Different Approaches to Determine of the Explosion Effect, of a Homemade Explosive, on the Structure

2015 ◽  
Vol 796 ◽  
pp. 77-84
Author(s):  
Lucia Figuli ◽  
Zuzana Zvaková

With the increase in acts of terrorism, the effects of the explosion on structures has become highly topical. The aim of the paper is an analysis of various approaches to determine the response of blast loaded reinforced concrete pillar. Homemade ANFO (Ammonium nitrate + fuel oil) explosive will be a reference explosive. Such type of explosives is the most used one in terroristic attacks. The paper will be focused on the analysis of the blast wave, based on the experimental tests, and dynamic analysis of a structure under such load.

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1813
Author(s):  
Lucia Figuli ◽  
Zuzana Zvaková ◽  
Vladimír Kavický ◽  
Tomáš Loveček

Most of the damage caused by an explosion is caused by a pressure effect. The magnitude of the pressure generated by the explosion is influenced by the external characteristics of the environment (surrounding objects, their arrangement, geometry, etc.) and internal characteristics (type of explosive, type of charge, booster and others). An effective combination of internal factors creates a symmetry that results in the highest possible value of pressure generated by the charge explosion. The paper focuses on the influence of the booster reaction on this symmetry. The scope of the paper is to understand the dependency of the blast wave pressure on the amount of used blaster to increase the efficacy of explosions on the environment and structures to increase the protection of affected structures. The open-air field tests were conducted using different types of explosives: trinitrotoluene and three different types of industrially made ANFO explosives (pure ammonium nitrate and fuel oil, ammonium nitrate and fuel oil plus aluminum powder, ammonium nitrate and fuel oil mixed with trinitrotoluene). The obtained data were compared with the analytical approach for setting the generated maximal pressure on the front of the blast wave.


2021 ◽  
pp. 136943322098165
Author(s):  
Hossein Saberi ◽  
Farzad Hatami ◽  
Alireza Rahai

In this study, the co-effects of steel fibers and FRP confinement on the concrete behavior under the axial compression load are investigated. Thus, the experimental tests were conducted on 18 steel fiber-reinforced concrete (SFRC) specimens confined by FRP. Moreover, 24 existing experimental test results of FRP-confined specimens tested under axial compression are gathered to compile a reliable database for developing a mathematical model. In the conducted experimental tests, the concrete strength was varied as 26 MPa and 32.5 MPa and the steel fiber content was varied as 0.0%, 1.5%, and 3%. The specimens were confined with one and two layers of glass fiber reinforced polymer (GFRP) sheet. The experimental test results show that simultaneously using the steel fibers and FRP confinement in concrete not only significantly increases the peak strength and ultimate strain of concrete but also solves the issue of sudden failure in the FRP-confined concrete. The simulations confirm that the results of the proposed model are in good agreement with those of experimental tests.


1995 ◽  
Vol 85 (4) ◽  
pp. 1232-1235
Author(s):  
Tom T. Goforth ◽  
Jessie L. Bonner

Abstract Chemical blasts from quarrying operations in central Texas are routinely recorded by the W. M. Keck Foundation Seismological Observatory near China Spring, Texas. The Keck Observatory consists of a single, broadband, three-component, borehole seismograph system. Five quarries, located at distances ranging from 16 to 101 km from the observatory, each detonate from 1 to 6 tons of ammonium nitrate/fuel oil explosive on the average of twice per week. For every quarry for which the orientation of the working face could be determined, dispersed Rg waves are recorded at the Keck Observatory from those quarries at which the working face is directed away from the observatory, but are not observed or are severely attenuated from those quarries at which the working face is directed toward the observatory. Seismograms containing the dispersed Rg are easily recognized as quarry blasts, but those in which the dispersed Rg is absent look like small earthquakes.


2013 ◽  
Vol 66 (4) ◽  
pp. 425-430 ◽  
Author(s):  
Jorge Luis Palomino Tamayo ◽  
Armando Miguel Awruch ◽  
Inácio Benvegnu Morsch

A numerical model using the Finite Element Method (FEM) for the nonlinear static and dynamic analysis of reinforced concrete (RC) beams, plates and shells is presented in this work. For this purpose, computer programs based on plasticity theory and with crack monitoring capabilities are developed. The static analysis of RC shells up to failure load is carried out using 9-node degenerated shell finite elements while 20-node brick finite elements are used for dynamic applications. The elasto-plastic constitutive law for concrete is coupled with a strain-rate sensitive model in order to take into account high loading rate effect when transient loading is intended. The implicit Newmark scheme with predictor and corrector phases is used for time integration of the nonlinear system of equations. In both cases, the steel reinforcement is considered to be smeared and represented by membrane finite elements. Various benchmark examples are solved with the present numerical model and comparisons with other published data are performed. For all examples, the path failure, collapse loads and failure mechanism is reproduced with great accuracy.


2015 ◽  
Vol 22 (5) ◽  
pp. 585-596 ◽  
Author(s):  
Damian BEBEN ◽  
Adam STRYCZEK

The paper presents a numerical analysis of corrugated steel plate (CSP) bridge with reinforced concrete (RC) relieving slab under static loads. Calculations were made based on the finite element method using Abaqus software. Two computation models were used; in the first one, RC slab was used, and the other was without it. The effect of RC slab to deformations of CSP shell was determined. Comparing the computational results from two numerical models, it can be concluded that when the relieving slab is applied, substantial reductions in displacements, stresses, bending mo­ments and axial thrusts are achieved. Relative reductions of displacements were in the range of 53–66%, and stresses of 73–82%. Maximum displacements and bending moments were obtained at the shell crown, and maximum stresses and axial thrusts at the quarter points. The calculation results were also compared to the values from experimental tests. The course of computed displacements and stresses is similar to those obtained from experimental tests, although the absolute values were generally higher than the measured ones. Results of numerical analyses can be useful for bridge engineering, with particular regard to bridges and culverts made from corrugated steel plates for the range of necessity of using additional relieving elements.


2018 ◽  
Vol 22 (5) ◽  
pp. 1106-1120
Author(s):  
Zhi Zheng ◽  
Changhai Zhai ◽  
Xu Bao ◽  
Xiaolan Pan

This study serves to estimate the seismic capacity of the reinforced concrete containment building considering its bidirectional cyclic effect and variations of energy. The implementation of the capacity estimation has been performed by extending two well-known methods: nonlinear static pushover and incremental dynamic analysis. The displacement and dissipated energy demands are obtained from the static pushover analysis considering bidirectional cyclic effect. In total, 18 bidirectional earthquake intensity parameters are developed to perform the incremental dynamic analysis for the reinforced concrete containment building. Results show that the bidirectional static pushover analysis tends to decrease the capacity of the reinforced concrete containment building in comparison with unidirectional static pushover analysis. The 5% damped first-mode geometric mean spectral acceleration strongly correlates with the maximum top displacement of the containment building. The comparison of the incremental dynamic analysis and static pushover curves is employed to determine the seismic capacity of the reinforced concrete containment building. It is concluded that bidirectional static pushover and incremental dynamic analysis studies can be used in performance evaluation and capacity estimation of reinforced concrete containment buildings under bidirectional earthquake excitations.


2018 ◽  
pp. 35-39
Author(s):  
D.S. Bonifácio ◽  
E.B.F. Galante ◽  
A.N. Haddad

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