An Improved Nonlinear Settlement Calculation Method for Soft Clay considering Structural Characteristics

The bond strength of adhesively bonded timber–concrete composites (ATCC) with prefabricated concrete elements is usually described using the shear strength of the timber. This approach, however, often fails to consider the actual failure modes of the bondline and also the interaction between shear stresses and stresses perpendicular to the bondline has not yet been comprehensively understood. To address this limitation, a reliable calculation method is required, where stress determination, failure criterion, and stress analysis are clearly defined to accurately predict the bond failure of ATCC specimens. In this study, three linear-elastic calculation methods and one non-linear calculation method are presented along with corresponding failure criteria and strength parameters. Regarding validation, the predicted failure load is compared to experimental results from 186 ATCC bond specimens to assess the method’s suitability. Based on the findings, appropriate calculation methods for a reliable prediction of the bond strength are recommended.

In many social science and natural science research, researchers are often faced with the problems such as: the system have no enough system distinctive features, the probability distribution unknown and the number of data very small. It is hard to use statistical theory in these researches. A novel method called non-statistical method is proposed in this paper to obtain more characteristics and further information in the system. The method permits the probability distribution unknown and the number of data very small, because of some deficiency of classical statistics in system and information science. In virtue of the special strategy of data processing, more characteristics and further information in the system could be obtained using this method. Some basic concepts, characteristics and elements of non-statistical method including point estimation, interval estimation, optimum level, practicable interval and systemic characteristic mapping etc, are also recommended. The validity of this method is examined by some measurement cases and practical engineering examples.

Real-coded Genetic Algorithms (RGAs) usually meet the demand of continuous and continuous/discreet mixed space problems and have been widely applied in many fields. The paper proposed a new Hybrid Real-coded Genetic Algorithm (NHRGA), in which the idea of Particle Swarm Optimization (PSO) is introduced into mutation operator and physics field theory is also employed in algorithm operators. The NHRGA reduces the possibility of trapping into the local optimal solutions and improves the computation efficiency. A practical engineering example is given to demonstrate computation efficiency and robustness of the proposed method.

The carbonation of reinforced concrete is one of the intrinsic factors that cause a significant decrease in service performance in concrete structures. To decrease the effect of carbonation-induced corrosion during the lifetime of the concrete structure, a prediction of carbonation depth should be made. The carbonation of concrete is affected by many factors, such as the compressive strength of the concrete, service life, carbonation time, carbon dioxide concentration, working stress, temperature, and humidity. On the basis of these seven parameters, combined with the predictive power of the adaptive network-based fuzzy inference system (ANFIS) and principal component analysis (PCA), which can reduce data dimensions before modeling, we introduced a novel approach—the PCA–ANFIS model—that can predict the carbonation of reinforced concrete. Practical engineering examples were adopted to verify the superiority of the suggested PCA–ANFIS model, with 90% of the carbonation depth data used for training and 10% used for testing. The root mean square error (RMSE) values for the ANFIS, ANN, PCA–ANN, and PCA–ANFIS training were 12.23, 6.28, 5.42, and 1.38, respectively. The results showed that the PCA–ANFIS model is accurate and can be used as a fundamental tool for predicting the service life of concrete structures.

Development of an object-oriented framework for the vibration characteristic computation of multibody systems

The cable clamp is the key node to connect the main cable and the suspender cable on the suspension bridge. The cable clamp which is divided into left and right halves or upper and lower halves is made of cast steel. In order to make sure the main cable can be confined by the cable clamp effectively, the bolt should retain appropriate pre-tension force when the bridges are under operational conditions. In construction period, several twists are done to make the pre-tension satisfy the design require. And it is inevitable to do additional twist during the operation period according to the statistics. According to relevant statistical data, variation of main cable section caused by creep of zinc coating and becoming small of the thinness of the main cable after pulling are the main causes leading to the decrease of the pre-tension of the bolts. When the additional twist is done with conventional method, manual pump matching with the jack is used. Pull the bolt to the required value, twist the nut using rotation bar with hand, and then unload the pump. After analysis the reason why the error of additional twist force is so big is that oil pump table, rotation circle number and retraction force can’t be controlled properly. Ultrasonic testing is a new testing method in recent years. The ultrasonic sensor placed at one end of the bolt can transmit and receive signals at the same time. According to the reflection theory, when the acoustic wave transmits from the low impedance to the high impedance, reflection will occur. Using this principle, the transmit time can be obtained. Based on the ultrasonic testing technology, a new pre-tension test method is introduced. In the process of the pull off there are two stages. Stage one, before the pressure on the jack reaches to the pre-tension of the bolt, the tension of the bolt is essentially unchanged, and the acoustic transmit time is unchanged theoretically. In stage two, when the pressure on the jack reaches to the pre-tension of the bolt, the bolt will stretch, and the stress in the bolt increases which makes the sound velocity reduces. The joint action of the two aspects increases the sound transmit time in the bolt, and the increase is linear. The core technology in this method is the test technology of pre-tension of bolts. On the basis of conventional additional twists, using high accurate ultrasonic test equipment, the ultrasonic transmit time from one side to the other side on the bolt is recorded. Relationship curve between tension and sound transmit time is recorded when the jack is tensioned hierarchically. Before and after the pressure of jack reaches the pretension of the bolt, the gradient of the relationship curve changes obviously, and then the pre-tension of the bolt can be obtained. Then a new additional twist method is introduced. The method flow is, test, then twist, and then test. According to the current bolt tension value, the bolt is tightened again or unloaded, ensuring the pre-tension reaches the target value. Finally the validity of the new method is verified by a practical engineering example of additional twists on a suspension bridge. In order to verify the validity of the operation process, the target tension and the measured tension are compared in the process of the additional twist of the bolts in a long span suspension bridge. Ten compared data are recorded. There are 2 bolts on which the error of the target tension and the measured tension is less than 1 ton. 4 bolts error are less than 2 tons., etc. Considering the 5 tons error of pressure on the jack, differences between the target force and the measured tension are in the range of 5 tons, so the additional twist procedure is valid.

In the tunnel engineering, concave edges can be formed by the intersections of roof and wall, floor and wall, wall and wall. If joints or fractures inside the rock mass cross the roof and wall at the same time, instable non-convex blocks can be formed possibly. However, the theorem of finiteness on the convex blocks in the classical block theory does not apply to the non-convex blocks. Combined with practical engineering example, all the simple convex blocks near the edge of a tunnel can be analysed by enumeration, and all the finite or removable convex blocks will be searched out. Thereafter, all the possible finite or removable non-convex blocks will be identified according to the principle that the codes of the joints keep the same all the time. The combination of convex blocks which are overlapped with each other can also be optimized further. Therefore, the non-convex blocks will be represented with several convex blocks which are connected only at the cutting planes. The mode and direction of sliding can be analysed with the stereographic projection and the visualized block sphere. Finally, the identification of non-convex block on the edges of tunnels will be realized. It not only have an active theoretical significance for extending the range of application of block theory, but also have the important reference values for protecting the safety of tunnels engineering.

For improving the efficiency of three-phase cable transient temperature calculation and the efficiency of rack pipe laying design, meeting the needs of running real-time analysis, a thermal circuit model of lumped parameter is established. It is used to quickly get the transient temperature rise of cable core and outer sheath. After the model is established, the accurate results of the transient temperature rise of the core and outer sheath can be obtained through the calculation of the simple hot path and the real-time correction of the loss directly. In this paper, a practical engineering example is given. This paper shows the convenience and accuracy of the quick calculation model mentioned by comparing the calculation results of the model and the calculation results of general software.

We propose a new surrogate modeling approach by combining two non-intrusive techniques: Kriging and Stochastic Collocation. The proposed method relies on building a sufficiently accurate Stochastic Collocation model which acts as a basis to construct a Kriging model on the residuals, to combine the accuracy and efficiency of Stochastic Collocation methods in describing stochastic quantities with the flexibility and modeling power of Kriging-based approaches. We investigate and compare performance of the proposed approach with state-of-art techniques over benchmark problems and practical engineering examples on various experimental designs.

In this paper, according to the type and scale of hazardous waste incineration, process selection, design of rotary kiln incinerator, and the engineering principle and performance characteristics of rotary kiln incinerator system are analysed, and the proposed method is verified by practical engineering examples. The results showed that the temperature of rotary kiln is controlled at about 850 °C, the residence time of hazardous waste in rotary kiln is about 60min, the rotating speed is 0.88r/min, and the inclination angle is 1.75. The temperature of the second combustion chamber is more than 1100 °C, and the residence time of flue gas in the second combustion chamber is more than 2S. After continuous incineration, the reduction rate of slag ignition is less than 5%, the removal rate of fly ash is more than 99.99%, and the flue gas is discharged up to the standard.

For the construction of the diversion tunnel discharge capacity problem, the difference of the starting point between the theory of uncertainty and the traditional deterministic theory is analyzed.The discharge capacity is affected by a comprehensive variety of factors, including the cross section area, roughness, wetted perimeter, Chézy coefficient and many other factors, and thus discharge capacity is multiple functions of these random variables.On the basis of the actual in-depth research and getting a lot of information, reasonable statistical analysis and properly determination of the distribution of various types of random variables are made.Establishing a reasonable probability density function and performance function, using Monte-Carlo method to simulate, the more objective and real discharge capacity reliability of the construction of the diversion tunnel can be accessed.Combined with practical engineering examples under the actual monitoring data for comparison, the results are objective and reasonable.The research results can provides a certain degree of programming reference for the same type for the future diversion project of the the same river basin.

With the acceleration of population aging in China, Shanghai, as a national super-large city, is now facing this situation more seriously. Improving the convenience of existing residential buildings for the senior citizen living in and installing elevators for these buildings have accordingly become an urgent issue. However, the safety of the additionally installed elevators in these buildings is the top priority for engineers. This paper focuses on the settlement calculation method of the additionally installed elevators, with emphasis on the settlement calculation standard, issues needing attention, and the process of settlement calculation, mainly including the selection of drilling parameters, the calculation method of foundation deformation and the selection of conditions.

Foundation settlement calculation has been a difficult and hot problem in geotechnical engineering study. The problems lies in the large differences between the geotechnical parameters of field and indoor test. The using of the tangent modulus method based on the field loading test to determine the calculation parameters can overcome this shortcoming, and reflect the non-linear of foundation settlement, which is a new progress of foundation settlement calculation. However, compared with other tests, the in situ plate loading test has higher difficulty, and it is also difficult to reflect the characteristics of deep soil. In this paper, by making use of systematic geotechnical test data by Riverside Campus, Texas A & M University, United States, it first examines the feasibility of the tangent modulus method used in sand foundation nonlinear settlement calculation, and then studies on the tangent modulus calculation methods of adopting lateral pressure test, The CTP test and other field tests to determine the different soil layers and lastly tests the results of loading tests for different plate sizes. The results show that the calculated parameters needed in the tangent modulus method determined by the lateral pressure test, The CTP test and other field tests are feasible. In addition, when the parameters thus determined are used in the tangent modulus method to calculate the load experimental curves of different plate sizes, the calculated nonlinear curve has good consistency with and experimental curves.

A robust reliability prediction method using Weighted Least Square Support Vector Machine equipped with Chaos Modified Particle Swarm Optimization and Online Correcting Strategy

Bounds-based structure reliability analysis of bogie frame under variable load cases