Report

on

Testing of Memorials

at

Parkside Cemetery, Kendal

 

 

 

 

 

 

 

 

 

National Association of Memorial Masons

Report prepared by:

John Knapton

Professor of Structural Engineering

University of Newcastle upon Tyne

29th June 1995

 

 

 

INTRODUCTION

This Report sets out the results of tests undertaken on a series of specially installed memorials at Parkside Cemetery, Kendal on 29th June 1995. The purpose of the tests was to produce technical information in support of NAMMís recommendations for the safe fixing of memorials. In each test, a previously installed memorial was subjected to a horizontal load applied at the uppermost point of the memorial. The load was applied by mechanically increasing tension in a steel rope connected between the memorial and a heavy vehicle positioned so as to allow the force to pull the memorial towards its rear, i.e. away from the position where in normal circumstances a grave would be dug. The force applied was measured by including in line a spring balance capable of measuring up to 150 kgf to an accuracy of 1 kgf. The memorials had been installed on 19th June 1995 so as to ensure that all materials having time dependent properties e.g. cement, resin had reached full strength by the time the testing was undertaken.

The tests were conducted by members of NAMM, assisted by local masons and the results were recorded Professor Knapton. The memorials were installed in part of the cemetery which had been filled with material surplus to backfilling of older graves. This material had consolidated and had an estimated California Bearing Ratio of 7% at the time of testing. The weather was hot and dry and there had been no rain for several days.

In addition to the information set out in the main body of this Report, a preliminary test was carried out to establish the value of the load which is applied to a memorial by someone using the memorial plate to assist in standing after, for example, attending to the vase in the base. It was found that a man weighing 14 stones would normally exhert a force of approximately 30 kgf. In view of this and in view of the other forces which it could be reasonably expected would be applied (excluding determined vandals), it is considered that all memorials in UK cemeteries should be designed to withstand a horizontal pulling force of 100 kgf and that they should be proof tested to 70 kgf. The proof force should be applied in each feasible direction, i.e. both forwards and backwards except for back to back memorials where the only feasible test direction is forwards, i.e. pulling over the grave.

Four types of foundation were included in the trials:

i) a single precast concrete slab (4.1 & 4.2)

ii) two precast concrete slabs fixed together (1.1 to 1.5)

iii) a single precast slab and two ground tubes (2.1 to 2.7, 4.3, 4.4 & 11)

iv) a specially moulded precast concrete multi-level foundation (JK1)

Additionally, four memorials supplied by Frank Bull Ltd. were tested (B1 to B4). No information was available regarding the foundations to these four memorials.

In cases where failure appeared to occur at a lower load than expected, a close examination of the detail was carried out to establish the quality of workmanship. It was found that as a result of wet weather during installation of the memorials, in some cases, workmanship defects had led to premature failure.

 

 

 

 

 

 

MEMORIAL REFERENCE No. 4.2

 

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

32

12

18

-

Width (in)

26

30

47

-

Thickness (in)

4

4

2

-

Dimensions of Memorial. Memorial was constructed from Black Granite.

 

DETAILS OF FIXING

The memorial base was connected to the precast concrete foundation by two vertical 16 mm diameter stainless steel dowel bars at 14 in centres. These bars were set into the memorial base by resin and were located dry into the foundation slab. Each dowel was 8 in long and was set 2 in into the base so that it protruded by 4 in into the ground beneath the foundation slab. The memorial plate was fixed to the memorial base by two 12mm diameter dowel bars set in resin both in the plate and in the base.

 

 

DETAILS OF TEST

The load was increased progressively to a maximum of 40 kgf at which a toppling failure of the whole memorial occurred. The plate, base and foundation remained intact. No further load could be sustained.

 

 

CONCLUSION

It is concluded that this method of fixing is inappropriate of normal UK cemetery memorials. The ultimate load of 40 kgf is insufficient and the toppling failure represents a dangerous situation since the memorial failed with little warning.

 

 

 

 

 

MEMORIAL REFERENCE No. 4.1

 

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

36

12

18

-

Width (in)

28

34

47

-

Thickness (in)

4

6

2

-

Dimensions of Memorial. Memorial was constructed from White Marble.

 

DETAILS OF FIXING

The memorial base was connected to the precast concrete foundation by two vertical 16 mm diameter stainless steel dowel bars at 14 in centres. These bars were set into the memorial base by resin and were located dry into the foundation slab. Each dowel was 8 in long and was set 2 in into the base so that it protruded by 4 in into the ground beneath the foundation slab. The memorial plate was fixed to the memorial base by two 12mm diameter dowel bars set in resin both in the plate and in the base.

 

 

DETAILS OF TEST

The load was increased progressively to a maximum of 39 kgf at which a toppling failure of the whole memorial occurred. The plate, base and foundation remained intact. No further load could be sustained.

 

 

CONCLUSION

It is concluded that this method of fixing is inappropriate of normal UK cemetery memorials. The ultimate load of 39 kgf is insufficient and the toppling failure represents a dangerous situation since the memorial failed with little warning.

 

 

MEMORIAL REFERENCE No. 2.3

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

38

11.5

18

-

Width (in)

28

31

40

-

Thickness (in)

4

6

2.5

-

Dimensions of Memorial. Memorial was constructed from Black Granite.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to 60 kgf at which load initial foundation movement was observed. The load was increased to 70 kgf at which load the memorial plate separated from the memorial base. There followed progressive failure during which the memorial plate gradually rotated and sustained an ultimate load of 100 kgf.

 

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 70 kgf without undue rotation. One rotation commenced, the ultimate load sustainable was 100 kgf. The mode of failure is progressive and is inherently safe in that no sudden catastrophic failure took place. This type of fixing would be suitable in most UK memorial situations.

 

 

MEMORIAL REFERENCE No. 2.7

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

37

13.5

18

-

Width (in)

30

36

42

-

Thickness (in)

4

11

2.5

-

Dimensions of Memorial. Memorial was constructed from Black Granite.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to 60 kgf at which load the memorial plate separated from the memorial base. A close inspection of the plate/base interface showed that one of the holes in the base had been overdrilled to 25mm instead of the 20mm as intended. Also, dust had been left in the hole prior to installing resin. As a result, a bond failure occurred at the circumference of that hole and the 60 kgf load at failure is not considered to represent the true potential of this type of fixing.

 

CONCLUSION

It is concluded that because of the errors in fixing the plate to the base, no conclusion can be formed in relation to the fixing system installed except that it could withstand a horizontal load of more than 60 kgf..

 

MEMORIAL REFERENCE No. 2.5

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

36

12

18

-

Width (in)

28

34

40

-

Thickness (in)

4

6

2.5

-

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to 60 kgf at which load the adhesive bonding the plate to the base failed. The load was increased to 70 kgf at which load the foundation slab began to move. There followed progressive failure during which the entire memorial gradually rotated and sustained an ultimate load of 117 kgf. Close inspection of the memorial indicated that the threaded studs connecting the memorial base to the foundation had bent along with the rotation of the memorial. One of the ground tubes had risen by 25mm and the other had remained in place.

 

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 70 kgf without undue rotation. One rotation commenced, the ultimate load sustainable was 117 kgf. The mode of failure is progressive and is inherently safe in that no sudden catastrophic failure took place. This type of fixing would be suitable in most UK memorial situations.

MEMORIAL REFERENCE No. 2.2

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

30

12

18

-

Width (in)

24

30

36

-

Thickness (in)

4

4

2.5

-

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to 85 kgf at which load the memorial base separated from the precast concrete foundation slab. The load was sustained at 85 kgf at which load the resin in the hole in the memorial base failed as a result of dust left in both of the holes causing bond failure. There followed progressive failure during which the entire memorial gradually rotated and sustained an ultimate load of 85 kgf. Close inspection of the memorial indicated that the tubes had remained in place and failure had occurred as a result of inadequate fixing of the threaded studs into the underside of the base.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 85 kgf without undue rotation. But for a defect in the setting of threaded dowels into the underside of the base, the load sustained may have been greater. The mode of failure is progressive and is inherently safe in that no sudden catastrophic failure took place. This type of fixing would be suitable in most UK memorial situations.

MEMORIAL REFERENCE No. 2.1

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

30

12

18

-

Width (in)

24

30

36

-

Thickness (in)

4

4

2.5

-

Dimensions of Memorial. Memorial was constructed from Black Granite.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to 65 kgf at which load the memorial base separated from the precast concrete foundation slab. The load was progressively increased to 123 kgf during which time progressive failure occurred with the memorial eventually leaning over by over 30 degrees. Close inspection of the memorial indicated that the tubes had risen. Eventually, the whole memorial was pushed over and the tubes came out of the ground by disturbing the earth surrounding them.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 65 kgf without undue rotation. The ultimate load was 123 kgf. The mode of failure is progressive and is inherently safe in that no sudden catastrophic failure took place. This type of fixing would be suitable in most UK memorial situations.

 

 

MEMORIAL REFERENCE No. 1.5

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

37

13.5

18

20

Width (in)

30

36

43

49

Thickness (in)

4

11

2.5

2.5

Dimensions of Memorial. Memorial was constructed from Black Granite.

DETAILS OF FIXING

The memorial base was fixed to the two precast concrete foundation slabs by two 8 in long 12mm diameter dowels set 2 in into the memorial base. They extended 5 in through the two precast concrete foundation slabs and protruded 1 in beneath the foundations. They were set at 14 in centres. Holes of diameter 22mm were drilled to accommodate the dowels in the precast concrete foundation slabs. The two slabs were cemented together. The plate and the base were connected by two 12mm diameter dowels set in resin in the plate and in cement in the base.

DETAILS OF TEST

The load was increased progressively to 40 kgf at which load the memorial plate separated from the memorial base. The load was increased progressively to 60 kgf at which load the memorial base separated from the precast concrete foundation slabs. At this time, the load reduced to 30 kgf as the memorial was gradually pulled over.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 40 kgf without undue rotation. The ultimate load was 60 kgf. The mode of failure is progressive. Whilst this is preferable to sudden catastrophic failure, the actual loads attained are considered to be insufficient to allow this fixing detail to be recommended.

 

 

 

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE No. 1.2

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

30

12

18

20

Width (in)

24

30

36

42

Thickness (in)

4

4

2.5

2.5

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

The memorial base was fixed to the two precast concrete foundation slabs by two 8 in long 12mm diameter dowels set 2 in into the memorial base. They extended 5 in through the two precast concrete foundation slabs and protruded 1 in beneath the foundations. They were set at 14 in centres. Holes of diameter 22mm were drilled to accommodate the dowels in the precast concrete foundation slabs. The two slabs were cemented together. The plate and the base were connected by two 12mm diameter dowels set in resin in the plate and in cement in the base.

DETAILS OF TEST

The load was gradually increased to 56 kgf at which value the foundation slabs began to lift. The load was increased progressively to 66 kgf at which load the memorial base separated from the precast concrete foundation slabs. The memorial continued to accept further load to an ultimate load of 83 kgf was attained. The memorial then commenced to rotate progressively whilst sustaining a load of 55 kgf. An inspection of the interface between the two precast concrete foundation slabs indicated that the cementing of them together was poorly undertaken.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 56 kgf without undue rotation. The ultimate load was 83 kgf. The mode of failure is progressive. Whilst this is preferable to sudden catastrophic failure, the actual loads attained are considered to be insufficient to allow this fixing detail to be recommended.

 

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE No. 1.4

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

36

12

18

20

Width (in)

28

34

40

40

Thickness (in)

4

6

2.5

2.5

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

The memorial base was fixed to the two precast concrete foundation slabs by two 8 in long 12mm diameter dowels set 2 in into the memorial base. They extended 5 in through the two precast concrete foundation slabs and protruded 1 in beneath the foundations. They were set at 14 in centres. Holes of diameter 22mm were drilled to accommodate the dowels in the precast concrete foundation slabs. The two slabs were cemented together. The plate and the base were connected by two 12mm diameter dowels set in resin in the plate and in cement in the base.

DETAILS OF TEST

The load was gradually increased to 80 kgf at which value the foundation slabs began to lift. The value of 80 kgf remained constant as the two precast concrete slabs continued to lift and without any increase in load, the memorial base separated from the two foundation slabs which remained joined together. After the base separated from the foundation slabs, the load reduced to 58 kgf and then fell to 55 kgf and finally to 40 kgf as the plate and the memorial base progressively rotated together. At the conclusion of the test, the two precast concrete foundation slabs remained cemented together.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 80 kgf without undue rotation. The ultimate load was 80 kgf. The mode of failure is progressive. Although the initial movement occurred at the relatively high load of 80 kgf, the fact that the ultimate load failed to increase beyond this value makes this type of fixing inadequate for UK cemetery installation.

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE No. 1.3

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

38

12

18

20

Width (in)

30

29.5

41

47

Thickness (in)

4

6

2.5

2.5

Dimensions of Memorial. Memorial was constructed from Black Granite.

DETAILS OF FIXING

The memorial base was fixed to the two precast concrete foundation slabs by two 8 in long 12mm diameter dowels set 2 in into the memorial base. They extended 5 in through the two precast concrete foundation slabs and protruded 1 in beneath the foundations. They were set at 14 in centres. Holes of diameter 22mm were drilled to accommodate the dowels in the precast concrete foundation slabs. The two slabs were cemented together. The plate and the base were connected by two 12mm diameter dowels set in resin in the plate and in cement in the base.

DETAILS OF TEST

The load was gradually increased to 50 kgf at which value the upper foundation slab began to lift leaving the lower foundation slab in place as the two slabs separated. After this, the force fell to 38 kgf and then rose to 52 kgf as the monument began to rotate progressively. Finally, the load rose to 60 kgf.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 50 kgf without undue rotation. The ultimate load was 61 kgf. The mode of failure is progressive. Whilst this is preferable to sudden catastrophic failure, the actual loads attained are considered to be insufficient to allow this fixing detail to be recommended. The relatively low loads in this test are a consequence of the separation of the upper and lower foundation slabs.

 

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE No. 1.1

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

30

12

18

20

Width (in)

23.25

30

36

42

Thickness (in)

4

4

2.5

2.5

Dimensions of Memorial. Memorial was constructed from Black Granite.

DETAILS OF FIXING

The memorial base was fixed to the two precast concrete foundation slabs by two 8 in long 12mm diameter dowels set 2 in into the memorial base. They extended 5 in through the two precast concrete foundation slabs and protruded 1 in beneath the foundations. They were set at 14 in centres. Holes of diameter 22mm were drilled to accommodate the dowels in the precast concrete foundation slabs. The two slabs were cemented together. The plate and the base were connected by two 12mm diameter dowels set in resin in the plate and in cement in the base.

DETAILS OF TEST

The load was gradually increased to 70 kgf at which value the foundation slabs began to lift. The load increased to 103 kgf as the two precast concrete slabs continued to lift. The memorial began to rotate progressively and achieved an ultimate load of 103 kgf. At the conclusion of the test, the two precast concrete foundation slabs remained cemented together and the memorial base remained connected to the plate.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 70 kgf without undue rotation. The ultimate load was 103 kgf. The mode of failure is progressive. The loads recorded just comply with recommended safety values. However, to achieve these values, all of the memorial had to remain fully connected during the test and tests on similar fixing methods indicate that this is likely to occur in the minority of installations. Effectively, the degree of workmanship required to ensure that this type of fixing will lead to a safe memorial is greater than will commonly occur.

 

 

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE Nos. B1, B2, B3 & B4

Four memorials had been installed by Frank Bull Memorial Mason and the results were as follows:

B1(No.1)

The load was increased progressively to 100 kgf at which load the memorial base and the plate separated suddenly. Following this, the memorial would not sustain any further load.

B2(No.2)

At 40 kgf, a little foundation movement was observed. At 65 kgf, the memorial base and the foundation began to move. At 113 kgf, the base separated from the foundation. After this, the memorial sustained a load of 45 kgf during which progressive rotational failure occurred.

B3(No.3)

The load was increased to 60 kgf at which sudden failure occurred as the memorial plate separated from the base. After this, no further load could be sustained.

B4(No.4)

The load was increased progressively to 43 kgf when the memorial plate first separated from the base. The load continued to increase to an ultimate value of 57 kgf, after which progressive rotation occurred at a low load value.

 

CONCLUSIONS RELATING TO B1-B4

As there is no information available relating to the details of the fixing system employed, it is difficult to draw detailed conclusions in these four cases. B1 has attained the load which would be considered to be safe whilst the others have failed to attain the proof load of 70 kgf or the design load of 100 kgf. If all of the conditions present in B1 can be guaranteed to be replicated in day to day practice, then B1 can be considered to represent a safe method of fixing.

 

 

 

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE No. 2.6

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

36

12

20

-

Width (in)

28

34

40

-

Thickness (in)

4

6

2.5

-

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to 85 kgf at which load the foundation slab began to move. There followed progressive failure during which the entire memorial gradually rotated and sustained an ultimate load of 139 kgf. Close inspection of the memorial indicated that the threaded studs connecting the memorial base to the foundation had bent along with the rotation of the memorial. One of the ground tubes had risen by 25mm and the other had remained in place.

 

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 85 kgf without undue rotation. Once rotation commenced, the ultimate load sustainable was 139 kgf. The mode of failure is progressive and is inherently safe in that no sudden catastrophic failure took place. This type of fixing would be suitable in most UK memorial situations.

 

MEMORIAL REFERENCE No. 4.3

 

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

36

12

18

-

Width (in)

28

34

47

-

Thickness (in)

4

6

2

-

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to 45 kgf at which load initial movement of the foundation was observed. The load was increased to 70 kgf and the foundation began to separate from the memorial base. The memorial began to rotate progressively as the ultimate load sustained rose to 90 kgf. Close inspection of the memorial indicated that the tubes had remained in place and during rotation, the foundation slab had risen over them.

 

 

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 70 kgf without undue rotation. The ultimate load was 90 kgf. The mode of failure is progressive and is inherently safe in that no sudden catastrophic failure took place. This type of fixing would be suitable in most UK memorial situations.

MEMORIAL REFERENCE No. 4.4

 

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

32

12

18

-

Width (in)

26

30

47

-

Thickness (in)

4

4

2

-

Dimensions of Memorial. Memorial was constructed from Black Granite.

 

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The load was increased progressively to a maximum of 80 kgf at which load the whole of the memorial commenced to rotate without any components separating. During rotation, the memorial sustained an ultimate load of 127 kgf. During the rotation, the ground tubes rose as the two precast concrete slabs lifted.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 70 kgf without undue rotation. The ultimate load was 90 kgf. The mode of failure is progressive and is inherently safe in that no sudden catastrophic failure took place. This type of fixing would be suitable in most UK memorial situations.

 

MEMORIAL REFERENCE No. 2.4

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

38

11.5

20

-

Width (in)

28

31

40

-

Thickness (in)

4

6

2.5

-

Dimensions of Memorial. Memorial was constructed from Black Granite.

DETAILS OF FIXING

The memorial plate was fixed to the memorial base with 10mm diameter galvanised steel dowels set 2.5 in into the plate with hot lead and set 3 in into the memorial base with cement. These dowels were set into 20mm diameter holes in both the plate and the base.

The memorial base was connected to the precast concrete foundation slab and also to the underlying ground by two 16mm diameter 8 in long threaded studs set with resin 2 in into the memorial base at 14 in centres. Two holes of diameter 18mm to 22mm (typically 20mm diameter) were drilled into the underside of the memorial base to accommodate the threaded studs. The two threaded studs protruded by 6 in downwards from the memorial base into two 15 in long 26mm diameter stainless steel tubes located but not set into 30mm diameter holes drilled into the foundation slab. The tubes had a 0.75 in long point on their lower end to facilitate driving into the ground.

 

DETAILS OF TEST

The purpose of this test was to evaluate the difference between a base of width 20 in and a base of width 18 in. The memorial was assembled during the day of testing as a result of which the resin bonding the memorial base to the foundation slab failed to cure and an unrepresentatively low ultimate load of 40 kgf was recorded.

CONCLUSION

No helpful conclusions can be drawn from this test.

 

 

 

 

 

 

MEMORIAL REFERENCE No. JK1

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

32.5

12

12

-

Width (in)

24

34

26

-

Thickness (in)

4

6

-

-

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

This memorial had been installed by JKH Drainage Ltd. using a double layer precast concrete foundation system incorporation soil between two concrete slabs. The concrete slabs were connected to each other and to the memorial by a system of bolts and other fixings.

DETAILS OF TEST

The memorial sustained the maximum load which could be applied (150 kgf) without any sign of distress. A small degree of rotational movement was observed.

CONCLUSION

It is concluded that this fixing system was able to sustain a load of at least 150 kgf without undue rotation. This type of fixing would be suitable in most UK memorial situations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE No. 3.1

DETAILS OF MEMORIAL TESTED

 

Memorial

Plate

Memorial

Base

Upper Foundation

Lower Foundation

Height or

Depth (in)

46

-

18

-

Width (in)

27

-

30

-

Thickness (in)

4

-

2.5

-

Dimensions of Memorial. Memorial was constructed from White Marble.

DETAILS OF FIXING

The foundation comprised a flat base set 8 in below ground level with in-situ concrete being placed above. Stainless steel dowels were bolted from the underside of the memorial.

DETAILS OF TEST

The load was progressively increased to 60 kgf at which time initial movement was observed. The load was increased progressively until the maximum possible load of 150 kgf was attained. At this load, the memorial had rotated such that a gap of 15mm had developed at the ground.

CONCLUSION

It is concluded that this fixing system was able to sustain a load up to 150 kgf without undue rotation. No failure occurred This type of fixing would be suitable in most UK memorial situations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MEMORIAL REFERENCE No. 11

DETAILS OF FIXING

A crucifix type memorial of height 1.7m was installed using the two ground tubes method. It was located on a single foundation precast concrete slab of dimensions 40 in x 18 in x 2.5 in. This slab was laid over a lower foundation comprising two concrete bearers running front to back with in-situ concrete placed between the bearers. The tubes were set into the in-situ concrete.

DETAILS OF TEST

The load was applied gradually and the foundation began to rotate at a load of 60 kgf. After that, the load fell to 50 kgf then rose to 67 kgf as the lower concrete foundation was raised. During this phase, the ground tubes rotated with the memorial

CONCLUSION

It is concluded that longer tubes would be required for this type of memorial. From the results, it is concluded that tubes of length 24 in would be required in this case.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SUMMARY

The following table summarises the test results

Memorial Reference

Proof Load

(kgf)

Ultimate Load

(kgf)

Load Height

(in)

Foundation Type

1.1

70

103

34

Two precast slabs

1.2

56

83

34

"

1.3

50

60

44

"

1.4

80

80

42

"

1.5

40

60

48

"

2.1

65

123

34

Single precast slab and two tubes

2.2

85

85

34

"

2.3

60

100

42

"

2.4

40

40

44

"

2.5

60

117

42

"

2.6

85

139

42

"

2.7

60

60

48

"

4.1

39

39

42

Single precast slab

4.2

40

40

36

"

4.3

70

90

42

Single precast slab and two tubes

4.4

80

127

36

"

B1

100

100

-

Unknown

B2

40

113

-

"

B3

60

60

-

"

B4

43

57

-

"

11

60

67

 

Single precast slab and two tubes

JK1

150

150

38.5

Special precast arrangement

Summary of loads applied to memorials at Parkside Cemetery, Kendal on 29th June 1995. The minimum Proof Load which a memorial should sustain is 70 kgf and the minimum Ultimate Load is 100 kgf. Some of the values in the table are lower than would have been recorded had workmanship been of a higher quality. In particular, bond between cements or resins and stone surfaces was sometimes weak as a result of damp conditions at the time of the memorials being installed.

The Proof Load and Ultimate Load values in the above table should be compared with those considered to be necessary to ensure memorial safety for all situations other than determined vandals. The minimum Proof Load required is considered to be 70 kgf and the minimum Ultimate Load is 100 kgf. The results indicate that foundations comprising either one or two precast concrete slabs fixed to the memorial base by conventional dowels cannot sustain those forces. In the case of memorials incorporating ground tubes, failure below those levels occurred only when an installation defect was apparent. In correctly fixed memorials having two ground tubes, typical Proof Load values are up to 85 kgf and typical Ultimate Load values are 100 kgf to 139 kgf. The special memorial B1 attained the required values but B2, B3 and B4 failed to achieve the Proof Load (B3 & B4 also failed to achieve the Ultimate Load). The special memorial JK1 was the strongest and had Proof Load and Ultimate Load values greater than 150 kgf, the limit of the spring balance used in the testing.

In all of the tests, where even a relatively minor defect in installation was evident, the strength of the memorial was reduced severely, often to half of the value which it could have been expected to achieve. From this, it is concluded that the importance of quality of workmanship in fixing memorials needs to be emphasised. Also, a system needs to be introduced to verify that workmanship is of high quality. It is recommended that all memorials should be subjected to the Proof Load (70 kgf) as soon as the materials used in installation have gained full strength and certainly no later than six months after installation. Any memorial which fails to accommodate the Proof Load without significant rotation should be dismantled and re-erected.

It is clear from the tests that there are many memorials which would not sustain the Proof Load. It is recommended that a program be introduced to test all UK memorials over a five years period and all those which fail should be dismantled and re-erected using a proven system to ensure stability. Thenceforth, testing of all memorials should be carried out at intervals of not greater than five years.

Other findings were as follows. Firstly, no difference was found in the performance of memorials constructed of different stone but similar in all other respects. There is no advantage in using Black Granite in preference to White Marble. There is a structural enhancement to be gained by using 20 inch wide bases instead of conventional 18 inch wide ones.

All of the memorials were pulled towards their rear which is their most vulnerable direction. In cases where back to back memorials preclude the possibility of rearwards rotation, the recommendations in this report may be conservative. It is recommended that cemetery authorities embarking upon a substantial test regime should test those memorials which can be pushed towards their rear first and leave the back to back memorial testing to the end of the test program.

Memorials of different size but incorporating similar foundations sustained different loads according to the weight of the memorial. The larger memorials withstood the required Proof Load and Ultimate Load values when fitted with ground tubes, whereas the smaller memorials were marginal. In the case of memorials incorporating one or two precast concrete slabs as their foundation, memorials of all sizes failed to meet the requirements.