scholarly journals Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hakan Yalciner
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Plastic Hinge ◽  
Structural Response ◽  
Blast Loading ◽  
Structural Safety ◽  
Terrorist Attacks ◽  
Important Place ◽  
The One ◽  
The Impact

Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

scholarly journals IRREGULAR STEEL BUILDING STRUCTURES SUBJECTED TO BLAST LOADING

2015 ◽  
Vol 22 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Amy Coffield ◽  
Hojjat ADELI
Keyword(s):  
Plastic Hinge ◽  
Structural Response ◽  
Blast Loading ◽  
Building Structures ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Concentrically Braced Frame ◽  
Concentrically Braced ◽  
Applied Element Method ◽  
The Impact

In seismic design, structural irregularity has been found to have a significant influence on structural response. The impact of structural irregularity on the global response of steel frame structures subjected to blast loading has not been examined. In the paper, six seismically designed steel framed structures are considered: moment resisting frames (MRF), concentrically braced frames (CBF) and eccentrically braced frames (EBF) each with geometric irregularity in the plan and with a geometric irregularity in the elevation. The blast loads are assumed to be unconfined, free air burst detonated 15 ft from one of the center columns. The structures are modeled and analyzed using the Applied Element Method, which allows the structure to be examined during and through structural failure. A plastic hinge analysis is performed as well as a comparative analysis observing roof deflection and acceleration to determine the effect of geometric irregularity under extreme blast loading conditions. Two different blast locations are examined. Conclusions of this research are a concentrically braced frame provides somewhat of a higher level of resistance to blast loading for irregular structures and geometric irregularity has an impact on the response of a structure subjected to blast loading.

scholarly journals Terrorist campaigns and the growth of the Muslim population: a reply

2021 ◽  
pp. 1-12
Author(s):  
Clara Egger ◽  
Raul Magni-Berton
Keyword(s):  
Political Violence ◽  
Religious Conversion ◽  
Empirical Support ◽  
Terrorist Attacks ◽  
Muslim Population ◽  
Terror Attacks ◽  
Terrorist Groups ◽  
The One ◽  
The Impact ◽  
The Relationship

Abstract A recently published paper in this journal (Choi, 2021) establishes a statistical link between, on the one hand, Islamist terrorist campaigns – including terrorist attacks and online propaganda – and, on the other the growth of the Muslim population. The author explains this result by stating that successful campaigns lead some individuals to convert to Islam. In this commentary, we intend to reply to this article by focusing on the impact of terrorist attacks on religious conversion. We first show that Choi's results suffer from theoretical flaws – a failure to comprehensively unpack the link between violence and conversion – and methodological shortcomings – a focus on all terrorist groups over a period where Islamist attacks were rare. This leads us to replicate Choi's analysis by distinguishing Islamist and non-Islamist terror attacks on a more adequate timeframe. By doing so, we no longer find empirical support for the relationship between terror attacks and the growth of the Muslim population. However, our analyses suggest that such a hypothesis may hold but only in contexts where the level and intensity of political violence are high.

scholarly journals Impact of Slab Thickness on Reinforced Concrete Buildings using Fragility Curves

2020 ◽  
Vol 8 (5) ◽  
pp. 4533-4538
Keyword(s):  
Reinforced Concrete ◽  
Fragility Curves ◽  
Structural Response ◽  
Software Tool ◽  
Slab Thickness ◽  
Ground Shaking ◽  
Code Of Practice ◽  
Short Period ◽  
Rc Frame Structures ◽  
The Impact

Earthquakes are the natural disaster occurring since years but during the last two decades they are causing huge looses whether it may economic or to life. This paper focuses to evaluate the seismic performance of various building confirming to Indian standard criteria for earthquake resistant design of structures and ductile detailing of reinforced concrete structures subjected to seismic Forces-code of practice, Bureau of Indian Standards, both as per the revised codes in the year 2016. Due to ground shaking, seismic loads are the governing load and thus it becomes necessary to assess the conditional probability of structural response. Use of HAZUS methodology is followed to construct seismic fragility curves as it is well-organized and defined approach. Spectral displacement plays the functional parameter to derive the expected damage for fragility. This work represented here is compiled by means of procedure for establishing the fragility curves for three typical Reinforced Concrete (RC) frame structures having variations resembling 3 storey intended for short-period structures, 6 storey used for medium-period structures and 12 storey representing long-period structures using SAP2000 as a software tool for analyzing the structure. Furthermore an attempt is made for focus on the variation of one of the major structural configuration i.e. slab thickness which is not certainly paid attention as compared to columns and beams. Slabs adds additional stiffness to the structure which can enlighten how it behaviour would be when subjected to ground excitation. As a result, the fragility curves are plotted to study the impact due to slab thickness in order they are carefully selected while design.

scholarly journals Transient Response of RC Panel Protected with Slurry Infiltrated Micro Reinforced Concrete Jacket under Blast Loading

2019 ◽  
Vol 8 (2) ◽  
pp. 1196-1210
Keyword(s):  
Reinforced Concrete ◽  
Blast Resistance ◽  
Structural Response ◽  
Time History ◽  
Damage Variable ◽  
Wire Mesh ◽  
Blast Load ◽  
Terrorist Attacks ◽  
Mesh Reinforcement ◽  
Single Side

With increase in terrorist attacks, there are definite priority to protect the important infrastructure facilities against possible terrorist attacks. In order to improve blast resistance capacity of RCC panel, in present study, it was strengthened with Slurry Infiltrated Micro Reinforced Concrete (SIMRC) jacket. . The SIMRC jacket strengthened RC panel was analyzed under blast load scenario using finite element method based application, ABAQUS. The dynamic behavior of concrete and grout of SIMRC was modeled using concrete damaged plasticity model. The structural response of RC panel without any strengthening was compared with SIMRC strengthened RC panel to investigate effectiveness of SIMRC jacketing to resist blast load. Parametric study was carried out considering SIMRC jacket on single side or both side of RC panel, with different ratio of thickness of jacket to thickness of RC panel (t/D) and different percentage of wire mesh reinforcement for jacket. Simulation of various analysis results were presented in form of displacement time history, distribution of tensile/compressive damage variable explaining the pattern of failure in the RC panel, comparison of distribution of tensile damage variable on front and back jacket, compression damage variable of RC panel. It was observed that for panels with strengthening displacement and damaged areas are reduced as compared to conventional RC panel. The increase in thickness ratio (t/D), percentage of wire mesh reinforcement in jacket also contribute to increase blast resistance capacity of SIMRC Jacket. It was also observed that the jacketing on both side of RC panel is more effective in reducing the displacement and the damage is observed to be spread over the support areas. Obtained results through present study demonstrate the effective use of SIMRC jacketing as blast mitigation measure.

scholarly journals Impact of Revised Code NBC105 on Assessment and Design of Low Rise Reinforced Concrete Buildings in Nepal

2021 ◽  
Vol 16 (1) ◽  
pp. 1-5
Author(s):  
Jagat K. Shrestha ◽  
Nirajan Paudel ◽  
Bishal Koirala ◽  
Binod R. Giri ◽  
Adarsha Lamichhane
Keyword(s):  
Reinforced Concrete ◽  
Residential Buildings ◽  
Structural Response ◽  
Building Codes ◽  
Seismic Load ◽  
Base Shear ◽  
Reinforced Concrete Buildings ◽  
Concrete Buildings ◽  
The Government ◽  
The Impact

Gorkha Earthquake in 2015 has impacted considerably in the design and construction of buildings in Nepal. Strength and Safety of life and constructions have become the prime concerns of the government and the public. Regulation is required to achieve the strength and safety in the constructions. Hence, a need for revision of building codes has been felt and Nepal Building Code, NBC105 has been revised. This paper presents the impact of the revised code on seismic load estimation for low rise reinforced concrete buildings. For the assessment of the impact linear and non- linear static and linear dynamic analysis of reinforced concrete residential buildings of two storey and four Storey has been taken subjected to Indian Standard Codes IS 1893: 2002, IS 1893:2016, Nepal Building Codes NBC 105: 1994 and NBC 105: 2020. The buildings were modeled and analyzed in SAP2000. The response of the buildings such as time period, base shear, drifts, and storey forces from the application of the four codes was compared. The comparison of the results shows that the structural response of the building under the revised NBC105:2020 is 60% to 65% higher compared to the previous code NBC105:1994.

scholarly journals Reinforced Concrete Plates under Impact Load—Damage Quantification

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4554
Author(s):  
Marcus Hering ◽  
Franz Bracklow ◽  
Silke Scheerer ◽  
Manfred Curbach
Keyword(s):  
Reinforced Concrete ◽  
Impact Load ◽  
Experimental Conditions ◽  
Steel Reinforced Concrete ◽  
Before And After ◽  
Concrete Plates ◽  
The One ◽  
Objective Description ◽  
The Impact ◽  
Impact Experiments

A large number of impact experiments have been carried out at the Technische Universität Dresden in recent years in several research projects. The focus was on reinforced concrete plates on the one hand and on subsequently strengthened reinforced concrete plates on the other hand. Based on these investigations, two fundamental tasks arose: (1) finding an objective description of the damage of components made of steel reinforced concrete that had previously been subjected to an impact load and (2) quantification of the effect of a subsequently applied strengthening layer. In this paper we will focus on both. At first, the experimental conditions and program as well as the used drop tower facility at the Otto Mohr Laboratory of the Technische Universität Dresden are briefly explained. In the summary presentation of the main test results, the focus is on the observed component damage. Based on the observations, an approach for a damage description is presented. To define global damage, the stiffness of the investigated structural components before and after the impact event is used. At the end of the paper, the potential of the method, but also gaps in knowledge and research needs are discussed.

scholarly journals Effect of Corrosion Damage on the Performance Level of a 25-Year-Old Reinforced Concrete Building

2012 ◽  
Vol 19 (5) ◽  
pp. 891-902 ◽  
Author(s):  
Hakan Yalciner ◽  
Serhan Sensoy ◽  
Ozgur Eren
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Plastic Hinge ◽  
Time Dependent ◽  
Earthquake Ground Motion ◽  
Rc Structures ◽  
Bond Slip ◽  
Structural Problems ◽  
Time Periods ◽  
The Impact

Corrosion is a long-term process resulting in the deterioration of the reinforced concrete (RC) structures. Most of the structural problems observed under the impact of either earthquakes or service loads might occur due to corrosion. Therefore, prediction of the remaining service life of a corroding RC structure plays an important role to prevent serious premature damage. In this study, a corroded, 25-year-old high school building which has been demolished at an earlier time was analyzed as a function of corrosion rate. Bond-slip relationships were taken into account in nonlinear analyses as a function of corrosion rate for different time periods (i.e., non-corroded (t: 0), existing (t: 25) and 50 years after construction); and they were used to ensure the effect of time-dependent slip rotation on the global structural behaviour by modifying the target post-yield stiffness of each structural member. Nonlinear push-over analyses were performed by defining the time-dependent plastic hinge properties as a consequence of corrosion effects. In order to define the performance levels of three different time periods, nonlinear incremental dynamic analyses (IDA) were performed for 20 earthquake ground motion records as a function of corrosion rate. Results showed that bond-slip relationship between concrete and steel is very important in evaluating the non-linear behaviour of corroded RC structures.

CONCRETING AND EARLY HARDENING PROCESSES IN MONOLITHIC REINFORCED CONCRETE STRUCTURES / PROCESAI, VYKSTANTYS BETONAVIMO IR PRADINIO KIETĖJIMO METU GELŽBETONINĖSE MONOLITINĖSE KONSTRUKCIJOSE

2012 ◽  
Vol 4 (2) ◽  
pp. 67-75
Author(s):  
Vigantas Antanas Žiogas ◽  
Svajūnas Juočiūnas ◽  
Violeta Medelienė ◽  
Giedrius Žiogas
Keyword(s):  
Reinforced Concrete ◽  
Structure Formation ◽  
Structural Strength ◽  
Concrete Strength ◽  
Time Moment ◽  
Concrete Structures ◽  
Concrete Mixture ◽  
Industrial Building ◽  
Reinforced Concrete Structures ◽  
The Impact

The exploitation time and reliability of monolithic reinforced concrete structures largely depend on concreting technology and process influence during concreting and early setting stages. Different types of cracks in monolithic reinforced concrete structures appear due to internal and external effects. Cracks appear when the technology of structure concreting is damaged, when formwork is removed during the further setting and structures loaded period. In order to avoid micro and macro cracks in monolithic structures, it is important to measure the particular setting time moment and technological process moment when stresses that exceed the permissible values appear in concrete. The article analyses the processes that appear when horizontal, sloping and vertical monolithic reinforced concrete structures are concreted. The analysis of concrete mixture pressure on formwork is performed. The pressure which is calculated according to different countries’ methodology is different: the smallest pressure is obtained calculating according to the British recommendations, and the largest pressure is obtained according to French CIB recommendations. In Lithuania, it is recommended to follow the German DIN 18218 standard. The balance conditions of concrete mixture concreting on slope surface are described. The main concreting technology parameters and their interaction are analysed; the speed, intensity and time of continuous concreting technology are presented. When the process of continuous concreting is performed, it is necessary to evaluate the interaction and values of parameters properly. Methodical theoretical calculation is presented. Practical solutions for industrial building construction applying the modern sliding formwork technology are presented. The impact of cement type, superplasticizers and temperature over the concrete mixture mobility, changes, fresh concrete structural strength and concrete setting kinetics are analysed. The main characteristics of the initial setting — the beginning of structure formation, when concrete mixture turns into concrete state — is analysed applying the ultrasonic method. The beginning of structure formation influences the regulated time of concrete mixture laying and compaction. The requirements for structural strength (permissible strength limits) and concreting rate (formwork movement) of freshly formed concrete are set when the construction is performed applying the continuous concreting technology method. The analysis is implemented performing the construction of cylindrical sludge tank with slipping formwork. While performing the analysis during concreting, it was stated that the concrete setting kinetics corresponds to the sludge tank concreting rate. The analysis performed after concreting and in 28 days of hardening revealed that there are no surface defects or cracks, and concrete strength exceeds the required sludge tank design strength. Santrauka Monolitinių gelžbetoninių statinių konstrukcijų eksploatacijos trukmė ir patikimumas daugiausia priklauso nuo betonavimo technologijos ir procesų poveikių betonavimo bei pradinio kietėjimo metu. Straipsnyje nagrinėjami procesai, vykstantys betonuojant horizontaliąsias, nuožulniąsias ir vertikaliąsias monolitines gelžbetonines konstrukcijas. Atlikta betono mišinio slėgio į formas analizė. Tiriami pagrindiniai betonavimo technologijos parametrai, analizuojamas jų ryšys, pateikiamas nepertraukiamo betonavimo technologijos betonavimo greitis, intensyvumas, trukmė. Atlikti teoriniai skaičiavimai ir siūlomi praktiniai sprendimai pramoninių statinių statybai, naudojant šiuolaikinę slankiųjų klojinių technologiją. Ištirta cemento tipo, superplastiklių, temperatūros įtaka šviežiai suformuoto betono struktūriniam stipriui ir betono kietėjimo kinetikai. Nustatyti reikalavimai šviežiai suformuoto betono struktūriniam stipriui, betonavimo greičiui (klojinių kėlimui), vykdant statybą nepertraukiamos betonavimo technologijos metodu. Tyrimai pritaikyti vykdant cilindrinio dumblo pūdytuvo statybą slankiaisiais klojiniais.

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