Applied Mechanics and Materials Vols. 744-746

Abstract: Multiple factors affect internal force and linear of catwalk, meanwhile, there are many safety and quality risks caused by these factors during its erection. So the control of the catwalks during its erection is very important. Based on the Puli grand bridge, the key control technology of catwalks erection is studied in this paper . The unstressed length of track cable in catwalks and the ultimate unbalance horizontal force on top of bridge tower during erection are calculated, which are part of precondition for safety control. The effects of temperature and tower deviation, which are main factors influenced the linear of catwalk track rop, are analyzed in this paper. Then the safety and linear control measures are put forward. The construction result shows that the safety control methods and linear adjustment measures are effective.

Abstract: In recent years, the lateral creeping happened from time to time to the curved concrete girder bridges when they are in service. This attracts much attention in the fields of the design, construction, maintenance of this kind of bridges since severe damage or collapse may happen to the whole structure when the lateral creeping displacement is large enough. In this paper, a comprehensive analysis is carried out on the lateral creeping of a curved two-span continuous concrete girder bridge which has been in service for 20 years to find out the possible reasons. A finite element model is appropriately developed for this example bridge using the commercial software Midas/Civil. Taking into account the dead loads, vehicle loads, thermal loads, etc., the safety and reliability of the original design of this bridge is proved first. And then the analysis is carried out for two possible reasons, bearing failure and expansion joints failure, respectively. The results show that the real reason of the bridge lateral creeping is that the expansion joints are stuck by the concrete blocks left when the expansion joints are replaced.

Abstract: Ling Bridge in Ningbo, a province-protected historic relic in Zhejiang, is the only three-hinged steel arch bridge existing in China as well as the first modern steel arch bridge co-constructed by Chinese engineers and foreign engineers in 1936. For over 70 years the bridge has served as an important transportation node on urban trunk road, bearing significant traffic pressure. It is necessary to have its status quo detected and its safe use evaluated to sustain normal operation of the bridge. The status assessment of the bridge is conducted in the following aspects: first, visual inspection was applied to check types of existing diseases and to estimate their threat degrees to the bridge; then, spatial linear examination was applied to detect structural deformation and to calculate whether there exists a instability hazard; finally, strength and fatigue calculation was made to determine safety degree of the bridge structure.

Abstract: The Sujia Road Bridge is under the construction,in order to ensure the construction will not have template problems,numerical simulation is needed.Analyze the internal force and deformation of the bridge pier template with the ABAQUS,and the results show that the internal force of the template is much less than yield stress.Therefore, the structure of the template can be optimized.

Abstract: The close-frame is the main structure type of underground passage in airport project. Its characteristics are long route, multi-zone crossing, heavy load capacity. The suitable calculation method is a key issue to simulate the force of structure. Single-span close frame bearing Class A380F aircraft load is discussed in detail about stress and moment by solid finite element analysis. Therefore, it has important engineering significance in guiding structural design.

Abstract: This paper is based on some curved wide extra-dosed cable-stayed bridge, and the finite element software MIDAS/CIVIL is applied to set up three different system models of semi-floating system, pylon-girder consolidation system and rigid frame system according to the practice engineering background. Compared the internal forces and displacements in three systems under dead load, temperature load and live load, conclusions can be drawn as, the overall stiffness of rigid-frame system is the largest, its deformation is the least under dead load and live load, but it is sensitive to temperature load which can cause large second internal force. According to the overall structure performance of three different systems, it is better understanding their superiority to different application range, which can be a reference for designing in the future.

Abstract: Redundancy is an important component of structural robustness. A method is proposed based on the response sensitivity for assessment of the redundancy of structure under earthquake. Redundancy analysis is carried out for a single-layer reticulated dome subjected to earthquake condition. The result shows that the redundancy values are able to reveal the weak links in the structure. Members with a small redundancy are identified as structural weaknesses that are easily damaged under loads, and their failure may cause catastrophic consequences to the structure. Therefore, the members with small redundancies must be treated as key components of the structures.

Abstract: Owing to the simulated ground motion energy distribution by stochastic finite-fault method is not reasonable, near-field bedrock strong ground motion acceleration time histories are used to study. Fourier transform is adapted to analysis the variation of the energy accumulation curve with frequency. The results show that the record energy accumulation curve is a steep rise curve, 80% of total energy of the vertical ground motion is concentrated on the 2.5-15Hz, while the horizontal is mainly concentrated on the 2-11Hz. An improved stochastic finite-fault method is proposed by multiplying an amplification factor in some frequency. The results show that multiplying an amplification factor, the simulated acceleration energy accumulation curve matches to the record acceleration energy accumulation curve, and the peak of simulated acceleration response spectrum tends to the record acceleration value.

Abstract: In the paper the influence of spatial variability of a seismic shock on an industrial steel hall was examined. Different models of seismic excitation were introduced. Firstly, a uniform seismic excitation model was applied, assuming identical motion of all supports of the hall. Then, a non-uniform excitation model was implemented. In that model subsequent points of the ground in the direction of wave propagation repeat the same motion with a certain time delay dependent on the wave velocity. Two direction of the wave passage were assumed: longitudinal (along the longer side of the hall) and transverse (along the shorter side of the hall). To guarantee proper nonlinear elasto-plastic behavior of the structure, the material parameters of the steel were determined experimentally. The dynamic analyses revealed that the response of the hall to the seismic shock was reported beyond the elastic range. Plastic effects appeared in some zones of the primary as well as the secondary structural members of the object, regardless of the excitation model. The model of non-uniform seismic excitation with transverse wave passage turned out to have the greatest impact on the dynamic response of the hall; the plastic strains obtained for that model were much greater than those obtained for other models. The transverse non-uniform excitation generated irreversible strains almost 3 times greater than the uniform excitation. The evolution of significant plastic effects was observed mainly for non-uniform excitations in the lower parts (girts and columns) of the hall, which were strongly affected by the different motions of the ground.

Abstract: In this paper, SAP2000 and ANSYS software are used to modeling and analysis athree-span continuous beam bridge with high piers case study.By using differentbearing types and combinations to form different options, create two finiteelement models.Analysis dynamic characteristics ,elastic response spectra,linear time history and nonlinear time history .And focus on comparing dynamiccharacteristics of the earthquake response of the two programs .Running outputdata processing and comparison results show that the application of thedifferent parameters of the rational combination of rubber bearing basin bridgearrangement has better seismic performance.