CA2057852A1 - Preformed duct bank - Google Patents
Preformed duct bankInfo
- Publication number
- CA2057852A1 CA2057852A1 CA 2057852 CA2057852A CA2057852A1 CA 2057852 A1 CA2057852 A1 CA 2057852A1 CA 2057852 CA2057852 CA 2057852 CA 2057852 A CA2057852 A CA 2057852A CA 2057852 A1 CA2057852 A1 CA 2057852A1
- Authority
- CA
- Canada
- Prior art keywords
- duct bank
- module
- mold
- concrete
- modules
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Rigid Pipes And Flexible Pipes (AREA)
Abstract
ABSTRACT
Preformed duct bank modules and a method of making thereof are disclosed. The duct bank modules allow for the formation of underground ducts for protecting and servicing of cables. These cables may be electrical, coaxial, telephone or any type of cable which is required to be buried underground. Preformed duct bank modules define duct segments and the modules interlock for defining a conduit from the connected duct segments. Thus, a prefabricated duct bank module can be manufactured at a factory and these prefabricated modules merely assembled on site.
Preformed duct bank modules and a method of making thereof are disclosed. The duct bank modules allow for the formation of underground ducts for protecting and servicing of cables. These cables may be electrical, coaxial, telephone or any type of cable which is required to be buried underground. Preformed duct bank modules define duct segments and the modules interlock for defining a conduit from the connected duct segments. Thus, a prefabricated duct bank module can be manufactured at a factory and these prefabricated modules merely assembled on site.
Description
2~7~
The invention relates to duct banks for underground cables for services to buildings and the like. In particular, the invention is directed to pre~abricated duct bank modules and duct banks formed by interconnecting duct bank modules.
Underground cables for servicing buildings, crossing of streets, etc. are buried using various methods. The particular method selected is based on the potential risk of damage to the cable in the area in which it is to ~e buried. In some cases the cables can be enclosed in plastic tubing and backfilled with soil. Cables can also be enclosed in several banks of plastic tubing, which banXs are then backfilled with ready mix concrete to form duct banks. Plastic tubing is used where it is necessary to pull the cables into position since plastic tubiny has a low co-efficient of friction and accordingly the risk of damaging the cables is reduced.
When the cables are routed under roads or the like, it is necessary to protect the cables so that thPy are not damaged by heavy loads on the roads. In order to protect the cables, they are enclosed ih plastic tubing held in place and spaced by plastic spacexs which are then covered with ready mix concrete.
Essentially the combination of tubing and concrete forms a buried structure. Where the cables are not subjected to heavy loads, the tubing need not be covered with concrete.
Where it is important to provide good protection to the cables, the on-site formed duct bank made of concrete and plastic .. .
2 2 ~ 78 ~ 2 tubing operates satisfactorily; however it requires substantial set up and substantial work at the site location. In addition, the concrete must have sufficient time to cure before the excavation can be backfilled thus requiring lengthy road closures or traffic detours. As well, this type of procedure can only be performed in appropriate weather conditions.
In the past, some contractors have attempted to overcome some of these problems by forming tubing and ready mix combinations near the road excavation and then placing them in the excavation. Using such a method of construction the combination of tubing and concrete should be cured in the mold typically for at least twenty-four hours. Further these tubing and concrete combinations are not easy to manoeuvre and are joined in the conventional method by pouring ready mix concre~e at the joint.
The present invention seeks to provide a duct bank module which can be formed off site and readily mated to a longitudinally adjacent module when positioned on site. Further, the present invention seeks to provide a duct bank module which engages a vertically adjacent module when a plurality of modules are stacked on site.
In one aspect of the invention there is provided a du~t bank module including an elongate concrete support body having a top and bottom surface and opposed end surfaces. A plurality of tubes being open at each end extend longitudinally through and 2~78 ~2 are supported by the support structure. The support body has lateral engaging means formed thereon. The lateral engaging including complementary locking structures formed on the top and bottom surfaces of the support body whereby stacking of one preformed duct bank module on another in a manner to engage complementary locking structure limits lateral movement of the stacked duct bank modules relative to each other.
In another aspect of the invention there is provided a duct bank module including an elongate concrete support body having a top and bottom surface and opposed end surfaces. A plurality of tubes being open at each end extend longitudinally through and are supported by the support body. The support body has longitudinally connecting means formed thereon. The longitudinally conne~cting means include complementary male/female locking surfaces formed on opposed ends of the support body whereby modules may be placed end to end to cooperatively define conduits by interconnecting the tubes.
In a further aspect of the invention there is provided a duct bank including a plurality of duct bank modules. Each module has an elongate concrete support body and a plurality of tubes which are open at each end and which are supported thereinO
The modules are stacked. Each module has complementary locking structures ~ormed on the top and bottom surfaces of the support body.
In a further aspect of the invention there is provided a '' ". '~ ' ' .
4 20~78~2 duct bank including a plurality of duct bank modules. Each module has an elongate concrete support body and a plurality of tubes which are open at each end and which are supported therein.
The modules are arranged end to end whereby spaced tubes collectively define spaced conduits. Each module includes connecting means including complimentary male/female locking surfaces.
In a still further aspect of the invention there is provided a method of dry casting a duct ~ank module including providing a mold pallet having a means for positioning one end o~ each of a plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module. An elongate mold shell is attached to the mold pallet whereby the mold shell together with the mold pallet ~orm a mold form. Concrete is poured into the mold form. The mold form is vibrated. A mold header is attached under pressure to the mold shell. The mold header has a means for positioning the other end of each of the plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module. The mold header has an opening formed therein for the excess concrete to be removsd. The mold header and mold shell are stripped from the concrete. The concrete is cured. The mold pallst is stripped from the concrete.
Preferred embodiments of the invention are shown in the drawings wherein:
2~7~2 Figure l is an end view of the duct bank module showing a male portion:
Figure 2 is a perspective view of a duct bank module showing a male portion:
Figure 3 is a side elevation of a plurality of stacked modules assembled to form a portion of a duct bank:
Figure 4 is an end view of an alternate embodiment of a duct bank module showing a female portion;
Figure 5 is an end view of an alternate embodiment o~ a duct bank module showing a male portion;
Figure 6 is a section view of a portion of a joint between two laterally adjacent duct bank modules;
Figure 7 is a top view of a mold pallet for use in making a duct bank module;
Figure 8 is a section view taken along lines 8-8 of Figure 7;
Figure 9 is a blown apart perspective view of a mold assembly for use in making a duct bank module;
Figure 10 is a top view o~ a mold header for use in making a duct bank module;
Figure 11 is a section view taken along lines 11-11 of Figure 10;
Figure 12 is a top view of an alternate embodiment of a mold header for use in making a duct bank module; and Figure 13 is a section view taken along lines 13-13 of 2~78~2 Figure 12.
Preferred embodiments of a duct bank module, a duct bank and a method of making a duct bank module will now be described with reference to the Figures wherein like numerals refer to like parts.
Referring to Figures 1 and 2, the duct bank module shown generally at 2 includes a concrete support body 4 which is generally elongate and rectangular. The support body 4 has two plastic tubes or ducts 6 extending therethrough. These tubes 6 are open at either end of the duct bank module, with the open ends indicated at 8. The top surface 9 of the duct bank module 2 includes a ridge 10 which cooperates with a complementary locking surface formed on the bottom surface 11 of the duct bank module 2 indicated by groove 12. This allows for stacking of the modules, one on top of the other, whereby ridge 10 engages groove 12 of the vertically adjacent duct bank module.
The duct bank module 2 also includes a male projection 14 at one end of the module and a complementary female connection at the opposed end of the module. The tubes or ducts 6 extand from the female connection to the male projection 14. Thus, an end to end interlock can be achieved when male projection 14 is connected to female connection of a longitudinally adjacent duct bank module as shown in Figure 3. As well, a top to bottom interlock is achieved through ridge and groove connection described above.
20a78~2 As shown in Figure 3, the duct bank 20 is formed from individual duct bank modules 2. Preferably the duct bank modules are offset, one from the other, with respect to the vertical levels on the duct bank such that joints are covered by the module above. This improves the overall strength of the duct bank. Preferably, the duct bank modules built will be made in varying lengths, as indicated, to facilitate the shifting of joints. It i5 preferred that the duct banks be made in four foot and eight foot lengths, although other lengths are possible. As can be appreciated, the complementary locking surfaces on the top and bottom surface of the duct bank module 2 stop horizontal shearing between layers of modules, whereas the male/female connection avoid shearing of bank modules placed in end to end relationship. When a module is stacked above an end to end abutment o~ a lower level, as generally indicated in Figure 3, the top module assists in opposing any horizontal shearing of the joint located therebelow. If desired a side to side shifting can also lock a lower level of adjacent modules.
Another embodiment of a duct bank module of the subiect invention is shown generally at 22 in Figure 4. Duct bank module 22 is similar to that shown at 2 except that it includes four tubes 6', two ridges 10' and two grooves 12'. It will be appreciated by someone skilled in the art that the selection of the number of tubes, ridges and grooves in a duct bank module can be adapted to any particular application. Figure 4 shows a .. ' ~
2037~2 female connection 16 which includes a sunken planar area generally indicated as 18.
Another embodiment of a duct bank module of the subject invention is shown generally at 30 in Figure 5. Duct bank module 30 is similar to that shown at 2 except for the following differences. The edges of the support body 4" have been bevelled. Ridge 10" and groove 12" are more rounded then those shown at 2. Male projection 14" is elliptical rather than rectangular as shown at 2.
In some applications, it will be desirable to provide a seal between one duct bank module 2 and an adjacent duct b~nk module 2 placed in end to end reIationship such that the tubes 6 form conduits. The conduits formed are a result of the tubes 6 being placed in end to end relationship. In order to at least partlally seal these conduits, a BUTYL (trade mark) rope seal or other synthetic rubber or suitable sealing material may he placed between and thereabout the male projection 14 and female connection 16 such that once the modules are connected, a seal is provided between the male and ~emale connection. Alternatively, a FORSHEDA (trade mark) gasket 32, as shown in Figure 6, may be used. In this instance a step 33 is formed on the outer surface o~ the male projection 14 for positioning the gas~et. It wi~l be appreciated that depending on the particular environmenk and application seals may not be re~uired.
The manufacturing process for the duct bank module 2 will 2~578~2 now be described with reference to Figures 7 through 11. Figures 7 and 8 show a mold pallet 50 which forms the bottom portion of the mold form (to be described later). Mold pallet 50 shapes the female connection 16 of the duct bank module 2 described above.
Mold pallet 50 has an edge portion 52 and an inner portion 54 spaced above the edge portion 52. A slightly sloping side portion 55 connects edge portion 52 to inner portion 54. A
projection 56 extends outwardly from one side of the edge portion 52 to form the ridge 10 (described above) and a groove 58 projects inwardly from the periphery of the edge portion 52 to form ths groove 12 (described above). The~upper surface 59 of the inner portion 54 of the pallet 50 has two suitable circular indentations 60 adapted to receive plastic tubes. Four legs 62 are provided which extend downwardly from the mold edge portion 52.
Figures 10 and 11 show the mold header 64 which is the top portion of the assembled mold ~to be described later). Mold header 64 shapes the male connection 14 of duct bank module 2 described above. Mold header 64 has a header edge portion 66 and a header inner portion 68 spaced above the header edge portion 66. ~eader side portions 70 connect header edge portion 66 and header inner portion 68. ~eader side portion has a step 72 formed therein. The inside surface 74 of header inner portion 68 has two suitable circular indentations 76 adapted to receive plastic tubes. Header inner portion 68 has an opening 78 formed , ' ' .
- ~ :
`- 20~78~2 therein to allow concrete to escape when the header is put on a filled mold. Header inner portion 68 is provided with four lugs 80 for attaching the mold header 64 to a hoist.
Figure 9 shows a blown apart view of the mold assembly shown generally at 82. Mold assembly 82 includes a mold pallet 50, mold header 64 and a mold shell 84. Mold pallet 50 and mold shell 84 together form the mold form into which the concrete is poured.
The manufacturing process for a duct bank module starts by attaching the mold shell 84 to mold pallet 50. Plastic tubes are then placed in the circular indentations 60 of the mold pallet 50. Concrete is then poured into the top open end portion of the mold shell 84. During the pouring proces~ the mold form is vibrated. By vibrating the mold form the density of the concrete is increased. The mold header 64 is then attached under pressure to the mold shell 84 while the mold form is being vibrated.
Excess concrete is forced out of the opening 78 in mold header 64 and is removed. The mold assembly 80 is then moved to a curing station. The mold header 64 and th~ mold shell 84 are stripped from the duct bank mbdule 2. Duct bank module 2 is then cured.
Finally the mold pallet 50 is stripped from the duct bank module.
Another embodiment of a mold header is shown generally at 86 in Figures 12 and 13. Mold header 86 is similar to that shown at 64 except for the following differences. Inner portion 88 i5 generally rectangular in shape as compared to inner portion 68 2~78~
(shown in Figure 10) which is elliptical. Similarly a companion mold pallet would be provided which has a generally rectangular shaped mold pallet inner portion.
A number of advantages are realized by precasting or molding in a manufacturing plant the individual duct bank modules 2.
Formed duct bank modules may be stored and a certain inventory developed to allow the necessary duct bank modules to be delivered to a job site for installation. The job site merely requires preparing a bed suitable for supporting the duct bank modules. Different duct bank modules can be used, depending upon the number and type of cables to be run. It is clearly shown in Figures 1 and 4 that the duct banks can be made in various capacities/ such as the two and four tube modules shown.
With the present invention, manufacturing and quality control of the duct bank modules is performed in the manufacturing plant and the contractor mersly has to provide the proper bed for recei~ing of the duGt bank modules. This results in improved guality control. Prefabricated duct banks are easily installed by the contractor who does not reguire the knowledge to properly manufacture the duct banks directly at the job site.
The use of the prefabricated duct bank modules will be more cost effective and allow the contractor to use less skilled labour.
The precast duct bank modules can b~ installed much faster than duct banks installed in the traditional methods.
Traditional methods require placing plastic tubing on spacers in 20~78~2 the excavation and pouring ready mix concrete around the tubing.
Ready mix concrete must be ordered and placed, and the concrete must have sufficient time to cure before the excavation can be back filled. It can also be appreciated that weather can influence an installation and particularly, winter weather can create a severe problem. Most concrete encased tubes are at road crossings and are running under roads. The use of the modules will allow faster backfilling and return of the road to its normal use.
In the preferred embodiment duct bank modules are made from concrete mix of 50% slag and 50~ portland. This concrete is resistant to sulphur and salt and therefore the duct bank module can be used in a wide variety of soils without modification.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by someone skilled in the art that variations may be made thereto without departing from the spirit of the invention or the-scope of the appended claims.
~ - , - : - . .
The invention relates to duct banks for underground cables for services to buildings and the like. In particular, the invention is directed to pre~abricated duct bank modules and duct banks formed by interconnecting duct bank modules.
Underground cables for servicing buildings, crossing of streets, etc. are buried using various methods. The particular method selected is based on the potential risk of damage to the cable in the area in which it is to ~e buried. In some cases the cables can be enclosed in plastic tubing and backfilled with soil. Cables can also be enclosed in several banks of plastic tubing, which banXs are then backfilled with ready mix concrete to form duct banks. Plastic tubing is used where it is necessary to pull the cables into position since plastic tubiny has a low co-efficient of friction and accordingly the risk of damaging the cables is reduced.
When the cables are routed under roads or the like, it is necessary to protect the cables so that thPy are not damaged by heavy loads on the roads. In order to protect the cables, they are enclosed ih plastic tubing held in place and spaced by plastic spacexs which are then covered with ready mix concrete.
Essentially the combination of tubing and concrete forms a buried structure. Where the cables are not subjected to heavy loads, the tubing need not be covered with concrete.
Where it is important to provide good protection to the cables, the on-site formed duct bank made of concrete and plastic .. .
2 2 ~ 78 ~ 2 tubing operates satisfactorily; however it requires substantial set up and substantial work at the site location. In addition, the concrete must have sufficient time to cure before the excavation can be backfilled thus requiring lengthy road closures or traffic detours. As well, this type of procedure can only be performed in appropriate weather conditions.
In the past, some contractors have attempted to overcome some of these problems by forming tubing and ready mix combinations near the road excavation and then placing them in the excavation. Using such a method of construction the combination of tubing and concrete should be cured in the mold typically for at least twenty-four hours. Further these tubing and concrete combinations are not easy to manoeuvre and are joined in the conventional method by pouring ready mix concre~e at the joint.
The present invention seeks to provide a duct bank module which can be formed off site and readily mated to a longitudinally adjacent module when positioned on site. Further, the present invention seeks to provide a duct bank module which engages a vertically adjacent module when a plurality of modules are stacked on site.
In one aspect of the invention there is provided a du~t bank module including an elongate concrete support body having a top and bottom surface and opposed end surfaces. A plurality of tubes being open at each end extend longitudinally through and 2~78 ~2 are supported by the support structure. The support body has lateral engaging means formed thereon. The lateral engaging including complementary locking structures formed on the top and bottom surfaces of the support body whereby stacking of one preformed duct bank module on another in a manner to engage complementary locking structure limits lateral movement of the stacked duct bank modules relative to each other.
In another aspect of the invention there is provided a duct bank module including an elongate concrete support body having a top and bottom surface and opposed end surfaces. A plurality of tubes being open at each end extend longitudinally through and are supported by the support body. The support body has longitudinally connecting means formed thereon. The longitudinally conne~cting means include complementary male/female locking surfaces formed on opposed ends of the support body whereby modules may be placed end to end to cooperatively define conduits by interconnecting the tubes.
In a further aspect of the invention there is provided a duct bank including a plurality of duct bank modules. Each module has an elongate concrete support body and a plurality of tubes which are open at each end and which are supported thereinO
The modules are stacked. Each module has complementary locking structures ~ormed on the top and bottom surfaces of the support body.
In a further aspect of the invention there is provided a '' ". '~ ' ' .
4 20~78~2 duct bank including a plurality of duct bank modules. Each module has an elongate concrete support body and a plurality of tubes which are open at each end and which are supported therein.
The modules are arranged end to end whereby spaced tubes collectively define spaced conduits. Each module includes connecting means including complimentary male/female locking surfaces.
In a still further aspect of the invention there is provided a method of dry casting a duct ~ank module including providing a mold pallet having a means for positioning one end o~ each of a plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module. An elongate mold shell is attached to the mold pallet whereby the mold shell together with the mold pallet ~orm a mold form. Concrete is poured into the mold form. The mold form is vibrated. A mold header is attached under pressure to the mold shell. The mold header has a means for positioning the other end of each of the plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module. The mold header has an opening formed therein for the excess concrete to be removsd. The mold header and mold shell are stripped from the concrete. The concrete is cured. The mold pallst is stripped from the concrete.
Preferred embodiments of the invention are shown in the drawings wherein:
2~7~2 Figure l is an end view of the duct bank module showing a male portion:
Figure 2 is a perspective view of a duct bank module showing a male portion:
Figure 3 is a side elevation of a plurality of stacked modules assembled to form a portion of a duct bank:
Figure 4 is an end view of an alternate embodiment of a duct bank module showing a female portion;
Figure 5 is an end view of an alternate embodiment o~ a duct bank module showing a male portion;
Figure 6 is a section view of a portion of a joint between two laterally adjacent duct bank modules;
Figure 7 is a top view of a mold pallet for use in making a duct bank module;
Figure 8 is a section view taken along lines 8-8 of Figure 7;
Figure 9 is a blown apart perspective view of a mold assembly for use in making a duct bank module;
Figure 10 is a top view o~ a mold header for use in making a duct bank module;
Figure 11 is a section view taken along lines 11-11 of Figure 10;
Figure 12 is a top view of an alternate embodiment of a mold header for use in making a duct bank module; and Figure 13 is a section view taken along lines 13-13 of 2~78~2 Figure 12.
Preferred embodiments of a duct bank module, a duct bank and a method of making a duct bank module will now be described with reference to the Figures wherein like numerals refer to like parts.
Referring to Figures 1 and 2, the duct bank module shown generally at 2 includes a concrete support body 4 which is generally elongate and rectangular. The support body 4 has two plastic tubes or ducts 6 extending therethrough. These tubes 6 are open at either end of the duct bank module, with the open ends indicated at 8. The top surface 9 of the duct bank module 2 includes a ridge 10 which cooperates with a complementary locking surface formed on the bottom surface 11 of the duct bank module 2 indicated by groove 12. This allows for stacking of the modules, one on top of the other, whereby ridge 10 engages groove 12 of the vertically adjacent duct bank module.
The duct bank module 2 also includes a male projection 14 at one end of the module and a complementary female connection at the opposed end of the module. The tubes or ducts 6 extand from the female connection to the male projection 14. Thus, an end to end interlock can be achieved when male projection 14 is connected to female connection of a longitudinally adjacent duct bank module as shown in Figure 3. As well, a top to bottom interlock is achieved through ridge and groove connection described above.
20a78~2 As shown in Figure 3, the duct bank 20 is formed from individual duct bank modules 2. Preferably the duct bank modules are offset, one from the other, with respect to the vertical levels on the duct bank such that joints are covered by the module above. This improves the overall strength of the duct bank. Preferably, the duct bank modules built will be made in varying lengths, as indicated, to facilitate the shifting of joints. It i5 preferred that the duct banks be made in four foot and eight foot lengths, although other lengths are possible. As can be appreciated, the complementary locking surfaces on the top and bottom surface of the duct bank module 2 stop horizontal shearing between layers of modules, whereas the male/female connection avoid shearing of bank modules placed in end to end relationship. When a module is stacked above an end to end abutment o~ a lower level, as generally indicated in Figure 3, the top module assists in opposing any horizontal shearing of the joint located therebelow. If desired a side to side shifting can also lock a lower level of adjacent modules.
Another embodiment of a duct bank module of the subiect invention is shown generally at 22 in Figure 4. Duct bank module 22 is similar to that shown at 2 except that it includes four tubes 6', two ridges 10' and two grooves 12'. It will be appreciated by someone skilled in the art that the selection of the number of tubes, ridges and grooves in a duct bank module can be adapted to any particular application. Figure 4 shows a .. ' ~
2037~2 female connection 16 which includes a sunken planar area generally indicated as 18.
Another embodiment of a duct bank module of the subject invention is shown generally at 30 in Figure 5. Duct bank module 30 is similar to that shown at 2 except for the following differences. The edges of the support body 4" have been bevelled. Ridge 10" and groove 12" are more rounded then those shown at 2. Male projection 14" is elliptical rather than rectangular as shown at 2.
In some applications, it will be desirable to provide a seal between one duct bank module 2 and an adjacent duct b~nk module 2 placed in end to end reIationship such that the tubes 6 form conduits. The conduits formed are a result of the tubes 6 being placed in end to end relationship. In order to at least partlally seal these conduits, a BUTYL (trade mark) rope seal or other synthetic rubber or suitable sealing material may he placed between and thereabout the male projection 14 and female connection 16 such that once the modules are connected, a seal is provided between the male and ~emale connection. Alternatively, a FORSHEDA (trade mark) gasket 32, as shown in Figure 6, may be used. In this instance a step 33 is formed on the outer surface o~ the male projection 14 for positioning the gas~et. It wi~l be appreciated that depending on the particular environmenk and application seals may not be re~uired.
The manufacturing process for the duct bank module 2 will 2~578~2 now be described with reference to Figures 7 through 11. Figures 7 and 8 show a mold pallet 50 which forms the bottom portion of the mold form (to be described later). Mold pallet 50 shapes the female connection 16 of the duct bank module 2 described above.
Mold pallet 50 has an edge portion 52 and an inner portion 54 spaced above the edge portion 52. A slightly sloping side portion 55 connects edge portion 52 to inner portion 54. A
projection 56 extends outwardly from one side of the edge portion 52 to form the ridge 10 (described above) and a groove 58 projects inwardly from the periphery of the edge portion 52 to form ths groove 12 (described above). The~upper surface 59 of the inner portion 54 of the pallet 50 has two suitable circular indentations 60 adapted to receive plastic tubes. Four legs 62 are provided which extend downwardly from the mold edge portion 52.
Figures 10 and 11 show the mold header 64 which is the top portion of the assembled mold ~to be described later). Mold header 64 shapes the male connection 14 of duct bank module 2 described above. Mold header 64 has a header edge portion 66 and a header inner portion 68 spaced above the header edge portion 66. ~eader side portions 70 connect header edge portion 66 and header inner portion 68. ~eader side portion has a step 72 formed therein. The inside surface 74 of header inner portion 68 has two suitable circular indentations 76 adapted to receive plastic tubes. Header inner portion 68 has an opening 78 formed , ' ' .
- ~ :
`- 20~78~2 therein to allow concrete to escape when the header is put on a filled mold. Header inner portion 68 is provided with four lugs 80 for attaching the mold header 64 to a hoist.
Figure 9 shows a blown apart view of the mold assembly shown generally at 82. Mold assembly 82 includes a mold pallet 50, mold header 64 and a mold shell 84. Mold pallet 50 and mold shell 84 together form the mold form into which the concrete is poured.
The manufacturing process for a duct bank module starts by attaching the mold shell 84 to mold pallet 50. Plastic tubes are then placed in the circular indentations 60 of the mold pallet 50. Concrete is then poured into the top open end portion of the mold shell 84. During the pouring proces~ the mold form is vibrated. By vibrating the mold form the density of the concrete is increased. The mold header 64 is then attached under pressure to the mold shell 84 while the mold form is being vibrated.
Excess concrete is forced out of the opening 78 in mold header 64 and is removed. The mold assembly 80 is then moved to a curing station. The mold header 64 and th~ mold shell 84 are stripped from the duct bank mbdule 2. Duct bank module 2 is then cured.
Finally the mold pallet 50 is stripped from the duct bank module.
Another embodiment of a mold header is shown generally at 86 in Figures 12 and 13. Mold header 86 is similar to that shown at 64 except for the following differences. Inner portion 88 i5 generally rectangular in shape as compared to inner portion 68 2~78~
(shown in Figure 10) which is elliptical. Similarly a companion mold pallet would be provided which has a generally rectangular shaped mold pallet inner portion.
A number of advantages are realized by precasting or molding in a manufacturing plant the individual duct bank modules 2.
Formed duct bank modules may be stored and a certain inventory developed to allow the necessary duct bank modules to be delivered to a job site for installation. The job site merely requires preparing a bed suitable for supporting the duct bank modules. Different duct bank modules can be used, depending upon the number and type of cables to be run. It is clearly shown in Figures 1 and 4 that the duct banks can be made in various capacities/ such as the two and four tube modules shown.
With the present invention, manufacturing and quality control of the duct bank modules is performed in the manufacturing plant and the contractor mersly has to provide the proper bed for recei~ing of the duGt bank modules. This results in improved guality control. Prefabricated duct banks are easily installed by the contractor who does not reguire the knowledge to properly manufacture the duct banks directly at the job site.
The use of the prefabricated duct bank modules will be more cost effective and allow the contractor to use less skilled labour.
The precast duct bank modules can b~ installed much faster than duct banks installed in the traditional methods.
Traditional methods require placing plastic tubing on spacers in 20~78~2 the excavation and pouring ready mix concrete around the tubing.
Ready mix concrete must be ordered and placed, and the concrete must have sufficient time to cure before the excavation can be back filled. It can also be appreciated that weather can influence an installation and particularly, winter weather can create a severe problem. Most concrete encased tubes are at road crossings and are running under roads. The use of the modules will allow faster backfilling and return of the road to its normal use.
In the preferred embodiment duct bank modules are made from concrete mix of 50% slag and 50~ portland. This concrete is resistant to sulphur and salt and therefore the duct bank module can be used in a wide variety of soils without modification.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by someone skilled in the art that variations may be made thereto without departing from the spirit of the invention or the-scope of the appended claims.
~ - , - : - . .
Claims (19)
1. A duct bank module comprising:
an elongate concrete support body having a top and a bottom surface and opposed end surfaces;
a plurality of tubes being opened at each end, extending longitudinally through and being supported in the support body;
the support body having lateral engaging means formed thereon, the engaging means including complementary locking structure formed on the top and bottom surfaces of the support body whereby stacking of one duct bank module on another in a manner to engage complementary locking structure limits lateral movement of the stacked duct bank modules relative to each other.
an elongate concrete support body having a top and a bottom surface and opposed end surfaces;
a plurality of tubes being opened at each end, extending longitudinally through and being supported in the support body;
the support body having lateral engaging means formed thereon, the engaging means including complementary locking structure formed on the top and bottom surfaces of the support body whereby stacking of one duct bank module on another in a manner to engage complementary locking structure limits lateral movement of the stacked duct bank modules relative to each other.
2. A duct bank module as claimed in claim 1 wherein the complementary locking structure includes a raised ridge formed on one of the top and bottom of the support body and a corresponding groove formed on the other of the top and bottom surface.
3. A duct bank module as claimed in claim 1 wherein the tubes are made from plastic.
4. A duct bank module as claimed in claim 1 and further including a means for connecting adjacent duct bank modules in end to end relationship.
5. A duct bank module as claimed in claim 4 wherein the connecting means includes complementary male/female locking surfaces formed on opposed end surfaces of the support body whereby modules may be placed to cooperatively define conduits by interconnecting the tubes.
6. A duct bank module comprising:
an elongate concrete support body having a top and bottom surface and opposed end surfaces;
a plurality of tubes being opened at opposed ends and extending longitudinally through and being supported in the support body; and the support body having connecting means formed therein, the connecting means including complementary male/female locking surfaces formed on opposed ends surfaces of the support body whereby modules may be placed end to end to cooperatively define conduits by interconnecting the tubes.
an elongate concrete support body having a top and bottom surface and opposed end surfaces;
a plurality of tubes being opened at opposed ends and extending longitudinally through and being supported in the support body; and the support body having connecting means formed therein, the connecting means including complementary male/female locking surfaces formed on opposed ends surfaces of the support body whereby modules may be placed end to end to cooperatively define conduits by interconnecting the tubes.
7. A duct bank module as claimed in claim 6 wherein said male/female complementary locking surfaces surround said plurality of tubes forming one male portion and one female portion.
8. A duct bank module as claimed in claim 7 and further including a means for laterally engaging vertically adjacent modules.
9. A duct bank module as claimed in claim 8 wherein the tubes are made from plastic.
10. A duct bank comprising a plurality of duct bank modules each having an elongate concrete support body and a plurality of tubes which are open at each end and which are supported therein, said modules being arranged end to end whereby spaced tubes collectively define spaced conduits, said modules including connecting means including complementary male/female locking surfaces.
11. A duct bank as claimed in claim 10 wherein each module further includes a means for laterally engaging vertically adjacent modules.
12. A duct bank as claimed in claim 11 wherein the lateral engaging means includes a raised ridge formed on the top and bottom of the support body of each module and a corresponding groove formed on the other of the top and bottom surface of the same module.
13. A duct bank comprising a plurality of duct bank modules each having an elongate concrete support body and a plurality of tubes which are opened at each end and which are supported therein, said modules being stacked and said modules including complementary locking structures formed on the top and bottom surfaces of the support body of each module.
14. A duct bank as claimed in claim 13 wherein the complementary locking structures include a raised ridge formed on one of the top and bottom of the support body and a corresponding groove formed on the other of the top and bottom surface of the support body of each module.
15. A duct bank as claimed in claim 13 wherein the tubes in each module are made of plastic.
16. A method of dry casting a concrete duct bank module comprising:
providing a mold pallet having a means for positioning one end of each of a plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module;
attaching an elongate mold shell to the mold pallet whereby the mold pallet and the mold shell together form the mold form;
pouring concrete into the mold form;
vibrating the mold form;
attaching a mold header under pressure to the mold shell, the mold header having a means for positioning the other end of each of the plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module and the mold header having an opening for the excess concrete to be removed;
stripping the mold header and mold shell from the concrete;
curing the concrete; and
providing a mold pallet having a means for positioning one end of each of a plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module;
attaching an elongate mold shell to the mold pallet whereby the mold pallet and the mold shell together form the mold form;
pouring concrete into the mold form;
vibrating the mold form;
attaching a mold header under pressure to the mold shell, the mold header having a means for positioning the other end of each of the plurality of tubes such that each tube remains free of concrete during the casting and each tube is open at the end of each module and the mold header having an opening for the excess concrete to be removed;
stripping the mold header and mold shell from the concrete;
curing the concrete; and
17 removing the mold pallet from the concrete.
17. A method of dry casting a concrete duct bank module as claimed in claim 16 wherein the mold form is continuously vibrated during the pouring step.
17. A method of dry casting a concrete duct bank module as claimed in claim 16 wherein the mold form is continuously vibrated during the pouring step.
18. A method of dry casting a concrete duct bank module as claimed in claim 17 and further including vibrating the mold form after the mold header is attached to the mold shell.
19. A method of dry casting a concrete duct bank module as claimed in claim 16 wherein the mold pallet, the mold shell and the mold header is each shaped to provide an elongate groove on one elongate side of the module and an elongate ridge on the other side of the module.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US63096390A | 1990-12-24 | 1990-12-24 | |
| US07/630,963 | 1990-12-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2057852A1 true CA2057852A1 (en) | 1992-06-25 |
Family
ID=24529273
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2057852 Abandoned CA2057852A1 (en) | 1990-12-24 | 1991-12-17 | Preformed duct bank |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2057852A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9410642B2 (en) | 2012-06-01 | 2016-08-09 | Cummings Electrical, L.P. | Method and apparatus for plastic duct bank manufacture |
| US20210305791A1 (en) * | 2020-03-26 | 2021-09-30 | Forterra Pipe & Precast, Llc | Stackable duct-bank stub-up assembly |
-
1991
- 1991-12-17 CA CA 2057852 patent/CA2057852A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9410642B2 (en) | 2012-06-01 | 2016-08-09 | Cummings Electrical, L.P. | Method and apparatus for plastic duct bank manufacture |
| US9719612B2 (en) | 2012-06-01 | 2017-08-01 | Cummings Electrical, L.P. | Method and apparatus for plastic duct bank manufacture |
| US10816109B2 (en) | 2012-06-01 | 2020-10-27 | Cummings Electrical, L.P. | Method and apparatus for plastic duct bank manufacture |
| US20210305791A1 (en) * | 2020-03-26 | 2021-09-30 | Forterra Pipe & Precast, Llc | Stackable duct-bank stub-up assembly |
| US11658469B2 (en) * | 2020-03-26 | 2023-05-23 | Forterra Pipe & Precast, Llc | Stackable duct-bank stub-up assembly |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3263378A (en) | Precast subterranean utility vault structures | |
| US3562969A (en) | Sectional catch basin | |
| US4836714A (en) | Enclosed structures of very large cross-section, such as conduits, silos or shelters | |
| KR100824833B1 (en) | The Prefabricated Precast Concrete Culvert Connecting By Inserting Steel Rod Into Ring. | |
| CN113668612A (en) | Modular combined prefabricated electric power working well and construction method thereof | |
| WO2005017290A1 (en) | Street light foundation | |
| KR20090049796A (en) | Box connector and precast concrete box connecting method using the same | |
| US3977703A (en) | Multiple duct underground conduit | |
| JP2634381B2 (en) | Split type box culvert and method of assembling the same | |
| CA2057852A1 (en) | Preformed duct bank | |
| JP2772618B2 (en) | Rigid protective fence capable of storing electric cables and the like, and its construction method | |
| EP0707121B1 (en) | Panels for the manufacture of circular above-ground tanks, mould, and associated manufacturing method | |
| JP3806218B2 (en) | Synthetic resin manhole construction method and synthetic resin manhole | |
| US5325643A (en) | Soil retainer block | |
| KR20070109423A (en) | Assembled precast reinforced concrete culverts with steel bar | |
| AU2020103734A4 (en) | An underground work bay | |
| KR20010016306A (en) | Method for constructing of assembly type manhole | |
| JP3470636B2 (en) | Junction between shaft and shaft at the end of submerged tunnel and construction method | |
| JP6126415B2 (en) | Co-grooving method for side grooves | |
| KR100661627B1 (en) | Method for paving field constrnction type grass block and shore protection block | |
| JPH03228921A (en) | Execution method for concrete foundation work | |
| JPH09273139A (en) | Underground structure for cable duct or the like and construction method thereof | |
| JPH0431780Y2 (en) | ||
| JP3048343U (en) | Concrete U-shaped groove block | |
| KR100910887B1 (en) | Fabricated manhole |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |