Papers by Keyword: RC Frame Structure

Abstract: In the present study, the effect of the structural simplicity on the progressive collapse resistance of a 13-story RC framed building is assessed. The existing structure from Brăila (a zone with high seismic risk from Romania) designed in 1972 according to the former seismic code P13-70, was re-designed in accordance to the provisions of the current seismic code P100-1/2013. The original building consists of beams and columns with different cross-sections along the height of the structure. To achieve the objective of this study, a new model with constant cross-sections was designed according to the current seismic and structural concrete codes. Following the provisions of the GSA (2003) Guidelines, nonlinear dynamic analyses are performed using the Applied Element Method incorporated in the ELS^® computer software. It was shown that, under the standard GSA loading (DL+0.25LL) the both two numerical models of the 13-story building are not expected to fail when a first-story corner column is suddenly removed. To estimate the ultimate load-bearing capacity of the structural models, a series of nineteen nonlinear dynamic analyses are carried out. The robustness analyses indicate that, the model with different cross-sections can sustain a maximum load 16% larger than the model with constant cross-sections along its height.

Abstract: According to the research data and achievements home and abroad, this paper puts forward the practical seismic design process and method of RC frame structure retrofitted by FRP, to promote the application of FRP in the field of RC frame retrofitting. And the ductility design of the column, the reinforcement design of the node area and the structures integral seismic action are discussed, providing a reference for future research and engineering application.

Abstract: This work is based on a typical RC frame that was closed to the epicenter and collapsed during the Wenchuan Earthquake. The seismic collapse resistance of the frame was strengthened by attached substructures, including conventional brace, buckling restrained brace (BRB) and viscous damper. Collapse fragility analysis based on incremental dynamic analysis is implemented for each strengthening scheme to compare their effects and to analyze the influence of critical parameters. The results show that the viscous damper performs better than the BRB, and the BRB performs better than the conventional brace. With the same strengthening parameters, the A-shaped bracing scheme is better than the X-shaped scheme.

Abstract: The corner joints of the fringe frame are the most vulnerable components among RC frame structural joints when subjected to progressive collapse, but very few research focused on its performance against progressive collapse. In this research, nonlinear static analysis method was used to analyze the vertical resistance of corner joint against progressive collapse by finite element software ANSYS. The influence of structural design parameters were also studied through comparative analysis. The result shows the joint ultimate vertical resistance is mainly influenced by the moment carrying capacity of the beam ends and column ends. Consequently, this research could offer reference for structural design against progressive collapse.

Abstract: This paper presents the results of a numerical investigation aimed at evaluation of damage accumulation in structures under different seismic sequences. For this purpose, a multi-story RC frame model representing the typical buildings was built and subjected to four sets of different repeating seismic sequences with different magnitude. The results indicate that the aftershock sequences will increase the damage accumulation in structures, and the damage index based on the Park and Ang model can qualitatively and quantitatively ascertain the damage state of the structure instead of the single index based on the lateral drift demands. Additionally, different sequences with the identical energy input will cause the same damage state in structures.

Abstract: Staircases in Reinforced Concrete (RC) frame structures suffered severe damages in recent earthquakes although they are regarded as critically important passages during emergencies. Staircases act as the first line of defense in earthquakes, and therefore they first yield and fail. Then they lose the action of safe passages so that the anticipated seismic performance objectives cannot be satisfied. To make sure that staircases work as safe passages in strong earthquakes, the current Chinese code for seismic design of buildings claims special requirements on the design of staircases. At first, the influence of staircases on the structural behavior of a typical RC frame structure is studied by the comparison of internal force in the structural members considering and neglecting the effect of staircases under frequent earthquakes. Besides, the effect of staircases on the yielding and failing mechanism of the frame structure is investigated through static elasto-plastic analyses. From this study the reason of the damages suffered by cast-in-site staircases in RC frame structures under earthquakes can be understood.

Abstract: Considering the interaction of building-soil-tunnel, the grillage beams foundation frame building vertical crossed by Double-Line (DL) parallel shield tunnel was simulated by 3D MIDAS/GTS software. The results show that: after left-shield tunnel construction had done, during the passage of the right shield tunnelling, the differential settlement decreased gradually, settlement is slightly larger than the left when the right tunnel had ready crossed the building. Uneven settlement first increases, and then decreases gradually tends to zero. Lateral horizontal displacement changes little, and longitudinal horizontal displacement first increased and then decreases. The building’s maximum first principal stress exceeds the standard value, which may cause cracking. With the increase of L the distance from frame axis to the axis of the two tunnels, the first principal stress P1 and maximum shear strain MSmax tended to reduce in general. The maximum differential settlement between columns first increased and then decreased.

Abstract: The article considers the two horizontal components of ground motion and torsional component, to do nonlinear time history analysis both on regular and irregular shaped column frame structure models. The results show that torsional component of ground motion haves some impact on torsion reaction of structures, stiffness of irregular shaped column frame structure is uneven, and angle of columns are greater than that of the regular structure; torsion haves some impact on the torque of structure, the torque increases of corner columns is maximum, so corner columns are weak links in shaped column structure, considered fully during the seismic design.

Abstract: The progressive collapse of the frame structure is simulated with testing a 1/3 scale, 4×2-bay and 3-storey reinforced concrete spatial frame in this paper. The experimental model was designed according to the non-seismic resistance demand, and the middle-side column of the bottom floor was replaced by a mechanical jack to simulate its initial local damage. Based on the experimental results, the applied load process and the load transferring mechanism of the model frame are analyzed. The progressive collapse-resisting performance of reinforced concrete frames with non-seismic demand are obtained.

Abstract: This paper introduces the ANSYS optimization design principles and proposes the specific operation steps of it. Through a case research, the paper gives an study on the entire process for the realization of ANSYS design optimization model and the major steps involved. The study results comfirmed the feasibility of optimizing the design model by ANSYS, and provide a new approach or tools for the analysis on the optimization of other complicated structures.