Free vibrations of cracked prestressed concrete beams

Hamed, Ehab; Frostig, Y.

doi:10.1016/j.engstruct.2004.06.004

Cited by 32 publications

(16 citation statements)

References 16 publications

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“…Hop experimentally showed similar results . Hamed and Frostig analytically showed a reduction in natural frequencies with increased cracking, but no model for the relationship to prestress force levels was developed . De Roeck agrees with the researchers and argues that loss of prestress can only be detected by vibration methods if accompanied by cracking …”

Section: Vibration Methodsmentioning

confidence: 68%

Monitoring of prestressing forces in prestressed concrete structures—An overview

Abdel-Jaber

Glišić

2019

Struct Control Health Monit

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This paper presents an overview of currently available methods for monitoring prestressing forces in prestressed concrete structure. Structural health monitoring has become an increasingly important tool for assessment of structural performance. Additionally, the value of the prestressing force represents an important parameter in prestressed concrete structures. Thus, several methods for monitoring prestress forces have emerged. This paper aims to consolidate the work performed in the area of prestressing force monitoring by presenting the most important advances and the directions for future research. The methods presented in this paper are based on indirect monitoring of the prestressing force through monitoring of another relevant parameter. They are divided into five general classes based on the relevant parameter they monitor:(a) vibration-based methods (based on acceleration), (b) impedance-based methods (based on electrical impedance), (c) acoustoelastic methods (based on wave velocity), (d) elasto-magnetic methods (based on magnetic permeability), and (e) strain-based methods (based on strain). The paper presents a table summarizing the comparison between the methods based on defined criteria.

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Section: Vibration Methodsmentioning

confidence: 68%

Monitoring of prestressing forces in prestressed concrete structures—An overview

Abdel-Jaber

Glišić

2019

Struct Control Health Monit

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“…In the modern highways and urban roads, the proportion of small and medium span bridge is very large in [1][2][3]. Essentially, reinforced concrete and prestressed concrete slab bridges are employed and the main beam is composed of Tshaped beam, hollow beam or a small box in [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Influence of Diaphragm Cracks on Load Transversal Distribution Coefficients of PC Multi Girder Bridge

Zhang²,

Wen-gai

et al. 2011

2011 International Conference on Computer Distributed Control and Intelligent Environmental Monitoring

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Based on nonlinear theory of reinforced concrete, the influence of diaphragms' cracking on the load transverse distribution for the prestressed concrete multi-T-girder bridge is studied. Compared with results from traditional theory called hardening connective plates, the applicable range of the theory is determined. From shell element degraded from continuous body, steel and concrete are modeled by layered shell element. With some available criteria, the material nonlinear properties of concrete and steel are considered. Then the procession of cracking, yielding and failure of prestressed concrete multi-T-girder bridge is imitated and the analytical three-dimensional procedure is compiled. For a certain prestressed concrete multi-T-girder bridge, combined with traditional theory of hardening connective plates, some loadcases including uniform loads, symmetric loads and offset loads are calculated. From the results, it is shown that the cracks in the diaphragm weaken the transverse connections between the beams, which leads to the unsatisfying change of the transverse distribution of the loads. When the bridge is subjected to uniform loads, the result from the nonlinear procedure is coordinative with that from the theory of hardening connective plates. When the bridge is subjected to symmetric loads and offset loads, the result from the nonlinear procedure is not in agreement with that from the traditional theory and when the diaphragms are in cracks, analysis by the theory of hardening connective plates may lead to large error, which will produce unsafe results.

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“…shrinkage and creep, may lead to not only excessive deflections of bridges but also a deterioration of the prestress in external tendons over time, which can severely curtail the life span and put the bridge out of service [1 -3]. The theoretical analysis revealed that the fundamental frequency of the simply supported prestressed beam fell off to less than 50% of the original frequency as a result of long-term behavior of concrete [4]. Insitu monitoring of creep and shrinkage effects in a real post-tensioned concrete box girder during construction and service was also performed in order to contribute knowledge to design practice [5].…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Study on Natural Frequency of Externally Prestressed Box-Girder with Corrugated Steel Webs

Liu¹,

Xu²,

Li³

et al. 2016

TOCIEJ

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Based on the characteristics of box girder with corrugated steel webs, the existing prestressing force, the effect of shear deformation of composite girder on the deflection, “folding effect” in longitudinal direction of corrugate steel webs and the arrangement of external tendons were considered comprehensively. With the experiment results of five literatures integrated,N/fcA(the axial compression ratio) was selected as regression parameter to develop a regression equation for the effective cross-section stiffness of the girder. Then a formula for natural frequency of the externally prestressed box girder with corrugated steel webs was proposed. Finally, thein-situmeasurement on an actual bridge and a laboratory dynamic test on the model box girder with seven prestressing levels were conducted. The test results showed that the natural frequency of box girders with corrugated steel webs increased along with the growing external force. In contrast to other related formulas, the calculated results of the formula proposed in this paper showed the same tendency with measured results and the maximum error is 1%.

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Free vibrations of cracked prestressed concrete beams

Cited by 32 publications

References 16 publications

Monitoring of prestressing forces in prestressed concrete structures—An overview

Monitoring of prestressing forces in prestressed concrete structures—An overview

Influence of Diaphragm Cracks on Load Transversal Distribution Coefficients of PC Multi Girder Bridge

Theoretical and Experimental Study on Natural Frequency of Externally Prestressed Box-Girder with Corrugated Steel Webs

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