Advanced Materials Research Vols. 446-449

Abstract: Cement concrete pavement road performance gradually decay with vehicle load and environmental factors in long-term effect. When the usability of the road surface reduces down to limiting bottom line standard, it can be used to repair asphalt overlay technique with the advantages of short duration, little impact on traffic road repair service and good performance. According to the force characteristics of old asphalt overlay concrete structure, this paper studies the impact of reflective crack propagation mode, fragments after impact on the asphalt overlay of the stress response with ANSYS finite element numerical simulation analysis, and it reveals the rolling technology can effectively reduce the impact of reflective cracking.

Abstract: Comparing with the frame structure without any aseismic members, bracing-frame is a better form for the aseismic frame structure. But the form of bracing –frame is determined by the engineering experience. The best design plan can’t be determined using the traditional design method. In order to find the optimal result for the bracing –frame structure, the bracing system topology and the semi-rigid connection topology was considered in this paper. And the optimal model was built based on on discrete topology math model. And the dominant winning role for genetic algorithm was adopted due to a large number of non-linear problems. Through the optimal design for active semi-rigid frame bracing system based on discrete topology method, we can get the best design plan in whole structure system, which have better engineering significance and reference value usually.

Abstract: Based on a steel concrete building, this paper presents a study on the fuzzy control of building vibration. The building structure is simplified into layer model and is applied with a fuzzy control. Three membership functions, Gaussian, triangel and π shap, are used for the simulation. Three earthquake waves, El_centro, Taft and Tianjinghuanhe, are utilized as well. Nine operating modes are proposed for fuzzy control. A series of fuzzy control rules are designed with ground acceleration and mass point displacement being regarded as firstly important components. The simulation results show the control ratio of decreased displacement to the maximum displacement without control varies from 12.67% of Mode I to 36.33% of Mode G. The average control ratio is 23.99%. The fuzzy control system has a quite good control effect on building vibration.

Abstract: Rail-cum-road cable-stayed bridge with single cable plane is eccentric under moving load, overlapping details for orthotropic steel bridge decks and transverse beams of stay cables are in typical complex space stress condition. A fatigue test is performed to evaluate anti-fatigue performance of overlapping details under the combination of highway and light railway loads. A 1:1 model is adopted for the overlapping details, where a fatigue loading test for 2×10⁶ cycles is carried out. Its test results show: the structural stress level is low, no crack is found on the test model after cyclic loading for 2×10⁶ cycles, then load amplitude is gradually increased and no crack is found after cyclic loading for 4.25×10⁶ cycles, finally a result is obtained that no fatigue crack will be found on the overlapping details for orthotropic steel bridge decks and transverse beams of stay cables within design life, because fatigue strength requirements are satisfied.

Abstract: Based on the anti-corrosion design plans and major response measures of part of the recent international bridges, the advantages and disadvantages of additional measures were compared. For the relatively favorable environment at the site of Pinghai Bridge, the basic measures and additional measures to improve the durability of concrete were proposed. Implementation of these measures played a significant effect to improve the durability of the structure and components of Pinghai Bridge and also provided a reference for the durability design for the same type bridge.

Abstract: How to get the enormous statistical information of target buildings has long been a very significant subject in urban earthquake disaster prevention planning. However, the traditional methods to extract the statistical information of urban buildings are complex and time consuming, proved to be difficult in application. This paper presents a new practical method to extract statistical information of urban buildings through rotating high resolution remote sensing images and scanning the pixels, and then compares the data from high resolution remote sensing images with measured data to verify the precision of the method. With this method, some buildings in a county in Henan province are analyzed as an illustrative example, the encouraging results of which demonstrate that this simple and practical method is not only theoretically correct but also precise enough to satisfying the demands of fast extraction of building information on in urban earthquake disaster prevention planning.

Abstract: An analytical model for RC beam strengthened with externally bonded laminates based on the strut-and-tie method is reported herein for predicting the strength and mode of failure of the strengthened RC beam. From the proposed model, four inequality equations were derived corresponding to four possible modes of failure. These four inequality equations define a safe domain. When the loading path up to the ultimate flexural limit state of a beam is plotted on the same diagram, the mode of failure and strength of the beam can be identified. The possible modes of failure consist of both flexure-type and shear-type failures. Flexure-type failure is due to the yielding of internal longitudinal reinforcement or the yielding of externally bonded laminates, whereas shear-type failure is due to the crushing of the diagonal compressive concrete strut or the yielding of the shear reinforcement. The failure mode initiated by one flexure-type followed by another is possible. Mode of failure initiated by one flexure-type followed by a shear-type is also possible but not otherwise. In short, this model describes the mode of failure and the corresponding strength of an RC beam strengthened with externally bonded laminates, which can be used to verify the adequacy of design for beam strengthening.

Abstract: The finite element modeling is established for reinforced concrete(RC) beam reinforced with fiber reinforced polymer (FRP) using the serial/parallel mixing theory. The mixture algorithm of serial/parallel rule is studied based on the finite element method. The results obtained from the finite element simulation are compared with the experimental data. The comparisons are made for load-deflection curves at mid-span. The numerical analysis results agree well with the experimental results. Numerical results indicate that the proposed procedure is validity.

Abstract: A modal test was carried out on a 120m span concrete filled steel tubular arch bridge under operational conditions. The moving traffic load is considered as uncorrelated white noises at various points of the road surface and the test is of the type of multi-input multi-output (MIMO). The modal parameters are identified by Global Rational Fraction Polynomials (GRFP) method, a frequency domain method. In order to taking the mobile nature of the traffic load into consideration, a multi-input NExT method is utilized to retrieve the frequency response function needed by GRFP. A proof of the NExT method in the case of multi-input case is also provided in this paper.

Abstract: Since the nineteen nineties, high strength concrete technology was developing rapidly in our country. However, high-strength concrete detection technology is relatively backward. According to the characteristic of the pumping concrete in Tangshan area and the requirements of JGJ/T23-2001, The paper adopted representative materials of Tangshan to divide high strength concrete test blocks which strength grade is from C50 to C80 into 4 ages of 14 days, 28 days, 60 days and 90 days, then adopted high strength concrete rebound apparatus to experimental research by the rebound method. At last, the test data was collected, and applied regression analysis theory, then used the principle of least square method for regression analysis. The optimal pumping concrete strength rebound curve formula could be obtained.