Applied Mechanics and Materials Vols. 90-93

Abstract: In this paper, the comparative study of RWIV will be proceeding. Aim at the model of rivulet, a kind of sine function is accepted, and another kind of rivulet model is established on the basis of analysis on the stress of the rivulet. Aim at the model of cable’s initial curve under gravity, a kind of parabolic function is accepted, and another kind of model accepted as a catenary. Then, solve the equations of cable and the rivulet jointly by numerical method, get the characteristics of motion of the cable and rivulet, then investigate the factors which is related with the model. The influence of the different model of cable is very little when the rivulet model is assumed as a sine function. However, the influence of the different model of cable is large when the rivulet model is established on the basis of analysis on the stress. Then discover the catenary cable with moving rivulet is more rational with the field observation.

Abstract: MR-TMD is a new type of semi-active control device which combines with Tuned Mass Damper (TMD) and a Magnetorheological (MR) Damper. Taking German ICE3 high-speed railway train through 32meters simply supported box girder bridge for example, a dynamical model of Train-Bridge coupling vibration system is established by considering track irregularities. The relations between the bridge vibration and track irregularities with dampers are studied and the effects of vibration control with TMD and MR-TMD on the bridge are comparatively analyzed. The results show that the effects of track irregularities on vertical displacement of the bridge are relatively small, but on vibration acceleration are relatively large. As the train speed increases, the effects of track irregularities on the vibration acceleration is lager. As the track irregularities increase, the accelerations are greater. MR-TMD is able to inhibit vibration of bridge effectively, and has a wider control range and frequency bandwidth.

Abstract: The dynamic response of simple supported beam under the moving load is analyzed. The finite element analysis software MIDAS is used to simulate the process of when the uniform constant force moving through the simply supported beam. The first 5 natural frequencies of simply supported beam are obtained with the modal analysis and compared with the analytical solution. The feasibility of the finite element method is verified.

Abstract: The analysis and design of a concrete filled steel tubular beam footbridge with corrugated steel webs are presented in this paper. The decreased dead weight of corrugated steel web results in a lower construction cost of the bridge. The bridge crosses an existing roadway, whose traffic should not interrupt during the construction of the footbridge. The considerations of the design is introduced. By analyzing the bridge using MIDAS program, the strength, stiffness and dynamic behavior can meet the requirements of the codes.

Abstract: The modern prestressed concrete bridges have the characteristics of large-span, high concrete strength, reinforced volume prestress and linear shape complexity. The structure bearing capacity and durability are considerable impacted by concrete creep, such as stresses redistribution and deflections increase. Some of the prediction concrete creep models that are being widely used at present are briefly introduced in this paper. Based on the analysis of existing research achievement, for the aim of improving the calculation accuracy of creep effects in bridge structures, several main problems that should be paid attention to in concrete creep analysis are pointed out from four aspects: (1) in design stage, the reasonable creep prediction model should be selected in accord with the local building materials and environment conditions; (2) during the analysis of creep effects, the initial stresses state and the stresses redistribution should be attended; (3) the reliability of prestress loss calculation should be considered in analysis of concrete creep effects; (4) the differences between normal construction materials and that of new types should be taken into account in concrete creep analysis.

Abstract: In order to study the reasonable thickness and width of bridge decks of concrete T beam bridge, 36 ANSYS finite element models of simply supported concrete T beam were established, stress performance of each models have been analyzed under the centre load. The analysis results indicated that when the bridge deck thickness reached 22cm, it was no much sense of influence of bridge decks stress and deflection change by increasing the thickness of the bridge deck, therefore, the recommended value of deck thickness was about 22cm. Since the width of the bridge deck has little effect of the mechanical properties and stiffness of it, so the recommended values of the bridge decks width should be determined combined with the diaphragm and the integral stiffness of T beam bridge.

Abstract: Nowadays, with the rapid development of the traffic infrastructure construction and the growing of the traffic flowing and speed, the vehicle-bridge coupling vibration research has become the focus of the bridge engineering study. The dynamic response of the bridge under the traffic flowing is one of the vital parameters for the vehicle-bridge coupling vibration analysis. In this paper, a methodology, employing the speed radar gun, the video recorder, and the dynamic strain tester in combination with manually recording is used to continuously and detailed investigate the traffic loads on the expressway bridge within 24 hours a day. With this approach introduced by this paper, all the critical parameters, such as the vehicle type, speed, traffic lane, the arriving time of the traffic and the bridge-vehicle dynamic interaction are all recorded. In this investigation, firstly the dynamic responses of 8 pieces of girders of the bridge under 5650 individual vehicles driving through the bridge are recorded, then in conjunction with the investigated traffic flowing samples, in terms of the vehicle type, some detailed statistics study is conducted on the collected records, and finally the space-time distribution laws of the dynamic response of the bridge under the traffic flowing are studied extensively. The result of this study could provide helpful theoretic guidance and supporting data for the vehicle-bridge coupling vibration research.

Abstract: The physical, mechanics, deformation, heat properties, pore structure of foamed concrete with polypropylene fiber and high volume fly ash were tested with the different water/binder ratio, perlite, foaming agent, polycarboxylate water reducer. The results showed that when adding foaming agent, PCA into foamed concrete with lower W/B ratio, it is possible to research the function integration foamed concrete with lower bulk density, higher compressive strength, smaller drying shrinkage, thermal insulation and waterproof.

Abstract: This paper takes Huzhou Baimitang Bridge as an engineering example, expounds the common diseases of through pre-stressed truss arch bridge and their causes. It uses structure calculation software to optimize the reinforcement methods of components, such as arch rib, diagonal brace, tie beam, etc. The results show that pasting steel for arch rib, diagonal brace and pasting carbon fiber sheet for tie beam can effectively enhance the stiffness and the carrying capacity of Baimitang Bridge. The reinforcing methods are good for reference of other similar engineering projects.

Abstract: Steel-concrete composite girder is consisted of concrete slab and steel girder connected through shear connectors. Owing to shrinkage and creep of concrete, redistribution of structural internal force and stress should be caused. It is widely accepted that shrinkage and creep models of concrete possess large randomness. The influences of stochastic variation of creep and shrinkage model, compressive strength of concrete, elastic modulus model of concrete, ambient humidity, load and shear connector stiffness on structural responses of continuous steel-concrete composite beam are investigated in the present study. Through Latin Hypercube Sampling (LHS) approach, the time variant probabilistic responses of deflection, interface slip, and stress of concrete slab and steel girder of continuous steel-concrete composite beam are studied.