scholarly journals Effect of Environmental Conditions on the Modal Response of a 10-Story Reinforced Concrete Tower

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Marco Regni ◽  
Davide Arezzo ◽  
Sandro Carbonari ◽  
Fabrizio Gara ◽  
Daniele Zonta
Keyword(s):  
Reinforced Concrete ◽  
Wind Velocity ◽  
Natural Frequencies ◽  
Structural Response ◽  
Low Noise ◽  
Effect Of Temperature ◽  
Modal Parameters ◽  
Reinforced Concrete Frame ◽  
Torsional Mode ◽  
Concrete Frame

We analyse the effect of temperature and wind velocity on the natural frequencies and modal damping ratios of the Faculty of Engineering Tower at the Università Politecnica delle Marche, a 10-story reinforced concrete frame building, permanently monitored with low-noise accelerometers. The data recorded over the first 5 months of monitoring demonstrate that temperature variations and wind intensity have a clear effect on the first three natural frequencies and the corresponding damping ratios. Temperature is positively correlated to the first and second frequencies, corresponding to shear displacement modes and negatively correlated to the third frequency, corresponding to a torsional mode. All frequencies are positively correlated to wind velocity and changes in damping ratios are inversely correlated to any change in frequency. A mechanical explanation of these phenomena is offered, based on a critical review of literature case studies. These results suggest that using changes in modal parameters for damage detection always requires accurate knowledge of the correlation between modal parameters and environmental quantities (temperature, humidity, and wind velocity), an information which is only available through long-term continuous monitoring of the structural response.

Vulnerability Assessment of Existing Low-Rise Reinforced Concrete School Buildings in Low Seismic Region Using Ambient Noise Method

2014 ◽  
Vol 931-932 ◽  
pp. 483-489 ◽  
Author(s):  
Ahmad Fahmy Kamarudin ◽  
Ibrahim Azmi ◽  
Zainah Ibrahim ◽  
Aziman Madun ◽  
Mohd Effendi Daud
Keyword(s):  
Reinforced Concrete ◽  
Vulnerability Assessment ◽  
Ambient Noise ◽  
Natural Frequencies ◽  
Structural Response ◽  
Reinforced Concrete Frame ◽  
Seismic Region ◽  
Concrete Frame ◽  
Adjacent Buildings ◽  
Ambient Noise Method

Ground movements triggered by the Bukit Tinggi earthquakes in 2007 to 2009 are believed to be the possible cause of several structural damages on a secondary school building of SMK Bukit Tinggi, in the state of Pahang, Malaysia. This paper describes the ambient noise study conducted on the damaged building (a 4-storey reinforced concrete frame laboratory building) and the adjacent buildings using tri-axial 1 Hz seismometer sensors. Fourier amplitude spectra (FAS) analysis was applied to determine the buildings natural frequencies for vulnerability assessment of the damaged structure in both longitudinal and transverse axes. Significant multiple peaks of FAS curves used for natural frequencies determination of the buildings show values between 4.18 to 4.34 Hz, 5.04 to 5.23 Hz, 6.07 to 6.54 Hz and 8.17 to 8.81 Hz, indicating the existence of translational and torsional vibration modes acting on the buildings. Differences in dynamic behaviour between the laboratory and the adjacent buildings may be responsible for the structural damages due to the independent structural response and excessive torsional effect during the Bukit Tinggi earthquake tremors.

Based on ANSYS Buckling-Restrained Brace Frame Structure Shock Absorption Analysis

2013 ◽  
Vol 477-478 ◽  
pp. 651-654
Author(s):  
Li Jun He ◽  
Yong Yao ◽  
Yun Peng Chu
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Structural Damage ◽  
Structural Response ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Story Drift ◽  
Design Earthquake ◽  
Rare Earthquake

Whether the design of new structure or reinforcement of the existing projects, structure earthquakereduction design is always the focus of research at home and abroad. The buckling restrained braces won the unanimous endorsement of the engineering sector with good energy dissipation capacity and simpleeasy construction process. This Paper based on the ANSYS analysis the structural response through simulated the bucklingrestrained brace frame structure and the general reinforced concrete frame on effect of the rare earthquake or design earthquake, and analysis the bucklingrestrained braces on the seismic performance of reinforced concrete frame structure. The analysis results show that the seismic performance of reinforced concrete frame with bucklingrestrained braces well, it can effectively reduce the maximum story drift and control structural damage. Therefore, Bucklingrestrained Brace should be used extensively to reinforced concrete framework .

scholarly journals Numerical Investigation of Influential Parameters Concerning the Experimental Testing of RC Frames Under Cyclic Loading

2013 ◽  
Vol 7 (1) ◽  
pp. 230-243
Author(s):  
E. Kirtas ◽  
D.J. Kakaletsis
Keyword(s):  
Reinforced Concrete ◽  
Numerical Simulations ◽  
Experimental Testing ◽  
Plastic Hinge ◽  
Structural Response ◽  
Experimental Results ◽  
Inelastic Behavior ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Influential Parameters

Numerical simulations have been widely used to study the inelastic response of reinforced concrete structures under earthquake loading. Yet, due to the complex nature of structural inelastic behavior, experimental results are often required to verify the efficiency of applied numerical schemes. In this paper, experimental results of bare reinforced concrete frame models are employed to validate numerical calculations using the code Seismostruct. Moreover, numerical simulations investigate the influential parameters related to the physical experiment configuration and numerical analysis options and determine their effect on the obtained structural response. The experimental setup concerns a well-defined case study of a reinforced concrete frame under cyclic horizontal loading. The fixed base frame is subjected to increasing horizontal forces, leading to the development of plastic hinges at the structural elements. The adopted numerical approach describes successfully the inelastic behavior of the frame, as indicated by the obtained results of the overall structural response as well as the plastic hinge formation at cross section level. Comparison of the plastic hinge formation mechanism in particular, raises interesting remarks on the conditions and constraints of the physical experiments and highlights the valuable contribution of numerical simulations in their design.

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.

Deformation Characteristics of Reinforced Concrete Beam-Column Joint Cores under Earthquake Loading

2003 ◽  
Vol 6 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Sayed A. Attaalla ◽  
Mehran Agbabian
Keyword(s):  
Reinforced Concrete ◽  
Shear Deformation ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Frame ◽  
Bond Failure ◽  
Strain Compatibility ◽  
Concrete Frame ◽  
Column Joint ◽  
Reinforced Concrete Frame Structures

The characteristics of the shear deformation inside the beam-column joint core of reinforced concrete frame structures subjected to seismic loading are discussed in this paper. The paper presents the formulation of an analytical model based on experimental observations. The model is intended to predict the expansions of beam-column joint core in the horizontal and vertical directions. The model describes the strain compatibility inside the joint in an average sense. Its predictions are verified utilizing experimental measurements obtained from tests conducted on beam-column connections. The model is found to adequately predict the components of shear deformation in the joint core and satisfactorily estimates the average strains in the joint hoops up to bond failure. The model may be considered as a simple, yet, important step towards analytical understanding of the sophisticated shear mechanism inside the joint and may be implemented in a controlled-deformation design technique of the joint.

Resistance of Reinforced Concrete Frames with Masonry Infill Walls to In-Plane Vertical Loading

2016 ◽  
Vol 711 ◽  
pp. 982-988
Author(s):  
Alex Brodsky ◽  
David Z. Yankelevsky
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Progressive Collapse ◽  
Lateral Loading ◽  
Masonry Walls ◽  
Reinforced Concrete Frame ◽  
Masonry Infill ◽  
Concrete Frame ◽  
Vertical Loading ◽  
Infill Masonry

Numerous studies have been conducted on the in plane behavior of masonry infill walls to lateral loading simulating earthquake action on buildings. The present study is focused on a problem that has almost not been studied regarding the vertical (opposed to lateral) in-plane action on these walls. This may be of concern when a supporting column of a multi-storey reinforced concrete frame with infill masonry walls undergoes a severe damage due to an extreme loading such as a strong earthquake, car impact or military or terror action in proximity to the column. The loss of the supporting column may cause a fully or partly progressive collapse to a bare reinforced concrete frame, without infill masonry walls. The presence of the infill masonry walls may restrain the process and prevent the development of a progressive collapse. The aim of the present study is to test the in-plane composite action of Reinforced Concrete (RC) frames with infill masonry walls under vertical loading through laboratory experiments and evaluate the contributions of infill masonry walls, in an attempt to examine the infill masonry wall added resistance to the bare frame under these circumstances. Preliminary results of laboratory tests that have been conducted on reinforced concrete infilled frames without a support at their end, under monotonic vertical loading along that column axis will be presented. The observed damages and failure modes under vertical loading are clearly different from the already known failure modes observed in the case of lateral loading.

Discussion of “Elasto-Plastic Seismic Response of Reinforced Concrete Frame”

1970 ◽  
Vol 96 (6) ◽  
pp. 1246-1250
Author(s):  
James C. Anderson ◽  
Vitelmo V. Bertero ◽  
O. A. Glogau
Keyword(s):  
Reinforced Concrete ◽  
Seismic Response ◽  
Reinforced Concrete Frame ◽  
Concrete Frame
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