Papers by Keyword: RC Frame Structure

Abstract: How to ensure the whole stability of structure and avoid progressive collapse of structure caused by destruction of local structures under accidental loading have been paid close attention to extensively by researchers all over the world. According to GSA guidelines, FEM model of 3-D frame structure was established by ANSYS software. Failure of frame structure local column is simulated with the method of "killing" columns of long side, short side, corner side, and interior side, and two columns of long sides, in order to explore the regularity for change of series performance parameters when the frame structure suffering accidental loading. And the alternative load path method was used to analyse the collapse of reinforced concrete frame structure. The result indicates that the frame structure local column damage can make structure basic natural vibration period and maximum interlayer displacement angle larger, and make minimum ratio between shearing force and weight smaller, and if two columns of long side are destroyed, the progressive collapse of frame structure will occur.

Abstract: This research presented the damage identification problem of frame structure using the wavelet transform of strain mode. Solving strain modal parameters of plane frames with cracks by means of the finite element theory, applying the gauss2 wavelet transform to analyze the stain mode of plane frame, and denoising the wavelet coefficients of the strain mode by db3 wavelet, then the location of crack of the plane frame could be identified by the maximum of wavelet coefficients after denoising. Taking one-layer plane frame as an example, this research gave the finite element model of framework with sheet crack (non-through surface crack and internal crack), calculated the strain mode of the structure, and identified the location of cracks by wavelet analysis of strain mode. Results show that this method is able to identify the damage of frame structure. Numerical calculation shows that the approach is effective. This paper provides a valuable reference of structural damage identification and diagnosis in engineering applications.

Abstract: Considering the interaction of building-soil-tunnel, the grillage beams foundation frame building vertical crossed by Double-O-Tube (DOT) shield tunnel was simulated by 3D MIDAS/ GTS software, and the impact of construction on the building was analyzed. The results show that: the ground settlement trough caused by DOT shield tunnel can be fitted by peck formula; during the passage of the shield tunneling through the building, the settlement of the building increased and settlement trough was wilder; the settlement was stable and had a little rebound when shield machine already passed the building; with the increase of driving distance, the first principal stress P1 increased and then was stable; with the increase of L, the shape of foundation settlement curve changed, and the maximum differential settlement between columns increased but was small.

Abstract: Study was carried out on the disadvantages of QR method while calculating structures and programming currently. According to its basic idea, the necessary condition for more simplification was pointed out. In the process of simplification, the shape function matrix and node displacement were calculated and saved only for parts of elements, the element stiffness matrix and load array were divided into sub-blocks, thereafter, these sub-blocks were multiplied by coefficients of certain items, finally assembled into the spline-discretization stiffness matrix and load array according to the series and spline knots number that were corresponding to nodes. One model was calculated by QR program with the method simplified or not and other methods. Results prove that this simplified approach is correct, feasible and suitable for structure calculation. It has a good theoretical and practical value.

Abstract: The cracks were pre-settled to the R.C. frame structure caused by earthquake which was defined as the damage index ω during the modeling process with analysis software-ANASYS. The temperature field contour curve were calculated for the column and beam, the law of deteriorated bearing capacity with time for the R.C. frame structure under elevated temperature were brought forward，which can adapt to R.C. frame structure with different damage index ω caused by earthquake.The relationship between ω and deteriorated bearing capacity for R.C. frame structure was also given, which was proved to be effective and correct according to comparison with the data recorded from the elevated temperature experiment designed by author.

Abstract: Three R.C. frame structure models were designed with named KJ1, KJ2 and KJ3. Elevated temperature experiments were carried out to KJ1 and KJ2 with concrete crack width 0.2mm and 0.4mm respectively which was taken as the damage index ω caused by earthquake, KJ3 was directly undertaken to elevated temperature experiment. The laws of concrete crack development, axial deformation of frame column and standard heating curves were studied. The law between concrete crack ω and deteriorated performance for concrete frame structure was put forward, which can be a good reference for research on fire resistance performance of R.C. frame structure after earthquake.

Abstract: Statically indeterminate frame, composed of beams and columns, is a widely used structure form in civil engineering. The frame carrying capacity under various actions is related to the absolute stiffness of frame components and relative beam-column line stiffness ratio. The matrix displacement method and programming based on MATLAB were employed in this study to calculate the internal forces and displacements of a 2-bay 2-story frame structure under the action of horizontal loads. The influence of the beam-column line stiffness ratio on the frame load capacity was discussed based on the calculated result. Furthermore some advises were provided about the reasonable beam-column line stiffness ratio for engineering design.

Abstract: Static method and energy method are two mainly solution methods for structure calculation presently. Static method often appears insoluble complicated transcendental equations and continues hardly. Energy method can solve force analysis of complicated structure and it is a widely used method at present, but in general it is not exact. In this article, analytic iterative method is a calculation method of analyzing geometrical nonlinear of frame Structures, considering the influence of geometrical nonlinear in structure calculation, on foundation of the analytic method that expressed with deflection equation of pressure column with geometry parameter expression with the combination of traditional linear analysis method. And a calculating application program is written to calculate displacement and force of frame structure in the environment of MATLAB language in order to apply conveniently. Because this method is on basis of analytic method, its results have sufficient accuracy. At last, there is an example to explain.

Abstract: In order to design the vibrator with the similar structure to military transport truck, which will be used in simulating transport environment and evaluating the transportation properties of the tested product, three-dimension model of overall structure of truck frame, crossbeams and floor is established with ADAMS/View based on multi-body dynamics theory and virtual prototyping technology. Post-processing of the simulation and analysis results is executed with ADAMS/Post Processor module with a military truck model in the study. According to the bump of vehicle during transport and the chassis vibration, the constraints, force and motion accord with the actual transport are put on the model. Vibration modes of all orders and the spectrum are gained and analyzed in detail. The results indicate that the simulation is consistent with the actual transport, which shows the simulation of the overall frame structure owns high credibility.

Abstract: This paper presents a seismic reinforcement approach to a frame structure, which was added from four-storey to six-storey, and is located at degree-8 earthquake intensity zone and type-II site, by using the Friction Damper. Firstly, the dynamic performance of the original structure had been tested and the performance parameters had been gotten, which were used to build up the F.E. model and to check its accuracy. Secondly, the structure simulation analysis was conducted by using the constructed F.E. model. Finally, the seismic strengthening of the frame structure being added to six-story was analyzed and calculated by using Friction Damper. This has effectively improved the structure seismic performance and the seismic performance of the reinforced structure meets well with the seismic code requirements. This approach will be helpful for the structural design engineers and the researchers.