• Structural Engineering and Mechanics
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• v.82 no.3
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• pp.343-354
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• 2022

An understanding of the mechanism of concrete girders repaired with CFRP plates and its influence on the dynamic parameters is presented in this paper. Dynamic parameters are governed by the relationship with the physical properties of concrete girders and CFRP plates as well as the adhesive layer between them. A brief explanation of the mechanism of the composite action of concrete girders repaired with CFRP is also given in this paper. Experimental work was carried out to validate the theory of the composite action. The results show a decrease in the modal parameters of CFRP repaired girders that were turned over during the repair procedure, which contrasts with the proven static-based results that CFRP plates increase the stiffness of repaired girders. The composite action theory has explained the results based on the tension and compression forces' growth at the adhesive layer between the CFRP plates and girder surface during the repair procedure. Other girders were prepared and repaired without turning over in order to avoid tension and compression forces at the adhesive layer. The experimental results show an increase in the dynamic parameters of CFRP repaired girders that were not turned over during the repair procedure, which aligns with the static-based results. The study concludes that the dynamic parameters are excellent indicators for the assessment of CFRP repaired concrete girders. The study also suggests that researchers should not turn over damaged concrete girders to repair them with CFRP plates if they intend to study the dynamic parameters, in order to avoid the proposed composite action effect on modal parameters.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.83-88
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• 2002

The present situation of CWE(Computational Wind Engineering) and the papers presented to the CWE 2000 Symposium are reviewed from the following viewpoints; 1) topics treated, 2) utilization of commercial code (software), 3) incompleteness of CWE, 4) remaining research subjects, 5) prediction accuracy, 6) new fields of CWE application, etc. Firstly, new tendencies within CWE applications are indicated. Next, the over-attention being given to the application field and the lack of attention to fundamental problems, including prediction error analysis, are pointed out. Lastly, the future trends of CFD (Computational Fluid Dynamics) applications to wind engineering design are discussed.

• Wind and Structures
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• v.2 no.4
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• pp.253-266
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• 1999

This paper presents the effects of free-stream turbulence on streamwise surface pressure fluctuations on two-dimensional rectangular cylinders. Particular attention is given to possible effects of turbulence integral scale on fluctuation and peak pressures. The mean, standard deviation, peak pressure coefficients, spectra and cross-correlation of fluctuating pressures were measured to investigate the nature of the separation and reattachment phenomenon in turbulent flows over a wide range of turbulence intensity and integral scale.

• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.47-60
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• 1993

The eigen-equation of a wave traveling over repetitive structure is derived directly form the stiffness matrix formulation, in a form which can be used for the case of the cross stiffness submatrix $K_{ab}$ being singular. The weighted adjoint symplectic orthonormality relation is proved first. Then the general method of solution is derived, which can be used either to find all the eigensolutions, or to find the main eigensolutions for large scale problems.

• Structural Engineering and Mechanics
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• v.10 no.1
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• pp.17-26
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• 2000

This paper presents a case study with a multi-degree-of-freedom (MDOF) system where the Floor Response Spectra (FRS) have been derived from a large ensemble of ground motion accelerograms. The FRS are evaluated by the frequency response function which is calculated numerically. The advantage of this scheme over a repetitive time-history analysis of the entire structure for each accelerogram of the set has been highlighted. The present procedure permits generation of FRS with a specified probability of exceedence.

• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.225-235
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• 2016

Fluid impact tests on plates containing mesh reinforcement and polypropylene fibers were modeled and simulated using explicit finite element analysis software, LS-DYNA. The scabbing dimensions obtained by the experiments and the simulations were compared and crack formations were matched. The objective was to test the accuracy and fidelity of the model and to confirm that damage caused by fluid impact on the plates can be estimated with a reasonable accuracy over a wide range of impact velocity.

• Structural Engineering and Mechanics
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• v.5 no.2
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• pp.127-135
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• 1997

Patch recovery attempts to derive a more accurate stress filed over a particular element than the finite element shape function used for that particular element. Elements that have a free edge being the boundary to the structure have particular stress relationship that can be incorporated to the stress field to improve the accuracy of the approximation.

• Earthquakes and Structures
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• v.10 no.1
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• pp.91-104
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• 2016

In this paper we investigate the existence of SH-waves in fiber-reinforced layer placed over a heterogeneous elastic half-space. The heterogeneity of the elastic half-space is caused by the exponential variations of density and rigidity. As a special case when both the layers are homogeneous, our derived equation is in agreement with the general equation of Love wave. Numerically, it is observed that the velocity of SH-waves decreases with the increase of heterogeneity and reinforced parameters. The dimensionless phase velocity of SH-waves increases with the decreases of dimensionless wave number and shown through figures.

• Steel and Composite Structures
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• v.50 no.2
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• pp.123-133
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• 2024

The paper deals with the propagation of Rayleigh waves in a nonlocal thermoelastic isotropic layer which is lying over a nonlocal thermoelastic isotropic half-space under the purview of Green-Lindsay model and Eringen's nonlocal elasticity in the presence of voids. The normal mode analysis is employed to the considered equations to obtain vector matrix differential equation which is then solved by eigenvalue approach. The frequency equation of Rayleigh waves is derived and different particular cases are also deduced. The effects of voids and nonlocality on different characteristics of Rayleigh waves are presented graphically.

• Interaction and multiscale mechanics
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• v.5 no.3
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• pp.187-210
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• 2012

Cable-stayed bridges are commonly used in modern bridge engineering for covering long spans. In some special cases, the designer is obliged to build such a bridge over an existing fault. Activation of this fault is possible to bring about a relative displacement or separation movement between two neighboring pylons of the bridge built on opposite sides of the fault. In this work, the effect of such a fault-induced pylon displacement on bridge's deformations and on cables' strength is thoroughly studied for several types of cable-stayed bridges and useful conclusions are drawn aiming the design. The influence of a possible earthquake and traffic loads crossing the bridge when the pylons are moving away from each other is not examined.