THE ARCHITECTURAL EVALUATION OF BUILDINGS’ INDICES IN EXPLOSION CRISIS MANAGEMENT

منبع مورد استناد :

[2] M. Bitarafan, S.B. Hosseini, S.J. Hashemi-fesharaki, A. Esmailzadeh, Role of architectural space in blast-resistant buildings, Front. Architectural Res. (2013).

 

https://cyberleninka.org/article/n/1495562

 

THE ARCHITECTURAL EVALUATION OF BUILDINGS’ INDICES IN EXPLOSION CRISIS MANAGEMENTAcademic research paper on "Civil engineering"

• Mahdi Bitarafan
• Sayed Bagher Hosseini
• Nasim Sabeti
• Ali Bitarafan

CC BY-NC-ND

 

ACADEMIC JOURNAL

Alexandria Engineering Journal

2017

OECD FIELD OF SCIENCE

• Civil engineering

KEYWORDS

{architecture / building / explosion / indices}

ABSTRACTof research paper on Civil engineering, author of scientific article — Mahdi Bitarafan, Sayed Bagher Hosseini, Nasim Sabeti, Ali Bitarafan

Abstract Identifying the probable damages plays an important role in preparing for encountering and resisting negative effects of martial attacks to urban areas. The ultimate goal of this study was to identify some facilities and solutions of immunizing buildings against marital attacks and resisting explosion effects. Explosionand its coming waves, which are caused by bombardment, will damage the buildings and cause difficulties. So, defining indices to identify architectural vulnerability of buildings in explosion is needed. The Basic indices for evaluating the blast-resistant architectural spaces were identified in this study using library resources. The proposed indices were extracted through interviewing architectural and explosive experts. This study has also applied group decision making method based on pairwise comparison model, and then the necessity degree of each index was calculated. Finally, the preferences and ultimate weights of the indices were determined.

ARTICLE PREVIEWDOI: 10.1016/j.aej.2016.08.015

 

 

SIMILAR TOPICSof scientific paper in Civil engineering , author of scholarly article — Mahdi Bitarafan, Sayed Bagher Hosseini, Nasim Sabeti, Ali Bitarafan

• Role of architectural space in blast-resistant buildings

  2013 / Mahdi Bitarafan, Sayed Bagher Hosseini, Sayed Javad hashemi-fesharaki, Armin Esmailzadeh

• Green Architecture as a Concept of Historic Cairo

  2017 / Hanan S. Saleh, Salah Z. Saied

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  2013 / Mahdi Bitarafan, Youssef Hossainzadeh, Saman Yaghmayi

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• A Study on the Sustainable Architectural Characteristics of Traditional Anatolian Houses and Current Building Design Precepts

  2016 / Kader Keskin, Muteber Erbay

ACADEMIC RESEARCH PAPERon topic "The architectural evaluation of buildings’ indices in explosion crisis management"

OURNAL

Alexandria Engineering Journal (2016) 55, 3219-3228

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Alexandria University Alexandria Engineering Journal

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ORIGINAL ARTICLE

The architectural evaluation of buildings' indices cn«^ in explosion crisis management

Mahdi Bitarafana*, Sayed Bagher Hosseinib, Nasim Sabetic, Ali Bitarafand

a Department of Civil Engineering, Engineering Research Institution of Natural Disaster Shakhes Pajouh, Isfahan, Iran b School of Architecture and Environmental Design, Iran University of Science and Technology, Tehran, Iran c Architecture Faculty of Islamic Azad University of Tabriz, Tabriz, Iran d Architecture Faculty of University of Applied Science And Technology, Tehran, Iran

Received 12 February 2013; revised 10 June 2016; accepted 16 August 2016

KEYWORDS

Architecture; Building; Explosion; Indices

Abstract Identifying the probable damages plays an important role in preparing for encountering and resisting negative effects of martial attacks to urban areas. The ultimate goal of this study was to identify some facilities and solutions of immunizing buildings against marital attacks and resisting explosion effects. Explosion and its coming waves, which are caused by bombardment, will damage the buildings and cause difficulties. So, defining indices to identify architectural vulnerability of buildings in explosion is needed. The Basic indices for evaluating the blast-resistant architectural spaces were identified in this study using library resources. The proposed indices were extracted through interviewing architectural and explosive experts. This study has also applied group decision making method based on pairwise comparison model, and then the necessity degree of each index was calculated. Finally, the preferences and ultimate weights of the indices were determined.

© 2016 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction

Every day, around the world we witness destruction of resources, assets and national infrastructures of countries caused by cities bombardments and terrorist attacks. Accordingly, all military and non-military buildings should be equipped against these threats to be less vulnerable; an archi-

* Corresponding author at: Engineering Research Institution of Natural Disaster and Passive Defense Shakhes Pajouh, Iran. E-mail addresses: [e-mail] (M. Bitarafan), Hosseini@ iust.ac.ir (S.B. Hosseini), [e-mail] (N. Sabeti). Peer review under responsibility of Faculty of Engineering, Alexandria University.

tectural design should be drafted to reduce the vulnerability of humans and buildings against unexpected threats.

In the design process, it is vital to determine the potential danger and the extent of it. Most importantly, human safety should be provided. Moreover, to achieve functional continuity after an explosion, architectural and structural factors should be taken into account in the design process, and also an optimum building plan should be considered [1].

According to the contemporary architectural theorists, the design of all spatial scales in a manufactured environment should be part of the architectural skills and knowledge. Thus, an architectural design is needed to reduce the potential vulnerabilities to human beings and buildings against threats [2]. In this regard, to identify the potential architectural

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1110-0168 © 2016 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

vulnerability of buildings against explosion, the indices need to be defined. This study addresses the absence of a codified and detailed criterion to evaluate architectural compatibility of buildings against terrorist attacks and aerial bombardments.

1.1. Literature review

Some studies on architecture of threat resistant buildings have been conducted including the investigation of Khairuddin et al. [3]. They focused on the impact of architectural elements on the vulnerability of structures against earthquake hazard. The importance of space organizing in architecture of civil defense and its variants was also expressed by Hashemi Fes-haraki et al. [4]. On the other hand, Gebbeken and Doge [5] researched on the geometry of buildings and the effect of surrounding systems to protect buildings from blasting waves. They concluded that the peak pressures and maximum impulses depend essentially on the distance of blasting center, the angle of reflected blast wave and the resistance against the waves. The structural elements of a building can reduce the explosive charges. Barakat and Hetherington [6] have studied the blasting effects on the various building forms such as cubic, cylindrical, hemisphere and prismatic forms and finally concluded that in addition to the structural components of the buildings, architectural forms can also be more effective in reducing the effect of explosion on buildings. Araghizadeh [7] has done a research on blast-resistant office buildings and represented 6 indices to evaluate these buildings and concluded that the location of the buildings toward the ground level is one of the most important factors in reducing the impact of explosion on buildings. We can also point to the study by Luc-cioni et al. [8]. The purpose of their research was failure analysis of buildings with concrete structures under explosion load; therefore, they modeled a three-dimensional model from a concrete building in AUTODYN software and finally they concluded that the failure mechanism started from the lower columns of the building and the building had been destroyed. Mojtahed-Pour [9] studied the effects of structures' shape on the stress distribution caused by the explosive loading and he mostly studied the structural aspects of the issue. In some parts of the research he studied the effect of induratives in buildings. In all mentioned researches only evaluating the reduction rate of explosion effect on form or materials has been considered. The main goal of this research was to rank various types of shapes and geometric forms of buildings' roof against explosion effects. Dermisi [20] proposes a layered approach for the protection and prevention of office buildings against terrorism attacks and the development of a city-wide Property Anti-Terrorism Taskforce, which will increase the cross-collaboration between real estate and law enforcement and emergency management agencies, while strategically preparing owners and property managers. Among other works, Hovaidafar [10] work can be mentioned which has investigated entrances and exits of shelters, and he further considered preventing explosion waves from entering into shelters and in the end he provided some considerations to design shelters' entrances. Bitarafan et al. [19] have conducted some researches on the entrance of secure underground spaces and proposed 17 patterns for secure arrival to the underground space. Rahim et al. [18] evaluated different shapes of the roof and the effect on the explosion. They modeled different kinds of roofs by ele-

ment software and concluded that flat roofs are the best kind against the explosion. Among other studies in this sense, we can refer to Nadel [22] who has focused on Building Security - Handbook for Architectural planning and design. FEMA-426 (2003), FEMA-427 (2003), FEMA-428 (2003) and FEMA-429 (2003) have emphasized on mitigation potential terrorist attacks against buildings. Many other studies have examined the buildings' behavior against explosion, but most of these studies have focused only on the one or some (not all) of the factors affecting on buildings' behavior, but the present study has focused on the all architectural indices to consider the resistance of buildings against explosion.

2. Methodology

Basic indicators for evaluating the blast-resistant architectural spaces were identified in this study using library resources. The proposed indices were extracted from interviews with experts in the field of architecture and explosives (Table 1). A questionnaire was presented to 31 experts to acquire ideas for determining the effective indicators. The degree of each index was determined in a frame of the nine-point Likert scale by applying the group decision-making method based on a pair-wise comparison model. Finally, the preferences and ultimate weights of the indices were determined. Moreover, the Cron-bach's Alpha test was used to evaluate the validity of the questionnaires [17].

2.1. AHP method

Analytical Hierarchy Process is designed in accordance with human nature and mind and goes with it. This process is a set of judgments (decisions) and personal valuations in a reasonable approach. So it can be said that the technique in one hand, depends on personal impressions and experiences to form and plan an issue hierarchically, and in the other hand, it depends on logic, understanding and experience for decision making and final judgment.

AHP method is based on three steps: first, structure of the model; second, comparative arbitration of options and criteria and third, combination of priorities [12].

Forman (1985) believes that Analytical Hierarchy Process is one of the most comprehensive systems designed for multi-criteria decision-making, because this technique provides the possibility to formulate the problem hierarchically and also has the ability to consider various quantitative and qualitative criteria in the issue. This process involves different options in decision making and has the possibility of sensitivity analysis on criteria and sub-criteria. Furthermore, it has been

Table 1 Nine-point intensity of importance scale and its

description. Source: Saaty (1980).

Definition Intensity of importance

Equally important 1

Moderately more important 3

Strongly more important 5

Very strongly more important 7

Extremely more important 9

Intermediate values 2, 4, 6, 8

established based on pairwise comparison, which facilitates judgments and calculations. It also shows the compatibility and incompatibility of the decision that is one of distinctive advantages of this technique in multi-criteria decision making.

Recently decision making models based on AHP method have some improvements including the following:

Medineckiene et al. [14] used AHP technique to assess resistant structures. Podvezko et al. [15] used AHP technique to assess contracts. Sivilevicius [16] used AHP technique in the quality of Technology. Fouladgar et al. [13] used AHP technique in prioritized strategies. Bitarafan et al. [19] used AHP technique in reconstructing damaged areas in natural crises.

In the first step, a sophisticated decision problem is structured as a hierarchy. This method breaks down a sophisticated decision construction problem into the hierarchy of objectives, criteria, and alternatives.

These decision elements make a hierarchy of the structure, including the goal of the problem at the top, criteria in the middle and the alternatives at the bottom of this hierarchy.

In the second step, the comparisons of the alternatives and criteria are made. In AHP, comparisons are based on a standard nine-point scale (Table 1).

Let C = {Cj\j = 1,2,..., n} be the set of criteria. The result of the pairwise comparison on n criteria can be summarized in an (n x n) evaluation matrix A in which every element ajj(i, j = 1,2,..., n) is the quotient of weights of the criteria, as shown in Eq. (1):

a11 a12 a21 a22

an1 an2

a1n a2n

aü = 1, aji = 1/a¡j

-0 (1)

At the third step, the mathematical process commences to normalize and finds the relative weights for each matrix. The relative weights are given by the right eigenvector (w) corresponding to the largest eigenvalue (kmax), as follows:

Aw = kmaxw. (2)

If the pairwise comparisons are completely consistent, the matrix A has rank 1 and kmax = n.

In this case, the weights can be obtained by normalizing any of the rows or columns of A [44]. The quality of the output of the AHP is strictly related to the consistency of the pairwise comparison judgements [3]. The consistency is defined by the relation between the entries of A: aij x ajk = aik. The consistency index (CI) is

CI = (kmax - n)/(n -

The final consistency ratio (CR), using which one can conclude whether the evaluations are sufficiently consistent, is calculated as the ratio of the CI to the random index (RI), as indicated in Eq. (4):

CR = CI/RI

The CR index should be lower than 0.10 to accept the AHP results as consistent [45]. If the final consistency ratio exceeds this value, the evaluation procedure has to be repeated to improve the consistency [33]. The CR index could be used to calculate the consistency of decision makers as well as the consistency of all the hierarchies [44].

2.2. Data gathering

At the first step, top managers with experience about architect engineer and a group of experts in architect engineer, civil defenses, and explosion participated in a conference meeting for decision making in this area and with a preliminary work the decision making team determined 12 important criteria for blast-resistant buildings architecture. Information about experts is shown in Table 2.

3. Effective indicators associated with buildings' architecture evaluation against explosion

Delphi method was used to evaluate the indicators associated with architecture of blast-resistant buildings including the fol-lowings: architectural forms, architectural spaces, buildings' decorations, building placement ratio to ground level, buildings prefabrication level, energy management, openings of the building, materials used in the building and camouflage designing.

The purpose of the questionnaires of this research was pair-wise comparison of the indicators and the results have been analyzed using SPSS and EXPERT CHOICE software and effectiveness level of each index was determined. Results are seen in Table 3.

The first defensive barrier against external explosions is the form of the building and also its behavior depends on the used

Table 2 Background information of experts (author

calculation).

Variable Items NO Variable Items NO

(1) Architect Bachelor (3) Civil Bachelor

engineer Master 9 defense Master 7

Ph.D. 6 Ph.D.

(2) Explosion Bachelor (4) Top Bachelor

experts Master 5 managers Master 2

Ph.D. 2 Ph.D. 1

Table 3 Weight and effectiveness of blast resistant buildings' architectural indicators.

Architectural indicators Weight of each indicator (total weighted of indicators is equal to 100)

X1 Form of the building 19.2

X2 Architectural spaces 6.2

X3 Openings of the building 6.9

X4 Entrance of the building 5.6

X5 Materials used in the 19.2

building

X6 Decorations 3.8

X7 Buildings placement 18

ratio to ground level

Xg Prefabrication 5

X9 Energy management 2

X10 Weight of the building 6.3

X11 Camouflage designing 5.9

X1 Ventilation 2

materials in the building; therefore, the most important indices include form and used materials. The next one is the location of building toward the ground. The considerable note is that the total rate of these three indices is more than 56 percent. The next stage includes the other three indices which are opening, weight of building and architectural spaces respectively. In the following we will discuss these indices in more detail.

3.1. Architectural form index

One of the most important issues which focuses on from Vitruvius to the present is architectural form, According to the views of experts on the community, architecture styles, and information from the book, ''Form, Space, and Order'' by Fransis D.K. Ching (2007), the indicators affecting architectural space include the followings:

• Basic form type (A1)

• Form synthesis of the building (A2)

• Splicing corners of the form (A3)

• Roof type (A4)

• Harmony between architectural and structural form (A5)

• Adaption level of architectural and environmental form

• Architectural elements attachment with each other (A7)

• Shape of the outer wall (A8)

• Surface ratio to the height of the building (A9)

• Plan disorders (A10)

• Facade disorders (A11).

A pairwise comparison matrix was considered for these indices to determine the weight and the effect of each factor in the explosion-resistant architecture. Following results were determined by analysis of questionnaires:

As shown in Table 4, the type of basic form and the form synthesis are the most effective ones in choosing a form corresponding to passive defense. The next one is the shape of outer shell which is effective as many as 15 percent. Totally, the effectiveness of these three indices on the architectural form corresponding to passive defense is as many as 50.4 percent.

3.2. Architectural space index

Architectural space is another effective topic on explosion-resistant architecture. The indicators affecting architectural space include the followings:

• Function of architectural spaces at different times (B^

• Amount of human-oriented (ergonomics) characteristics of the building space (B2)

• Method of locating the vital and critical areas in the building (Bi)

• Independency of the building spaces (B3)

• Density of the building spaces (B4).

A pairwise comparison matrix was considered for these indices to determine the weight and the effect of each factor in the explosion-resistant architecture. Following results were determined by analysis of questionnaires:

Picture: final pairwise comparison matrix associated with architectural space subindices in blast resistant buildings.

As seen in the table mentioned below the two factors of ergonomy rate and locating vital spaces have the most important role in blast-resistant buildings according to the experts. About ergonomy, we can say that, this index plays a big role in reduction in human casualties and facilitating crisis management. Buildings vital functional continuity during and after explosion is the reason why critical spaces locating was chosen as a highly important index. Function of different spaces at different times takes the third place in ranking and independence and density of the building spaces are the least important factors (see Tables 5 and 6).

3.3. Building decorations index

In this regard, subindices associated with building decorations are studied from three aspects:

• blast effect reduction

• facilitating crisis management

• Immunization to reduce human casualties.

The results of the questionnaire indicated that the ability to facilitate crisis management (emergency evacuation of the building) is very significant. However, immunization to reduce human casualties was considered a lesser priority. The ability to reduce the explosion effect also had little significance.

On the other hand, building decorations subindex was evaluated in three mentioned topics and we came to the result that elimination of decorative elements leads to buildings higher compatibility with the purpose and principles of civil defense (see Tables 7 and 8).

3.4. Building locating site ratio to the ground level

In this regard, subindices associated with building locating site ratio to the ground level are studied from four aspects including the following:

• Underground buildings

• Semi-underground buildings

Table 4 Weight of architectural form subindices.

Subindices of the architectural form in Weight and influence

blast resistant buildings of each indicator (total

weighted of indicators

is equal to 100)

Type of basic form 17.7

Forms synthesis 17.7

Splicing corners of the forms 4.3

Roof type 4.7

Harmony between architectural and 5.3

structural form

Adaption level of architectural and 6.4

environmental form

Architectural elements attachment with 6.8

each other

Shape of the outer wall 15

Surface ratio to the height of the building 6.4

Plan disorders 9.1

Facade disorders 6.8

Table 5 Final pairwise comparison matrix of architectural form subindices.

Ai A2 A3 A4 a5 A6 A7 A8 A9 A10 A11

Ai 1 1 4.12 3.74 3.37 2.77 2.62 1.0 3.0 2.1 2.82

A2 1 4.12 3.74 3.37 2.77 2.62 1.0 3.0 2.1 2.82

A3 1 0.833 0.820 0.671 0.637 0.243 0.730 0.510 0.685

A4 1 0.909 0.820 0.699 0.267 0.800 0.562 0.758

a5 1 0.901 0.775 0.297 0.893 0.625 0.840

A6 1 0.943 0.361 1.08 0.758 1.01

a7 1 0.382 1.14 0.806 1.08

a8 1 1.43 1 1.34

A9 1 0.699 0.943

A10 1 1.34

Aii 1

Table 6 Weight of architectural space subindices.

Architectural indicators Weight and influence of each

compatible with the purposes indicator (total weight of

and principles of civil defense indicators is equal to 100)

Function of architectural spaces 18.9

at different times

The humanist(ergonomic) of 36.1

building spaces

Method of locating vital and 32.6

critical areas in the building

Independence of the building 6.2

spaces

Density of the building spaces 6.2

Table 7 Final pairwise comparison matrix of architectural

space form subindices.

B1 B2 B3 B4 B5

B, 1 0.444 0.537 3.383 3.384

B2 1 1.038 5.491 5.491

B3 1 4.877 4.877

B4 1 1

B5 1

Table 8 Importance level of considerable indices associated with building decorations.

Immunization to Facilitating Blast effect

reduce human casualties crisis management reduction

7.70 6.22 3.29

Very important Important Less important

• Ground level buildings

• Above ground level buildings.

The results of the survey indicate that underground buildings have more appropriate behavior against explosion. It should be mentioned that if placement of the building above ground level is above standard limit and especially if a pilot

is designed under the building the vulnerability against blast wave decreases (see Table 9).

3.5. Pre-fabrication level index

Industrialization includes three main areas of quality, speed and price.

Quality: This index causes building resistance against natural disasters such as flood and earthquake and also man-made harms such as impacts and blasts and it leads to long servicelife of the building.

Speed: According to the need of quick repair and reconstruction, this factor is considerably important and requirements should be estimated based on present conditions and standards and in an acceptable time.

Price: According to the fact that economic justification is highly considerable in buildings' construction and repair, these materials can fulfill the desired conditions for buildings' resistance against possible attacks with minimum price. So according to these factors pre-fabrication level of the building is studied from three aspects which are as follows:

• Blast effect reduction capability

• Construction speed increase capability

• Building reparability.

Results of the survey determined that first one is the least important one and second and third are the most important ones (see Tables 10 and 11).

3.6. Energy management method index

In this regard, this index is studied from three aspects:

• Self-sufficiency of the building in generating energy

• Using national energy network

• Using national energy network and considering emergency

energy generators.

According to the conducted researches, it's obvious that more self-sufficient in generating energy the building, the more sustainable it is and functional continuity in crisis conditions is more desired. Therefore, first and third cases are highly compatible and second one is highly incompatible due to reliance on national energy network and its vulnerability (see Table 12).

Table 9 Results of the questionnaires associated with building decoration index.

Decorations level of the building

Extravagant decorations

Structure as a decorative element

Decorative elements elimination

Blast effect reduction capability

Facilitating crisis management

Immunization to reduce human

casualties

Final score

Compatibility

4.55 2.25 1.59

Very incompatible

5.3 4.55

Incompatible

6.51 7.27 7.75

Very compatible

Table 10 Results of the questionnaires associated with building locating ratio to the ground level index.

Above ground level

Ground level

Underground

Underground-semi

Very incompatible

Incompatible

Very compatible

Compatible

Table 11 Importance of mentioned indices associated with building prefabrication level.

Reparability of Ability to increase Blast effect

the building construction speed reduction capability

7.70 8.44 4.48

Very important Very important Less important

3.7. Building ventilation system index This index is studied from two aspects:

• Blast effect reduction capability

• Functional continuity during crisis condition.

Natural ventilation is proper and affordable in normal conditions and also after crisis, when power-outage is mostly to happen, but during the explosion and possible chemical pollution and blast waves, vulnerability of the building increases. In

Table 12 Results of the questionnaires associated with building prefabrication level.

Considerable indicators Prefabrication level of the building

Constructing the whole Constructing some parts building in place of the building in factory Constructing all parts of the building in factory

Blast effect reduction capability Ability to increase construction speed Reparability of the building Final score 4.55 4.55 3.70 6.92 4.11 6.29 4.04 6.15 4.62 8.48 6.96 7.07

Table 13 Results of the questionnaires associated with energy management index.

Using national energy network and considering emergency energy generators Using national energy network Self sufficiency of the building in generating energy

7.92 Very compatible 3.59 Incompatible 7.81 Very compatible

Table 14 Importance of considerable indices associated with ventilation system in blast-resistant buildings.

Ability to continue operations in crisis Blast effect reduction

situation capability

7.6 5.48

Very compatible Compatible

this condition mechanical ventilation system comes in handy. On the other hand relying on mechanical ventilation is not affordable due to need of electric energy and it's high cost (see Table 13).

Both natural and mechanical ventilation systems have been studied and it was determined that using both systems with each other, leads to high compatibility in explosion crisis management (see Table 14).

3.8. Indices associated with buildings openings axis

Openings are one of the most important factors in explosion crisis of the building and design method of these elements plays a big role in vulnerability level of the building. Thereof, follow-ings should be taken into account:

• Openings placement location to wall surface (C1)

• Sky-lighting ways (C2)

• Openings placement system on wall surface (C3)

• Openings surface ration to wall surface (C4)

• Openings distribution on wall surface (C5)

• Openings placement location ratio to wall height (C6)

• Frame materials of the windows (C7).

The more the number of openings and their areas at the building face, the more waves and quivers would enter the buildings, and then the structures would damage less, but as far as the main aim was to reduce human beings fatality, the prevention of explosive waves and quivers is seriously concerned. So, as shown in Table 16, it could be concluded that among the effective indices in terms of openings, the relation of opening area to the wall area is the most important factor. The next one is sky-lightening method. According to the results, these two factors are as effective as more than 50 percent in designing openings corresponding passive defense (see Table 15).

3.9. Building entrance index

Design method of the entrance plays a big role in reduction of vulnerability. Thereof, following subindices should be taken into account:

• Form of the access to the entrance (Di)

• Functionality (D2)

• Entrance shape and form (D3)

• Entrance placement location ratio to the ground level (D4)

• Number of the building entrances and exits (D5).

In the following table final matrix of pairwise comparison subindices is seen and by analysis of the matrix in Expert Choice software, weight of the subindices has been gathered in Table 2.

Picture4 41: final pairwise comparison matrix associated with building entrance subindices in blast resistant buildings.

According to the obtained result, placement location of the entrance is the most effective criterion in reduction in building

Table 15 Results of the questionnaires associated with ventilation system in building.

Considerable indicators

Ventilation systems in the building

Both systems(natural and mechanical) Mechanical ventilation Natural ventilation

Blast effect reduction capability 5.74

Ability to continue operations in crisis situation 8.59

Final score 7.4

Compatibility level Very compatible

5.14 5.51 5.35

Compatible

4.81 5.55 5.24

Compatible

Table 16 Weight of building openings subindices in blast resistant buildings.

X1 X2 X3 X4 X5 X6 X7

X1 1 0.79 0.85 0.20 0.95 1.01 4.74

X2 1 1.89 0.55 1.50 2.16 6.00

X3 1 030 0.69 1.17 5.80

X4 1 2.95 4.32 7.91

X5 1 1.43 6.54

X6 1 5.91

X7 1

Table 17 Weight of building openings subindices in blast

resistant buildings.

Indicators associated with the Weight and influence

architectural form in blast resistant of each indicator (total

buildings weighted of indicators

is equal to 100)

Opening placement ratio to the surface of 10.4

the wall

Skylighting ways 17.6

Opening placement on wall surface 10.9

Opening area ratio to the wall area 35.8

Openings distribution on wall surface 13.1

Openings placement ratio to the height of 9.7

the wall

Windows frame material 2.5

Table 18 Weight of building openings subindices in blast

resistant buildings.

Di D2 D3 D4 D5

Di 1 1.79 0.95 0.38 0.75

D2 1 0.74 0.33 0.61

D3 1 0.37 0.55

D4 1 1.43

d5 1

Table 20 Weight of building openings subindices in blast

resistant buildings.

E1 E2 E3 E4 E5

E1 1 1.66 4.60 2.84 2.35

E2 1 3.28 1.65 1.27

E3 1 0.40 0.44

E4 1 0.91

E5 1

Table 21 Weight of subindices associated with the materials

used in the blast resistant buildings.

Indicators associated with the Weight and influence of each

materials used in the blast indicator (total weighted of

resistant buildings indicators is equal to 100)

Structural system material used 38.1

in the building

Exterior walls material 23

Interior cutoff walls material 7.1

Facade outer layer material 15.1

Ceiling system of the buildings 16.7

floors

Table 19 Weight of subindices associated with entrances of

the building.

Indicators associated with the Weight and influence of each

building entrance in crisis indicator (total weighted of

condition indicators is equal to 100)

Form of the access to the 15.9

building entrance

Entrance functionality 11.1

Shape of the entrance 14.3

Placement location of the 36.2

entrance to ground level

Number of entrances and exits 22.5

of the building

vulnerability in terrorist attacks. The reason of this choice by experts is importance of the index in blast effect reduction in the entrance part of the building. Number of the entrances, that has positive impact on building evacuation and rescue operation and negative impact on explosion takes the second place in our ranking; Types of the entrance, different in shape and access form take the third and fourth place in the ranking within a hair's breadth and according to the experts functionality subindex takes the last place in the ranking (see Tables 17 and 18).

3.10. Materials used in the building

The materials used in the building play an important role in vulnerability of the building. About effect and role of different materials against blast effects, according to the studies and the

wars happened in recent years, we can categorize this index into three sub categories:

Buildings with damage booster materials: Curtain wall is a good example for damage booster elements in a building. Curtain walls increase vulnerability of the people extremely. The more the height of the wall is, the bigger glass fragments will be. The collapse of the sound barrier will merely cause fatal debris and harmful flying fragments of glass.

Buildings with vulnerable materials: Some of the materials or their combinations do not have the optimal resistance against quivers and blast waves and can get damaged easily during the explosion.

Buildings with less vulnerable materials: Buildings with those solid materials such as concrete or a combination of different materials such as fiber concrete have been used in their facade or structure is more resistant and less vulnerable against explosion.

Thereof, following subindices should be taken into account:

• Type of the Structural system material used in the building

• Exterior walls material (E2)

• Cutoff walls material (E3)

• Facade outer layer material (E4)

• Ceiling system of the building floors (E5).

According to the results, structural system material is the most important criterion and the least important one is interior cutoff walls material (see Tables 19 and 20).

Final pairwise comparison matrix of materials was used in blast resistant buildings.

3.11. Building weight index

This index has been studied from two aspects of blast impact reduction and debris-removal capability, for light weight

Table 22 Importance level of considerable indices associated with weight of the building.

Debris removal capability Blast effect reduction capability

7.88 6.96

Table 23 Results of the questionnaires associated with

building weight index.

Purpose Building weight level

Heavy weight Light weight

building building

Blast effect reduction 7.51 2.92

capability

Debris removal capability 2.59 8.25

Final score 4.89 5.75

Compatibility Incompatible Compatible

Table 24 Results of the questionnaires associated with camouflage design of the building.

Both roof and facade Camouflage design Camouflage

camouflage design of the facade design of the roof

8.22 5.74 6.70

buildings and heavy weight buildings, and it's been determined that, the less the building weighs, the more compatible it is with the aims and principles of the research (see Tables 21 and 22).

3.12. Building camouflage design index

Each criterion of camouflage design and green roof topic is highly compatible when applied hand in hand. One of the proper methods of the camouflage design is using green roof or green facade.

Green roofs or living roofs are partially or completely covered with vegetation instead of common materials such as mosaic and asphalt. In recent decades, this kind of roof has been used in different parts of the world. Using green roof is very efficient in aerial bombardment crisis management and reduction in energy consumption (see Tables 23 and 24).

4. Conclusion

Identifying hazard of possible damages plays a big role in preparation for encountering and defensing the negative impacts of terrorist threats in urban areas. If we study the aspects of terrorist attack hazards and possible damages in a proper way, we can define and expand the level and type of the defense operations against these damages.

The purpose of pathology is identification of facilities and immunization methods of the buildings against military attacks and blast impacts. A bomb explosion within or around a building can have catastrophic effects, damaging and

destroying internal and external portions of the building. It blows out large frameworks, walls, doors and windows. It shuts down building services. The impact from the blast causes debris, fire and smoke and hence can result in injury and death to occupants. Bomb damage to buildings depends on the types and layout of the structure, material used, range of the located explosive device, charge weight and the contents of the bomb.

According to the fact that resistance of a building against blast wave depends on shape and form, number of openings and windows, materials used and their strength, most of the mentioned factors are related to architectural science and knowledge. Hence to evaluate architecture of blast resistant buildings, Delphi method has been used and AHP method has analyzed the results. AHP method is an efficient, low cost, and highly accurate method in the determination of the best and appropriate decision-making choice. This method can be a good model as a management tool with minimal time and cost that provides the best choice among the available options. With the use of the AHP method, this study determined that among all 12 mentioned indices for blast resistant buildings three indices of form, materials and locating ratio to the ground level gain 63% of the importance.

References

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[2] M. Bitarafan, S.B. Hosseini, S.J. Hashemi-fesharaki, A. Esmailzadeh, Role of architectural space in blast-resistant buildings, Front. Architectural Res. (2013).

[3] A. Khairuddin, H. Naderpour, S.R. Hosaini Wae'ez, Evaluation of the effect of architectural form on the way of structural vulnerability, in: The First National Congress of Structure and Architecture, Tehran, 2007.

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[7] M. Araghizadeh, Requirements and considerations of architectural design of administrative buildings from the perspective of passive defense Thesis of MA, Industrial University of Malek Ashtar, 2011.

[8] B.M. Luccioni, R.D. Ambrosini, R.F. Danesi, Failure of a reinforced concrete building under blast loads, WIT Trans. Eng. Sci. 49 (2005).

[9] M. Mojtahed-Pour, The influences of the shape of instruction on stress distribution from eruptive loading, University of Khalige Fars-the educational research institution of defensive crafts, Engineering Faculty, 2009.

[10] B. Hovaidafar, Theoretical principles of shelters' entrance and exit with the perspective of passive defence, MSc thesis, 2007.

[12] M. Da"gdeviren, Decision making in equipment selection: an integrated approach with AHP and PROMETHEE, J. Intell. Manuf. 19 (2008) 397-406.

[13] M.M. Fouladgar, A. Yazdani-Chamzini, E.K. Zavadskas, An integrated model for prioritizing strategies of the Iranian mining sector, Technol. Econ. Dev. Econ. 17 (3) (2011) 459-484.

[14] M. Medineckiene, Z. Turskis, E.K. Zavadskas, Sustainable construction taking into account the building impact on the environment, J. Environ. Eng. Lands. Manage. 18 (2) (2010) 118-127.

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[17] R.H. Carver, J.G. Nash, Doing data analysis with SPSS version 18, Cole Cengage Learning, 2009.

[18] A.A. Pouri Rahim, M. Bitarafan, Sh. Lale Arefi, Evaluation of types of shapes of building roof against explosion, in: International Conference on Civil Engineering and Architecture, China, 2012.

[19] M. Bitarafan, S. Hashemkhani Zolfani, S.L. Arefi, E.K. Zavadskas, Evaluating the construction methods of cold-formed steel structures in reconstructing the areas damaged in natural crises, using the methods AHP and COPRAS-G, Arch. Civ. Mech. Eng. 12 (3) (2012) 360-367.

[20] S. Dermisi, Terrorism protection and prevention measures for office buildings, J. Real Estate Literature 14 (2) (2006) 59-86.

[22] B. Nadel, Building Security—Handbook for Architectural Planning and Design, McGraw Hill, 2004.

Further reading

[11] M. Bitarafan, Design and documentation of entrances and relevant components in secure spaces and their modeling in 3D-Max software Research project, Malek Ashtar University, 2011.

[21] American Institute of Architects, Security Planning and Design—A Guide for Architects and Building Design Professionals, John Wiley, 2004.

[23] Multiple FEMA and GSA unclassified documents could be included (http://www.fema.gov/media-library/assets/ documents/13311?id = 3270, etc.).

 

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