• Earthquakes and Structures
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• v.8 no.6
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• pp.1407-1433
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• 2015

The objections raised by researchers to the design provisions reported in Eurocode 8 make the efficient seismic performance of the eccentrically braced structures designed according to this code unlikely. Given the rationality and the number of the objections, this paper aims to summarize the criticism of researchers and report the opinion of the Authors. The objections raised to the design procedure of eccentrically braced structures regard aspects common to the design of steel structures and aspects specifically related to the design of eccentrically braced structures. The significance of these objections is also shown by means of exemplary cases.

• Structural Engineering and Mechanics
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• v.8 no.6
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• pp.531-546
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• 1999

The paper presents an experimental and theoretical study on the influence of steel fibers and longitudinal tension and compression reinforcements on immediate and long-term deflections of high-strength concrete beams of 85 MPa (12,300 psi) compressive, strength. Test results of eighteen beams subjected to sustained load for 180 days show that the deflection behavior depends on the longitudinal tension and compression reinforcement ratios and fiber content; excessive amount of compression reinforcement and fibers may have an unfavorable effect on the long-term deflections. The beams having the ACI Code's minimum longitudinal tension reinforcement showed much higher time-dependent deflection to immediate deflection ratio, when compared with that of the beams having about 50 percent of the balanced tension reinforcement. The results of theoretical analysis of tested beams and those of a parametric study show that the influence of steel fibers in increasing the moment of inertia of cracked transformed sections is most pronounced in beams having small amount of longitudinal tension reinforcement.

• Structural Engineering and Mechanics
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• v.54 no.3
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• pp.579-595
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• 2015

A general geometrically non-linear model for lateral-torsional buckling of thick and thin-walled FGM box beams is presented. In this model primary and secondary torsional warping and shear effects are taken into account. The coupled equilibrium equations obtained from Galerkin's method are derived and the corresponding tangent matrix is used to compute the critical moments. General expression is derived for the lateral-torsional buckling load of unshearable FGM beams. The results are validated by comparison with a 3D finite element simulation using the code ABAQUS. The influences of the geometrical characteristics and the shear effects on the buckling loads are demonstrated through several case studies.

• Structural Engineering and Mechanics
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• v.54 no.3
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• pp.545-560
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• 2015

In this paper, blast-induced vibration effects on buildings located in rural areas were investigated. Damages to reinforced concrete, adobe and masonry buildings were evaluated in Çatakk$\ddot{o}pr\ddot{u}$ and Susuz villages in Silvan district of Diyarbakir, Turkey. Blasting of stiff rocks to construct highway at vicinity of the villages damaged the buildings seriously. The most important reason of the damages is lack of engineering services and improper constructed buildings according to the current building design codes. Also, it is determined that, inappropriate blast method and soft soil class increased the damages to the buildings. The study focuses on four points: Blast effect on buildings, soil conditions in villages, building damages and evaluation of damage reasons according to the current Turkish Earthquake Code (TEC).

• Structural Engineering and Mechanics
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• v.19 no.5
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• pp.519-533
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• 2005

The numerical simulations on the influence of mesoscopic structures on the macroscopic strength and fracture characteristics are carried out based on that the concrete is assumed to be a three-phase composite composed of matrix (mortar), aggregate and bond between them by using a numerical code named MFPA. The finite element program is employed as the basic stress analysis tool when the elastic damage mechanics is used to describe the constitutive law of meso-level element and the maximum tensile strain criterion and Mohr-Coulomb criterion are utilized as damage threshold. It can be found from the numerical results that the bond between matrix and aggregate has a significant effect on the macroscopic mechanical performance of concrete.

• Geomechanics and Engineering
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• v.21 no.3
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• pp.259-268
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• 2020

The synthetic rock mass (SRM) were used to investigate the influence of specimen size on the mechanical properties of jointed rock mass. The SRM were established based on parallel bond model (PBM) and smooth joint model (SJM) and the scaled rock specimens were sampled in two SRMs considering three sampling locations. The research results show that the smaller the initial fracture density is, the greater the uniaxial compressive strength (UCS), elastic modulus (E) is when compared with the same sampling location. The mechanical properties of rock specimens obtained by different sampling methods in different SRMs have different scale effects. The strength of rock specimens with more new cracks is not necessarily less than that of rock specimens with fewer new cracks and the failure of rock is caused by the formation of macro-fracture surface.

• Coupled systems mechanics
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• v.10 no.6
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• pp.491-507
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• 2021

The aim of this paper is to conduct a hydrodynamic analysis of fluid flow over different weir types using the analytical solution, the physical model taken from another article, and numericalsimulations through the Smoothed particle hydrodynamic method (SPH) using the compiled DualSPHysics source code. The paper covers the field of real fluid dynamics that includes a description of different proposed types of weirs in various flow regimes and the optimal solution for the most efficiency structure shape. A detailed presentation of the method, the structure and it's characteristics are included. Apart from the single stepped weir, two other weir types are proposed: a Divided type and a Downstream slopped type. All of them are modeled using the SPH method.

• Advances in concrete construction
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• v.14 no.2
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• pp.131-137
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• 2022

Based on the design of reinforced concrete columns in Chinese design codes, the failure function of reinforced concrete (RC) columns cannot be expressed as a linear function. This makes it difficult to reveal the level of reliability control in Chinese design code. Therefore, the failure function of dimensionless form is established in this paper, and the typical components (Industrial plant columns) are selected for analysis. At last, numerical simulation proves that the proposed model can be used to analysis reliability of columns. The results based on this model indicate that there is a strong difference in the reliability of RC columns designed with different design parameters, and the reliability would be lower when the eccentricity produced by crane load is smaller.

• Advances in concrete construction
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• v.14 no.5
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• pp.331-339
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• 2022

Geopolymer concrete (GPC) is one of the best substitute materials for conventional concrete in construction. The conventional concrete provided by Portland cement has a detrimental influence on the environment during its production. In this study, the bond strength, which is an important structural property, of deformed steel bars with slag-based GPC was measured. In accordance with the ASTM C234 procedure, bond strength was measured on 18 specimens of slag-based GPC with three sizes of steel bars and different embedded lengths. Two groups of GPC specimens with different compressive strengths, which were cured under ambient conditions, were tested. The results indicated that the bar diameter has a great effect on the bond strength, and the bond strength behavior of the slag-based GPC is comparable with that of conventional concrete. The ACI-318 Code for the bond strength of ordinary Portland cement concrete can be used conservatively to determine the bond strength of the GPC reinforced with deformed steel bars.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.495-501
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• 2011

The load combinations in current KCI Design Code are determined with reference to those in ACI 318-05, which adopts the LRFD (load and resistance factor design) format. The load and resistance factors in LRFD format should be determined to meet the required levels of reliability index or probability of failure for various predetermined failure modes, which are also based on the statistical data reflecting locality and contemporary situation. However, the current KCI Design Code has been written utilizing foreign data, because of insufficiency in accrued data in Korea. This study considered the current safety levels of KCI Code based on published domestic data to evaluate appropriateness of the current KCI regulations. Based on the calibrated reliability index of the existing Code, the new resistance factors are suggested. The results presented in this paper can be considered as a basic research for establishment of unique design format for future Korean Codes.