scholarly journals An Efficient Reliability-Based Approach for Evaluating Safe Scaled Distance of Steel Columns under Dynamic Blast Loads

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 606
Author(s):  
Mohammad Momeni ◽  
Chiara Bedon ◽  
Mohammad Ali Hadianfard ◽  
Abdolhossein Baghlani
Keyword(s):  
Structural Reliability ◽  
Progressive Collapse ◽  
Structural Members ◽  
Blast Loads ◽  
Explicit Finite Element ◽  
Scaled Distance ◽  
Steel Columns ◽  
Damage Probability ◽  
Critical Issues ◽  
Building Load

Damage to building load-bearing members (especially columns) under explosions and impact are critical issues for structures, given that they may cause a progressive collapse and remarkably increase the number of potential victims. One of the best ways to deal with this issue is to provide values of safe protective distance (SPD) for the structural members to verify, so that the amount of damage (probability of exceedance low damage) cannot exceed a specified target. Such an approach takes the form of the so-called safe scaled distance (SSD), which can be calculated for general structural members but requires dedicated and expensive studies. This paper presents an improved calculation method, based on structural reliability analysis, to evaluate the minimum SSD for steel columns under dynamic blast loads. An explicit finite element (FE) approach is used with the Monte Carlo simulation (MCS) method to obtain the SSD, as a result of damage probability. The uncertainties associated with blast and material properties are considered using statistical distributions. A parametric study is thus carried out to obtain curves of probability of low damage for a range of H-shaped steel columns with different size and boundaries. Finally, SSD values are detected and used as an extensive databank to propose a practical empirical formulation for evaluating the SSD of blast loaded steel columns with good level of accuracy and high calculation efficiency.

scholarly journals Effect of blast loading and resulting progressive failure of a cable-stayed bridge

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Ravi Mudragada ◽  
S. S. Mishra
Keyword(s):  
Progressive Failure ◽  
Blast Resistance ◽  
Progressive Collapse ◽  
Building Structures ◽  
Structural Elements ◽  
Blast Loads ◽  
Cable Stayed Bridge ◽  
Bridge Performance ◽  
Cable Stayed Bridges

AbstractMany researchers have carried out experimental and numerical investigations to examine building structures’ response to explosive loads. Studies of bridges subjected to blast loads are limited. Hence, in this study, we present a case study on a cable-stayed bridge, namely, Charles River Cable-Stayed Bridge-Boston, to assess its robustness and resistance against the progressive collapse resulting from localized failure due to blast loads. Three different blast scenarios are considered to interpret the bridge performance to blast loads. To monitor the progressive failure mechanisms of the structural elements due to blast, pre-defined plastic hinges are assigned to the bridge deck. The results conclude that the bridge is too weak to sustain the blast loads near the tower location, and the progressive collapse is inevitable. Hence, to preserve this cable-stayed bridge from local and global failure, structural components should be more reinforced near the tower location. This case study helps the designer better understand the need for blast resistance design of cable-stayed bridges.

Novel Hanger Design to Improve the Robustness of Through Arch Bridges

2011 ◽  
Vol 90-93 ◽  
pp. 862-868
Author(s):  
Qi Ming Wu ◽  
Dang Qi Yang ◽  
Fei Cui ◽  
Xiao Wei Yi ◽  
Rui Juan Jiang
Keyword(s):  
Progressive Collapse ◽  
Time History ◽  
Structural Members ◽  
New Approach ◽  
Arch Bridge ◽  
Structural Robustness ◽  
Arch Bridges ◽  
Dynamic Time ◽  
The Impact ◽  
Emergency Measures

Hangers in through arch bridges are important components since they suspend the bridge deck from the arch ribs. Local damage at a hanger may lead to progressive damage of various components in the arch bridge or even progressive collapse of the bridge. In this paper, the conventional design of double-hangers in through arch bridges is reviewed. Then a new approach to design the double-hangers is put forward. The suitability and robustness of this approach is then verified by a numerical simulation of a real through arch bridge. The impact effects induced by local hanger fracture on other structural members are simulated by dynamic time-history analyses. The new approach to design the hangers for through arch bridges is shown to improve the structural robustness. With the application of the new way put forward here, when one or more hangers are damaged to fail, the through arch bridge will not be endangered and will still maintain the overall load-bearing capacity during an appropriate length of time to allow necessary emergency measures to be taken, which illustrates the leading principle of structural robustness well.

Numerical Analysis for Progressive Collapse of a Multi-Storey Building due to an Explosion in its Basement

2011 ◽  
Vol 250-253 ◽  
pp. 3115-3119 ◽  
Author(s):  
Li Tian ◽  
Hao Wang
Keyword(s):  
Numerical Analysis ◽  
Progressive Collapse ◽  
Simulation Method ◽  
Structural Members ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Whole Process ◽  
Main Work ◽  
Storey Building

A numerical analysis for the progressive collapse of a reinforced concrete frame caused by an explosion in this structure’s basement is presented in this paper. The whole process from the detonation of the explosive charge to the complete demolition is reproduced. The main work is focused on the role of soil in structural collapse and failure mode of structural members. The analysis is simulated using ANSYS/LS-DYNA and proposes a new simulation method which is comparatively accurate and economic.

scholarly journals Prediction of Damage Level of Slab-Column Joints under Blast Load

2020 ◽  
Vol 10 (17) ◽  
pp. 5837
Author(s):  
Kwang Mo Lim ◽  
Do Guen Yoo ◽  
Bo Yeon Lee ◽  
Joo Ha Lee
Keyword(s):  
Numerical Analysis ◽  
Prediction Equation ◽  
General Purpose ◽  
Blast Loads ◽  
Joint Region ◽  
Element Analysis ◽  
Scaled Distance ◽  
Damage Level ◽  
Disturbed Zone ◽  
Column Joint

The behavior of a slab-column joint subjected to blast loads was studied by numerical analysis using a general-purpose finite element analysis program, LS-DYNA. Under the explosive load, the joint region known as the stress disturbed zone was defined as a region with a scaled distance of 0.1 m/kg1/3 or less through comparison with ConWep’s empirical formula. Displacement and support rotation according to Trinitrotoluene (TNT) weight and scaled distance were investigated by dividing in and out of the joint region. In addition, fracture volume was newly proposed as an evaluation factor for blast-resistant performance, and it was confirmed that the degree of damage to a member due to blast loads was well represented by the fracture volume. Finally, a prediction equation for the blast-resistant performance of the slab-column joint was proposed, and the reliability and accuracy of the equation were verified through additional numerical analysis.

Experimental Study on the Fire Resistance of Rectangular Hollow Sections Steel Columns

2012 ◽  
Vol 557-559 ◽  
pp. 112-115
Author(s):  
In Kyu Kwon ◽  
Heung Youl Kim ◽  
Hyung Jun Kim
Keyword(s):  
Engineering Design ◽  
Fire Resistance ◽  
Scientific Method ◽  
Maximum Temperature ◽  
Structural Elements ◽  
Structural Members ◽  
Building Collapse ◽  
Steel Columns ◽  
Fire Engineering ◽  
Limiting Temperatures

A fire occurring at a building causes severe damages to its structural members and brings unexpected collapse. Therefore, the building regulation of each nation has to define fire resistance to prevent building collapse due to high temperatures. In general, the fire resistance of each structural member can be evaluated by two methods. One is prescriptive method that is guided by a specific building regulation containing fire resistance examples or by the application of new examples tested fire experimental procedures. The other is performance based fire engineering design. Being an engineered and scientific method, it utilizes the results obtained from the calculation of fire severities, temperatures of members and so on. The easiest way to evaluate the fire resistance of a steel member is to compare its limiting temperature and maximum temperature. Therefore, constructing the database of the limiting temperatures of structural elements is very important in performance based fire engineering design. This paper is to derive the fire resistance and limiting temperatures of rectangular hollow sections under loads.

Dynamic Response and Failure Mode Analysis on Light-Weight Steel Columns under Blast Loads

2012 ◽  
Vol 166-169 ◽  
pp. 1489-1497 ◽  
Author(s):  
Shi Yan ◽  
Lei Liu ◽  
Peng Li ◽  
Zhi Qiang Xin ◽  
Bao Xin Qi
Keyword(s):  
Dynamic Response ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Mode Analysis ◽  
Material Strength ◽  
Light Weight ◽  
Blast Loads ◽  
Element Analysis ◽  
Steel Columns

The dynamic response and failure mode of light-weight steel columns under blast loads were studied in this paper by using nonlinear finite element analysis (FEA) software ANSYS/ LS-DYNA, aiming to develop the degree and modes of the excessive plastic deformation during failures of the columns under diverse parameters. The damaged columns with initial blast-induced deformation may evidently influence vertical stability of light-weight steel frame structures. During the numerical simulation, the element of three dimensional solid SOLID164 was used, and the strain rate effect on material strength was included in the material model with Plastic-Kinematic (MAT-03). The main parameters included in the analysis were boundary conditions, scaled distances of explosions, and the vertical compressive load ratios applied on tops of the columns. The results showed that the column with both two fixed ends was the most beneficial to resist blast shock wave, the horizontal displacement at the middle span of the columns were obviously decreasing as increasing of the scaled distances of the explosion, and the axial compression ratio only significantly influenced the column with a sliding end. The failure modes of the developed columns may be summarized as bending failure, direct shear failure, and bending shear combination failure.

Performance-Based Fire Safety Design of Special Structures in Germany

2014 ◽  
Vol 5 (2) ◽  
pp. 125-134
Author(s):  
Jochen Zehfuß ◽  
Christoph Klinzmann ◽  
Karen Paliga
Keyword(s):  
Concrete Slab ◽  
Steel Structure ◽  
Steel Beams ◽  
Structural Members ◽  
Railway Bridge ◽  
Steel Columns ◽  
Natural Fires ◽  
Safe Side ◽  
Fire Safety Design ◽  
Bearing Structure

The objective of this article is the illustration of the calculation of natural fires and fire resistance of structural members based on the Eurocodes of two types of special structures, in this case a railway bridge and an airplane hangar. The railway bridge has a width of nearly 70 meters and consists of steel beams and a massive concrete slab that are supported by massive columns and walls and for that reason can be compared to a tunnel. The load-bearing structure of the roof of the hangars is made of steel and is supported by steel columns. The choice of a fire scenario on the safe side is crucial for the design process of the unprotected steel structure.

Structural Reliability of a Suezmax Oil Tanker Designed According to New Joint Tanker Project Rules

2006 ◽  
Author(s):  
C. Guedes Soares ◽  
Josˇko Parunov
Keyword(s):  
Structural Reliability ◽  
Progressive Collapse ◽  
Bending Moment ◽  
Single Step ◽  
Moment Capacity ◽  
Hull Girder ◽  
Term Operation ◽  
Reliability Method ◽  
Wave Induced

The paper aims at quantifying the changes in notional reliability levels that result from redesigning an existing suezmax tanker to comply with new Joint Tanker Project (JTP) rule requirement for ultimate vertical bending moment capacity. The probability of structural failure is calculated using a first-order reliability method. The evaluation of the wave-induced load effects that occur during long-term operation of the ship in the seaway is carried out in accordance to IACS recommended procedure. Comparative analysis of long-term distributions of vertical wave bending moment calculated by two independent computer seakeeping codes is performed. The still water loads are defined on the basis of a statistical analysis of loading conditions from the loading manual. The ultimate collapse bending moment of the midship cross section, which is used as the basis for the reliability formulation, is evaluated by JTP single-step procedure and by program HULLCOLL for progressive collapse analysis of ship hull-girders. The reliability assessment is performed for “as-built” and “corroded” states of the existing ship and a reinforced design configuration complying with new JTP rules. It is shown that hull-girder failure probability of suezmax tanker reinforced according to new JTP rules is reduced several times. Sensitivity analysis and a parametric study are performed to investigate the variability of results to the change of parameters of pertinent random variables within their plausible ranges.

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