scholarly journals Blast Loading and Its Effects on Building

Author(s):  
Mohini Chaurasiya

Abstract: Terrorist assaults have become more common in recent years. Their main purpose is to destroy important structures such as areas of defense, hospitals, schools, buildings. Due to the explosion, high pressure is generated and the blast time is also very short, but it can damage the structure from outside and inside. Which can cause a lot of damage to human life. There has an influence on the nation's economy. Like the earthquake and wind load, the blast load should also be designed, keeping in mind the important structures that have to be avoided from the explosion. In this research paper, six story R.C.C. Structures exposed to explosion loads are analyzed. We study the effect on the building by changing the weight of the explosive and the distance between the explosion source and the building. The IS 4991-1968 code has been used to calculate the parameters of the explosion pressure waves. The program ETabs 2019 has been used to analyze the effect of blast load. The structure has been modified by providing shear walls to reduce excessive displacement due to blast loading on the building. The results of the analysis are compared after adding the shear wall with the general building model. The result was that after the addition of the shear wall, the effect of blast loading is greatly reduced. Keywords: Blast phenomena, Standoff distance, detonation charge weight (TNT), Front face pressure, Side face pressure, ETABS, RCC, Blast waves, explosive effects, Story Displacement, Storey Drift, Overturning Moment, Shear wall.

The dynamic response of reinforced concrete (RC) panels without and with different configuration of opening under blast load scenario is investigated in the present study. The numerical simulations were carried out using finite element method with ABAQUS application. The concrete behavior under blast loading was modelled using Concrete damaged plasticity model. The material parameters for concrete damaged plasticity model were determined using methodology proposed by [14]. The parametric study was carried out using variation in blast load due to different charge weight. It was observed that the peak displacement increases with increase in blast load. It was also observed that at lower blast load, failure of reinforced concrete panel was initiated by cracking at rear face of panel but as the blast load increases the RC panel was failed by combination of crushing of front face of panel along with cracking of rear face. It was observed that for the given blast load, the RC panel without opening is less affected by crushing failure as compared to RC panel with opening configuration studied. It was also observed that the RC panel with circular opening at center is stiffer than other opening configuration and observed to have stable structural performance against the blast load studied.


2021 ◽  
Vol 4 (1) ◽  
pp. 1-17
Author(s):  
Kasilingam Senthil ◽  
Muskaan Sethi ◽  
Loizos Pelecanos

The tunneling system has become an important part of the present infrastructure system in all over the world. Therefore, it has become important to ensure the safety of the tunnels against any type of man-made blasting activities or other accidental blasting occurrence. In order to evaluate the performance of the tunnels against blast loading, a detailed review is carried out. Based on the review in the last couple of decades, the various parameters such as tunnel lining materials, tunnel shapes, tunnel lining thickness, tunnel burial depth, charge weight and standoff distance are high influences on the performance of underground tunnels against blast loading. It was observed that the tunnel roof and the tunnel wall center are most vulnerable to the blast loads. Also, it was found that more of the tunnel lining thickness results in lesser deformation at the tunnel roof and the tunnel wall center. The increase in the burial depth of the tunnel would reduce the extent of damage to the tunnel caused by effects of surface blast loading. The stiffness and strength of the ground media may be enhanced against the effects of blast loading by grouting measures. The studies revealed that the lining materials possessing blast waves absorbing properties can be best suited to be used in tunnel linings. Further, it was observed that more damage was caused to the tunnels due to the magnitude of the charge weight. An increase in the blast load causes a significant increase in the fracture area, residual stress and lateral displacement caused to the tunnel by the action of blast load. The standoff distance of the blast load from the tunnel also plays a significant role in the damage of the tunnel. More is the distance between the charge and the tunnel, lesser damage caused to the tunnels. In addition to that, the lining thickness was predicted and the trend was calibrated and fitted logarithmically with the available results. Based on the observation from the literature, it is concluded that the use of a single lining material in the tunnel against blast loading was studied predominantly in the couple of decades. Further, the performance of the tunnels in combination of different tunnel lining materials against blast loading was found limited. The influence of barriers to save the underground tunnels against blast loading was found limited.


2020 ◽  
Vol 6 (1) ◽  
pp. 31
Author(s):  
Mustafa Tolga Çöğürcü ◽  
Mehmet Uzun

In developing countries, the need for shelter, working area, shopping and entertainment centers is increasing due to the increasing population effect. In order to meet this need, it is necessary to turn to high-rise buildings. Significant damages have been observed as a result of insufficient horizontal displacement stiffness of high-rise buildings in major earthquakes in previous years. It is known that as the height of the structure increases, the displacement demand of the structure also increases. Since it is accepted that the structure will make inelastic deformation in the design of the structure, these displacements increase to very high levels as the number of stories increases. For this reason, damages can be much higher than expected. In order to limit the level of damage that may occur in high-rise buildings, the horizontal displacement of buildings is limited in many regulations in our age. This limitation is possible by increasing the rigidity of the structures against horizontal displacement. In recent years, the use of shear wall has increased due to the horizontal displacement limitation in the regulations. The use of shear walls in buildings limits the horizontal displacement. However, the choice of where the shear walls will be placed on the plan is very important. Failure to place the shear walls correctly may result in additional loads in the structure. It can also lead to torsional irregularity. In this study, a 10-storey reinforced concrete building model was created. Shear wall at the rate of 1% of the plan area of the building was used in the building. The shear walls are arranged in different geometric shapes and different layouts. The earthquake analysis of 5 different models were performed. Equivalent Earthquake Load, Mode Superposition and Time History Analysis methods were used for earthquake analysis. The results were compared and a proposal was made for the geometry and configuration of the shear wall.


2019 ◽  
Author(s):  
Hossein Alimohammadi ◽  
Mostafa Dalvi Esfahani ◽  
Mohammadali Lotfollahi Yaghin

In this study, the seismic behavior of the concrete shear wall considering the opening with different shapes and constant cross-section has been studied, and for this purpose, several shear walls are placed under the increasingly non-linear static analysis (Pushover). These case studies modeled in 3D Abaqus Software, and the results of the ductility coefficient, hardness, energy absorption, added resistance, the final shape, and the final resistance are compared to shear walls without opening.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Sung-Jun Pang ◽  
Kyung-Sun Ahn ◽  
Seog Goo Kang ◽  
Jung-Kwon Oh

AbstractIn this study, the lateral resistances of mass timber shear walls were investigated for seismic design. The lateral resistances were predicted by kinematic models with mechanical properties of connectors, and compared with experimental data. Four out of 7 shear wall specimens consisted of a single Ply-lam panel and withdrawal-type connectors. Three out of 7 shear wall specimens consisted of two panels made by dividing a single panel in half. The divided panels were connected by 2 or 4 connectors like a single panel before being divided. The applied vertical load was 0, 24, or 120 kN, and the number of connectors for connecting the Ply-lam wall-to-floor was 2 or 4. As a result, the tested data were 6.3 to 52.7% higher than the predicted value by kinematic models, and it means that the lateral resistance can be designed by the behavior of the connector, and the prediction will be safe. The effects of wall-to-wall connectors, wall-to-floor connectors and vertical loads on the shear wall were analyzed with the experimental data.


2017 ◽  
Vol 21 (3) ◽  
pp. 838-864 ◽  
Author(s):  
Yuansheng Cheng ◽  
Tianyu Zhou ◽  
Hao Wang ◽  
Yong Li ◽  
Jun Liu ◽  
...  

The ANSYS/Autodyn software was employed to investigate the dynamic responses of foam-filled corrugated core sandwich panels under air blast loading. The panels were assembled from metallic face sheets and corrugated webs, and PVC foam inserts with different filling strategies. To calibrate the proposed numerical model, the simulation results were compared with experimental data reported previously. The response of the panels was also compared with that of the empty (unfilled) sandwich panels. Numerical results show that the fluid–structure interaction effect was dominated by front face regardless of the foam fillers. Foam filling would reduce the level of deformation/failure of front face, but did not always decrease the one of back face. It is found that the blast performance in terms of the plastic deflections of the face sheets can be sorted as the following sequence: fully filled hybrid panel, front side filled hybrid panel, back side filled hybrid panel, and the empty sandwich panel. Investigation into energy absorption characteristic revealed that the front face and core web provided the most contribution on total energy absorption. A reverse order of panels was obtained when the maximization of total energy dissipation was used as the criteria of blast performance.


Author(s):  
Prashant Sunagar ◽  
Manish S Dharek ◽  
K Nruthya ◽  
K S Sreekeshava ◽  
B Nagashree ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
pp. 22-39
Author(s):  
Saha Dauji

Underground blasts are conducted for deep excavations, tunneling, or mining activities. Scaled distance regression analysis is performed in industry to estimate peak particle velocity from charge weight and distance. For addressing the uncertainties in estimating safe charge weight for controlled blasting, 95% confidence expression is generally used. For addressing inaccuracies arising from superimposition of blast waves in multi-hole blasting when using attenuation equation developed from single-hole blast data, a modified approach was proposed in literature. This article presents comparisons to establish that industrial practice of scaled distance regression would be as satisfactory as the proposed modified approach, when various performance measures (including parsimony) are considered together. Furthermore, industrial practice of using 95% confidence expression generated from sufficient data (say, 40 numbers) would result in safe charge weight estimation, whereas modified scaled distance approach (mean expression) could still result in few non-conservative values.


2018 ◽  
Vol 65 ◽  
pp. 08008
Author(s):  
Syed Muhammad Bilal Haider ◽  
Zafarullah Nizamani ◽  
Chun Chieh Yip

The reinforced concrete structures, not designed for seismic conditions, amid the past earthquakes have shown us the significance of assessment of the seismic limit state of the current structures. During seismic vibrations, every structure encountered seismic loads. Seismic vibrations in high rise building structure subjects horizontal and torsional deflections which consequently develop extensive reactions in the buildings. Subsequently, horizontal stiffness can produce firmness in the high rise structures and it resists all the horizontal and torsional movements of the building. Therefore, bracing and shear wall are the mainstream strategies for reinforcing the structures against their poor seismic behaviours. It is seen before that shear wall gives higher horizontal firmness to the structure when coupled with bracing however it will be another finding that in building model, which location is most suitable for shear wall and bracing to get better horizontal stability. In this study, a 15 story residential reinforced concrete building is assessed and analyzed using building code ACI 318-14 for bracing and shear wall placed at several different locations of the building model. The technique used for analysis is Equivalent Static Method by utilizing a design tool, finite element software named ETABS. The significant parameters examined are lateral displacement, base shear, story drift, and overturning moment.


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