VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY The Charles E. Via, Jr. Department of Civil and Environmental Engineering Blacksburg, VA 24061 Structural Engineering and Materials

VEHICULAR ACCESS DOORS UNDER HURRICANE FORCE WIND PRESSURE: EXPERIMENTS TO STUDY JAMB BEHAVIOR

by Tian Gao

Graduate Research Assistant

Cristopher D. Moen, Ph.D., P.E. Principal Investigator

Submitted to the:

Metal Building Manufacturers Association 1300 Sumner Ave

Cleveland, OH 44115-2851

Report No. CE/VPI-ST-12/01

March 2012

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Acknowledgements

The authors are appreciative of the support they received from MBMA throughout this project, especially the thoughtful advice from the steering group. Mr. Jerry Hatch of NCI provided valuable guidance throughout the test program. Coordination with the sponsor was provided by Dr. Lee Shoemaker and Mr. Dan Walker of MBMA. Mr. Joe Hetzel of DASMA provided important input regarding access door design procedures and details.

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Contents 1. Introduction ......................................................................................................................................... 3

2. Experimental Program ....................................................................................................................... 3

2.1. Door details ................................................................................................................................... 3

2.2. Wall frame and jamb details ......................................................................................................... 3

2.3. Test matrix ..................................................................................................................................... 5

3. Instrumentation ................................................................................................................................... 5

3.1. Pressure ......................................................................................................................................... 6

3.2. Curtain deflection .......................................................................................................................... 7

3.3. Strain gages ................................................................................................................................... 7

3.4. Wind-lock displacement ................................................................................................................ 8

3.5. Jamb deformation .......................................................................................................................... 9

4. Results and Discussion ........................................................................................................................ 9

4.1. Loading history ............................................................................................................................. 9

4.2. Curtain deflection ........................................................................................................................ 10

4.3. Wind-lock axial force .................................................................................................................. 13

4.4. Wind-lock bending ....................................................................................................................... 15

4.5. Wind-lock displacement (#10 and #11) ....................................................................................... 17

4.6. Jamb deformation (at wind-lock#11) .......................................................................................... 18

4.7. Door failure ................................................................................................................................. 20

5. Comparison with CSBA Prediction Model ..................................................................................... 21

6. Proposed Limit State Design Methodology for Vehicular Access Doors ..................................... 23

7. Conclusions ........................................................................................................................................ 24

References .................................................................................................................................................. 25

AppendixA: Measured Strains ................................................................................................................. 25

AppendixB: Janus 3100 ............................................................................................................................ 45

 

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1. Introduction In August of 2009, two 10 ft by 10 ft DBCI 5000 vehicular access doors were tested with a

simulated hurricane force wind pressure at the DBCI in Douglasville, GA (Gao and Moen 2009). After evaluating the results from this study, it was hypothesized that the door curtain deflection and wind-lock axial force are sensitive to the jamb stiffness: a stiffer jamb limits curtain deflection, but at the same time increases wind-lock axial force. A subsequent analytical and computation study (Janas and Moen 2011) confirmed this hypothesis, leading to the development and validation of a general mechanics-based prediction model that was implemented as a computer program CSBA. In this study, two 10 ft by 10 ft access doors are tested with different wind-lock details and door jambs than those considered in the August 2009 study. Jamb stiffness and jamb deformation are directly measured, providing useful data for validating the CSBA prediction model. The access doors (Janus 3100) were provided by Janus International, and the tests were again conducted at DBCI in Douglasville, GA in November of 2011.

2. Experimental Program

2.1.Door details

The wind-guide details and the curtain cross-section are shown in Figure 1. The curtain sheet is consistent with the DBCI 5000 door (ASTM A653 GR80 26GA) tested in 2009, but the wind-guide configuration is different. Specifically, the Janus wind-bar has a shorter wind-lock bearing lip than the DBCI door (compare 0.19 in. to 0.58 in.). Also, the Janus wind-guide is attached with two screw fasteners to the jamb compared to one fastener for the DBCI system. The Janus wind-guide is wider (compare 4 in. to 3 in.) requiring a wider jamb face for attachment.

Figure 1: (a) Janus 3100 door wind-guide details, and (b) curtain cross-section

2.2.Wall frame and jamb details

The wall frame (Figure 2) used in this study is the same as the one used in the 2009 tests except for the jambs (Type: C in Figure 2), which were detailed differently to represent a

WINDLOCKGAP

(a) (b)

WINDGUIDE

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“flexible” jamb and “stiff” jamb. The jambs for Door#1 and Door#2 are shown in Figure 3. Jamb#1 is the “flexible” jamb - a 0.1 in. thick C12x3.5. At each jamb/girt connection, the two jamb flanges were connected with a 0.25 in. x3 in. x 3 in. angle which was fillet welded (top and underside faces of the angle) to the jamb flanges. The Jamb#1outer flange was not fastened to the purlin bearing leg (PBR) wall panel.

Jamb#2 is the “stiff” jamb - a 0.1 in. thick by 12 in. deep press-braked cross-section (see Figure 3c).The flange attached to the wind-guide is 6.5 in. wide and bolted to the girt flange. The other flange is 3.5 in. and fastened to the PBR wall panel using screw fasteners every 12 in. along the height of the door. At the jamb/girt connections, the two flanges were welded together with a 0.25 in. x 3 in. x 3 in. angle, the same detail used in Jamb#1 (see Figure 4).

Figure 2: Wall frame

Figure 3: (a) Jamb#1 for Door#1 (b) Jamb#2 for Door#2 (c) Jamb#2 dimensions

Type: A

Type: A

Type: A

Type: A

Type: CType: A

Type: A

Type: A

Type: A

Type: C

Type

: C

5’ 10’ 5’

24’

10’

3’6“

5’2“

7’4“

10’6“

12’8”

Type: D

Type: B

15’8”

Type: A 12X3.5 Z 14Type: B 12X3.5 Z 12Type: C See Jamb detailsType: D C12X20.7

(g)

(g)

(g)

(g)

(g)

(g)

#10#11

C12x3.5

Welding

Angle

Type A GirtWelding

Type A Girt

3.5”

6.5”

12”

(a) (b)

1.0”

1.0”

90o

90o

(c)

1.0”

PBR panel Screw fastener

Bolt (Φ=1/4”)

  5

Figure 4: Girt connection at Jamb#2

2.3. Test matrix

Door#1 was tested under a (N) negative pressure (wind pulling door out of the building) where the plastic sheeting covers the outside of the pressure chamber (loading up to -43 psf, unloading, and reloading up to -42 psf) followed by three (P) positive pressures (wind pushing door into the building) where the plastic sheeting covers the inside of the chamber. “R” indicates that the bolts connecting the jamb and certain girts (denoted as “g” in Figure 2) were removed to study their influence on jamb stiffness. Door#2 was tested under two (P) positive pressures. The girts and jambs were replaced after the Door#1 tests.

Table 1: Testing matrix

3. Instrumentation As shown in Figure 5, three wire potentiometers (wirepots, ‘¨’in Figure 5) were used to

measure the curtain deflection, 36 strain gages measured the strains in the wind-locks, two wirepots (crossed squares in Figure 5) were used to measure the wind-bar displacements, and three LVDTs measured the jamb deformation.

Name Peak (psf) Name Peak (psf)- 43 P1 + 39- 42 P2 + 200+ 38+ 35 ( R )+ 39 ( R ) ( R ): Girts Removed+ 46

P3 + 77

Door#1 Door#2

N

P1

P2

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Figure 5: Instrumentation layout

3.1.Pressure A pressure transducer (Omega-PX309-001GV, range of 1-144psf, accuracy=+/- 0.4 psf) was

used to measure the pressure in the chamber during the test. According to the communication with technical service, the pressure out of the measurement range may be not accurate. The pressure transducer (Figure 6a) was calibrated before the test using U-manometers (Figure 6b). See Moen and Gao (2009) for the calibration procedure.

Figure 6: (a) Pressure transducer (b) U-manometers

Wirepot-top

Wirepot-mid

Wirepot-bottom

30”

120”

120”

30”

30”

30”

60”

LVDTs

Wirepot-top

Insid

e of t

he ch

ambe

r

#1

#18

Door top

Door bottom

BA

LVDTs

#18

#1

BA

6.5”

6.5” (Typ.)6.5” (Typ.)

#10#11

Wirepots

#10#11

Wirepot-mid

Wirepot-bottom

LVDTsWirepots

(a) (b)

  7

3.2.Curtain deflection

Three wirepots are used to measure the curtain deflection at the top, middle and bottom of the door (Figure 7).

Figure 7: Curtain deflection measurement

3.3.Strain gages

The wind-lock forces were measured on vertical edge of the access door (18 wind-locks total). For each wind-lock, a steel extension was welded to the original wind-lock, and the strain gages were installed on both sides of the wind-lock. The extension was fastened to the curtain using six rivets. The distance of the strain gages from the riveted connection was set at approximately two times the width of the wind-lock to allow the concentrated forces at the rivets to spread before reaching the strain gage. Axial force, P (lbs), and moment, M (lbs·in), in the windlock at the gage location are calculated with the formulas:

EAP BA ⎟⎠⎞⎜

⎝⎛ +=

2εε

, (1) and

ESM AB ⎟⎠⎞⎜

⎝⎛ −=

2εε , (2)

where εA and εB are the strains measured by gage A and B respectively (note positive strain is tension), and A and S are the cross-sectional area and section modulus of the wind lock respectively. The modulus of elasticity for steel, E, is assumed as 30,000,000 psi.

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Figure 8: Strain gage location on the wind-locks

3.4.Wind-lock displacement

The in-plane displacements of wind-lock #10 and #11 (see Figure 5) were directly measured using the wirepot as shown in Figure 9. A 0.75 in. dia. hole was cut in the wind-guide, and the wire was attached to the wind-lock with a magnet. The locations of the wind-lock #10 and #11 relative to the girts are shown in Figure 10. The wind-lock displacements were only measured for the positive pressure tests, since the plastic covered the wall frame during the negative pressure tests.

Figure 9: Wind-lock displacement measurement

Figure 10: Wind-lock #10 and #11 locations relative to the girts

3.158”Original wind-lock

4.932”Extension

1.5”

6 Rivets

4.5”

Strain gage A

Strain gage B

1.165”

0.13”

Wind-lock displacement

Girt

Girt

#10

#11

Jamb 20”

2.5”

6.5”

11”

  9

3.5.Jamb deformation Jamb deformation at the location of the wind-lock #11 was measured using LVDTs as shown

in Figure 11. The jamb deformation was only measured for the positive pressure tests, since the plastic covers the wall frame during the negative pressure tests.

Figure 11: Jamb deformation measurement (a) Door#1, (b) Door#2

4. Results and Discussion

4.1.Loading history The loading histories are shown in Figure 12. The loading rate varied approximately from 0.3

psf/sec to 1psf/sec. Each door was preloaded to approximately 10 psf to ensure that the plastic sheeting hugged the door tightly. After the preload, each door was loaded and unloaded at least once and sometimes twice as summarized in Table 1 (also see Figure 12). Several unanticipated loading and unloading steps occurred during Door#1-N when the seal was lost in the vacuum chamber.

(a) (b)

2”

4”

4”

2”a

b

c

a

b

c

  10

Figure 12: Loading history

4.2.Curtain deflection

Curtain deflection at the top, middle and bottom of the door are shown in Figure 13. The trends are consistent with the 2009 tests, where the curtain deflection at the middle of the door is greater than the top and bottom of the door. Also, there is a clear bilinear system stiffness defined by the curtain flexural rigidity before the wind-locks engage and by the jamb stiffness after the wind-locks engage. If the maximum curtain deflection is less than 10 in. the door curtain returns to its original position (curtain deflection is zero) when unloaded. This deflection limit, expressed in terms of door width (W), is W/12, which could be useful information for a design procedure, and specifically, for a door deflection limit state.

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Figure 13: Curtain deflection

The first loading of each door (Door#1-P1+38 and Door#2-P1+39) was high enough to cause bearing engagement of the bolted girt-jamb connections and the screw-fastened wind bar to jamb connections. This bearing engagement stiffened the jamb/wall system for the second tests (compare P1 to P2 in Figure 14). The wind-lock gap also increased in the P2 tests, again a result

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of the bolt and screw-fastener slip as well as some permanent bending deformation in the wind-locks.

Figure 14: Effect of the first loading.

Figure 15 confirms that the curtain deflection is sensitive to jamb stiffness. Remember that Door#1-P2(+39)(R) was paired with Jamb#1 and had the girts removed; Door#1-P3(+77) used Jamb#1 with the girts engaged; and Door#2-P2(+200) was paired with Jamb#2(see Figure 3 for jamb details). The stiffness (X-Y slopes, psf/in.) are shown in Figure 15.

Door#2-P2 (+200) demonstrated trilinear stiffness behavior that occurred because of the Jamb#2 details. In Figure 15 it is believed that the stiffness leg 1 is caused by the initial jamb translation/deformation where the bolted connections are engaged through friction; the stiffness leg 2 is a result of bolt slipping between the jamb flange and the girt flange; the stiffness leg 3 is when the flanges bear against the bolts. This trilinear stiffness complicates wind-lock force and door deflection predictions, however within a typical wind pressure design range of 40 psf the jamb stiffness could be considered linear (using the leg 1 stiffness) without significant error. Another possibility is to add a stepped stiffness function to a future version of the CSBA program.

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Figure 15: Effect of jamb stiffness

4.3.Wind-lock axial force The wind-lock axial forces at the loading peaks(“Peak” in Table 1)are summarized in Figure

16 and Table 2. The force trends are consistent with the 2009 tests – compression at the top of the door and transitioning to tension towards the middle and bottom of the door. It is hypothesized that that the wind-locks at the top and the bottom of the door were twisting in the wind-guide during the test, causing the compressive strain readings (see Figure 17).When the door is loaded near failure (see Door#2-P2+200), the door curtain deformation respresents more uniform one-way bending along the full height of the door, and therefore the effect of wind-lock twisting reduces. The axial forces in Door#2-P1(+39) are approximately 40% higher than the ones in Door#1-P1(+38) because Jamb#2 is stiffer than Jamb#1.

  14

Figure 16: Wind-lock axial forces

Figure 17: Wind-lock twisting in the wind-guide at the top and bottom

Curtain

Wind-guide

Wind-lock

a a

Section a-a

  15

Table 2: Axial forces

4.4.Wind-lock bending The wind-lock bending moments at the loading peaks are provided in Figure 19 and Table 3.

Positive moment is defined as shown in Figure 18. Note that in positive pressure test, the moment is also positive because of the wind-lock bending at the wind-guide.

Figure 18: Bending moment in negative and positive pressure test

P3 (lbs) P1 (lbs) P2 (lbs)at - 43 psf at -42 psf at +38 psf at +35 psf (R) at +39 psf (R) at +46 psf at +77 psf at +39 psf at +200 psf

1 50 40 2 2 0 0 -1 10 3652 -110 -120 182 166 185 195 155 118 103 270 230 -750 -170 -340 -855 -960 124 9504 -320 -310 -80 -380 -380 -95 -685 -1140 28005 40 80 -610 -830 -800 -520 -1080 -1150 23006 425 430 400 300 330 465 800 230 18007 170 150 -10 -100 -140 0 310 6008 475 435 420 300 420 480 600 270 13609 415 415 310 170 250 445 660 570 1850

10 530 480 330 270 330 410 580 390 180011 200 190 150 0 55 135 440 530 225012 340 320 340 175 330 470 650 230 172013 490 450 310 270 290 250 460 500 190014 680 690 440 300 380 500 590 480 210015 840 770 690 470 580 720 880 450 146016 510 440 160 175 230 170 370 250 57017 430 425 1220 1050 1050 1000 820 1250 46018 -50 50 560 120 280 800 1380 115 800

P1 (lbs) P2 (lbs)Door#2

Lock #Door#1

N(lbs)

mom

ent

Negative Pressure Positive Pressure

mom

ent

mom

ent

mom

ent

+

-

+

-

+

-

+

-Strain gauge location Strain gauge location

  16

Figure 19: Wind-lock bending moment

  17

Table 3: Wind-lock bending moment

4.5.Wind-lock displacement (#10 and #11) The in-place displacements of wind-lock #10 and #11 measured during the tests are plotted in

Figure 20. The initial linear region represents the wind-lock gap (see Figure 1a), and the second linear region represents the wind-bar displacement in the plane of the door. The wind-lock gaps, axial forces and wind-bar displacement at the loading peaks are summarized in Table 4. The jamb stiffness is calculated as Kjamb=wind-lock axial force/wind-bar displacement at wind-lock #10 and #11 respectively. The average jamb stiffness is calculated as Kjamb-

ave=(Kjamb@#10+Kjamb@#11)/2. Note that the result for wind-lock #10 in Door#2-P2 is unusual (Kjamb-ave=Kjamb @ #11). This is likely because that the magnet on the wind-lock partially obstructed by the wind guide.

The results demonstrate that Jamb#2 is approximately 4.5 times stiffer than Jamb#1. In Table 4, compare Kjamb-ave=3392lbs/in. (Jamb#2) to Kjamb-ave=782 lbs/in. (Jamb#1). Removing the girts decreased jamb stiffness by more than half, compare Kjamb-ave=782 lbs/in. (Jamb#1) to Kjamb-ave=307 lbs/in. (Jamb#1R).

P3 (lbs-in.) P1 (lbs-in.) P2 (lbs-in.)at - 43 psf at -42 psf at +38 psf at +35 psf (R) at +39 psf (R) at +46 psf at +77 psf at +39 psf at +200 psf

1 57 56.5 -0.5 -0.5 -0.8 0.8 -0.8 -3 662 12.3 12.3 -5 -4.5 -5 -5 -4.5 -3 203 27.5 27 7.5 -4 -1.8 9 14 -7 344 10.5 10 29.5 7.5 14 33 42 17 435 28 28 51 36.5 44 53.5 57 48.5 516 36.5 35.5 63.5 53 62 64 63 57 567 43.5 42.5 65 56 65 64 63 54.5 548 48 47.5 67.5 61.5 70 68 65 49.5 509 47 47 64 59 66 62 58 46.5 47

10 49.5 49 64 58 65 60 57.5 45 4211 54.5 54 66 61.5 68 63 60 41.5 4112 58.5 58.5 66.5 64.5 69 63 61 42.5 43.513 61.5 61 67.5 62.5 68 65 63 45 4414 53 50 63.5 57 63 62 62 45 4515 35 32.5 52.5 48.5 53 51 52 43 4316 21.5 21 49.5 44 48 49 48 44 4417 21 21 36 24 28 39 44 24 4018 27 27 7.7 -1 1 11 19 -1 31.5

Lock #Door#1 Door#2

N(lbs-in.) P1 (lbs-in.) P2 (lbs-in.)

  18

Figure 20: Wind-lock #10 and #11 displacements

Table 4: Jamb stiffness at the wind-lock #10 and #11

4.6.Jamb deformation (at wind-lock#11) Jamb deformation results are reported in Figure 21 and can be interpreted as a combination

of three deformation modes- twisting, translation in the plane of the door, and bending as described in Figure 22. Jamb#1 deformation is controlled by twisting; the deformation of Jamb#1 with the girts removed is a combination of twisting and cross-section bending; Jamb#2 deformed in translation at a pressure lower than 60 psf, and in a combination of twisting and bending at a pressure higher than 60 psf.

Kjamb-ave

#10 #11 #10 #11 #10 #11 #10 #11 lbs/in.+ 38 0.35 0.32 330 150 0.31 0.30 1065 500 782+ 35 ( R ) 0.50 0.50 270 0 0.44 0.44 614 0 307+ 39 ( R ) 0.50 0.50 330 55 0.56 0.56 589 98 344+ 46 0.52 0.50 410 135 0.38 0.37 1079 365 722

P3 + 77 0.60 0.60 580 440 0.72 0.65 806 677 741P1 + 39 0.41 0.36 390 530 0.12 0.15 3250 3533 3392P2 + 200 0.31 0.52 1800 2250 0.07 1.00 27692 2250 2250

P2#1

#2

Door TestPeak (psf)

Wind-lock gap (in.) Axial force (lbs) Wind-bar disp (in.) Kjamb(lbs/in.)

P1

  19

Figure 21: Jamb deformation

  20

Figure 22: Three jamb deformation formats

4.7.Door failure

Door#2 failed at 200 psf with a net section failure at the riveted connections between the wind-lock and the door curtain (Figure 23). The net section failures were focused at the mid-height of the door. At failure, the wind-locks hooks were bent straight (Figure 23b), and the door disengagement occurred in dramatic fashion after the initial connection failure. There was no observable plastic deformation observed in the Jamb#2after the test (see Figure 23c).

Figure 23: (a) Door failure (b) failed wind-lock (c) Jamb#2 after test

- 0 + - 0 + - 0 +

Jamb displacement

Pres

sure

Jamb displacement Jamb displacement

a

b

c

abc

Twisting Translation Bending

(a) (b) (c)

  21

5. Comparison with CSBA Prediction Model The experimental results (curtain deflection at the middle of the door) are compared with the

CSBA model prediction in Figure 24. The parameters used in the CSBA model are summarized in Table 5, including the average jamb stiffness Kjamb-ave from Table 4. The CSBA model accurately predicts the initial loading curve before the wind-lock engages the wind-bar. The predicted loading curve is stiffer than the experimental results. The prediction to Door#2-P2(+200) is not as consistent with the test data because the model assumes a linear jamb stiffness and the test demonstrated a tri-linear jamb stiffness(see Figure 20).

The test-to-predicted comparison is summarized in Table 5. As discussed previously, the wind-lock axial forces at the top and the bottom of the door are influenced by the wind-lock twisting, so the average of the axial forces are compared only from the middle four wind-locks (#8-#11). The experimental results of both axial force and curtain deflection are higher than the CSBA model predicted results (see Table 5 Test/CSBA). This trend is likely caused by the flattening of the cold-formed steel corrugated curtain which causes the loading area to increase as illustrated in Figure 25 (see Janas and Moen 2011 for details). On average, the measured axial wind-lock force is 19% higher than the predicted wind-lock force with a COV of 8%, and the tested curtain deflection at mid height is 16% higher than the predicted deflection with COV of 8%. A multiplication factor on the wind-lock force and deflection predictions in CSBA may we warranted to compensate for the larger door area under pressure.

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Figure 24: Comparison with CSBA model for the first loading

Figure 25: Loading increase due to the flattening of the corrugated curtain

CSBA Prediction Experimental

Pressure, Pis constant

d1 d2

Pd1<Pd2

  23

Table 5: Parameters used in CSBA model for the first loading comparison

6. Proposed Limit State Design Methodology for Vehicular Access Doors

The experiments described in this report have confirmed that jamb stiffness is an important parameter to consider in design of vehicular access doors. The computer program CSBA provides a method for predicting wind-lock demand forces and door deflections including jamb stiffness, and so the next step is to develop a general design approach that considers potential design limit states, including door deflection, jamb capacity, and wind-lock strength. Specifically, a design procedure could be implemented that includes the following steps: (1) input door dimensions, jamb stiffness, and design pressure into CSBA; (2) determine the wind-lock demand load C and door deflection D; (3) check that the door deflection D is less than S/12 where S is the door span; (4) check that the wind-lock capacity Cn is greater than the demand C; and (5) check that jamb capacity is greater than the total demand on the jamb.

In Step (1), it is important to input an accurate jamb stiffness into CSBA. Jamb stiffness can be approximated with tests (Table 5) or calculated, for example, jamb stiffness prediction for a C-section braced by girts is treated in Janas and Moen (2011). As far as the design checks go, limit state (3) is simple to evaluate. In limit state (4), it is proposed that Cn is calculated as the minimum of Cn,curtain and Cn,windlock. The capacity Cn,curtain is the connection strength of the wind-lock to the door curtain which could be provided by manufacturers or potentially calculated with AISI S100-07. The wind-lock capacity Cn,windlock is calculated with the following equation:

Cn,windlock =Fy

dZ

+1A

!"###

$%&&&

(3)

where Fy is the wind-lock yield stress, d is the distance from the wind-bar to the wind-lock as shown in Figure 26, A=bt is the cross-sectional area of the wind-lock, and Z=bt2/4 is the weak axis plastic modulus of the wind-lock. (Note that the wind-lock width is b and its thickness is t.) Equation (3) is derived by assuming that wind-lock failure will occur as a combination of plastic bending caused by the load eccentricity from the wind-bar to the wind-lock and the axial force in the wind-lock as shown in Figure 27. Limit state (5), i.e., the jamb capacity check, is dependent

*Average axial force in the middle 4 wind-locksGap (in.) Kjamn-ave

AVER lbs/in. *Test(lbs) CSBA(lbs) Test/CSBA Test(in.) CSBA(in.) Test/CSBAP1 38 0.335 782 303 270 1.12 9.5 7.9 1.20P1 35(R) 0.5 185 182 1.02 10.4 9.8 1.06

39(R) 0.5 263 200 1.32 10.8 10.0 1.0846 0.51 722 367 294 1.25 10.2 9.2 1.11

P3 77 0.6 741 570 491 1.16 12.3 10.7 1.15P1 39 0.385 3392 440 348 1.26 8.0 6.8 1.18P2 200 0.52 2250 1815 1517 1.20 14.0 10.4 1.35

AVER 1.19 1.16COV 8% 8%

#1

#2

326P2

Door Test Axial force Middle deflectionPeak (psf)

  24

upon the jamb and wall framing details and will most likely require an engineer to calculate bending+torsion capacity and demands from multiple wind-locks along the height of the door.

Figure 26: Distance between the wind-bar and wind-lock

Figure 27: Yielding caused by both bending and tension

7. Conclusions

Two rolling sheet doors with different jamb design were tested in this study. The results clearly showed that the curtain deflection and the axial force in the wind-lock are functions of the jamb stiffness: a stiffer jamb can limit the curtain deflection, but at the same time introduce a higher axial force in the wind-lock. The wind-lock gap and the jamb stiffness were determined by measuring the wind-lock displacement during the test, and applied to the CSBA model. The CSBA model accurately predicted the door load-deformation response before the wind-lock engages the wind-bar. After the wind-lock engages the wind-bar, CSBA prediction was stiffer than the experimental result because of the curtain deformation that increases the loading area. The jamb deformation due to the catenary force includes cross-section twisting, cross-section translation and web bending.

d

Wind-bar

Wind-lock

Tension

Compression

Stress due to the plastic bending, M

+

Stress due to the axial force, N

=Tension

Compression

Fy=M/Z +N/A

Fy

  25

References Gao, T., and Moen, C. D. (2009). "Experimental Evaluation of a Vehicular Access Door Under

Hurricane Force Wind Pressures." Virginia Tech Dept. of Civil and Environmental Engineering, Report No. CE/VPI-ST-09/03, Blacksburg, VA

Janas, M., and Moen, C.D. (2011). "Vehicular Access Doors Under Hurricane Force Wind

Pressure: Analysis Methods and a Design Tool." Virginia Tech Dept. of Civil and Environmental Engineering,Report No. CE/VPI-ST-11/02, Blacksburg, VA

AppendixA: Measured Strains

The strain gage A and B were installed on both sides of the wind-lock as shown in Figure A1. The strain gage A faces inside of the building (outside of the chamber), and the strain gage faces the outside of the building (inside of the chamber). The strain measured is shown as a function of time below.

Figure A1: Strain gage location on the wind-lock

Door#1-N

3.158”Original wind-lock

4.932”Extension

1.5”

6 Rivets

4.5”

Strain gage A

Strain gage B

1.165”

0.13”

  26

  27

  28

  29

Door#1-P1

  30

  31

  32

Door#1-P2

  33

  34

  35

Door#1-P3

  36

  37

  38

Door#2-P1

  39

  40

  41

Door#2-P2

  42

  43

  44

  45

Appendix B: Janus 3100 details