ML20091C482

Rev 0 to Masonry Unit Wall,Fort Calhoun Power Station

ML20091C482
Person / Time
Site:	Fort Calhoun
Issue date:	05/10/1984
From:	Chhina R, Hendrickson M, Nanda B OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20091C466	List: ML20091C464 ML20091C482
References
FC-81-180, FC-81-180-R, FC-81-180-R00, MR-FC-81-180, NUDOCS 8405300579
Download: ML20091C482 (9)

Text

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GSE-B-2-2 Form PREPARED BY Baljit S. Manda CHECKED BY R,s. chA;,m APPROVED BY M.C. Handickeen SH. 1 CONT. ON SH. 2 REV. o DATE Sho/a4 Mt No. FC-81-180 OMANA PUBLIC POWER DISTRICT GENERATING STATION ENGINEERING MAS 0?RY UNIT WALL FORT CALHOUN POWER STATION MR-FC-81-180 8405300579 840522 PDR ADOCK 05000285 O PDR Rev. 1/84

CLIENT Omaha Public Power District (0 PPD)

ANALYSIS TITLE Block Pull Out Evaluation of Masonry Walls at Fort Calhoun Station AUTHOR IDENTIFICATION Baljit S. Nanda, NUS Corporation PURPOSE The Nuclear Regulatory Commission asked the District to perform Block Pull Out Calculations during a seismic event (Ref. #1, Item 4) to consider whether the attachments on the wall could cause a block pull out during a seismic event.

ETHOD OF ANALYSIS Seismic loads caused by the attachment on a wall will be calculated and compared against the block pull out capacity of a block at that location.

IMPUT INFORMATION - FURNISHED BY CLIENT

1. Updated Sa fety Analysis Report (USAR), Appendix F. " Classification of Structures and Equipment and Seismic Criteria."

2. Location of Attachments on Masonry Walls.

3 Cable Tray Seismic Analysis by Gibbs, Hill, Durham & Richardson (dated 6/30/71).

ASSUNPTIONS

1. Walls are unreinforced hollow masonry unit walls.

2. Mortar shear strength is compatible with the shear strength of concrete block.

3. Concrete block shell will fail before the failure of attachment anchors (Casei).

4 Pull out force is evenly transferred to the perimeter of concrete block (Case II) with possible block pull out.

5 No through bolts are installed at any location.

6. Anchor embedment length meets the manut'acturer's requirements and will develop full strength. ,,

REFERENCE DOCUMENTS

1. Letter from NRC to OPPD, dated February 6,1984, " Request for Additional Information, Masonry Wall Design IE Bulletin 80-11."

2. Updated Safety Analysis Report (USAR) Fort Calhoun Station Unit No. 1, Appendix F. " Classification of Structures and Equipment and Seismic Cri te ri a."

3. ACI 531-79, Building Code Requirements for Concrete Masonry Structures.

4. Technical Specification No. 14 - Masonry, Contract #764, Fort Calhoun Station Unit No.1.

5. ASTM Specifications for Concrete Masonry Units.

6 Cable Tray Seismic Analysis by Gibbs, Hill, Durham & Richardson, (dated 6/30/71).

7 Specification for the Design and Construction of Load-Bearing Concrete Masonry,1979 - National Concrete Masonry Association.

8 Dynamic Analysis of Masonry Walls, Calculated by B. S. Nanda.

9. Reinforced Masonry Engineering Hand Book, Fourth Edition, by James Amrhein.

REFERENCE DRAWINGS

1. Gibbs, Hill, Durham & Richardson Drwg. 11405-A-5

2. Gibbs, Hill, Durham & Richardson Drwg.11405-A-6

3. Gibbs, Hill, Durham & Richardson Drwg. 11405-A-7

4. Gibbs, Hill, Durham & Richardson Drwg.11405-A-8 MATERIALS OF CONSTRUCTION - (Ref. #4)

Existing Masonry Walls have the following properties:

a. Concrete Masonry Units- - ASTM C90, Type P-II

b. Mortar - ASTM C270, Type N

c. Vertical Joint - Running Bond

d. Installation - Pluab true to lines, full nortar joints, 3/8" joints, 40*F ambient temperature

ANALYSIS APPROACH

1. Seismic loads on the wall attachment anchors will be calculated based on acceleration values from floor response spectras provided by the Omaha Public Power District.

2. Block resistance against pull out will be calculated based on the following cases:

Case I: Blocks are not grouted and wall attachment anchors are sup-ported by the block shell only.

(This case may cause local shell failure only)

Case II: Blocks are solid grouted and anchor load is transferred evenly to the perimeter of the block.

(This case may cause a block pull out)

3. Block pull out forces will be compared against the block resistance to conclude that block pull out is possible or not.

ALLOWABLE STRESSES

1. Allowable Shear Strength of Type "N" Mortar = 23 psi (Ref. #7).

2. Coef ficient of Friction = 0.7 (Ref. #9). g g ggy PROPERTIES OF CONCRETE BLOCK ,

Block Area Contributing to Bond: ij g o .o o4 (Consider Q toQ of Mortar Joint) g g 5 a

] b'g 8" Block. ]l1 d

{

Side Shell Area = 2(2 x 1.25" x 8" Ht.) g/

= 40 IN2 Top & Bottom Area = 2(2 x 16" x 1.25")

= 80 IN2 Total Area = 40 + 80 = 120 IN2 (Ignore Web Area)

_ ,m_-

6" Block Side Shell Area = 2(2 x 1.00" x 8" Ht.)

= 32 IN2 Top & Bottom Area = 2(2 x 16" x 1.00")

= 64 IN2 Total Area = 32 + 64 = 96.0 IN 2 (Ignore Web Area) L j RESISTANCE AGAIRST BLOCK PULL OUT m.,

n Case I - Unreinforced Masonry Block: ' ~<

4 G" f ,j . -]

Allow Shear Stress = 23 psi h ' "

j

, MM Shaar Cone Surface Area = fr(S l#f #-

I yp 8" Block: h=P=1.25,S=ih2 + r2 =11.252 + 1.252 = 1.768" Area = fr x 1.25 x 1.768 = 6.94 IN2 P = Pull Out Force = 23 x 6.94 = 159.6#

6" Block: h=P=1.0,S=dh2+r2=12=1.414 l Area = ?r x 1.0 x 1.414 = 4.44 IN2 P = Pull Out Force = 23 x 4.44 = 102.12#

I Case II - Unreinforced - Grouted Masonry:

Resisting Forces:

Total Resisting Force = Shear Bond Resistance & Shear Frictional Forces due to weight wall above block course.

1. Shear Bond Resistance:

a. 8" Block = 23 psi x 120 IN2 = 27608

b. 6" Block = 23 psi x 96.0 IN2 = 22088

2. Shear Frictional Force:

This force depends on the height of wall above the subject block course and will be calculated for individual cases (if needed).

Seismic Forces Causing Block Pull Out:

1. Factors Causing Block Pull Out:

a. Total number of anchors used for attachment

b. Number of anchors in one block

c. Weight of attachment

d. Elevation of anchor

e. Thickness of wall CONTROL ROOM - SOUT!! WALL OF COMPUTER ROOM. LOOKING NORTH (8" WALL)

Attachment:

Electrical Distribution Panel (480V)

Data:

af Panel size = 60" x 33' x 9" 4' W 4L, Panel Wt. = 500# (Approx.) ,y r 1!?

No. of Anchors = 4-1/2" 0 ,

Max. No. of Anchors / Block = 1  !  ! ,I $

Panel is design as rigid panel - +H F

.g-Top anchor bolt El. = 1053'-0" Top of wall El. = 1065'-6" Calculations:

Panel is designed as rigid panel so acceleration -

f # , su race value from Fig. F-16(Ref. #2).

= 0.3299 x 1.5 (conservative) 'I" /~~

/

~

= 0.4949 ,

, /

Acceleration value from dynamic analysis masonry wall = 1.611 g (Calculation by B. Nanda) of C~*

/ y # p,d

, /-

Assune Horiz. Acceleration = 2.0g !A

/

Vert. Acceleration = 2/3 x 2.0g = 1.33g _. d l

Horizontal Seismic Load = 500+ x 2.0 = 1000#

Vertical Seismic Load = 500# x 1.33g = 665#

Horizontal Force 8 Top Anchor = 1000/4 + '(665#+500#)xj x 1/2

~

48-

= 322.8#

l Resistance Capacity of 8" Block Against

, Pull Out.(Without Shear Friction Resistance) = 2760# > 322.8#

l l BLOCK PULL OUT IS NOT POSSIBLE i

i

BATTERY ROOM - NORTH WALL LOOKING SOUTH (8" WALL)

Attachment:

Cable Tray Support (Horizontal)

Cable Tray Data:

Size = 24" Span = 16.7' (Max) (Ref. #6) Page 61.

Cable Tray with Cables = 56.8#/Ft.

NOTE: Cable trays have two support systems:

a. Hanger rod and unistruts are designed to carry dead load of cable trays and vertical seismic load,

b. Horizontal supports are designed to resist horizontal seismic loads.

Seismic Load:

Dead load of cable tray on support = 56.88 /'x 16.7'

= 948.6#

Natural Frequency of Cable Tray = Rigid Zone For L = 16.7' (Ref. #6)

From Fig. F-16 (Ref. #2), Response of Equipment located in Aux. Building (Mass #4) acceleration for rigid zone = 0.3299 x 1.5 = 0.4949 Ref: (Dynamic Analysis of Masonry Walls)

Acceleration from Dynamic Analysis of Wall = 0.9169 ::51.09(conservative)

Horizontal Seismic Load = 948.6 x 1.0g = 948.6# gfl i

No of bolts on support = 4 _, +

Assume 2 bolts per block 44 __

Block Pull Out Force = 948.6x2 = 474.38 '"""

T --i-g i~~T'-~

am Resistance of 8" Block Against Pull Out (Without Shear Friction) = 2760# > 474.3#

SO DURING A SEISMIC EVENT BLOCK WILL NOT PULL OUTI 7

AUXILIARY BUILDING North wall of corridor between column line 7a_ and 7b_ - looking north (6" wall).

Attachment:

Cable Tray Supports (Horizontal Only)

Cable Tray Data:

No. of stacked cable trays = 3 Cable tray size = 24" Wt. of cable tray full of cable = 56.8 /Ft. # (Ref. #6)

Span of cable trays supports = 16.7' NOTE: Horizontal supports are designed to support horizontal loads only.

Vertical dead load and seismic load are supported by unistrut and hanger rod system.

Block Pull Out Load:

Dead load of cable trays = 3 x (56.8# /Ft. x 16.7')

= 2845.7# _, qw.

$- ssesmc.

Assuming cable trays and supports are designed as \.,p rigid (Ref. #6), acceleration for rigid zone Fig. F-16 (Ref. #2) = 0.329 x 1.5 = 0.496 h*hD g., g. N W p,

Acceleration value for wall from dynamic analysis = 1.4929 \ k u \ . w

.e-gd yj, w Using conservative value for Horizontal Seismic Load "/4"s#A -

- S

= 2845.7# x 1.4929 s 4 = Elev.

l = 4245.8#

l Assuming load is resisted b support = 4245.8/2 = 2122.9# y 2 leg supports, load per 2123#

Assuming that both bolts at top are anchored in the same block, block pull out force = 2123#

Resistance of 6" block pull out (Without Shear Frictional Resistance) = 2208# > 2123#

BLOCK PULL OUT IS NOT POSSIBLE l

l

-- . . _ . , . .__,._.__._-_.-~___,---_-,,_..,_....______._.....,_-_..__.---__,_.m .

j .-

CONCLUSI0ll The analysis shows that block pull out will not occur in a seismic event. The analysis performed is conservative because of the following:

1. In Case II, even though the block cells were considered to be grouted, the shear resistance of grout area was neglected.

2 Shear frictional resistance due to weight of block wall above the block course was neglected.

3. Web area of the shell was not considered.

3 i ,

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