Comparison on Dynamic Parameters of Structures with Different Additional Steel Frame Stories Constructed on the Prototype Reinforced Concrete Frame

2013 ◽  
Vol 438-439 ◽  
pp. 756-761
Author(s):  
Jian Xue Song ◽  
Hong Tuan Wu ◽  
He Shan Cheng
Keyword(s):  
Reinforced Concrete ◽  
Shear Force ◽  
Horizontal Displacement ◽  
Steel Frame ◽  
Original Structure ◽  
Dynamic Parameters ◽  
Reinforced Concrete Frame ◽  
Vibration Period ◽  
Concrete Frame ◽  
Displacement Angle

Based on a practical project, the dynamic parameters for a 4-story reinforced concrete frame, with additional different stories of steel frame constructed on its top, are investigated, including vibration period, frequency, and seismic response under minor shock, such as inter-story maximum horizontal displacement, inter-story maximum horizontal displacement angle, inter-story shear force and so on. It reveals that the maximum number of additional stories may be determined by the inter-story maximum horizontal displacement angle. With the additional steal frame adding on the top of the original structure, the maximum horizontal displacement angle often comes into being as the second story from the top of the structure, at the same time, a certain story in the prototype structure may evolve into a weak story which has to be reinforced. However, with the increasing of additional stories, the total shear force in the bottom story decreases, which leads to a new anti-seismic design concept.

Mechanical Property Analysis on Joints of Steel Secondary Beam Inserted in Reinforced Concrete Frame Girder

2012 ◽  
Vol 166-169 ◽  
pp. 3087-3094
Author(s):  
Qiong Yu ◽  
Jian Li Xu ◽  
Xing Zhuang Zhao
Keyword(s):  
Reinforced Concrete ◽  
Shear Force ◽  
Design Method ◽  
Internal Force ◽  
Joint Moment ◽  
Secondary Beam ◽  
Vertical Force ◽  
Horizontal Force ◽  
Reinforced Concrete Frame ◽  
Concrete Frame

Models for internal force analysis and strain distribution of joints of steel secondary beam inserted in reinforced concrete frame girder were analyzed. The horizontal internal force and vertical force were considered separately during calculation and analysis process. Bending-shearing correlation of vertical internal force was studied while the horizontal force wasn’t taken into account. Results show that the non-dimensional moment varies linearly with the non-dimensional shear force. Base on this, the formulas by which the joint moment and shear force are calculated are derived, and are related to depth ratio of forward to backward compression zone .And then the method to calculate joint moment capacity under horizontal force is put forward. By investigating the moment and shear force variation, the relationship between the yielding stress of the bar in the slab and the boundary concrete under the steel secondary beam crushing is identified. In the end, practical design method is proposed, and problems need further research are mentioned.

Comparative study of strengthening strategies for reinforced concrete frame with soft ground story

2017 ◽  
Vol 8 (4) ◽  
pp. 122
Author(s):  
Md. Shafiqul Islam ◽  
Aojoy Kumar Shuvo
Keyword(s):  
Reinforced Concrete ◽  
Poor Performance ◽  
Ground Level ◽  
Point Of View ◽  
Original Structure ◽  
Reinforced Concrete Frame ◽  
Economic Point ◽  
Concrete Frame ◽  
Open Ground ◽  
Strengthening Technique

One of the common forms of reinforced concrete (RC) framed building is to provide parking facility at ground level which is created by not providing any infill masonry at parking floor level. Due to the presence of infill walls in the entire upper story except for the ground story makes the upper stories much stiffer than the open ground story resulting in their poor performance during earthquakes. So strengthening of such reinforced concrete (RC) frame buildings with an open ground story is indispensable. In the present study several Strengthening options were evaluated for their effectiveness in improving the performance of such building without disturbing the parking facility of ground story based on linear and nonlinear analysis. The strengthening techniques studied were changing column dimension, providing diagonal bracing, lateral buttresses, shear wall, and providing chevron. The Strengthened building results were compared with the results of the original structure to deduce the structural performance improvement and cost associated to each solution were determined to develop cost efficiency relation for different strengthening technique. Providing lateral buttresses in the open first story was found to be more feasible in both case of increase ground story strength and economic point of view among all strengthening options.

The Effect on The Overall Performance of Frame Structure of Local Column Destruction

2011 ◽  
Vol 71-78 ◽  
pp. 315-320
Author(s):  
Yue Dong Sun ◽  
Yu Ming Lin
Keyword(s):  
Progressive Collapse ◽  
Frame Structure ◽  
Load Path ◽  
Reinforced Concrete Frame ◽  
Short Side ◽  
Vibration Period ◽  
Concrete Frame ◽  
Software Failure ◽  
Local Structures ◽  
Displacement Angle

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.

scholarly journals Model of prefabricated concrete frame in the condition of southern Vietnam

2019 ◽  
Vol 135 ◽  
pp. 03043 ◽  
Author(s):  
Hong Quan Tran ◽  
Thanh Quang Khai Lam ◽  
Thi My Dung Do
Keyword(s):  
Reinforced Concrete ◽  
Mekong Delta ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Climatic Conditions ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Southern Vietnam ◽  
Frame System ◽  
Frame Systems

In recent years in Vietnam, the structure of multi-storey buildings has been strongly developed in both quantity and quality, especially multi-storey buildings made from prefabricated reinforced concrete structures. Collecting documents shows that the Mekong Delta of southern Vietnam has built many multi-storey buildings using prefabricated reinforced concrete frame systems. In the southern climatic conditions, these multi-story buildings are directly affected by climate change, especially the seasonal wind load and the intensity of the wind is getting stronger and more complex, so the the work at the nodes of the frame will be affected. In this study, the authors studied the displacement of the frame system by horizontal displacement, vertical displacement, moment, shear and axial force of the frame according to three models: rigid linked frame, joint linked frame and semi-rigid linked frame.

Application of Buckling-Restrained Braces in Prefabricated Reinforced Concrete Frame

2013 ◽  
Vol 351-352 ◽  
pp. 1527-1531
Author(s):  
Hong Nan Wang ◽  
Hua Bo Liu ◽  
Jian Feng Wang
Keyword(s):  
Reinforced Concrete ◽  
Time History ◽  
Lateral Force ◽  
Original Structure ◽  
Design Code ◽  
Reinforced Concrete Frame ◽  
Seismic Excitations ◽  
Concrete Frame ◽  
History Analysis ◽  
Present Design

The old prefabricated reinforced concrete buildings have been designed with old standards that are lower than the present design code provisions. These buildings are likely to be vulnerable to severe damage or total collapse under strong seismic excitations. Hence, it is necessary to evaluate these buildings seismic performance and to retrofit them using appropriate methods. Buckling-restrained brace (BRB) is a kind of prospective energy dissipation component. As a brace, it is also a lateral force resistant member. Based on the characteristics of prefabricated frame and BRB, the time history analysis of a prefabricated frame strengthening by BRB is carried out by using software ANSYS to input the seismic wave. Then, the seismic behavior of this kind of frame is studied. It is observed that the seismic response of the retrofitted structures reduces significantly in comparison with the corresponding original structure without any retrofit measures.

Natural Vibration Period Analysis of Multi-Storey Reinforced Concrete Frame Structure

2012 ◽  
Vol 226-228 ◽  
pp. 351-354
Author(s):  
Li Na Hao ◽  
Yong Sheng Zhang
Keyword(s):  
Reinforced Concrete ◽  
Frame Structure ◽  
Ambient Vibration ◽  
Reinforced Concrete Frame ◽  
Natural Period ◽  
Test Technique ◽  
Infill Walls ◽  
Vibration Period ◽  
Concrete Frame ◽  
Reinforced Concrete Frame Structure

Field measurements of dynamic characteristics of the multi-storey reinforced concrete frame structure buildings were carried out, by using the ambient vibration test technique, and structural modal parameters were extracted. The measured results and calculated results in accordance with current design specifications were compared. Results show that for multi-storey reinforced concrete frame structure, the measured vibration period of structure is close to the natural period calculated in accordance with the empirical formula of the “Load Code for the Design of Building Structures”. In the actual project, when the designer calculate the natural period if considering only the quality of the infill walls, without considering the stiffness of the infill walls, the period should be shortened. In this paper, the recommended period shortening factor for the multi-storey reinforced concrete frame structure is gave 0.4~0.5.

scholarly journals Shear Behavior of a Reinforced Concrete Frame Retrofitted with a Hinged Steel Damping System

2020 ◽  
Vol 12 (24) ◽  
pp. 10360
Author(s):  
Hyun-Do Yun ◽  
Sun-Woong Kim ◽  
Wan-Shin Park ◽  
Sun-Woo Kim
Keyword(s):  
Reinforced Concrete ◽  
Shear Behavior ◽  
Seismic Retrofitting ◽  
Reinforced Concrete Frame ◽  
Main Research ◽  
Torsion Spring ◽  
Concrete Frame ◽  
Energy Dissipation Capacity ◽  
Research Questions ◽  
Torsion Springs

The purpose of this study was to experimentally evaluate the effect of a hinged steel damping system on the shear behavior of a nonductile reinforced concrete frame with an opening. For the experimental test, a total of three full-scale reinforced concrete frame specimens were planned, based on the “no retrofitting” (NR) specimens with non-seismic details. The main research questions were whether the hinged steel damping system is reinforced and whether torsion springs are installed in the hinged steel damping system. From the results of the experiment, the hinged steel damping system (DR specimen) was found to be effective in seismic retrofitting, while isolating the opening of the reinforced concrete (RC) frame, and the torsion spring installed at the hinged connection (DSR specimen) was evaluated to be effective in controlling the amount of deformation of the upper and lower dampers. The strength, stiffness, and energy dissipation capacity of the DSR specimen were slightly improved compared to the DR specimen, and it was confirmed that stress redistribution was induced by the rotational stiffness of the torsion spring installed in the hinge connection between the upper and lower frames.

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