Static and Dynamic Stiffness in Connection with Ball Screws and Reinforced Concrete Components

2020 ◽  
pp. 99-106
Author(s):  
Dan Mihai Ştefănescu
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Stiffness

Simplified Modeling Research of Reinforced Concrete Based on the Dynamic Stiffness Equivalence

2012 ◽  
Vol 446-449 ◽  
pp. 458-462
Author(s):  
Jie Hu ◽  
Jia Quan Feng ◽  
Xi Nong Zhang
Keyword(s):  
Reinforced Concrete ◽  
Reference Model ◽  
Dynamic Stiffness ◽  
Optimization Method ◽  
Simplified Model ◽  
Response Analysis ◽  
Reinforced Concrete Structure ◽  
Optimization Function ◽  
Nature Frequency ◽  
Simplified Modeling

This paper proposed a simplified modeling method of reinforced concrete based on the equivalence of dynamic stiffness, the parameters of simplified model were modified to make the error of nature frequency between reference model and simplified model as small as possible, and an appropriate optimization function was designed. The essentiality of the proposed method is parameter optimization, with the advantages such as fewer elements and calculation assumption. The numerical simulation result indicated that this optimization method is suitable for the dynamic response analysis of complicated reinforced concrete structure.

scholarly journals Influence of steel–concrete bond damage on the dynamic stiffness of cracked reinforced concrete beams

2018 ◽  
Vol 21 (13) ◽  
pp. 1977-1989 ◽  
Author(s):  
Tengfei Xu ◽  
Jiantao Huang ◽  
Arnaud Castel ◽  
Renda Zhao ◽  
Cheng Yang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Natural Frequencies ◽  
Concrete Beams ◽  
Dynamic Stiffness ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Reinforcing Bar ◽  
Sustained Loading ◽  
Inertia Model

In this article, experiments focusing at the influence of steel–concrete bond damage on the dynamic stiffness of cracked reinforced concrete beams are reported. In these experiments, the bond between concrete and reinforcing bar was damaged using appreciate flexural loads. The static stiffness of cracked reinforced concrete beam was assessed using the measured load–deflection response under cycles of loading and unloading, and the dynamic stiffness was analyzed using the measured natural frequencies with and without sustained loading. Average moment of inertia model (Castel et al. model) for cracked reinforced beams by taking into account the respective effect of bending cracks (primary cracks) and the steel–concrete bond damage (interfacial microcracks) was adopted to calculate the static load–deflection response and the natural frequencies of the tested beams. The experimental results and the comparison between measured and calculated natural frequencies show that localized steel–concrete bond damage does not influence remarkably the dynamic stiffness and the natural frequencies both with and without sustained loading applied. Castel et al. model can be used to calculate the dynamic stiffness of cracked reinforced concrete beam by neglecting the effect of interfacial microcracks.

Damage identification in reinforced concrete structures by dynamic stiffness determination

2000 ◽  
Vol 22 (10) ◽  
pp. 1339-1349 ◽  
Author(s):  
J Maeck ◽  
M Abdel Wahab ◽  
B Peeters ◽  
G De Roeck ◽  
J De Visscher ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Damage Identification ◽  
Dynamic Stiffness ◽  
Concrete Structures ◽  
Reinforced Concrete Structures

scholarly journals Static and Dynamic Stiffness of Reinforced Concrete Beams Strengthened with Externally Bonded CFRP Strips

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 910
Author(s):  
Michał Musiał ◽  
Tomasz Trapko ◽  
Jacek Grosel
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Stiffness ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Experimental Investigations ◽  
Cross Sectional ◽  
Three Point Bending ◽  
Reinforced Polymer ◽  
Externally Bonded

This paper presents experimental investigations of reinforced concrete (RC) beams flexurally strengthened with carbon fiber reinforced polymer (CFRP) strips. Seven 3300 mm × 250 mm × 150 mm beams of the same design, with the tension reinforcement ratio of 1.01%, were tested. The beams differed in the way they were strengthened: one of the beams was the reference, two beams were passively strengthened as precracked (series B-I), two beams were passively strengthened as unprecracked (series B-II) and two beams were actively strengthened as unprecracked (series B-III). Moreover, the strengthening parameters differed between the particular series. The parameters were: CFRP strip cross-sectional areas (series B-I, B-II) or prestressing forces (series B-III). The beams were statically loaded, up to the assumed force value, in the three-point bending test and deflections at midspan were registered. After unloading the beams were suspended on flexible ropes (the free-free beam system) and their eigenfrequencies were measured using operational modal analysis (OMA). The static measurements (deflections) and the dynamic measurements (eigenfrequencies) were conducted for the adopted loading steps until failure. Static stiffnesses and dynamic stiffnesses were calculated on the basis of respectively the deflections and the eigenfrequencies. The qualitative and quantitative differences between the parameters are described.

Dynamic stiffness of reinforced concrete beams

2003 ◽  
Vol 156 (4) ◽  
pp. 373-379 ◽  
Author(s):  
K. S. Numayr ◽  
S. A. Al-Jallamdeh ◽  
N. M. Al-Akhras
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Dynamic Stiffness ◽  
Reinforced Concrete Beams

Evaluation of the Compressed Reinforced Concrete Elements Dynamic Strength, Taking into Account the Temperature Influence on the Strength and Deformability of Reinforcement Steel and Concrete

2018 ◽  
Vol 931 ◽  
pp. 334-339
Author(s):  
Levon A. Avetisyan ◽  
Mikhail V. Danilov
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Dynamic Strength ◽  
Concrete Element ◽  
Internal Forces ◽  
The Moment ◽  
Increasing Temperature ◽  
In Fire ◽  
Concrete Elements

In the article the results of the eccentrically compressed reinforced concrete element calculation operating under the dynamic loading in fire conditions are shown. The calculation of the compressed reinforced concrete element was carried out, taking into account the conducted experimental studies. The calculation showed that, depending on the temperature effects, the curvature of the reinforced concrete element in stages I and II decreases while the class concrete, which varies from 28.9% to 55%, is increasing. When the temperature reaches 2500, the cracking moment and the moment of internal forces at the end of the stage II are reduced to 22% with respect to these forces at normal conditions. With increasing temperature, the dynamic stiffness of the element in the stage I is reduced by 29.3%.

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