Applied Mechanics and Materials Vols. 578-579

Abstract: In this paper, to study mechanical behavior of steel box stub column under cyclic uniaxial tensile and compressive load, elasto-plastic analysis of the segment is carried out by using ABAQUS package. In this study, with changing parameters (such as length-width ratio L/B, width-thickness ratio R_R) of the box stub column, the hysteresis curves, skeleton curves, stress distribution and deformation of the ultimate state for the steel box stub-column are investigated. These results show the L/B and R_R have little impact on the ultimate strength and ductility of stub-columns during the tensile stage. However, R_R has obvious impact on the elasto-plastic mechanical behavior and local deformation under compressive load.

Abstract: The brittle failure finite element method is widely used in arch dam safety evaluation, but it also has some problems, the concrete strength criterion is different, the dam failure range is different. This article first introduces brittle failure constitutive relation and three strength criterions, then takes a high arch dam as an example to compute, obtains some conclusions that the relative failure range of foundation plane corresponds to blaxial strength criterion is slightly bigger than the result of uniaxial strength criterion, is almost the same as the result of triaxial strength criterion. Because the influence of the third principal stress is compressed stress to the dam crack is taken into account under multiaxial strength criterion, therefore using multiaxial strength criterion is more reasonable.

Abstract: A kind of channel type embedded part which has been disposed through extrusion forming new technology needed to extensive apply in engineering. Theoretical analysis and experimental research have been carried out on shear properties of bolt and one-way static pull-out performance of channel. Got the ultimate bearing capacity, deformation and failure mode, compared the results between test and finite element analysis, fit a formula for calculating the bearing capacity of channel. Experimental result shows that embedded parts working performance is good. It has higher strength than work load and the expected ultimate load according to the theoretical calculation. Meantime, specimens has relatively good ductility before failure. The test results have provided the experimental basis for the application of embedded parts in engineering.

Abstract: This paper presents an analytical study on the behavior of reinforced concrete walls with rectangular cross section and aspect ratio less or equal to one. Several experiments on such walls have been selected to be studied. Database from various experiments were collected and nominal shear wall strengths have been calculated using formulas, such as those of the ACI (American), NZS (New Zealand), and Wood and Barda equations. Subsequently, nominal shear wall strengths from the formulas were compared withthe peak shear wall strengths from the database. These formulas vary substantially in functional form and do not account for all variables that affect the response of walls. There is substantial scatter in the predicted values of ultimate shear strength. A new semi empirical equation is developed using data from tests of 126 walls with the objective of improving the prediction of peak strength of walls with the most possible accurate.

Abstract: The article describes the traditional methods used in Russia for testing of reinforcement corrosion conditions including peculiarities and weak sides of it. The new methods of non-destructive testing, which are used mainly in foreign countries, are overviewed there. The physical basics and the advantages of the testing method of half-cell potential are also characterized. A relatively new method of non-destructive testing of reinforcement corrosion condition is the method of measuring the concrete resistivity. The article describes the principal of its application and the factors influencing the measuring result. There are also the data of this method application for covering inspection of the Kurskiy station in Moscow.

Abstract: Preliminary study the damage of concrete beam by the ultrasonic-rebound method.The contents of the ultrasonic-rebound method are shown below: the concrete rebound value was determined by Rebound method and the ultrasound propagation time in concrete beam was determined by ultrasonic meter to calculate the ultrasonic velocity value in concrete, finally based on the concrete rebound value and the ultrasonic velocity value to confirm the strength of concrete beam.Because of a single rebounding or ultrasonic method is limit in theory and application, and lead to the defect in the application. But the ultrasonic-rebound synthetic method is much better than the above two methods respectively, and it improves the testing precision to apply to the engineering practice.

Abstract: In a high-rise building located in Nanchong of Sichuan Province, after the removal of template of the crossbeam of the concrete transfer storey in the basement, there are many vertical and diagonal cracks which can be detected directly by human eyes. According to the structure design data and structural working drawing of this project, multiple detection methods are adopted for the detection on and analysis to the factors caused the cracks. From that, the thesis proposes some feasible handling suggestion as the reference for the similar engineering in future.

Abstract: The separation between the filled-concrete and the steel tube would reduce tremendously the bearing capacity of the concrete-filled steel tubular (CFST) arch bridge. However, there is no efficient method to monitor and detect the separation so far, which is a great engineering problem we have to solve. Therefore, this paper firstly proposes a vibration test method aiming at the local modal of the steel tube. Distributed accelerometer array deployed along the tube is used to acquire the vibration signal induced by quantitative excitation via telecontrol. Changes in frequency and amplitude of the steel tube are selected as parameters for the separation detection based on the theory of surface wave transmission. This method can satisfy the demand of the real-time monitoring of interface separation of the CFST arch bridge.

Abstract: Traditional tuned mass damper (TMD) can reduce the dynamic response of structure under earthquake, but the traditional tuned mass damper is not effective to reduce translation-torsion coupled vibration. A two-directional horizontal and torsional tuned mass damper, which includes tuned mass blocks, torsional blocks and rotation lever, is proposed. The horizontal and torsional response of the building structure is controlled by the movement and the rotation of the multi-dimensional tuned mass damper (MDTMD) in different directions. According to the movement mechanism of the MDTMD, the dynamic equation for the control system considering eccentric torsion effect is established. An eccentric structure with MDTMD is analyzed to verify the control effctive for the horizontal and torsional coupled system under earthquake, and the reduction effect is compared with the traditional TMD. The results show that the coupled response can be reduced effectively by MDTMD and the vibration reduction ration is much higher than traditional TMD.

Abstract: In view of the rapid development of the high-speed rail construction in China at present, some new plain concrete piers of railway bridges cracked in an increasing trend. Combining a real project, this paper analyzed the causes of the cracking in massive concrete piers through the actual construction condition and the materials prosperities, and made corresponding prevention and improvements for the cracking, provided the reinforcing treatment of cracking piers with corresponding programmes. The analysis and treatment measures for the project will present a reference for the similar projects in the future.