Advanced Materials Research Vols. 163-167

Abstract: The Minneapolis bridge disaster that happened recently shows, our quality of science of bridge building taking quantitative index as main basis in use evaluates and has certain defects systematically synthetically at present, reflect the actual conditions in order to enable thinking the system can be true effectively, need to introduce into expert's system of judging, utilize its abundant experience to carry on the qualitative judgment to the bridge. This paper makes use of unascertained theory dealt with synthetically systematically to that the expert judge, the ones that avoided evaluating in the work are subjective and random, strengthen the scientific and objective fairness of evaluating the work, thus improve the authenticity of appraising the result.

Abstract: This paper present results and discussions on an experiment study on the impact of corrosion ratio to the RC beams under fatigue and monotonic loads. Seven reinforced beams with the same steel type, concrete cover, steel diameter and ratio were test. The effect of corrosion ratio on flexural stiffness of these RC beams was discussed. Based on fatigue and monotonic test for these beams, the most investigated parameters in this experimental study were distortion, stress distribution, ultimate load of corroded reinforced concrete beams. The results indicate that the effect of corrosion ratio on flexural stiffness of RC beams is very obviously, curvatures of corroded beams increase monotonically with degree of corrosion. Fatigue loading has great impact on the performance of corroded RC beams; it can reduce the ultimate strength and ductility of the beams significantly as corrosion ratio increase.

Abstract: CFRP(Carbon Fiber Reinforced Plastics) reinforced structure, as one kind of new technology, has been applied extensively in concrete structure, and CFRP reinforced masonry structure has been began studying and applied. But reliability research of masonry strengthened with CFRP is less, which restrains applying of CFRP. In the paper, Combined with the theory of reliability and tests, supposed that it is basic random variable that strength of brick and mortar and geometry dimension of members and effect of load, it is established that the stability probabilistic formula of brick column reinforced by CFRP under axial-loading. Its reliability is calculated, by means of Matlab. Under the action of different loads and total loads being constant, it is analyzed that the relationship of index of reliability and ratio of loading effect. Some useful results are gotten. And the result calculated is reasonable and reliable and it may supply engineering personnel with computer basis.

Abstract: The paper gives efficient algorithm of engineering structural reliability and its source program in Matlab with example. The paper introduces Mento-Carlo method, and stable reliability formula of slag concrete brick under compressed is established. And combined with data of experiment, it is given that its source program in Matlab. Matlab supplies many kinds of operation of matrix, and includes some toolboxes for the calculation of reliability, and it is very efficiency and convenience to make program of Matlab for the reliability calculation, which is easy to be grasped for the engineers. So its applying research on the reliability calculation will push forward the theory and application of structural reliability theory.

Abstract: Algorithm of most optimization calculation is favor for the most technology personnel, for its result is ideal and it doesn’t need derivative of performance function. Combined with theory of nonlinear programming and method of optimization calculation for structural reliability, the program calculation is written by means of Lingo, including system reliability calculation. With the example, the results prove the method was accurate and fast. It was very efficiency and convenience and objection to make program of Lingo for the reliability calculation, which is grasped for the engineers. So its applying research would push forward application of structural reliability theory and optimization design in structural engineering.

Abstract: An experimental program was conducted to investigate the effect of elevated temperatures on bond between reinforcing steel and concrete. By regressing the pullout test data, simple empirical models were proposed to predict the percentage reduction in bond strength accounted for effects of high temperature. Based on the empirical models, the resistance and the reliability of RC members after fire were analyzed using J.C. method. The engineering example indicates that the method of reliability analysis is suitable for predicting the change of post-fire resistance with temperature.

Abstract: This paper presents a new method to simultaneously search for the minimum reliability index and the critical probabilistic slip surface of earth slopes. By introducing the Hasofer-Lind reliability index, the probabilistic slope stability analysis problem is modeled as a constrained optimization problem. A recently proposed intelligent global optimization algorithm differential evolution with a penalty function is adopted to solve the constrained optimization problem. Numerical results on two slopes show that the propose technique is efficient and practical to reliability analysis of earth slopes.

Abstract: Artificial bee colony algorithm is a noval optimization method which is inspired by bee colony foraging behavior. Its use in the structure reliability field presents not only the advantage of its facility of implementation, but also the capability to obtain the design point and the failure probability with good accuracy. And by this method, the reliability index of nonlinear and complex limit state function which iteration scheme may fail to converge could be obtained with efficiency. It is demonstrated by four examples that the present method is reliable and accurate in reliability analysis of engineering structures.

Abstract: Reliability analysis is the premise for reinforcement and maintenance of an existing highway tunnel. In order to understand the structure reliability of an existing highway tunnel, a fuzzy mat-ter-element evaluation method was put forward based on entropy weight according to the fuzzy matter-element analysis method. Firstly, levels of inspection results were regarded as objects of matter-element and composite fuzzy matter-elements were constructed considering such factors and their evaluation indexes as cracks of concrete lining, lining thickness, concrete strength, cavities behind the lining and water leakage conditions. Secondly, reliability evaluation results of the existing tunnel structure were obtained by calculating the relevancy. Lastly, fuzzy matter-element evaluation model was effectively used to evaluate reliability of one highway tunnel structure.

Abstract: Based on the vibration equation of beam plate, under mechanical loading in a uniform transverse magnetic field, the vibration equation of the conductive beam plate is reduced to two cases ,which is no-pertubation system and pertubation system. For pertubation system ,n-order harmonic orbit is given by means of the Melnikov method. Finally, the critical condition of chaos phenomena is given in the transformation of Smale horseshoe.