacity and temperature rise are most suitable. When the angle of the deep cavity is 10°， the dynamic pressure effect of the oil film is the most obvious， and the oil film bearing capacity is the strongest. [ABSTRACT FROM AUTHOR]

To study the mechanical behavior of concrete-filled rectangular steel tube ( CFST) beams with differences in flange thickness, four-point bending tests on 7 CFST beams were conducted. The primary parameters of specimens were thickness of top and bottom steel flanges and concrete strength. The results indicate that a smaller top-to-bottom flange thickness ratio leads to a lowered location of the neutral axis under the ultimate stale, which means that more concrete contributes to the flexural resistance of the composite cross-section. When the flange thickness ratio is about 1/3, increasing concrete strength can effectively improve the bending capacity of the beams. Finite element program ABAQUS has been used to simulate the whole process of the tests, and the numerical results agree well with test results. Simulation analysis indicates that an optimized thickness ratio can not only increase the moment carried by the steel tube but also increase the working area of the concrete core, both of which improve the bending capacity of the members. When the steel ratio is about 0. 2, the bearing capacity of the optimized section can be more than 15% higher than the identical thickness one. An analytical expression for the bending capacity of CFST beams with nonidentical thickness flanges was derived based on the plane cross-section assumption, and in addition, the optimization issue of the cross-section was discussed. In particular, for high strength concrete members with a large steel ratio, the optimal section design can improve the bearing capacity remarkably. The research indicates that CFST beams with nonidentical thickness flanges have satisfactory bearing and deformation capacity. [ABSTRACT FROM AUTHOR]

Punching shear failure of slab-column joints tends to trigger the progressive collapse of a flat plate structural system. A static progressive collapse test was conducted on a 2×2 bay flat plate substructure with a missing interior column. At first, a downward concentrated force was applied on the central removed column till the initial punching shear failure occurred. Subsequently, a downward uniformly distributed load was alternatively imposed on the slab, and the load was maintained until the progressive collapse of the substructure. The collapse mechanism and collapse-resisting resistance of the substructure under different deformation stages were analyzed and evaluated. Results show that the punching shear failure of the slab-column joint within a substructure exhibits a certain level of ductility. But the tensile force of the membrane action developed in the slab results in a 50% decrease of the punching capacity of the joint compared to that calculated by the Chinese code. In the initial stage, 82% and 18% of the applied load are resisted by the middle edge and corner columns, respectively. Then the slab-column joints at the middle edge columns are gradually damaged as the deformation increased, which lead to a decrease and an increase of the loads carried by the middle edge and corner columns, respectively. At the end of the test, 51% and 49% of the applied load are resisted by the middle edge and corner columns when the substructure collapsed. At small deformation, the substructure resists the load via out-of-plane bending capacity and in-plane compressive membrane action. The compressive membrane action contributes to 12% of the collapse resistance when the joint of the central column damaged in punching shear. At large deformation, both the residual flexural capacity of the remaining joints and the tensile membrane action contribute to the collapse resistance. When the slab-column joints are severely damaged, only the integrity reinforcement at the bottom of the slab effectively provides the collapse resistance in the form of tensile membrane action. [ABSTRACT FROM AUTHOR]

To study the load carrying behaviour of column connections in multi-and high-rise steel structures under the combination of tension,bending moment and shear,full-scale model tests and finite element analysis were performed on four bolted-flange connection specimens with different flange thicknesses. The influence of axial tension ratio on the performance of the connection was analyzed by finite element analysis. The results show that the lateral rigidity and horizontal bearing capacity of the connection increase, and at the mean time the prying force between the flange surfaces of the connection tension zone decreases as the flange thickness increases. Under the combination of tension, bending moment and shear,the neutral axis of the flange is near the second row of bolts on the compression side,and the position of the neutral axis gradually moves from the compression zone to the centroid of the flange as the flange thickness increases. The action effects of the axial tension and the horizontal force led on the connection are in the same direction. The horizontal yield load of the connection is reduced due to the existence of the axial tension, and the flange rotation angle increases with increase in axial tension ratio. [ABSTRACT FROM AUTHOR]

Offshore shallow foundations are generally subjected to combined vertical, horizontal and moment loading due to the complex environmental and operational conditions. The failure envelopes theory developed in recent years overcomes shortages of traditional method to shallow foundations, and is especially suitable for design and optimization of shallow foundations under combined loading. In order to discuss the application of failure envelopes on engineering practice, based on the published results of failure envelope, we proposed the procedure for design of shallow foundations by failure envelopes through a design example of bucket foundation for offshore wind turbines, and presented the application of failure envelope on calculation of load safety factor, material factor for the soil shear strength, and foundations optimization. It indicates that the failure envelopes theory can be conveniently applied on design and optimization of shallow foundations. [ABSTRACT FROM AUTHOR]

Shallow Plate Loading Test (PLT) is an in-situ testing method which is widely used in evaluation of subsoil bearing capacity in civil engineering. However, side load induced by soils surrounding the plate may affect results of plate loading test. Combined with specific engineering cases, a numerical analysis is carried out based on Mohr-Coulomb model. By adjusting the range of side load around loading plate in PLT, pressure versus displacement (P-S) curve and parameter sensitivity are analyzed with summary of side load effect on shallow plate loading test. It is found that as to over consolidated sand foundation, side load does influence the results of PLT. However, this does not affect the determination of whether design subsoil bearing capacity is achieved in engineering practice. [ABSTRACT FROM AUTHOR]