Attachment_3_-_UFC_4-022-22_(9_Aug_10).pdf

UFC 4-022-02

8 June 2009

Change 1, 9 August 2010

UNIFIED FACILITIES CRITERIA (UFC)

SELECTION AND APPLICATION OF

VEHICLE BARRIERS

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

SELECTION AND APPLICATION OF VEHICLE BARRIERS

Any copyrighted material included in this UFC is identified at its point of use.

Use of the copyrighted material apart from this UFC must have the permission of the copyright holder.

U.S. ARMY CORPS OF ENGINEERS

NAVAL FACILITIES ENGINEERING COMMAND (Preparing Activity)

AIR FORCE CIVIL ENGINEER SUPPORT AGENCY

Record of Changes (changes are indicated by \1\ ... /1/)

Change No. Date Location 1 August 9, Revisions throughout Document: Deleted Appendix B – List of Manufacturers; revised document text and appendices accordingly.

This UFC supersedes MIL-HDBK-1013/14, dated 1 February 1999.

FOREWORD

The Unified Facilities Criteria (UFC) system is prescribed by MIL-STD 3007 and provides planning, design, construction, sustainment, restoration, and modernization criteria, and applies to the Military Departments, the Defense Agencies, and the DoD Field Activities in accordance with USD(AT&L) Memorandum dated 29 May 2002. UFC will be used for all DoD projects and work for other customers where appropriate. All construction outside of the United States is also governed by Status of Forces Agreements (SOFA), Host Nation Funded Construction Agreements (HNFA), and in some instances, Bilateral Infrastructure Agreements (BIA.)

Therefore, the acquisition team must ensure compliance with the more stringent of the UFC, the SOFA, the HNFA, and the BIA, as applicable.

UFC are living documents and will be periodically reviewed, updated, and made available to users as part of the Services’ responsibility for providing technical criteria for military construction. Headquarters, U.S. Army Corps of Engineers (HQUSACE), Naval Facilities Engineering Command (NAVFAC), and Air Force Center for Engineering and the Environment (AFCEE) are responsible for administration of the UFC system. Defense agencies should contact the preparing service for document interpretation and improvements.

Technical content of UFC is the responsibility of the cognizant DoD working group.

Recommended changes with supporting rationale should be sent to the respective service proponent office by the following electronic form: Criteria Change Request. The form is also accessible from the Internet sites listed below.

UFC are effective upon issuance and are distributed only in electronic media from the following source:

• Whole Building Design Guide web site http://dod.wbdg.org/.

Hard copies of UFC printed from electronic media should be checked against the current electronic version prior to use to ensure that they are current.

JAMES C. DALTON, P.E.

Chief, Engineering and Construction U.S. Army Corps of Engineers

JOSEPH E. GOTT, P.E.

Chief Engineer Naval Facilities Engineering Command

PAUL A. PARKER

The Deputy Civil Engineer DCS/Installations & Logistics Department of the Air Force

MICHAEL McANDREW Director, Facility Investment and Management Office of the Deputy Under Secretary of Defense (Installations and Environment) http://www.wbdg.org/pdfs/ufc_implementation.pdf� http://dod.wbdg.org/�

NEW DOCUMENT SUMMARY SHEET

Document: UFC 4-022-02, Selection and Application of Vehicle Barriers Superseding: Military Handbook 1013/14, Selection and Application of Vehicle Barriers

Description: Provides a unified approach for the design, selection, and installation of active and passive vehicle barriers associated with Department of Defense (DoD) facilities. The examples provided in this UFC are for illustration only and shall be modified and adapted to satisfy installation specific constraints. This UFC is not intended to address procedural issues such as threat levels or to provide specific design criteria such as impact forces.

This UFC was developed by consolidating and refining criteria from USACE Protective Design Center, Security Engineering Working Group (SEWG); Naval Facilities Engineering Command (NAVFACENGCOM), Engineering Criteria Office, Engineering Service Center and available military, government, and commercial sources\1\ /1/.

Commanders, security and antiterrorism personnel, planners, designers, architects, and engineers should use this UFC when evaluating existing and providing new vehicle barriers. Technical information considered generally known to professional designers, architects, engineers, or readily available in technical references (UFC, Military Handbooks, Technical Manuals, etc.) has not been included.

Reasons for Document: Vehicle barriers are primarily used as one of many elements that define perimeters that require a final denial barrier to be provided for certain restricted areas. This UFC focuses of the design, selection, and application of active and passive vehicle barriers.

Impact: The following direct benefits will result:

• A standardized approach for identifying and justifying security and antiterrorism design criteria for DoD facilities;

• A standardized nomenclature and criteria for asset, threat, and level of protection definition;

• A standardized procedure for identifying costs for DoD facilities with security and antiterrorism requirements to a planning level of detail;

• A standardized process for evaluating design criteria and protection options based on cost and risk management;

• Guidance for incorporating security and antiterrorism principles into installation master planning; and

• There are no adverse impacts on environmental, sustainability, or constructability policies or practices.

CHAPTER 1 - INTRODUCTION

1-1 PURPOSE.

This UFC provides the design requirements necessary to plan, design, construct, and maintain vehicle counter-mobility barriers used within Entry Control Facilities (ECF) or as perimeter protection. This UFC is to be used during the design of Department of Defense (DoD) facilities to ensure an optimal vehicle barrier system is selected by engineers and security personnel for a specific operation within an installation. Barrier performance, maintenance, and cost should all be optimized. It is intended to establish consistent requirements, standards, and design basis for barrier planning, design, construction, and maintenance for all military departments. This UFC identifies design features necessary to ensure that infrastructure constructed today will have the flexibility to support future technologies, a changing threat environment, and changes in operations.

1-2 INTRODUCTION.

A vehicle barrier selection and placement process is presented herein, along with criteria for the design, selection, installation, operation, and maintenance of security barrier systems. The selected barrier system must effectively stop and/or disable vehicles that pose a threat, including explosive laden vehicles, of breaching the perimeter of a protected area. Both passive (static or non-movable) perimeter barriers and active (operational for access control) barriers at facility entrances are included.

The examples presented in this UFC are for illustration purposes only and should be modified and adapted to satisfy installation specific constraints. This UFC is not intended to address procedural issues such as tactics and techniques; however, an appropriately designed vehicle barrier system used within an ECF/ACP or along an installation perimeter can enhance and improve operations.

1-3 BACKGROUND.

Guidance and documentation regarding issues of vehicle barriers and vehicle counter-mobility design are provided within the joint military services. Each document presents useful information to engineers, planners, architects, and security personnel responsible for Entry Control Facilities (ECFs) and Access Control Points (ACPs), both existing and new facility construction involving vehicle barriers and counter-mobility techniques.

Until now, there has been no single DoD document that provides all the information required for vehicle barrier design. This UFC, in conjunction with UFC 4-022-01 for Entry Control Facilities/Access Control Points, establishes consistent standards and requirements for each military service branch. The UFC supplements and is referenced by the Security Engineering Facility Planning Manual (UFC 4-020-01) and the Security Engineering Facility Design Manual (UFC 4-020-02). The design of a vehicle barrier system should begin with planning as directed in UFC 4-020-01, then graduate to design guidance provided in UFC 4-020-02, then culminate with selection and installation of a barrier system using this UFC.

1-4 SCOPE AND USE OF GUIDANCE.

Commanders, security personnel, planners, designers, and engineers should use this UFC when designing vehicle barrier systems for ECFs or other perimeter locations.

Technical information considered generally known to professional designers or engineers or readily available in existing technical references (Unified Facility Criteria, Military Handbooks, Technical Manuals, etc.) has not been included.

1-5 SECURITY ENGINEERING UFC SERIES.

This UFC is one of a series of security engineering Unified Facilities Criteria documents that cover minimum standards, planning, preliminary design, and detailed design for security and antiterrorism. The manuals in this series are designed to be used sequentially by a diverse audience to facilitate development of projects throughout the design cycle. The manuals in this series include the following:

a. DoD Minimum Antiterrorism Standards for Buildings. UFC 4-010-01 DoD Minimum Antiterrorism Standards for Buildings and UFC 4-010-02 DoD Minimum Antiterrorism Standoff Distances for Buildings establish standards that provide minimum levels of protection against terrorist attacks for the occupants of all DoD inhabited buildings. Those UFC are intended to be used by security and antiterrorism personnel and design teams to identify the minimum requirements that must be incorporated into the design of all new constructions and major renovations of inhabited DoD buildings. They also include recommendations that should be, but are not required to be, incorporated into all such buildings.

b. Security Engineering Facilities Planning Manual. UFC 4-020-01 Security Engineering Facilities Planning Manual presents processes for developing the design criteria necessary to incorporate security and antiterrorism into DoD facilities and for identifying the cost implications of applying those design criteria. Those design criteria may be limited to the requirements of the minimum standards, or they may include protection of assets other than those addressed in the minimum standards (people), aggressor tactics that are not addressed in the minimum standards or levels of protection beyond those required by the minimum standards. The cost implications for security and antiterrorism are addressed as cost increases over conventional construction for common construction types. The changes in construction represented by those cost increases are tabulated for reference, but they represent only representative construction that will meet the requirements of the design criteria. The manual also includes a means to assess the tradeoffs between cost and risk. The Security Engineering Planning Manual is intended to be used by planners as well as security and antiterrorism personnel with support from planning team members.

c. Security Engineering Facilities Design Manual. UFC 4-020-02 Security Engineering Facilities Design Manual provides interdisciplinary design guidance for developing preliminary systems of protective measures to implement the design criteria established using UFC 4-020-01. Those protective measures include building and site elements, equipment, and the supporting manpower and procedures necessary to make them all work as a system. The information in UFC 4-020-02 is in sufficient detail to support concept level project development, and as such can provide a good basis for a more detailed design. The manual also provides a process for assessing the impact of protective measures on risk. The primary audience for the Security Engineering Facility Design Manual is the design team, but it can also be used by security and antiterrorism personnel.

d. Security Engineering Support Manuals. In addition to the standards, planning, and design UFC mentioned above, there is a series of additional UFC that provide detailed design guidance for developing final designs based on the preliminary designs developed using UFC 4-020-02. These support manuals provide specialized, discipline specific design guidance. Some address specific tactics such as direct fire weapons, forced entry, or airborne contamination. Others address limited aspects of design such as resistance to progressive collapse or design of portions of buildings such as mailrooms.

Still others address details of designs for specific protective measures such as vehicle barriers or fences. The Security Engineering Support Manuals are intended to be used by the design team during the development of final design packages.

CHAPTER 2 - EXISTING REQUIREMENTS AND TECHNICAL GUIDANCE

2-1 GENERAL.

This UFC should be used in conjunction and coordination with UFC 4-020-01 Security Engineering Facilities Planning Manual, UFC 4-020-02 Security Engineering Facilities Design Manual, UFC 4-022-01 Security Engineering: Entry Control Facilities/Access Control Points, and UFC 4-022-03 Security Engineering: Fences, Gates and Guard Facilities to guide the user through a selection process to establish a protective barrier system around a DoD installation and designated restricted areas within the installation (enclave areas). A systematic approach is used. The main issues to be considered during the selection and design of a vehicle barrier include:

a. Threat Analysis – to quantify the potential threat. For threat analysis, refer to UFC 4-020-01 Security Engineering Facilities Planning Manual and UFC 4- 020-02 Security Engineering Facilities Design Manual. The procedures in these manuals will quantify and qualify all potential threats, including the “moving” vehicle bomb threat necessary for the determination of the appropriate vehicle barrier for a given location.

b. Performance – to determine the appropriate levels of protection (both to personnel and property). An acceptable level of protection must be defined by the installation commander.

c. Access Control Measures – physical controls, operating procedures, hardware and software features used in various combinations to allow, detect, or prevent access.

d. Requirements – appropriate standoff distance to maintain a level of protection compatible with operational needs; passive or active barrier systems to stop the threat vehicle; barrier reliability and maintainability, safety, sabotage and malfunction protection, and cost effectiveness.

e. Response – potential structural damage to the vehicle barrier from blast loads produced during an explosion.

f. Liabilities – potential liability effects on the decision to protect assets against the effects of a terrorist act.

g. Cost – security expenditures based on the value of the asset to be protected and the importance of the asset to national security and readiness. For protection against vehicle bombs, the potential loss of human life generally drives the cost of security, overriding the value of the property to be protected. The decision to use vehicle barriers and provide protection against terrorist vehicle bombs is primarily motivated by protection of personnel.

2-2 DOD REQUIREMENTS. There are several instructions and publications within the Department of Defense that establish access control, physical security, and antiterrorism requirements for the Department of Defense installations and restricted areas.

2-2.1 DOD 5200.8-R Physical Security Program.

This regulation requires DOD Components to determine the necessary access control based on the requirements of a developed physical security program. Emergency planning is specified to include establishment of a system for positive identification of personnel and equipment authorized to enter and exit the installation and maintenance of adequate physical barriers that will be deployed to control access to the installation.

Planning will also include increasing vigilance and access restrictions during higher force protection conditions

2-2.2 DOD 2000.12 DOD Antiterrorism (AT) Program.

This directive provides DOD policies for ATFP and assigns responsibilities for implementing the procedures for the DOD ATFP Program. It authorized the publication of DOD O-2000.16 as the DOD standards for ATFP and DOD O-2000.12-H DOD Antiterrorism Handbook as guidance for the DOD standards. DOD O-2000.12H defines the DOD Force Protection Condition (FPCON) System, which describes the potential threat levels and the applicable FPCON measures to be enacted for each level. It also requires Commanders to develop and implement Random Antiterrorism Measures (RAM) as an integral part of their AT Program.

2-2.3 DOD 2000.16 DOD Antiterrorism Standards.

This instruction and service directives require the installation or activity Commanding Officer to define the access control measures at installations. Additionally DOD

2000.16 requires Commanders at all levels to develop and implement a comprehensive Antiterrorism (AT) Program, which should define the necessary action sets, including identification and inspection procedures, at each of the potential Force Protection Condition (FPCON) levels.

2-3 COMBATANT COMMANDER REQUIREMENTS

Combatant Commanders issue requirements for Antiterrorism and physical security for installations within their area of responsibility. Ensure any such requirements are incorporated in addition to the requirements found in this UFC

2-4 ADDITIONAL REFERENCES.

Other documents, drawings, and publications that could contribute to the guidance provided in this UFC are listed below.

PDC-TR90-2 Barrier Impact Response Model 3

Dimension (BIRM 3D)

SD-STD-02.1, Revision A Specification for Vehicle Crash Test of

Perimeter Barriers and Gates

UFGS 34 71 13.19 Unified Facilities Guide Specification, Active Vehicle Barriers

UFGS 12 93 00 Unified Facilities Guide Specification, Site Furnishings

ASTM F 2656-07 Standard Test Method for Vehicle Crash Testing of Perimeter Barriers

Means, R.S., “Building Construction Cost Data”, 61st Edition, 2003 (Copies can be ordered from the R.S. Means website: http://www.rsmeans.com)

2-5 REFERENCE WEBSITES.

Copies of many of the documents referenced in this chapter can be obtained from the following websites.

a. Whole Building Design Guide web site http://www.wbdg.org/references/pa_dod.php (See Service Specific information on the right hand side of the website.)

b. United States Army Corps of Engineers (USACE), Protective Design Center, Omaha District https:/pdc.usace.army.mil/library/drawings/acp http://www.wbdg.org/references/pa_dod.php� https://pdc.usace.army.mil/library/drawings/acp�

CHAPTER 3 - DEFINITIONS

3-1 ACRONYMS.

The acronyms used in this UFC are defined below.

a) BDAM - Blast Damage Assessment Model

b) CCTV - Closed-Circuit Television

b) DOD - Department of Defense

c) DODISS - DOD Index of Specifications and Standards

d) DOS - Department of State

e) ERASDAC - Explosive Risk and Structural Damage Assessment Code

f) FACEDAP - Facility and Component Explosive Damage Assessment Program

g) FRF - Fragment-Retention Film

h) MIL-HDBK - Military Handbook

i) NAVFAC - Naval Facilities Engineering Command

j) NFESC - Naval Facilities Engineering Service Center

k) PDC - Protective Design Center

CHAPTER 4 - VEHICLE BARRIER DESIGN PARAMETERS

4-1 GENERAL.

Vehicles loaded with explosives can detonate as a large bomb, inflicting severe damage on critical military facilities and potentially injuring DoD personnel. Such vehicle bombs are effective terrorist tools because they facilitate the transport of large quantities of explosives to any desired location. When planning and selecting vehicle barriers to be used for facility perimeter protection, the first step is to determine the Design Basis Threat (DBT) for any given location in the facility. Table B-1 provides active vehicle barrier kinetic energy rating and vehicle penetration based on the SD-STD-02.1 Revision A test standard. The DBT may vary within and around the installation. It can be affected by guidance instructions specific to the area and service specific guidance.

UFC 4-010-01 DoD Minimum Antiterrorism Standards for Buildings, as well as local and service specific guidance documents, should be consulted in defining Design Basis Threats at each location where barriers are required.

Several factors should be considered when setting up defense against the DBT: (1) the occupied structures in a particular area; (2) the barrier penetration capabilities of the DBT vehicle (based on the maximum vehicle velocity to the barrier location, the angle of impact, and the area around the barrier location); and (3) the structural response of and potential debris throw from the barrier, if the vehicle bomb detonates.

Both stationary and moving vehicle bombs need to be considered. To effectively prevent a moving vehicle from getting close to the intended target, the perimeter barrier must absorb the kinetic energy produced by the total weight of the vehicle bomb (vehicle weight plus the weight of explosives and any other cargo in the vehicle) and the vehicle’s maximum attainable speed at the point of impact. Thus, kinetic energy is a primary factor used to establish performance requirements for moving vehicle barriers.

Another primary consideration for either stationary or moving vehicle bombs should be the barrier’s response to the load produced by detonation of the explosives in the vehicle. The amount of debris produced and subsequent debris throw distance should also factor into the selection of appropriate barriers.

4-2 SITE SURVEY.

The process of selecting and designing a barrier system begins with determination of the Design Basis Threat (DBT) and required levels of protection. Reference UFC 4- 020-01, Security Engineering Facilities Planning Manual and UFC 4-020-02, Security Engineering Facilities Design Manual for methods to determine the DBT and levels of protection. Next, preparations are made for a site survey. First, a scaled map of the protected area must be prepared from detailed plans of the facility that must include at least one block beyond the perimeter. This map should include the relative locations, major dimensions and descriptions of structures, roads, terrain and landscaping, existing security features, and property perimeter. Any features outside the perimeter (within one block or so) that could possibly be used to reduce vehicle speed, prevent access to the perimeter barrier, shield structures from damage in the event of an explosion, or affect an aggressor’s progress in any other way should be shown on the site map as well. This map will permit careful analysis of distances and topographical features between the perimeter and the facility. The map identifies potential vulnerabilities. Due to the information included on any such site map, it may need to be a classified document. Figure 4-1 shows an example site map for a facility.

As shown in Figure 4-1, the individual segments of the perimeter can be attacked from a variety of paths. For example, for Building 827 with a controlled area on two sides of the perimeter, the two remaining sides (Perimeter Roads “A” and “B”) are vulnerable to a vehicle attack. The Entrance Road and the extension of Perimeter Road “B" are perpendicular and lead directly to the compound boundary. Each of these roads is a potential attack path. Certain segments of the perimeter can be attacked from more than one street. In addition, for Perimeter Roads “A” and “B”, running parallel to the perimeter, there are an infinite number of impact points and angles depending upon vehicle location and speed. As a result, a large number of potential impact conditions (the combination of vehicle speed and impact angle) can occur at any point along the perimeter boundary.

Figure 4-1 Example Site Layout

NORTHNORTH

4-3 INTEGRATED PHYSICAL SECURITY SYSTEM.

Any vulnerabilities identified in the site survey should be addressed by developing an integrated physical security protection system. Design Basis Threats identified for the specific facility and current security requirements need to be considered. These threats are determined by assessment of site-specific threats or are specified by an installation.

Comprehensive protection can be provided by coordinating physical barriers (such as fences, active barriers, and passive barriers) with other security components and options. For example, perimeter sensors, lights, and closed circuit television can be used to detect vehicles attempting to covertly penetrate the perimeter. Sallyports can be used to detect bombs hidden in vehicles entering a facility. Performance of the perimeter barrier can be enhanced with strategic placement of bollards, ditches, and planters. A wide range of potential threats can be detected early using clear zones as well. All barrier requirements should be coordinated with the ECF design guidance given in UFC 4-022-01 Security Engineering: Entry Control Facilities/Access Control Points. Figure 4-2 illustrates some examples of integrated physical security measures.

Figure 4-2 Integrated Physical Security System

4-4 ATTAINABLE VEHICLE SPEED.

The speed of a vehicle at the point of impact on a vehicle barrier is a major parameter in determining the required performance of the barrier. The impact is calculated from the initial speed, “v”, the acceleration rate, “a”, and the distance, “s”, available for acceleration between the starting point and the point of impact. Additional factors that must be considered are the general terrain, the surface condition of the path, whether or not the path is straight, curved, or banked. Information presented in Figure 4-1 through Figure 4-7 allows calculation of maximum attainable vehicle speed, or suggests strategies for modifying possible attack paths to control vehicle speed.

The impact speed along the perimeter should be calculated for all possible driving paths identified on the site survey map. The strategy for barrier system design, selection, and installation can then be developed using this data.

The methods presented in this section for determining attainable vehicle speeds assume flat roadway surfaces. Most roadways are not flat, either due to super-elevation or to typical roadway crowning and constructed transverse slopes. If a driver can use a non-flat roadway surface to his advantage in attaining a higher speed, this needs to be taken into consideration. The use of any geometrics in the selection of barriers and design of an ECF should only be provided under the guidance of an engineer experienced in roadway/transportation engineering. Otherwise, some of the assumptions for the methods in this section may be highly conservative and may lead to designs that are treacherous for vehicles traveling at normal/design speeds, for vehicles traveling during wet conditions, or for large commercial and emergency vehicles.

Consult with the AASHTO Roadside Design Guide and AASHTO Geometric Design of Highways and Streets for roadway design and road geometry/geometric requirements.

4-4.1 Attainable Vehicle Speed on a Straight Path.

The highest attainable vehicle speed results from a long, straight path between the starting point and a vehicle barrier.

a) On a Horizontal Surface. On a horizontal, straight path, the speed attainable by an accelerating vehicle depends primarily on its initial speed, “v0”, the acceleration, “a”, and the distance, “s”, traveled during acceleration. The relationship among these parameters is given in Equation (1).

v = (v0 2 + 2as)1/2 (1) where:

v = final vehicle speed (mph or kph) v0 = initial vehicle speed (mph or kph) a = acceleration (ft/sec2 or m/sec2) s = distance traveled (feet or meters)

For convenience, Equation (1) is plotted as Figure 4-3, using a conversion factor for values in ft/sec2 and mph.

Figure 4-3 Vehicle Speed vs. Acceleration Distance

To illustrate its use, consider the case of a high performance car accelerating on a 300-ft (91.5 m), straight, horizontal path with initial speed, v0 = 25 mph (15.53 kph), and acceleration, a = 11.3 ft/sec2 (3.4 m/sec2). The speed at the end of the path will be determined as follows:

Locate v0 = 25 mph (15.53 kph) on the vertical axis (point A).

Draw a horizontal line from point A until it intersects the curve (at point B) for a =

11.3 feet per second2 (3.4 m/sec2).

Draw a vertical line down from point B until it intersects the horizontal axis (point C). This is the point from which velocity will be calculated.

Locate point D on the horizontal axis so that the distance between points C and D is the accelerating distance [300 feet (91.5 m) in this example].

Draw a vertical line up from point D until it intersects the curve (at point E) for a =

11.3 ft/sec2 (3.4 m/sec2).

Draw a horizontal line from point E until it intersects the vertical axis (point F).

The value of the speed, “v”, at point F, 61.5 mph (98.97 kph), is the answer.

Note: If “v0” = 0, the graph can be used to determine velocity from a dead start.

b) On a Slope. Due to gravitational effect, to achieve the same final speed as that on a horizontal path, the required distance for acceleration on a slope will be shorter (longer) if the vehicle is traveling downhill (uphill). Let, “s”, be the acceleration distance needed to also attain final speed, “v”, on a horizontal path, and let, “s'”, be the acceleration distance needed to attain, “v”, on a sloped path. The following relationship shown in Equation (2) applies:

s'/s = 1/[1 + (g/a)sinθ] (2) s' = acceleration distance needed to attain final speed on a sloped path s = acceleration distance needed to attain final speed on a horizontal path g = gravitational constant = 32.2 ft/sec2 (9.82 m/sec2) a = acceleration of the vehicle, ft/sec2 θ = angle between the slope and the horizontal in degrees

This correction factor relationship is plotted as Figure 4-4.

Figure 4-4 Speed Correction Factor for Vehicles Driving on a Sloped Path

To illustrate the use of this figure, consider the example used in 4-4.1a, except the vehicle is traveling downhill on a 5-degree slope. The steps are:

Locate 5 degrees on the horizontal axis (point A).

Draw a vertical line up from point A until it intersects the curve (at point B) for a =

11.3 ft/sec2 (3.4 m/sec2).

Draw a horizontal line from point B toward the vertical axis and read off the “s'/s” value at the intersecting point C.

The value of s'/s is 0.8. Because s' = s x (s'/s) and s = 300 feet (91.5 m), therefore s' = 300 feet (91.5 m) x 0.8 = 240 feet (73.2 m).

This example shows that to accelerate the vehicle to the same 61.5 mph speed (98.97 kph), a 5-degree slope will help shorten the accelerating distance from 300 feet (91.5 m) to 240 feet (73.2 m). It clearly demonstrates the increased vulnerability caused by local terrain sloping down toward a protected area. Modifying the local terrain is an effective way to minimize vulnerability.

4-4.2 Attainable Vehicle Speed on a Curved Path.

Centrifugal force makes it difficult to drive fast on a curve unless the road surface is properly banked. The centrifugal force, “CF”, of a vehicle moving on a curved path depends on its weight, “w”, the radius of the curvature, “r”, and the speed, “v”, and g = gravitational constant = 32.2 ft/sec2 (9.82 m/sec2), as shown in Equation (3).

CF = wv2 /(gr) (3)

CF = centrifugal force (lbs/kgs) W = vehicle weight (lbs/kgs) r = radius of curvature (feet/meters) v = vehicle speed (mph/kph) g = gravitational constant = 32.2 ft/sec2 (9.82 m/sec2)

When the “CF” is large enough, it will overcome the road friction and a vehicle will skid.

The vehicle could also topple if its center of gravity is too high. Because skidding usually occurs first, only this condition will be considered here. Road friction force, “FF,” equals the product of the vehicle weight, “w,” and the friction coefficient, “f,” between the tires and the road surface, as shown in Equation (4).

FF = fw (4)

FF = road friction force f = friction coefficient w = vehicle weight

NOTE: The value of friction coefficient, “f”, is between 0 and 1 and is highly variable. It depends on the tire and its condition, the material and condition of the drive path, any oil or water on the drive surface, etc. On a roadway, under normal conditions, f = 0.6 is usually used. If unable to determine, use f = 1, which will provide a more conservative value.

a) On a Horizontal Surface. The skidding speed (the speed at which skidding occurs), “vS”, is obtained by equating the centrifugal force and the road friction force, as shown in Equations (5) and (6).

fw = w vS 2 /(gr) (5) w = vehicle weight vS = skidding speed g = gravitational constant r = radius of curvature

From which, vS = fgr (6) vS = skidding speed g = gravitational constant = 32.2 ft/sec2 (9.82 m/sec2) r = radius of curvature

Because “v” must be made as small as possible for the most cost-effective protection, this relationship suggests that options for the physical security planner include making the drive path slippery, with a small radius of curvature, or both. The above relationship is plotted as Figure 4-5, using “f” as a parameter using a conversion factor for values in ft and mph.

Figure 4-5 Skid Speed vs. Radius of Curvature

Using this figure, with a chosen value of “f” (see previous Note) and the tolerable vehicle impact speed of the selected barrier, a curved path can be designed to cause any vehicle driving above that velocity to skid.

b) On a Slope. Unlike a straight downhill path (see Paragraph 4-4.1), a curved downhill path is actually effective in deterring vehicle attacks. This is because the extra velocity gained from traveling downhill can easily cause the vehicle to skid or topple. Therefore, if a protected area has downhill approach paths, the local terrain can be modified so that a straight driving path is impossible. Caution should be exercised when designing roads to decrease velocity. Posting speed restrictions along the path is strongly recommended to reduce the possibility of accidental skidding.

To determine the final velocity at the end of a curved path, use the length of the curved path as the acceleration distance in Figure 4-3 and as the acceleration distance needed to attain final speed on a horizontal path (s) in Figure 4-3. Figure 4-4 can then be used to determine the velocity at which the vehicle will skid.

4-4.3 Attack Routes Parallel to the Barrier.

A reduction in energy transferred to a barrier can be accomplished by forcing a vehicle to make an abrupt (short radius) turn before impacting the barrier. Short radius turns effectively reduce vehicle speed by forcing the vehicle to slow down to avoid skidding, reducing the load transfer if the impact angle is less than 90 degrees to the barrier.

Thus, the amount of energy that must be absorbed by a perimeter barrier depends on the impact angle, see Figure 4-1, perimeter roads A and B for a graphical representation of this angle of impact) and the final speed of the vehicle at impact. The load transferred to the barrier is determined by the perpendicular component of the velocity. By using Figure 4-6 and Figure 4-7, the impact angle directed toward the barrier, based on the offset distance (distance between restricting barriers, i.e., the distance between curbs or barriers that will limit the available turning radius), can be determined. These figures are based on the formulas provided in Paragraphs 4-4.2 and 4-4.3. Figure 4-6 and Figure 4-7 show the impact angle versus speed for a given offset distance for friction factors f = 0.5 and f = 0.9. The curves can be used to determine the angle of impact, “θ”, knowing the values of the friction coefficient, “f”, speed at the start of the turn, “v”, and the offset distance available.

Once the angle of impact is determined from Figure 4-6 and Figure 4-7, the speed component perpendicular to the barrier, “Vp”, can be calculated using Equation (7), where “sinθ” is the correction factor.

Vp = v sinθ (7)

Vp = speed component perpendicular to barrier V = speed at start of turn θ = angle of impact

Figure 4-6 Correction Factor for Vehicle Traveling Parallel to Barrier (Based on Coefficient of Friction, f = 0.5)

Figure 4-7 Correction Factor for Vehicle Traveling Parallel to Barrier (Based on Coefficient of Friction, f = 0.9)

For convenience, Table 4-1 provides a correction factor for “Vp” based on the speed of the vehicle at the beginning of the turn, the offset distance available for negotiating the turn, and a friction coefficient f = 1.0 (the most conservative value). Thus, “Vp” is calculated by multiplying the initial speed of the vehicle by the correction factor from Table 4-1.

Table 4-1 Speed Correction Factor for a Vehicle Traveling Parallel to Barrier (Based on Friction Coefficient = 1.0)

Speed of Vehicle in mph (kph)→

(32)

(48)

(64)

(80)

(97)

(113)

(129)

Max. Radius of Curve @ f=1.0 ft (m)→

(8)

(18)

(33)

(51)

(73)

(100)

(56)

Offset Distance in ft (m) ↓

10 (3.1) 0.616 0.559 0.438 0.342 0.292 0.242 0.208 20 (6.2) 0.966 0.743 0.588 0.470 0.407 0.342 0.309 30 (9.3) 1.0 0.866 0.707 0.547 0.485 0.423 0.375 40 (12.4) 1.0 0.946 0.788 0.656 0.559 0.470 0.423 50 (15.3) 1.0 0.988 0.848 0.707 0.616 0.545 0.470 60 (18.3) 1.0 1.0 0.899 0.766 0.656 0.588 0.515 70 (21.4) 1.0 1.0 0.940 0.809 0.707 0.629 0.545 80 (24.4) 1.0 1.0 0.966 0.867 0.743 0.656 0.574

4-5 VEHICLE KINETIC ENERGY.

The kinetic energy of a moving vehicle is measured by its weight and speed, calculated as shown in Equation (8).

KE (ft-lbf) = 0.0334 wv2 (8) KE (kgf-m) = 0.0039 wv2

KE = kinetic energy in ft-lbs force (kgf-m) W = vehicle total weight in lbs (kg) V = vehicle speed in mph (kph)

A vehicle must have a certain amount of kinetic energy to penetrate perimeter security barriers. The vehicle must penetrate these barriers to inflict damage on a protected facility. Since kinetic energy is a function of vehicle weight and speed, a heavy vehicle moving slowly and a lighter vehicle moving fast could have the same kinetic energy.

Kinetic energy for 4,000-lb and 15,000-lb vehicles, traveling at various speeds, is shown in Table 4-2. Once the kinetic energy of the vehicle has been determined, active and passive barriers that are capable of stopping the vehicle can be selected from the information contained in Chapters 5 and 6.

In some cases (with dead men, bollards, cabled concrete tee walls or chained vehicles etc.) some of these being unique expeditionary uses based on available material there may be a requirement for the design of system of barriers other than those listed herein.

Those cases may require the computation of an impact force to design that system. An impact force is a high force or shock applied over a short time period. Since force is the product of mass times acceleration for a mass m accelerating at an acceleration, then assuming an ideal system, we can set the impact force as, mass times the difference in velocity for a time interval dt. (F= mXdv/dt)

For example, a car that weighs 1 kg moving at 500 m/s and that hits a 'perfect' steel barrier where it uniformly decelerates from 500 m/s to 0 m/s in .02 seconds, has an approximate impact force of 25000 N. Thus, a body, which decelerates more quickly, has a greater effective impact force than one that decelerates more slowly.

Table 4-2 Kinetic Energy Developed by Vehicle, ft-lbf (kgf-m) x 1,000

Speed of Vehicle in mph (kph)

Vehicle Weight in lbs

(kg) ↓

(16)

(32)

(48)

(64)

(80)

(97)

(113)

4,000-lb (1,818 kg) Vehicle

(2)

(7)

(17)

(29)

(46)

(66)

(90)

15,000-lb (6,818 kg) Vehicle

(7)

(28)

(62)

(111)

1,253 (173)

1,804 (249)

2,455 (339)

CHAPTER 6 - ACTIVE AND PASSIVE BARRIERS

6-1 ACTIVE BARRIER SYSTEMS.

Commercially available active vehicle barrier systems are presented in this section as generic representations. Inclusion of any equipment in this section does not constitute an endorsement, nor is this a complete listing of vehicle barriers that are commercially available. The equipment shown here is for illustration purposes only. Selection of a specific barrier should be based on site conditions and results of the design, selection, and installation checklist provided in Chapter 5. Results of this checklist can be used to establish cost, operational, performance, and environmental requirements. The checklist results can also be used to select the optimum active and passive barriers from those presented in this section. Users are advised to consult with manufacturers on current and more detailed information regarding products and options available. \1\ /1/ See United States Army Corps of Engineers (USACE), Protective Design Center, Omaha District (https://pdc.usace.army.mil/library/BarrierCertification for latest versions of DoS and DoD certified anti-ram vehicle barriers. Currently barriers are being tested to be in conformance with ASTM F 2656-07. DoS and DoD are beginning to accept vehicle barriers systems tested in conformance with ASTM F 2656-07.

Barrier systems used must be listed in either the Department of State (DoS) certified or Department of Defense (DoD) approved anti-ram vehicle barrier lists. Barrier widths shall be 'as certified/approved' on these lists. Alternatively, if a barrier system's width is between the widths of two listed barrier systems that are identical except for their widths, then that barrier system is also acceptable. Exceptions and acceptable widths will only be taken from the DoD anti-ram vehicle barrier list. The design and structural materials of the vehicle barrier furnished shall be the same as those used in the crash tested barrier. Crash test must have be performed and data compiled by an approved independent testing agency in accordance with either ASTM F 2656 or SD-STD-02.01.

Barriers tested and certified on the previous Department of State standard, SD-STD- 02.01, April 1985, and listed on the DoD approved anti-ram vehicle barrier list are also acceptable.

6-1.1 Portable Vehicle Barriers.

6-1.1.1 Description.

The portable vehicle barrier shown in Figure 6-1 is a movable, self-contained, portable roadway barrier, referred to as the vehicle surface barrier system (Example 1). It can be controlled as a manned checkpoint. Example standard equipment for this sample portable vehicle barrier is a 50-ft (15.2-m) cord attached to a control box. For unmanned control, options include either an electric card reader or keypad. The self-contained hydraulic system is located in the curb panels and sealed to prevent fluid leaks. The unit can be placed on any roadway or other flat surface (with passive barriers installed to prevent bypass). Once the electricity is connected, the system is operational. This barrier is best used for temporary installations, where high water table https://pdc.usace.army.mil/library/BarrierCertification� is a concern, or where portability is a requirement. Contact the manufacturer for current cost information. Example performance data are shown in Table 6-1 as Example 1.

A second example of a portable barrier system is depicted in Figure 6-2. This portable high security anti-terrorist vehicle crash barrier can be towed into position by a medium-sized truck. The barrier can be deployed in 15 minutes and can be operated either locally or remotely. The wheels are stored on the side, and the vehicle ramps are folded out upon deployment. Its deployment, retrieval, and operation are all hydraulic and push-button controlled. The system can be equipped with a battery-operated power unit or a hydraulic power unit operated on a locally-supplied power or full manual system, or combination. Example performance data are provided in Table 6-1 as Example 2.

Another portable barrier system (Example 3) is shown in Figure 6-3. This barrier is designed to be rapidly deployed in an emergency situation and fully operational in 15 minutes. It can be towed to a site by a truck then lowered into position using built-in jacks. The barrier can be an instant road block and can be installed in areas where foundation work cannot be safely or quickly poured. Stabilizers on the back side of the unit serve as additional reinforcement. The electro-hydraulic version of this barrier uses standard relay logic to allow control of the barrier with the supplied push-button control station. Example performance data are provided in Table 6-1 as Example 3.

A fourth example of a portable barrier system is illustrated in Figure 6-4. This maximum security vehicle arrest barrier can be relocated and deployed in less than 20 minutes upon arriving at its intended setup destination. The barrier does not require excavation and will not mark or damage the road surface. Although it is normally operated manually, it can be supplied with a hydraulic operating system. Example performance data are provided in Table 6-1 as Example 4.

6-1.1.2 Testing.

The vehicle surface barrier (Example 1) was tested by the Naval Facilities Engineering Command (NAVFAC), Naval Facilities Engineering Service Center (NFESC) at a vehicle barrier test bed in China Lake, California. Upon impact, the cab of a 15,200-lb (6,909-kg) truck, moving at 50.5 mph (81 kph), was crushed. The portable vehicle barrier, with the truck on top, slid 9.2 ft (2.8 m).

Both the Example 2 and Example 3 portable barrier systems have been certified by DoS as Level K4/L1 barriers. They will stop and disable a 15,000-lb (6,818-kg) truck, moving at 30 mph (48 kph). The manufacturers can provide crash test data.

The Example 4 portable barrier system has several versions. The version depicted in Figure 6-4 has been crash-certified by DoS as K12/L2. It will stop a 15,000-lb (6,818-

kg) truck, traveling at 50 mph (80 kph). Specific crash test data can be obtained from the manufacturer.

Figure 6-1 Vehicle Surface Barrier (Example 1)

Table 6-1 Performance Data for Portable Vehicle Barriers

Example 1*

2*

Example 3*

Example 4*

Height, in. (cm) 30 (76) 31 (78.7) Width, in. (cm) 96 (244) 144 (366) 144 (366) Normal operating cycle (seconds) 3 10 - 15 15 3 - 5 Emergency operating cycle (seconds)

Kinetic energy absorbed in impact testing, ft-lbf (kgf-m) x one million

1.2 (0.16) 1.2 (0.16)

*DoS certified

Figure 6-2 Portable High Security Anti-Terrorist Vehicle Crash Barrier (Example 2)

Figure 6-3 Portable Barrier (Example 3)

Figure 6-4 Maximum Security Vehicle Arrest Barrier (Example 4)

6-1.2 High-Security Barricade System.

6-1.2.1 Description.

The high-security barricade systems, shown in Figure 6-5 and Figure 6-6, are self-contained, hydraulically or pneumatically-operated units that, depending on the model, rise to various heights. These barriers are intended for high-speed impact conditions.

Models are available for site conditions where shallow foundations are required.

Performance data for an example system are shown in Table 6-2.

6-1.2.2 Testing.

Numerous manufacturers now produce DoS-certified high-security barriers which have been formally crash-tested\1\ /1/ The manufacturers should provide crash data for DoS-certified models. An example model was tested by Sandia National Laboratories with a 6,000-lb (2,727-kg) vehicle, traveling at 50 mph (80 kph), that penetrated the barrier 27 ft (8.2 m) and an 18,000-lb (8,182-kg) vehicle, traveling at 30 mph (48 kph), that penetrated 29 ft (8.8 m). Another model was tested by Southwest Research Institute for DoS using a 15,000-lb (6,818-kg) vehicle, traveling at 50 mph (80 kph), that penetrated less than 3 ft (0.9 m). A manufacturer tested a third model, using a 15,000-lb (6,818-kg) vehicle, traveling at 50 mph (80 kph), that penetrated less than 3 ft (0.9 m).

Figure 6-5 Example High-Security Barricade System (Wedge Type)

Figure 6-6 Example High-Security Barricade System (Flush-Mounted)

Table 6-2 Performance Data for Example High-Security Barricade System

System* Example

Flush- Mounted System*

Height, in. (cm) 38 (96) 36 (91) Width, in. (cm) 84 to 144

(213 to 366)

144 (366)

Normal operating cycle (seconds)

3 to 15 3 to 15

Emergency operating cycle (seconds)

<1.5 <1.5

Kinetic energy absorbed in impact testing, ft-lbf (kgf-m) x one million

.12 (0.16) .12 (0.16)

Kinetic energy rating by engineering analysis, ft-lbf (kgf-m) x one million (destruction of vehicle with some damage to barrier)

.40 (0.55) .32 (0.44)

*DoS certified

6-1.3 Bollard System.

6-1.3.1 Description.

Numerous manufacturers now produce DoS-certified bollard systems which have been formally crash-tested. \1\ /1/ The manufacturers should provide crash data for DoS-certified models. The example bollards shown in Figure 6-7 are 10-in (25.4-cm) diameter steel bollards that are 30 in. (0.76 m) high. They can be lifted into position either manually (60-lb (27-kg) pull) or hydraulically. The compact size and ease of operation make this system particularly well-suited as either a stand-alone or a backup to existing pedestrian gates in the single post configuration. They can also be used to secure wide entrances when the cost for installing larger systems becomes prohibitive.

Flush mount top of bollard system to surrounding pavement is required.

Hydraulically-operated bollards can be operated individually or in sets, with up to 24 bollards controlled from a single hydraulic power unit. Typical performance data are shown in Table 6-3.

See paragraph 5.3 h Additional Design Considerations, for handicap accessibility requirements.

6-1.3.2 Testing.

Sandia National Laboratories tested an example model with a 15,180-lb (6,900-kg) vehicle at 32 mph (51 kph), penetrating the barrier 12.2 ft (3.7 m). An example model was tested by the NFESC and DoS with a 10,000-lb (4,545-kg) vehicle at 40 mph (64 kph) that failed to penetrate the barrier.

Figure 6-7 Example Bollard System

Table 6-3 Performance Data for Example Bollard System

Example *

Height, in. (cm) 30 (76) Width, in. (cm) 10 (25) @ 2 ft (0.6 m) on center

Normal operating cycle (seconds)

3 to 15

Emergency operating cycle (seconds)

<1.5

Kinetic energy absorbed in impact testing, ft-lbf (kgf-m) x one million

0.445…