MEMORANDUM TO:	Project Engineers
	Project Design Engineers
FROM:	W. J. Rogers, P. E.
	State Bridge Design Engineer
DATE:	October 8, 1997
SUBJECT:	POT BEARINGS

Due to the number of plan revisions inherent in the existing pot bearing policy, the following policy will be effective with the December letting:

• Manufactures will be required to fabricate the overall height of the pot bearing assembly to within 1/2" (13mm) of the dimension shown on the contract plans.
  
  
• The pot bearing fabricator will be required to provide the masonry plate thickness as shown on the contract plans.
  
  
• In lieu of the current substructure note shown in Section 8-1(0) of the Design Manual, place the following note on the superstructure typical section sheet:
  
  "The Contractor shall adjust the girder build-ups as necessary to incorporate a maximum permissible variation in pot bearing depth of 1/2 inch (13mm), see special provision for Pot Bearings."
  
  
• Use the values shown in the Pot Bearing Design Data chart for detailing the pot bearings. To account for sole plate bevel increase the overall height of the bearing assembly by adding 1/8 inch (3mm) per percent of grade. Show the slope on the sole plate but do not dimension it otherwise.

The attached charts have been revised to correct an error on the metric chart and to reflect the revised policy. The Project Special Provision will be revised to reflect this policy change with the December letting.

WJR/RGW/ap

cc: N. M. Salmon, P. E.
T. V. Rountree, P. E.
T. Misenheimer, P. E.

Design Data for Fixed Pot Bearings
Vertical	Masonry	Bolt	Masonry	*Bearing	**Total
Load	Plate W	Gage	Plate t	Height	Height
(kN)	(mm)	(mm)	(mm)	(mm)	(mm)
222	358	206	18	96	119
333	378	226	22	96	123
444	396	244	22	96	123
556	410	258	25	96	126
667	426	274	25	96	126
889	450	298	25	96	126
1334	488	336	28	96	129
1779	524	372	28	105	138
2224	568	416	30	115	150
2668	622	470	32	127	164
3113	674	520	38	137	180
3558	720	568	38	147	190
4003	762	610	45	150	200
4448	804	650	45	166	216
Design Data for Expansion Pot Bearings
Vertical	Masonry	Bolt	Masonry	*Bearing	**Total
Load	Plate W	Gage	Plate t	Height	Height
(kN)	(mm)	(mm)	(mm)	(mm)	(mm)
222	358	206	18	108	131
333	378	226	22	108	135
444	396	244	22	110	137
556	410	258	25	110	140
667	426	274	25	110	140
889	450	298	25	112	142
1334	488	336	28	124	157
1779	524	372	28	132	165
2224	568	416	30	147	182
2668	622	470	32	159	196
3113	674	520	38	167	210
3558	720	568	38	185	228
4003	762	610	45	185	235
4448	804	650	45	198	248
* Includes sole plate thickness
** Includes preformed bearing pad thickness
Note: Add 3mm per percent of grade to the overall bearing height shown in the table.
Show the slope required on the sole plate to accommodate the required grade.
Bearings of these sizes will accommodate .02 radians rotation.
The bolt gages shown are for square masonry plates.

Design Data for Fixed Pot Bearings

Vertical

Masonry

Bolt

Masonry

*Bearing

**Total

Load

Plate W

Gage

Plate t

Height

Height

(kips)

(in.)

(in.)

(in.)

(in.)

(in.)

50

14 1/8

8 1/8

3/4

3 3/4

4 11/16

75

14 7/8

8 7/8

7/8

3 3/4

4 13/16

100

15 5/8

9 5/8

7/8

3 3/4

4 13/16

125

16 1/8

10 1/8

1

3 3/4

4 15/16

150

16 3/4

10 3/4

1

3 3/4

4 15/16

200

17 3/4

11 3/4

1

3 3/4

4 15/16

300

19 1/4

13 1/4

1 1/8

3 3/4

5 1/16

400

20 5/8

14 5/8

1 1/8

4 1/8

5 7/16

500

22 3/8

16 3/8

1 1/4

4 1/2

5 15/16

600

24 1/2

18 1/2

1 3/8

5

6 9/16

700

26 1/2

20 1/2

1 1/2

5 3/8

7 1/16

800

28 3/8

22 3/8

1 1/2

5 3/4

7 7/16

900

30

24

1 5/8

5 7/8

7 11/16

1000

31 5/8

25 5/8

1 3/4

6 1/2

8 7/16

Design Data for Expansion Pot Bearings

Vertical

Masonry

Bolt

Masonry

*Bearing

**Total

Load

Plate W

Gage

Plate t

Height

Height

(kips)

(in.)

(in.)

(in.)

(in.)

(in.)

50

14 1/8

8 1/8

3/4

4 1/4

5 3/16

75

14 7/8

8 7/8

7/8

4 1/4

5 5/16

100

15 5/8

9 5/8

7/8

4 5/16

5 3/8

125

16 1/8

10 1/8

1

4 5/16

5 1/2

150

16 3/4

10 3/4

1

4 5/16

5 1/2

200

17 3/4

11 3/4

1

4 3/8

5 9/16

300

19 1/4

13 1/4

1 1/8

4 7/8

6 3/16

400

20 5/8

14 5/8

1 1/8

5 3/16

6 1/2

500

22 3/8

16 3/8

1 1/4

5 3/4

7 3/16

600

24 1/2

18 1/2

1 3/8

6 1/4

7 13/16

700

26 1/2

20 1/2

1 1/2

6 9/16

8 1/4

800

28 3/8

22 3/8

1 1/2

7 1/4

8 15/16

900

30

24

1 5/8

7 1/4

9 1/16

1000

31 5/8

25 5/8

1 3/4

7 13/16

9 3/4

* Includes sole plate thickness.

** Includes preformed bearing pad thickness.

Note: Add 1/8 inch per percent of grade to the overall bearing height shown in the table.

Show the slope required on the sole plate to accomadate the required grade.

Bearings of these sizes will accomodate .02 radians rotation.

The bolt gages shown are for square masonry plates.