BEHAVIOR OF ARCHITECTURAL AND STRUCTURAL FOR STEEL …

BEHAVIOR OF ARCHITECTURAL AND

STRUCTURAL FOR STEEL FRAM TALL

BUILDING SUBJECTED TO BLAST LOADS

Abstract

This paper aims at studying the effect of blast loading on the constructional design of a 12-

storey Steel frame residential building from different weight of TNT. This type of loading

should be taken into considerations now in Iraq, especially after the The terrorist attack is

from the explosions that the State of Iraq is going through from the year 2003 to the present

day. The explosions must be studied in Iraq to avoid significant losses in human lives and

human and economic equipment. The same Steel frame multistory building was designed

with three different weights of TNT 100,350 and 750kg in order to discuss the difference

from structuring and analysis from drift, displacement and story shear. A commercial

package ETABS2018 was used to analyze this 36-meter-high building. The building was

analyzed according to the American code, while it was designed according to AISC 360-10

(LRFD) and US Department of Defense TM5-1300 for blast load. The maximum increase

displacement it was seen on the 6th and 7th storeys amount 291.2%, 291.4% for

weight TNT between 350kg-750kg, and the maximum increase displacement it was

seen on the 2nd and 3rd storeys amount 256.7%, 256% for weight TNT between

100kg-350kg.The maximum increase drift it was seen on the 6th and 7th storeys

amount 295%, 293% for weight TNT between 350kg-750kg, and the maximum

increase drift it was seen on the 2nd and 3rd storeys amount 256%, 254% for weight

TNT between 100kg-350kg., we can see the increase base shear with different

weight 100kg-350kg, take result base shear, amounts increased by about 256 % of

blast load 100 kg-350, and the maximum increase base shear it was seen in the

amount 283% for weight TNT between 350kg-750kg

Keywords: Blast load, ETABS, Tall building, standoff, TNT. Irregular building

Ali Kifah Kadhum2

Assistant Lecturer /University of AL-

Mustansiriyah /College of Engineering/ Department

of Water Resources

https://orcid.org/0000-0002-6722-1890

e-mail: [email protected]

Lina K. Kadhum1

Assistant Lecturer /University of AL-

Mustansiriyah /College of Engineering/ Department

of architecture

e-mail: [email protected]

Journal of Xi'an University of Architecture & Technology

Volume XII, Issue IV, 2020

ISSN No : 1006-7930

Page No: 5762

1. INTRODUCTION

Since the 1980’s terrorists have used car bombs to attack buildings throughout the world,

causing tragic consequences, loss of lives and injuries to thousands of people. Figure 1.1

shows the three important measures taken to protect buildings against car bomb attacks. The

first and most effective measure is to gather intelligence on terrorist activities in an effort to

find out about those activities in advance and prevent their occurrence. The second step is to

provide physical barriers and standoff distances around the buildings such that car bombs

cannot be detonated close to buildings. The third line of defense is to harden the building.

The hardening, which is done through blast-resistant design, should be done such that if the

first and second steps fail and the car bomb explodes close to the building casualties are

prevented and injuries to people and damage to the building are minimal with no progressive

collapse. Past experience with car bomb attacks on buildings indicate that if a progressive

collapse occurs, it can cause a very high number of casualties and injuries. The third measure

is the responsibility of the engineer designing the blast

The resistance of the building and this report is prepared to be of some help to that end.

Structural engineers and other design professionals are often asked what can be done to

protect

(a) To minimize local damage and;

(b) To prevent progressive and catastrophic collapse

A terrorist attack applying ground-based explosions, such as car bombs, or using a flying

object, such as airplanes or rockets, can result in:

1. Serious but very localized damage to a few columns and beams in the vicinity of the

Impacted zone, and;

2. Progressive collapse initiated by the local failures which spreads in a domino effect

resulting in the collapse of large portions or even the entire structure. In the case of critical

buildings, such as nuclear power plants and military command and control centers, even a

local damage to a small portion of the building can have catastrophic consequences.

Therefore, for those structures, even a local damage due to terrorist or other attacks using

explosives is not tolerated. The Progressive collapse of the U.S. buildings either abroad or

at home has resulted in thousands of deaths in military barracks in Beirut in the 1980’s, in

embassy buildings in Africa and in Murrah Federal building in the 1990’s, in the World

Trade Center and Pentagon in 2001 and various civilian buildings throughout the world. In

other less sensitive buildings, such as office or residential buildings, assuming a low

probability of a terrorist attack, currently the protection measures are not so unanimously

accepted [1].

1.2 The building's architecturally blast-resistant design.

The architectural knowledge of the design of building structures resistant to the

effects of explosions is important in strengthening the buildings to mitigate the

effects of this. The Planning and layout is the most important stage to be taken into

consideration when designing a new building to reduce potential threats and

associated risks of injury and damage to the building. The risk of explosion should

be considered, as the appropriate shelter spaces within the building should be

allocated to provide explosive protection for structural and non-structural organs,

and with regard to the external threat, the priority should be to create as much

confrontation as possible between the explosion and the building. This can be

achieved through the strategic location of obstacles such as pollards, trees and street

furniture. The architectural form also has a significant impact on the building's

explosion loads. Architectural elements such as arches and domes are structural

elements that minimize the effects of the explosion of the building, but the



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architectural plan has a significant impact on the size of the blast load it faces. Keep

away from the layout of complex shapes (u-shaped buildings) which in turn cause

multiple reflections of the blast wave. It was noted that one-story buildings are more

explosively more resistant than multi-story buildings. The event of explosions.As

for the internal planning of the building has a great effect to resist the effects of the

explosion by protecting the foyer areas with armed concrete walls; With control of

the entrance of the building and separate it from other parts of the building of a

solid building to provide physical protection of the building. The presence of the

basements within the building or the parking lot at the bottom of the building should

also be avoided unless access can be effectively controlled.

Fig 1: Blast loading on the building

1.3 Characteristics of Blast Wave

Blast waves cause damage due to a mixture of dangerous air compression in front

of the wave (which forms a shock front) and the winds that follow. The blast wave

travels faster than the speed of sound, and the shock wave usually only takes a few

milliseconds to pass. Like other types of explosions, an explosion wave can also

cause damage to objects and people due to explosion winds, debris, and fires. The

original blast will send fragments that travel very quickly. Wreckage of the

explosion wave can sometimes be caused, causing more injuries such as penetration

of wounds, deformities, broken bones or even death. Blast winds are the low-

pressure area that causes debris and splinters to actually rush toward the original

explosions. An exploding wave can also cause fires or even secondary explosions

through a combination of high temperatures caused by detonation and physical

destruction of objects containing fuel [2].

2. Main Sources of Information on Blast Resistant Design

In recent years, the U.S. Federal government has increasingly focused on protecting

buildings and their occupants against terrorist attacks and has funded research and

development projects to address the problem. These efforts are aimed at the

development of protective measures to prevent casualties and serious injuries and

to reduce the damage in the event of terrorist car bomb attack on a building. Major

efforts are made by the federal government agencies and professional organizations

such as the General Services Administration, the Department of Defense and the



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American Society of Civil Engineers to develop and release guidelines and

information on blast protection of buildings. An important document used for past

several decades in blast resistant design of buildings and other facilities is the

manual “TM5-1300, Structures to Resist the Effects of Accidental Explosions”

(Army, 1990), developed by the Department of Defense in the late 1960’s. The

initial version primarily had information on reinforced concrete. The 1990 version

of the TM5-1300 (Army, 1990), in addition to concrete, included some information

on steel as well.

2.1. Shock Wave Created by Blast in the Air

When condensed high explosive charges such as TNT detonate, the ensuing

detonation waves turn into blast waves causing pressure pulse in the air. The

dynamic pressure wave is very complex depending on parameters such as the shape

and chemical composition of the charge, the characteristics of the container, the

distance from the charge as well as the properties of the ground under the charge.

The presence of other structures and obstacles also affect the free field blast waves

due to refraction and reflection of waves on those structures. Despite the

complexity of those parameters in blast-resistant design of ordinary buildings

subjected to external car bomb blasts, it is assumed that the blast occurs in a still,

homogeneous atmosphere and the source is semi-spherically symmetric charge

placed on the surface of the ground. As a result, the magnitude, wave length and

velocity of the free-field pressure waves are assumed dependent only on the

distance of the surface from the center of the charge, RG, and the weight of

detonated charge, W.

In the equations and graphs used to establish blast pressure, the two parameters; W

and RG are combined and defined as Scaled Ground Distance, ZG given by the

following equation;

ZG=RG /W 1/ 3 (1)

Figure 2. shows time history of a typical free field blast pressure. The free field

pressure is also called incident pressure. The most important parameter is the peak

incident pressure Pso, which is the maximum pressure at the time of arrival of the

pressure wave. As the time passes the incident pressure drops and after time To,

becomes a negative pressure [1].

Fig 2 Time-History of Incident Pressure for Typical Blast Wave

3. Modelling and analysis 3.1 Description and Modeling of Building



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The goal over that assignment is according to ask abroad there sponse concerning

informal Building. To understand the behavior of structure different condition

charge weights of 100 kg and 350 kg and 750 kg are applied at a standoff distance

of 5m the objective over that task is as per asks abroad the s reaction concerning

the casual building. To comprehend the conduct of structure in various condition

charge loads of 100 kg and 350 kg and 750 kg are applied at a standoff separation

of 5m Prior a few scientists chipped away at the structures with shaft segment

associations.

The impact of shoot load on chunk are

considered by just a couple of scientists.

Henceforth, during this work. This errand

manages displaying and the examination of

(G+11), structure exposed to 100kg of TNT

explosives with various showdown

separations utilizing ETABS 2016 [3]. The

foreordained impact loads are appointed as

static joint loads inside the level chunk

structure and straight static examination is

directed for level piece structures. At first,

the structures are displayed and broke down

for the doled out shoot stacks in ETABS

apparatus and consequently the structures

are made safe for different material

properties and area properties. The level chunk structures are broken down for

seismic examination and time-history investigation right off the bat. At that point,

impact examination is managed for different cases and remain off separations

which are resolved. At that point the reaction of the structure examined in ETAB

apparatus for story floats, story shears, and relocations and so on.

Fig 4 Top view plan of Steel

building

Scaled Distance, Z

Fig. 5 - 3D plan of irregular Steel

building

Fig.6 Positive Phase Shock Wave

Parameters for Hemispherical TNT

Explosion on the Surface at Sea Level

(Adapted from: UFC/DoD, 2008,

Formerly TM5-1300)



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3.2 Computer Modeling and Analysis

ETABS programming program is utilized in light of the fact that demonstrating

shaft segments are displayed as a lot of casing component chunks are demonstrated

so hold components in flexible stomach is appointed to all and someone floors firm

help situation is applied. Impact load estimations are regulated to be specific

consideration of the system's plot in share 5 of tm5 – 1300 the explosion loads are

disseminated concerning entire the basic factors over the turn face likewise as like

right surface concerning the structure. Following techniques or TM5 1300 diagrams

[4], programming named at impact was once best in class through are applied query

partners, which ascertains blow up hundreds for incomplete Quast and off bout

worth loads yet standoff separations. This product computes explosion loads solid

parameters like stroke go speed, motivation period or time concerning appearance

Unified Facilities Criteria (UFC). (2008) [5]: Introduced a chart to calculate the

maximum pressure and blast durations for a free-air burst as shown in Figure 6 [6].

3.3 Model Description

Plan: 30m x 36m

X- direction: 6 space 5m

Y- direction: 6 space 6m

The height of each story 3m

3.4 Properties of materials

Table 1: define material

3.5 Sectional Properties Column: HE360

Beam: IPE330

Secondary beams=W12X30

Deck Slab: 155 mm

Slab concrete = 80 mm

Ribbed Deck=75 mm

shear Stud= 127 mm

3.6 General Loadings Live load: 2.5kN/m2 (Floor)

Floor Finish: 1.5 kN/m2

Wall load: 15 kN/m

Fig 7. Apply blast load (side face)

Grade

Density concrete

25kN/m3

Density Steel 78.5kN/m3

Table 1: define material

Mode

l No.

Type of

Building

Weight

TNT

(kN)

Standoff

Distance

(m)

M1 Irregular

100 5

M2 Irregular

350 5

M3 Irregular

750 5

Table -2: Model Description



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Joint

Story

1 2 3 4 5 6 7

1 730 1600 1600 1500 1600 1600 730

2 715 1450 1450 1482 1450 1450 715

3 700 880 880 1464 880 880 700

4 680 855 855 1430 855 855 680

5 665 825 825 1400 825 825 665

6 640 790 790 1380 790 790 640

7 620 780 780 1355 780 780 620

8 590 765 765 1320 765 765 590

9 575 758 758 1290 758 758 575

10 550 750 750 1260 750 750 550

11 543 742 742 1200 742 742 543

12 278 374 374 265 374 374 278

Table 3 (p kN) story with joint standoff 5m 100 kg

Joint

Story

1 2 3 4 5 6 7

1 3885 11500 11500 8000 11500 11500 3885

2 3690 10800 10800 7800 10800 10800 3690

3 3500 9800 9800 7660 9800 9800 3500

4 3330 9500 9500 7330 9500 9500 3330

5 3115 9100 9100 7000 9100 9100 3115

6 2890 8550 8550 6780 8550 8550 2890

7 2700 7950 7950 6460 7950 7950 2700

8 2530 7420 7420 6130 7420 7420 2530

9 2500 6850 6850 5700 6850 6850 2500

10 2475 6150 6150 5370 6150 6150 2475

11 2440 5500 5500 5040 5500 5500 2440

12 1185 2600 2600 1200 2600 2600 1185

Table 4 (p kN) story with joint standoff 5m 750kg

4.RESULTS

4.1displacements:- According to the results the chart 1 ,2 and 3 show in Table 5,6 and 7 the different

amount building, From chart1, 2 and 3, we can see the increase displacement with

different weight 100kg-350kg, take result story 2nd,3rd,6th,7th,11th and story12th,

amounts increased by about 256%-256% -250%-248%-244.6% and 244.4 % of

blast load 100 kg-350kg. We can see the increase displacement with different

weight 350kg-750kg, take result story 2nd,3rd,6th,7th,11th and story12th, amounts

increased by about 286%-287%-291%-291%-290% and 289% of blast load 350

kg-750kg. The maximum increase displacement it was seen on the 6th and 7th

storeys amount 291.2%, 291.4% for weight TNT between 350kg-750kg, and the

maximum increase displacement it was seen on the 2nd and 3rd storeys amount

256.7%, 256% for weight TNT between 100kg-350kg.

4.2Drift:- According to the results the chart 4 (a-b-c) show in Table 8,9 and 10 the drift



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amount building, From chart 4 (a-b-c), we can see the increase drift with different

weight 100kg-350kg, take result story 2nd,3rd,6th,7th,11th and story12th, amounts

increased by about 256%-254% -238%-234%-228% and 230 % of blast load 100

kg-350kg. We can see the increase drift with different weight 350kg-750kg, take

result story 2nd,3rd,6th,7th,11th and story12th, amounts increased by about 287%-

290%-295%-293%-277% and 274% of blast load 350 kg-750kg. The maximum

increase drift it was seen on the 6th and 7th storeys amount 295%, 293% for weight

TNT between 350kg-750kg, and the maximum increase drift it was seen on the 2nd

and 3rd storeys amount 256%, 254% for weight TNT between 100kg-350kg.

4.3 Base shear: -

According to the results the chart 5, show the different amount building, from

chart 4, we can see the increase base shear with different weight 100kg-350kg,

take result base shear, amounts increased by about 256 % of blast load 100 kg-

350, and the maximum increase base shear it was seen in the amount 283% for

weight TNT between 350kg-750kg.

Chart 1. Max story displacement Chart 2. Max story displacement

Story Elev X-Dir Y-Dir

m mm mm

12 36 2276.544 2.967

11 33 2240.293 4.529

10 30 2179.224 5.487

9 27 2086.511 5.735

8 24 1959.393 5.872

7 21 1796.169 6.08

6 18 1595.627 5.849

5 15 1358.223 5.798

4 12 1085.614 6.117

3 9 782.395 6.832

2 6 462.442 7.833

1 3 163.241 5.012

Base 0 0 0


m mm mm

12 36 5566.092 9.149

11 33 5481.629 12.973

10 30 5342.495 16.025

9 27 5130.387 17.299

8 24 4837.841 18.373

7 21 4459.118 19.665

6 18 3989.437 21.131

5 15 3424.675 23.09

4 12 2760.35 25.057

3 9 2003.189 26.411

2 6 1187.283 24.55

1 3 419.348 14.426

Base 0 0 0

Table -5 (standoff 5 m – TNT 100 kg) Table -6 (standoff 5 m – TNT 350

kg)



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m mm mm

12 36 16139.352 21.882

11 33 15910.668 35.158

10 30 15525.017 44.96

9 27 14930.109 51.696

8 24 14094.683 56.911

7 21 12996.37 61.136

6 18 11618.004 64.984

5 15 9947.617 68.208

4 12 7986.312 70.463

3 9 5767.064 70.956

2 6 3401.208 65.327

1 3 1195.384 38.575

Base 0 0 0

Table -7 (standoff 5 m – TNT 750 kg) Chart 3. Maximum story

displacement

(a-100 kg) (b-350kg)

(c-750 kg)

Chart 4. Maximum Drift



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Story Response Values

Story Elevation X-Dir Y-Dir

m

12 36 0.012821 0.000593

11 33 0.020703 0.000319

10 30 0.031002 0.0001

9 27 0.042428 0.000046

8 24 0.054456 0.000069

7 21 0.066905 0.000077

6 18 0.079145 0.000019

5 15 0.090966 0.000106

4 12 0.101264 0.000239

3 9 0.106933 0.000334

2 6 0.099836 0.00094

1 3 0.054414 0.001671

Base 0 0 0

Table-8 (standoff 5m - 100 kg) Chart 5. Base shear


m

12 36 0.029573 0.001275

11 33 0.047347 0.001017

10 30 0.071069 0.000425

9 27 0.097854 0.000358

8 24 0.126629 0.000431

7 21 0.157012 0.000489

6 18 0.188993 0.000653

5 15 0.222115 0.000656

4 12 0.252877 0.000451

3 9 0.27219 0.000782

2 6 0.25605 0.003375

1 3 0.139783 0.004809

Base 0 0 0


m

12 36 0.081106 0.004425

11 33 0.131564 0.003267

10 30 0.200407 0.002245

9 27 0.280102 0.001738

8 24 0.367432 0.001409

7 21 0.460714 0.001283

6 18 0.557894 0.001075

5 15 0.654585 0.000752

4 12 0.740007 0.000164

3 9 0.789497 0.002658

2 6 0.735603 0.008917

1 3 0.398461 0.012858

Base 0 0 0

Table-9 (standoff 5m - 350 kg) Table-10 (standoff 5m - 750 kg)

0

100000

200000

300000

400000

500000

600000

700000

BASE SHAER (kN)

Base Shear (kN) standoff

5 m

100 kN 350 kN 750 kN



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5. CONCLUSION

The blast load applied affective lateral forces on the building side [7]. This effect

was obvious in the compare building of three cases with different weight TNT

100,350 and 750kg [8]. Columns, beams, especially in the joints between them.

These joints have been strengthened by additional reinforcement to withstand the

lateral forces of the blast load. The maximum increase displacement it was seen on

the 6th and 7th storeys amount 291.2%, 291.4% for weight TNT between 350kg-

750kg, and the maximum increase displacement it was seen on the 2nd and 3rd

storeys amount 256.7%, 256% for weight TNT between 100kg-350kg.The

maximum increase drift it was seen on the 6th and 7th storeys amount 295%, 293%

for weight TNT between 350kg-750kg, and the maximum increase drift it was seen

on the 2nd and 3rd storeys amount 256%, 254% for weight TNT between 100kg-

350kg., we can see the increase base shear with different weight 100kg-350kg,

take result base shear, amounts increased by about 256 % of blast load 100 kg-350,

and the maximum increase base shear it was seen in the amount 283% for weight

TNT between 350kg-750kg. Therefore, when the increase weight of TNT it will

increase the amount of (displacement, drift and base shear). Through the results,

the risk in the architectural design is when the weight of the TNT load increases,

and this affects the interior design in choosing the function of each floor due to the

increased influence of the lower and middle floors of the buildings exposed to the

explosion.

References

[1] A. Astaneh-Asl, Blast Resistance of Steel and, Berkeley: University of

California, Berkeley, 2010.

[2] H. D. a. V. Sigmund, "Blast Loading on Structures," Journal:

International Journal of Engineering Research and Applications

(IJERA) ISSN 1330 – 3651 UDC/UDK 624.01.04:662.15. Technical

Gazette 19, 3..

[3] ETABS 2016 V16.2.1 Integrated Building Design software manual by

Computers and Structures Inc, 2016.

[4] TM5 – 1300 (1990). Design of Structures to resist the effect of

accidental explosions. Washington D C. U. S. Department of Army.,

1990.

[5] UFC, 2008. Unified Facilities Criteria 3-340-02: Structures to resist

the effects ofaccidental explosions, Dept. of the Army, the NAVY and

the Air Force, Washington DC,, 2008.



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[6] A. K. K. a. K. S. Abdul-Razzaq, "Effect of Seismic Load on Reinforced

Concrete Multistory Building from Economical Point of View,"

International Journal of Civil Engineering and Technology (IJCIET,

vol. 9, no. 11, pp. 588-598, 2018.

[7] a. a. K. S. A.-R. Ali Kifah Kadhum1, "Effect of seismic load on steel

frame multistory building from economical point of view," AIP

Conference Proceedings , vol. 2213, no. 1, 2020.

[8] AISC 360-10 (LRFD) Building Code Requirements for Structural steel

frame.

[9] S. V. M. S. B. P. Aditya C Bhatt, "Comparative Study of Response of

Structures Subjected to Blast and Earthquake Loading,"

International Journal of Engineering Research and Applications,

ISSN:2248-9622, Vol. 6, Issue 5,, May 2016..

[10] A. A. B. a. W. A. Attia, "Assessment of existing structures under the

action of gravity, earthquake and blast loads," International Journal

of Engineering Science and Innovative Technology (IJESIT) , vol. 5,

no. 3, pp. 37-47, (2016.

[11] H. S. M. R. R. Jayashree S M, "Dynamic response of a space framed

structure subjected to blast load," International Journal of Civil and

Structural Engineering, vol. 4, no. 1, 2013.

[12] A. T. S. Osman Shallan, " Response of Building Structures to Blast

Effects," International Journal of Engineering and Innovative

Technoogy, vol. 4, no. 2, 2014.

[13] Swathi Ratna. K, "Analysis of RCC and Simcon Buildings Subjected

To Blast Effects," 11- Swathi Ratna. K, Analysis of RCC and Simcon

Buildings Subjected To Blast Effects. International Journal of Civil

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BEHAVIOR OF ARCHITECTURAL AND STRUCTURAL FOR STEEL …