Engineering_Analysis_of_Modified_DS-50_Barrier.pdf

I

Prepared for:

Michael Van Valkenburgh Associates, Inc.

16 Court Street, 11th Floor Brooklyn, NY 11241

ABS Job Number: 3014553

CityArchRiver 2015 (CAR) Jefferson National Expansion Memorial St. Louis, Missouri

Engineering Analysis of a Modified DS-50 Barrier

June 6, 2013

CITYARCHRIVER 2015 (CAR)

JEFFERSON NATIONAL EXPANSION

MEMORIAL

ENGINEERING ANALYSIS OF A

MODIFIED DS-50 BARRIER

JUNE 6, 2013

Prepared By:

ABS Consulting Risk Consulting Division

77 Westport Plaza, Suite 210 St. Louis, MO 63146

(314) 819-1550

Project Number: 3014553

03 TOC.doc i

Table of Contents

Executive Summary .............................................................................................. E-1

1.0 Purpose ...................................................................................................... 1-1

1.1 Overall Project Purpose ................................................................... 1-1

2.0 Background Information .......................................................................... 2-1

2.1 Criteria ............................................................................................. 2-1

2.2 Vehicle ............................................................................................. 2-1

2.3 Soil ................................................................................................... 2-2

2.4 Concrete Barrier .............................................................................. 2-2

3.0 Finite Element Set Up and Description ................................................... 3-1

3.1 Finite Element Set Up and Description ............................................ 3-1

4.0 Simulation Results ................................................................................... 4-1

4.1 Simulation Results ........................................................................... 4-1

4.2 DOS 50 Barrier K12 Threat (Benchmark Simulation) ...................... 4-1

4.3 Modified DOS 50 Barrier (12 in.) K8 Threat ................................... 4-2

4.4 Modified DOS 50 Barrier (18 in.) K8 Threat .................................... 4-3

TABLES

E-1 Simulation Findings ..................................................................................... E-1

2-1 Test Criteria ................................................................................................. 2-1

4-1 Summary of Numerical Modeling Results ................................................... 4-1

FIGURES

2-1 DS-50 Anti-Ram Wall .................................................................................. 2-2

2-2 Modified DS-50 Anti-Ram Wall .................................................................... 2-2

CityArchRiver 2015 (CAR) Jefferson National Expansion Memorial St. Louis, Missouri Engineering Analysis of Modified DS-50 Barrier June 6, 2013 ii

3-1 Barrier Model Domain ................................................................................. 3-2

3-2 Illustration of Typical Cap Model Shape

Showing Three-Dimensional Yield Surface ................................................. 3-3

3-3 Demonstration of Strain Softening and Modulus Reduction

Due to Reduction Factor ............................................................................. 3-4

3-4 Barrier Cross Section Model ....................................................................... 3-5

3-5 Steel Rebar Layout ...................................................................................... 3-5

3-6 Ford F-800 Vehicle Model ........................................................................... 3-6

3-7 DS-50 Barrier, Mod DS-50 (12” thk), Mod DS-50 (18” thk), Clockwise from Top Left .............................................................................. 3-6

3-8 Boundary Conditions ................................................................................... 3-7

3-9 Initialized Vertical Stress ............................................................................. 3-7

4-1 Final Plot State with Concrete Damage (Side View, Front View) ................ 4-2

4-2 Truck Velocity (MPH), 12” Modified Barrier ................................................. 4-2

4-3 Final Plot State with Concrete Damage (Side View, Front View) ................ 4-3

4-4 Truck Velocity (MPH), 12” Modified Barrier ................................................. 4-3

4-5 Final Plot State with Concrete Damage (Side View, Front View) ................ 4-4

4-6 Truck Velocity (MPH), 18” Modified Barrier ................................................. 4-4

04 Exec Sum.doc

E-1

Executive Summary

This report summarizes the predicted vehicle/barrier response of a modified DS-50 anti-ram wall subjected to a K-8 (M40) vehicle threat. An LS-DYNA finite element model was constructed and calibrated to investigate a variety of wall configurations. LS-DYNA is a general purpose finite element code for analyzing the large deformation static and dynamic response of structures. It is commonly used in impact type problems and has been validated for vehicle to barrier interactions. Material and section properties specific to this wall design were incorporated into the model and are discussed in detail within the body of the report.

The following table summarizes the findings of the simulations:

TABLE E-1

SIMULATION RESULTS

RUN ID

Height Above

Grade (in)

Wall Thickness

(in)

ASTM

Desig.

DOS

Equiv.

Vehicle Weight (lbs)

Vehicle Speed

(MPH)

Penetration Distance (ft)

P Rating

1-Benchmark 40 12 M50 K-12 15,000 50 <3.3 P1 2-Mod 12" 30 12 M40 K-8 15,000 40 10.0 P2 3-Mod 18" 30 18 M40 K-8 15,000 40 10.0 P2

A benchmark case was used to verify/calibrate the barrier model. The results from the benchmark simulation match the K-12 (M50) criteria specified for the standard DS-50 anti-ram wall. Modified reduced height barriers with two different thicknesses were simulated using the K-8 (M40) threat. It was concluded that both of the barriers would not be able to fully resist the threat and significant penetration into the protected area is expected. At the end of both simulations, the truck model was airborne and the front axle was torn off. Using the initial velocity and position from simulations, projectile motion calculations show the truck impacting the ground in time for the rear wheels to engage the wall section and come to a complete stop. The vehicle would at this point would be completely damaged and not be able to function or continue moving past the barrier. Assisting with limiting the penetration distance is the sloped landscaping area beyond the barrier.

E-2

The estimated penetration distance of ten feet would rate this barrier as a P-2 classification, as it is less than 23.1-ft.

The primary results of the engineering analysis are summarized below:

1. The standard DS-50 40-inch above grade anti-ram wall design was verified to conform to the K-12 (M50) P-1 classification.

2. Both of the proposed reduced height barriers (12 and 18-inch thick walls) were unable to prevent the design vehicle from penetrating past the controlled perimeter defined by the anti-ram barrier wall due to the vehicle’s high center of gravity and frame height.

3. The barriers are predicted to achieve a P-2 rating with approximately ten feet of penetration when subjected to the design basis K-8 (M40) threat.

05 Ch1 Purpose.doc

1-1

1.0 Purpose

1.1 Overall Project Purpose

A design team, led by MVVA, has been engaged in the planning, approval, and design process for the CityArchRiver 2015 (CAR) project at the Jefferson National Expansion

Memorial in St. Louis, Missouri. ABS Consulting is providing Anti-Terrorism/Force

Protection (AT/FP) engineering services to the MVVA team in support of this project.

The design team indicated a preference to use a 30-inch tall anti-ram barrier wall at numerous locations around the JNEM site as part of a comprehensive strategy to enforce the required protected perimeter. The National Park Service (NPS) representatives have specified that the barriers used to enforce the perimeter protection be rated as “K-8” at a minimum.

The "K" protection level refers to Department of State (DOS) criteria1 that barriers are required to be tested to per SD-STD-02.01. The K rating is related to the kinetic energy (a combination of mass and velocity – KE=0.5*m*v2) associated with the test protocol. The rating of the barrier is determined when a 15,000-lb (6810-kg) gross-weight vehicle impacts a barrier from a perpendicular direction. A K-8 rating is achieved when a vehicle traveling at a nominal speed of 40-mph (65-kph) is successfully arrested by the barrier at an angle of impact normal to the surface.

ASTM F-26562 is an alternative standard for vehicle barrier rating and is more commonly specified. The ASTM F-2656 “M50” designation is equivalent to the K-12 designation, while the ASTM F-2656 “M40” designation is equivalent to K-8.

1 Vehicle Crash Testing of Perimeter Barriers and Gates, U.S. Department of State (DoS) SD-STD-02.01.

2 Standard Test Method for Vehicle Crash Testing of Perimeter Barriers, American Society of Testing and Materials, ASTM F2656 (2007).

1-2

The Department of State (DOS) has barrier wall designs that conform to an M30 and M50 criteria, but not the M40 (K-8) criteria.

The purpose of this project is to investigate if a reduced height DS-50 barrier will be sufficient to prevent significant penetration of vehicle conforming to the M40 (K-8) design vehicle threat

06 Ch2 Background Information.doc

2-1

2.0 Background Information

2.1 Criteria

The design criterion for this modeling simulation conforms to Department of State (DOS) K ratings as well as the equivalent ASTM F-2656 standard rating criteria. A summary of test criteria referenced in this report can be found in Table 1. Target penetration for the modified barriers was based on a P1 rating which requires less than 3.3 feet of penetration.

TABLE 2-1

TEST CRITERIA

ASTM

Designation

DOS

Equivalent

Vehicle Weight

(lbs)

Vehicle Speed

(MPH)

Target Penetration

(ft) M30 K-4 15,000 30 3.3 M40 K-8 15,000 40 3.3 M50 K-12 15,000 50 3.3

2.2 Vehicle

Based on the design criteria discussed above, a 15,000-pound gross weight vehicle was used for all simulations detailed in this report. The vehicle used was obtained from the

National Crash Analysis Center (NCAC1). The model selected was a Ford F-800 truck commonly used for security barrier impact analysis. The model has been validated by

George Washington University for impact into concrete F Shape barriers2. Mass verifications were conducted to confirm the gross weight of the vehicle.

1 NCAC, www.ncac.gwu.edu 2 Int. J. of Vehicle Systems Modelling and Testing, 2007 Vol.2, No.1, pp.1 - 15

2-2

2.3 Soil

Soil conditions were obtained from geotechnical reports provided to ABS Consulting. It was determined that the primary soil found beneath the footing was an existing fill compromised of silty clay as well as clay with variable amounts of sand, gravel, concrete, brick, and limestone gravel. The clay had an approximate dry unit weight of 110 pounds per cubic foot.

Shear modulus, cohesion value, and angle of friction were calculated and/or approximated from typical values of firm clay.

2.4 Concrete Barrier

The DS-50 concrete barrier is a reinforced concrete barrier embedded in a soil foundation with a compressive strength of 44-ksi (25-MPa). Parameters that will be investigated in this report include the thickness of the wall as well as its height above grade. The standard

Department of State barrier design for a K-12 threat includes a wall with a 40-inch (1000-

mm) above grade height as well as a 12-inch (300-mm) thickness as shown below in

Figure 2-1. The existing DS-50 barrier design was modified to have a 30-inch above grade height, with wall thicknesses of 12 and 18 inches, as shown below in Figure 2-2. These two modified DS-50 barriers were simulated versus a K-8 (M40) threat.

Figure 2-1: DS-50 Anti-Ram Wall Figure 2-2: Modified DS-50 Anti-Ram Wall

07 Ch3 F

3.0

3.1

The a explic

LS-D

static explic easily availa mode

The s formu to ve desir

Prage overa

1 LS DY

Finite Element.docx

Finite

Finite El assessment cit finite elem

DYNA1 is a ge c and dynam cit time integ y treated acr able for each els and ten e soil was mod ulation. A va ry soft mode ed response er yield surfa all dimension

YNA Theory M e Eleme lement Se of vehicle im ment modelin eneral purpo mic response gration. A co ross the con h element ty equations-of deled using ariety of soil els. A final m

e. The mater ace to enabl ns of the soi anual, Livermo nt Set U et Up and mpact and p ng code, LS ose finite ele e of structure ontact-impac ntact interfac ype. LS-DYN f-state to cov

8-noded sol material mod material mode rial model us le a realistic l can be see ore Software T

3-1

Up and d Descript enetration w

-DYNA.

ement code f

es. The main ct algorithm ces and a va

NA contains ver a wide ra id elements dels were us el was chos sed was MA distortion fo en in Figure

Technology Cor

Descrip tion was performe for analyzing n solution m allows diffic ariety of elem approximat ange of mate with a cons sed in calibr en based on

AT_198 whic or the soil as

3-1.

rporation, Hall ption ed using the g the large d methodology cult contact p ment formula tely two-hun erial behavio stant stress s ration rangin n model stab h uses a mo s well as failu quist, John O., e nonlinear deformation is based on problems to ations are dred constit or.

solid elemen ng from very bility as well odified Druck ure planes. T

, March 2006.

be utive nt stiff as ker-

The

CityA Jeffers Engin

The s elasti comm durat the C defin

The v and q

Symo stress dyna

The c impa mate incre concr

2 Struc

ArchRiver 2015 on National Ex neering Analys steel rebar re ic-plastic ma monly used f tion transien

Cowper-Sym ed constants values used q are commo onds parame s suggested mic and stat concrete bar

ct. In order t rials were m ased elemen rete was mo ctural Impact, 5 (CAR) xpansion Mem is of Modified einforcemen aterial card M for metals w t dynamic lo onds model s that descri to define the only intercha eters) based d by Jones fo tic yield stres rrier was mo to capture th merged to on nt dimension odeled using

Cambridge Un morial DS-50 Barrier

Figure 3-1:

nt was mode

MAT_24 with where strain r oading condi

(Eq.1) whic ibe the scali ese parame angeable ter d on the leas or structural sses, respec

= 1 odeled using he concrete t e another (F ns to an ave the MATER niversity Press, r

3-2

Barrier Mo eled using be h a yield stre rate effects a itions). Strain ch scales the ng behavior ters in this m rms in literat st square fit i impact stud ctively.

an average to soil intera

Figure 3-4). A erage of 75-m

RIAL_CSCM

Jones, Norma odel Domain eam elemen ess of 60-ksi are an impo n rate effect e true yield s r and are dep model were ture for C an in logarithmi ies using mi

(1) e mesh size action the ele

A gradient m mm towards

M_CONCRET

n, 1989.

nts (Figure 3

i. This mate rtant consid ts were acco stress. “C” a pendent on

D=40.4 (1/se nd p for the C ic scale of th ild steel2. σd

30-mm at th ement nodes mesh was im the model e

TE [MAT 15

St. Louis, Mi June 6

-5) and an erial model is eration (i.e.

ounted for us and “p” are u the material

ec) and q=5

Cowper and he dynamic y d and σs are he region of s from the tw mposed whic extents. The

9] card and issouri

6, 2013 s short sing user-

5 (D yield the wo ch e a

Engin comp betwe with t dama surfa

The d modu d). Da dama

ArchRiver 2015 on National Ex neering Analys pressive stre een the shea the yield sur age paramet ce is shown damage para uli is reduced amage is ind age threshol

5 (CAR)

xpansion Mem is of Modified ength of 44-k ar yield surfa rface. Both d ter calculatio below in Fig

Figure 3 Sho ameter rang d (Eq.2) sim duced and is d (~2.5% str morial DS-50 Barrier ksi (25-MPa) ace and hard ductile and b ons. A gener gure 3-2.

3-2: Illustrat owing Three-ges from zero ultaneously s accumulate rain)

= 1 r

3-3

). This is a c dening cap.

brittle damag ral shape rep ion of Typica -Dimensiona o to 1 for co and proport ed after the cap model w

The initial d ge failure mo presenting t al Cap Mode al Yield Surf mplete dam tionally base strain based ith a smooth damage surf odes are con he concrete el Shape face age (d). The ed on the red d energy exc

(2)

St. Louis, Mi June 6 h intersection face coincide nsidered in th model yield e shear and duction facto ceeds the n es he d bulk or (1-

Engin

Due t

3), el shoot is rea

LSDY

eleme

As m confo beam const

Wash vehic at the

(Figu

Boun cond

3 NCA

4 Int. J

ArchRiver 2015 on National Ex neering Analys

Figure to an elemen ement erosi ting nodes. A ached. This i

YNA simulat ents to prev entioned pre orm to initial m, shell, and tructed using hington Univ cle model wa e barrier mid re 3-7).

ndary conditi itions were a

C, www.ncac.g J. of Vehicle S

5 (CAR)

xpansion Mem is of Modified e 3-3: Demo nt losing all on had to be

An element information tion. Hourgla ent non phy eviously the weight and solid eleme g 35,353 ele versity for im as then impo dpoint while a ons along th applied to th gwu.edu Systems Mod morial DS-50 Barrier onstration of

Due to strength and e incorporate will erode w is very helpf ass control w sical hourgla vehicle mod velocity para nts with elas ements (Figu mpact into co orted into the allowing som he soil were e extents of delling and Te r

3-4 f Strain Softe o Reduction d stiffness as ed to preven when d > .99 ful when ana was added d assing mode del was obta ameters. Th stic plastic m ure 3-6). The ncrete F Sh e 3 variation me initial sep fixed in the f the model ( esting, 2007 V ening and M

Factor s d approac nt computati and a define alyzing dama ue to the us es.

ained from N he vehicle mo material mod e model has ape barriers s of wall con paration in th vertical dire

(Figure 3-8).

Vol.2, No.1, p

Modulus Red hes a value onal difficult ed maximum age contour se of reduced

NCAC3 and m odel was co dels. The ent been valida s4. The F-800 nfigurations he impacting ctions. Sym

. Gravity initi pp.1 - 15

St. Louis, Mi June 6 duction of 1 (Figure ties such as m principal s plots of d integration modified to nstructed fro tire vehicle w ated by Geor

0 modified and position g direction metry bound ialization for e 3-strain n om was rge ned dary r the

Engin concr initial

(Figu

ArchRiver 2015 on National Ex neering Analys rete/soil barr izations wer re 3-9).

5 (CAR)

xpansion Mem is of Modified rier was sim re saved as

Fig morial DS-50 Barrier ulated sepa an initial stre gure 3-4: Ba

Figure 3-5 r

3-5 rate from the ess and imp arrier Cross

5: Steel Reb e impact mo ported into th

Section Mo bar Layout odel. The res he impact mo del

St. Louis, Mi June 6 sults from th odels e

Engin

Figu

ArchRiver 2015 on National Ex neering Analys ure 3-7: DS

5 (CAR)

xpansion Mem is of Modified

Fi

-50 Barrier, morial DS-50 Barrier igure 3-6: F

Mod DS-50 r

3-6

Ford F-800 V

(12" thk), M

Left

Vehicle Mod

Mod DS-50 (1 del

18"thk). Cloc ckwise from

Top

Engin

ArchRiver 2015 on National Ex neering Analys

5 (CAR)

xpansion Mem is of Modified

F morial DS-50 Barrier

Figure 3-8

Figure 3-9:

r

3-7

: Boundary

Initialized Ve

Conditions ertical Stres ss

08 Ch4 Simulation Results.doc

4-1

4.0 Simulation Results

4.1 Simulation Results

Results of all simulations are summarized below in Table 2. Simulations were run out to

0.5-seconds which captured the full response of the barrier. As expected, the benchmark barrier was able to contain the K-12 vehicle threat without any penetration and conforms to a P-1 rating. The modified 30 inch above-grade barriers, with both 12 and 18-inch thick walls, were unable to contain the K-8 threat and penetration was observed. The 12-inch modified barrier was able to absorb more damage and slow the vehicle more effectively. It is more flexible than the thicker 18-inch barrier which sheared the front axle and propelled the vehicle into the air sooner. At the end of the simulation the truck model was airborne and the front axle was torn off. It was confirmed using projectile motion calculations that the vehicle would return to the ground in time for the rear wheels to engage the barrier and stop the vehicle with an approximate penetration distance of ten feet. Both modified barriers would then conform to a P-2 rating (penetration distance less than 23.1 feet) for a K-8 threat.

TABLE4-1

SUMMARY OF NUMERICAL MODELING RESULTS

RUN ID

Height Above

Grade (in)

Wall Thickness

(in)

ASTM

Desig.

DOS

Equiv.

Vehicle Weight (lbs)

Vehicle Speed

(MPH)

Penetration Distance (ft)

P Rating

1-Benchmark 40 12 M50 K-12 15,000 50 <3.3 P1 2-Mod 12" 30 12 M40 K-8 15,000 40 10.0 P2 3-Mod 18" 30 18 M40 K-8 15,000 40 10.0 P2

*Penetration distance was calculated by extrapolating velocity data and position from simulation at final state

4.2 DOS-50 Barrier K12 Threat (Benchmark Simulation)

The benchmark model was run in order to validate the results of the ensuing modified barriers. As expected the K-12 threat was contained and came to a complete stop around

4-2

0.3-seconds (Figure 4-2). No penetration of the barrier was seen in the model. Some cracking and spalling can be seen in Figure 4-1 and is typical for this type of impact.

Figure 4-1: Final Plot State with Concrete Damage (Side View, Front View)

Figure 4-2: Truck Velocity (MPH), 12” Modified Barrier

4.3 Modified DOS-50 Barrier (12 in.) K8 Threat

The modified DS-50 12-inch thick barrier was simulated with an above grade height of

30-inches. Due to the shortened wall height the frame of the truck was located at the top end of the wall section. When impacted the front axle was dislocated from the vehicle and the truck became airborne (Figure 4-3). The velocity of the vehicle was reduced from 40-

MPH to 6-MPH due to the barrier impact (Figure 4-4). It was predicted using projectile motion calculations that the truck would impact the ground in time for the rear wheels to

4-3 engage the wall section and come to a complete stop. The vehicle would at this point would be completely damaged and not be able to function or continue moving past the barrier. The estimated ten foot penetration distance would rate this barrier as a P-2 classification as it is less than 23.1 feet.

Figure 4-3: Final Plot State with Concrete Damage (Side View, Front View)

Figure 4-4: Truck Velocity (MPH), 12” Modified Barrier

4.4 Modified DOS-50 Barrier (18 in.) K8 Threat

The modified DS-50 18-inch thick barrier was simulated with an above grade height of 30-inches. Due to the shortened wall height the frame of the truck was located at the top end of the wall section. When impacted the front axle was dislocated from the vehicle and the truck became airborne (Figure 4-5). The velocity of the vehicle was reduced from 40-MPH to 14-

MPH due to the barrier impact (Figure 4-6). It was predicted using projectile motion

4-4 calculations that the truck would impact the ground in time for the rear wheels to engage the wall section and come to a complete stop. The vehicle would at this point would be completely damaged and not be able to function or continue moving past the barrier. The estimated ten foot penetration distance would rate this barrier as a P-2 classification as it is less than 23.1 foot limit that defines the P-2 classification.

Figure 4-5: Final Plot State with Concrete Damage (Side View, Front View)

Figure 4-6: Truck Velocity (MPH), 18” Modified Barrier

Americas Alexandria, VA Houston, TX Irvine, CA Knoxville, TN Lakewood, CO Richland, WA Rockville, MD Stratham, NH Wilmington, DE

Ciudad del Carmen, Mexico Mexico City, Mexico Monterrey, Mexico Poza Rica, Mexico Reynosa, Mexico Veracruz, Mexico

Chuao, Venezuela Macae, Brazil Sao Paulo, Brazil Rio de Janeiro, Brazil Valparaiso, Chile

Europe Aberdeen, UK Abu Dhabi, UAE Cheshire, UK Doha, Qatar Dubai, UAE Genoa, Italy Istanbul, Turkey Dammam, Saudi Arabia Las Arenas, Spain London, UK Muscat, Oman Piraeus, Greece Rotterdam, The Netherlands Sofia, Bulgaria

Asia-Pacific Ahmedabad, India Alexandria Point, Singapore Bangkok, Thailand Beijing, China Busan, Korea Kaohsiung, China Kuala Lumpur, Malaysia Manila, Philippines Navi Mumbai, India New Delhi, India Seoul, Korea Shanghai, China Tokyo, Japan Yokohama, Japan

Other Offices Worldwide:

CORPORATE HEADQUARTERS

ABSG Consulting Inc.

16855 Northchase Drive Houston, TX 77060

Tel: (281) 673-2800, Fax: (281) 673-2812 www.absconsulting.com

Risk Consulting Division Offices:

300 Commerce Drive, Suite 200 Irvine, CA 92602 USA Tel: 714-734-4242/Fax: 714-734-4262

475 14th Street, Suite 550 Oakland, CA 94612 USA Tel: 510-817-3100/Fax: 510-663-1046

310 South Main St., Suite 300 Salt Lake City, Utah 84101 USA Tel: 801-333-7676/Fax: 801-333-7677

15600 San Pedro Avenue, Suite 400 San Antonio, TX 78232 USA Tel: 210-495-5195/Fax: 210-495-5134

77 Westport Plaza, Suite 210 St. Louis, MO 63146 USA Tel: 314-819-1550 /Fax: 314-819-1551