• Earthquakes and Structures
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• v.9 no.2
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• pp.281-303
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• 2015

The effects of infill panels on the response of r.c. frames subjected to seismic action are widely recognized. Numerous experimental investigations were effected and several analytical models were developed on this subject. This work, which is part of a larger project dealing with specific materials and structures commonly used in Italy, discusses experimental tests on masonry and samples of bare and infilled portals. The experimental activity includes tests on elemental materials, and 12 wall samples. Finally, three one-bay one-story reinforced concrete frames, designed according to the outdated Italian technical code D.M. 1996 without seismic details, were tested (bare and infilled) under constant vertical and cyclic lateral load. The first cracks observed on the framed walls occurred at a drift of about 0.3%, reaching its maximum capacity at a drift of 0.5% while retaining its capacity up to a drift of 0.6%. Infill contributed to both the stiffness and strength of the bare reinforced concrete frame at small drifts thus improving overall system behavior. In addition to the experimental activities, previously mentioned, the recalibration of a model proposed by Comberscue (1996) was evaluated. The accuracy of an OpenSees non linear fiber based model of the prototype tested, including a strut element was verified through a comparison with the final experimental results. This work has been partially supported by research grant DPC-ReLUIS 2014.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.381-396
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part I, finite element (FE) models establishment and validations for both the aircrafts and NPP buildings are performed. (i) Airbus A320 and A380 aircrafts are selected as the representative medium and large commercial aircrafts, and the corresponding fine FE models including the skin, beam, fuel and etc. are established. By comparing the numerically derived impact force time-histories with the existing published literatures, the rationality of aircrafts models is verified. (ii) Fine FE model of the Chinese Zhejiang Sanao NPP buildings is established, including the detailed structures and reinforcing arrangement of both the containment and auxiliary buildings. (iii) By numerically reproducing the existing 1/7.5 scaled aircraft model impact tests on steel plate reinforced concrete (SC) panels and assessing the impact process and velocity time-history of aircraft model, as well as the damage and the maximum deflection of SC panels, the applicability of the existing three concrete constitutive models (i.e., K&C, Winfrith and CSC) are evaluated and the superiority of Winfrith model for SC panels under deformable missile impact is verified. The present work can provide beneficial reference for the integral aircraft crash analyses and structural damage assessment in the following two parts of this paper.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.4
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• pp.1-10
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• 1983

The deformation and crack width of concrete walls of slabs, plates, panels and shells reinforced by a regular rectangular net of reinforcing bars and subjected to in-plane (membrane) internal forces is analyzed on the basis of a realistic model which takes into account the frictional-dilatant behavior of rough interlocked cracks, the effect of tension stiffening, and the dowel action of bars at crack crossings. Extensive numerical computer studies are carried out, and the reinforcement designs obtained from equilibrium conditions alone on the basis of either the classical frictionless approach or the recent frictional approach are compared in terms of the resulting crack widths. It is found that the use of frictional equilibrium design based on a low friction coefficient leads to a much smaller crack width than the classical frictionless design. The influences of bar diameter and crack spacing on the crack width are also studied. The model allows more realistic deformation analysis of reinforced concrete structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.727-732
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• 2002

Steel Fiber Reinforced Shotcrete(SFRS) has been prevalently used in lining to stabilize tunnel structures as temporary or permanent support. In recent, it is one of the major elements of tunnel construction, and so the quality control of SFRC should be clarified to guarantee the safety. The experimental study has been performed to verify the possible correlations in several chracteristics related to quality of SFRC and examine the applicability of round panel test for in field. The test variables were the type and dosage of accelerator, aspect ratio of fiber, and fiber content. The test results such as compressive strength, flexural strength, flexural toughness, and energy absorption capacity, were exmained and analyzed scrutinizingly.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.171-174
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• 2003

The Special orthotropic plate theory is used for analysis of panels made of steel girders and cross-beams, and made of reinforced concrete. The cross-sections of girders and cross-beams are WF types. The result is compared with that of the beam theory. According to the numerical examination given in this paper, the result by the plate theory is 2.43 times stiffer than that of beam theory, The result for the concrete slab in given for the practicing engineers.

• Computers and Concrete
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• v.13 no.6
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• pp.749-764
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• 2014

Structural safety has always been a key preoccupation for engineers responsible for the design of civil engineering projects. One of the mechanisms of structural failure, which has gathered increasing attention over the past few decades, is referred to as 'progressive collapse' which happens when one or several structural members suddenly fail, whatever the cause (accident, attack, seismic loading(.Any weakness in design or construction of structural elements can induce the progressive collapse in structures, during seismic loading. Masonry infill panels have significant influence on structure response against the lateral load. Therefore in this paper, seismic performance and shear strength of R.C frames with brick infill panel under various lateral loading patterns are investigated. This evaluation is performed by nonlinear static analysis. The results provided important information for additional design guidance on seismic safety of RC frames with brick infill panel under progressive collapse.

• Journal of the Korea Concrete Institute
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• v.27 no.5
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• pp.481-488
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• 2015

The purpose of this study is to provide analytical method to reasonably predict the overall behavior up to destruction of reinforced concrete panel specimens using high-strength reinforcing bar. A total of 12 specimens of reinforced concrete panels with a wall thickness one-third the size of the actual nuclear containment structures under various loading conditions and design parameters were selected and the analysis was performed using a non-linear finite element analysis program (RCAHEST) was developed by the authors. The mean and coefficient of variation for shear strength at cracking point and maximum shear strength from the experiment and analysis results was predicted 1.03 and 12%, 0.97 and 9%, respectively. For the shear strain at the maximum shear strength from the experiment and analysis results was predicted 0.96 and 30%, respectively. Based on the results, the analysis program that was applied newly modified constitutive equation in this study is judged as having a relatively high reliability for the analysis results.

• Computers and Concrete
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• v.17 no.2
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• pp.201-214
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• 2016

The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridianally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.

• Structural Engineering and Mechanics
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• v.87 no.3
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• pp.273-282
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• 2023

Concrete construction, one of the oldest building practices, is commonly used in all parts of the world. Concrete is the primary building material for both residential and commercial constructions. The challenge of protecting the buildings, hence nation, against the attack of terrorism has raised the importance to explore the understanding of building materials against the explosion. In this research, a security check-post (reinforced concrete frame filled with plain cement concrete) has been chosen to study the behavior of structural elements under blast loading. Eight nitroglycerines-based dynamite blasts with varying amounts of explosive charge, up to 17 kg weight has been carried out at various scale distances. Pressure and acceleration time history records are measured using blast measuring instruments. Security check post after being exposed by explosive loading are photographed to view cracking/failure patterns on the structural elements. It is noted that with the increase of quantity of explosive, the dimensions of spalling and crack patterns increase on the front panels. Simple empirical analyses are conducted using ConWep and other design manuals such as UFC 3-340-02 (2008) and AASTP-1 (2010) for the purpose of comparison of blast parameters with the experimental records. The results of experimental workings are also compared with earlier researchers to check the compatibility of developed equations. It is believed that the current study presents the simple and preliminary procedure for calculating the air blast and ground shock parameters on the structures exposed to blast explosion.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.98-105
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• 2016

In this study, projectiles with 2 kinds of nose shape: spherical and flat were impacted into normal concrete and fiber reinforced concrete panels. The fracture depth and form, crater diameter, tensile strain at rear face were evaluated. It was confirmed that smaller projectile nose areas resulted in deeper penetrations associated with concentrated impact forces and small front-face crater diameters in impact test. Conversely, larger projectile nose areas resulted in shallower penetrations and larger front-face fracture diameters. Similar front-face failure and strain distribution relationships based on the projectile nose shape were observed for normal and fiber-reinforced concrete although the rear-face tensile strain and scabbing were significantly reduced by the fiber reinforcement. In addition, a direct relationship was confirmed between the penetration depth based on the projectile nose shape and the tensile strain on the rear face. Thus the impact strain behavior is required to predict the scabbing behavior with penetration depth.