718 - Drilled Shafts - Revision history

McGowanR: /* Tremie Tube Concrete Placement */ Duplicate Text

2019-01-22T16:19:20Z

Tremie Tube Concrete Placement: Duplicate Text

McGowanR: Provided clarification relating to Tremie Tube Concrete Placement along with inspection of shaft after Placing Steel Reinforcement cage

2019-01-22T16:15:29Z

Provided clarification relating to Tremie Tube Concrete Placement along with inspection of shaft after Placing Steel Reinforcement cage

McGowanR: Reverted edits by McGowanR (talk) to last revision by JohnsonN23

2019-01-22T15:57:47Z

Reverted edits by McGowanR (talk) to last revision by JohnsonN23

McGowanR: /* Placing Steel Reinforcement */ Clarification for inspection after placement of reinforcement cage

2019-01-22T15:55:14Z

Placing Steel Reinforcement: Clarification for inspection after placement of reinforcement cage

McGowanR: /* Tremie Tube Concrete Placement */ Clarification for Tremie Tube Concrete Placement

2019-01-22T15:33:47Z

Tremie Tube Concrete Placement: Clarification for Tremie Tube Concrete Placement

JohnsonN23: /* DRILLED SHAFT CONSTRUCTION */ relink

2017-02-14T13:27:28Z

DRILLED SHAFT CONSTRUCTION: relink

McGowanR: /* Concrete, Grade S2, and Grade T */

2015-11-11T01:28:26Z

Concrete, Grade S2, and Grade T

Greenes2 at 14:46, 14 November 2014

2014-11-14T14:46:26Z

HarrisR18: /* Mechanically Stabilized Earth Wall */

2014-11-12T19:36:08Z

Mechanically Stabilized Earth Wall

HarrisR18: /* Mechanically Stabilized Earth Wall */

2014-11-12T19:35:39Z

Mechanically Stabilized Earth Wall

@@ Line 272: / Line 272: @@
 For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.
-The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. The contractor may need to use a retarder in the mix on larger, longer tremie pours to maintain concrete slumps throughout the pour.  See Figure 9 for an example of concrete not filling the required shaft diameter. The contractor may need to use a retarder in the mix on larger, longer tremie pours to maintain concrete slumps throughout the pour.
+The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. The contractor may need to use a retarder in the mix on larger, longer tremie pours to maintain concrete slumps throughout the pour.  See Figure 9 for an example of concrete not filling the required shaft diameter.
 Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid.  Drilling fluid at the top of the shaft may have to be pumped of.

@@ Line 238: / Line 238: @@
 Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.
 {{top}}
@@ Line 263: / Line 266: @@
 Ensure the Contractor is using a tremie tube of at least 10 inches in diameter.  Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.
-The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.
+The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube. When initially starting the flow of concrete in the tremie pour, the end of the tremie tube must be within one tremie tube diameter of the base
-It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.
+It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.  The contractor and their concrete supplier should plan ahead and stage and sequence trucks accordingly to ensure a continuous tremie pour.
-For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness.  If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.
+For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.
-The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter.  See Figure 9 for an example of concrete not filling the required shaft diameter.
+The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. The contractor may need to use a retarder in the mix on larger, longer tremie pours to maintain concrete slumps throughout the pour.  See Figure 9 for an example of concrete not filling the required shaft diameter. The contractor may need to use a retarder in the mix on larger, longer tremie pours to maintain concrete slumps throughout the pour.
 Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid.  Drilling fluid at the top of the shaft may have to be pumped of.

@@ Line 4: / Line 4: @@
 <center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center>
-<center>[https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center>
+<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center>
@@ Line 53: / Line 53: @@
 ===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===
-Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction.  Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.
+Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction.  Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.
 Concrete mix design and spacing of reinforcing bars are critically important construction parameters that help ensure the free passage of concrete through the cage and into the space between the cage and borehole wall.
-The modified slump requirements described in [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction supersede the slump requirements shown in [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf#page=3 Table 701-1A] in Section 701 of the Standard Specifications for Construction.  Construction staff must review and only approve contractor submitted concrete mix designs and concrete quality control (QC) plans, for drilled shaft construction, that meet the modified slump requirements of [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction.  The Special Provision for Quality Control and Acceptance of Portland Cement Concrete, [http://mdotcf.state.mi.us/public/dessssp/spss_source/12SP-604B-05.pdf 12SP-604B-05], does not supersede these requirements.
+The modified slump requirements described in [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction supersede the slump requirements shown in [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf#page=3 Table 701-1A] in Section 701 of the Standard Specifications for Construction.  Construction staff must review and only approve contractor submitted concrete mix designs and concrete quality control (QC) plans, for drilled shaft construction, that meet the modified slump requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction.  The Special Provision for Quality Control and Acceptance of Portland Cement Concrete, [http://mdotcf.state.mi.us/public/dessssp/spss_source/12SP-604B-05.pdf 12SP-604B-05], does not supersede these requirements.
-If concrete for drilled shaft foundations does not meet the modified slump requirements of [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction it should not be allowed.
+If concrete for drilled shaft foundations does not meet the modified slump requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction it should not be allowed.
 {{top}}
@@ Line 83: / Line 83: @@
 When wet construction methods are required, polymer type slurry is required.  Bentonite slurry is prohibited.  Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement.  The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.
-Ensure any polymer slurry used meets the requirements of [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 Table 718-1] from the Standard Specifications for Construction.  Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.
+Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction.  Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.
 Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation.  The polymer slurry should be agitated to prevent setting up in the shaft.
@@ Line 122: / Line 122: @@
 ====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====
-The Contractor is required to submit a Drilled Shaft Installation plan, per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.03.A] of the Standard Specifications for Construction.  This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc.  The Geotechnical Services area will review and approve the Drilled Shaft Installation plan.  Review and understand the following:
+The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction.  This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc.  The Geotechnical Services area will review and approve the Drilled Shaft Installation plan.  Review and understand the following:
 * Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.
@@ Line 157: / Line 157: @@
 * Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.
-* Construction Method Log:  The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.03.5] of the Standard Specifications for Construction.  Ensure the following information is shown on the logs:
+* Construction Method Log:  The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction.  Ensure the following information is shown on the logs:
 * Start dates and completions dates
@@ Line 197: / Line 197: @@
 Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation.  Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.
-Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans.  For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections.  [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.
+Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans.  For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections.  [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.
 Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings.  Ensure the Contractor stores soil cuttings away from the drill shaft locations.
@@ Line 205: / Line 205: @@
 ===[[#Obstruction Removal|Obstruction Removal]]===
-Obstructions are to be removed per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.03.F.2] of the Standard Specifications for Construction.  Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles.  Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions.  Special procedures and tools include:
+Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction.  Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles.  Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions.  Special procedures and tools include:
 * Chisels
@@ Line 215: / Line 215: @@
 * Enlarging the drilled shaft diameter
-Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.04.D] of the Standard Specifications or Construction.  A budget amount will be established to pay for removing obstructions.  If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.
+Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction.  A budget amount will be established to pay for removing obstructions.  If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.
 {{top}}
@@ Line 239: / Line 239: @@
 Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.
 {{top}}
@@ Line 264: / Line 263: @@
 Ensure the Contractor is using a tremie tube of at least 10 inches in diameter.  Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.
-The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube. When initially starting the flow of concrete in the tremie pour, the end of the tremie tube must be within one tremie tube diameter of the base.
+The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.
 It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.

← Older revision		Revision as of 15:55, 22 January 2019
Line 239:		Line 239:
	Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.		Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.

		+	After the reinforcement cage is set, check the depth of the shaft at the center and around the edge of the shaft. If material entered the shaft after the reinforcement cage was set, the reinforcement cage will need to be removed and the entire cross-section of the shaft will need to be re-cleaned in accordance to subsection [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 718.03.F.1.]
	{{top}}		{{top}}

@@ Line 4: / Line 4: @@
 <center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center>
-<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center>
+<center>[https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center>
@@ Line 53: / Line 53: @@
 ===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===
-Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction.  Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.
+Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction.  Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.
 Concrete mix design and spacing of reinforcing bars are critically important construction parameters that help ensure the free passage of concrete through the cage and into the space between the cage and borehole wall.
-The modified slump requirements described in [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction supersede the slump requirements shown in [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf#page=3 Table 701-1A] in Section 701 of the Standard Specifications for Construction.  Construction staff must review and only approve contractor submitted concrete mix designs and concrete quality control (QC) plans, for drilled shaft construction, that meet the modified slump requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction.  The Special Provision for Quality Control and Acceptance of Portland Cement Concrete, [http://mdotcf.state.mi.us/public/dessssp/spss_source/12SP-604B-05.pdf 12SP-604B-05], does not supersede these requirements.
+The modified slump requirements described in [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction supersede the slump requirements shown in [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf#page=3 Table 701-1A] in Section 701 of the Standard Specifications for Construction.  Construction staff must review and only approve contractor submitted concrete mix designs and concrete quality control (QC) plans, for drilled shaft construction, that meet the modified slump requirements of [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction.  The Special Provision for Quality Control and Acceptance of Portland Cement Concrete, [http://mdotcf.state.mi.us/public/dessssp/spss_source/12SP-604B-05.pdf 12SP-604B-05], does not supersede these requirements.
-If concrete for drilled shaft foundations does not meet the modified slump requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction it should not be allowed.
+If concrete for drilled shaft foundations does not meet the modified slump requirements of [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.02] of the Standard Specifications for Construction it should not be allowed.
 {{top}}
@@ Line 83: / Line 83: @@
 When wet construction methods are required, polymer type slurry is required.  Bentonite slurry is prohibited.  Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement.  The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.
-Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction.  Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.
+Ensure any polymer slurry used meets the requirements of [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 Table 718-1] from the Standard Specifications for Construction.  Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.
 Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation.  The polymer slurry should be agitated to prevent setting up in the shaft.
@@ Line 122: / Line 122: @@
 ====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====
-The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction.  This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc.  The Geotechnical Services area will review and approve the Drilled Shaft Installation plan.  Review and understand the following:
+The Contractor is required to submit a Drilled Shaft Installation plan, per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.03.A] of the Standard Specifications for Construction.  This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc.  The Geotechnical Services area will review and approve the Drilled Shaft Installation plan.  Review and understand the following:
 * Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.
@@ Line 157: / Line 157: @@
 * Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.
-* Construction Method Log:  The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction.  Ensure the following information is shown on the logs:
+* Construction Method Log:  The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.03.5] of the Standard Specifications for Construction.  Ensure the following information is shown on the logs:
 * Start dates and completions dates
@@ Line 197: / Line 197: @@
 Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation.  Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.
-Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans.  For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections.  [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.
+Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans.  For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections.  [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.
 Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings.  Ensure the Contractor stores soil cuttings away from the drill shaft locations.
@@ Line 205: / Line 205: @@
 ===[[#Obstruction Removal|Obstruction Removal]]===
-Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction.  Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles.  Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions.  Special procedures and tools include:
+Obstructions are to be removed per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.03.F.2] of the Standard Specifications for Construction.  Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles.  Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions.  Special procedures and tools include:
 * Chisels
@@ Line 215: / Line 215: @@
 * Enlarging the drilled shaft diameter
-Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction.  A budget amount will be established to pay for removing obstructions.  If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.
+Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [https://mdotjboss.state.mi.us/SpecProv/getDocumentById.htm?docGuid=90d58f15-5ac0-42b1-89fc-35076be2c080&fileName=%22718%20Drilled%20Shafts.pdf%22 subsection 718.04.D] of the Standard Specifications or Construction.  A budget amount will be established to pay for removing obstructions.  If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.
 {{top}}
@@ Line 263: / Line 263: @@
 Ensure the Contractor is using a tremie tube of at least 10 inches in diameter.  Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.
-The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.
+The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube. When initially starting the flow of concrete in the tremie pour, the end of the tremie tube must be within one tremie tube diameter of the base.
 It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.

@@ Line 116: / Line 116: @@
 ===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===
-To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.
+To track drilled shaft operations, use MDOT [http://mdotjboss.state.mi.us/webforms/GetDocument.htm?fileName=1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.
 {{top}}

← Older revision		Revision as of 01:28, 11 November 2015
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	Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.		Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.
		+
		+	Concrete mix design and spacing of reinforcing bars are critically important construction parameters that help ensure the free passage of concrete through the cage and into the space between the cage and borehole wall.
		+
		+	The modified slump requirements described in [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction supersede the slump requirements shown in [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf#page=3 Table 701-1A] in Section 701 of the Standard Specifications for Construction. Construction staff must review and only approve contractor submitted concrete mix designs and concrete quality control (QC) plans, for drilled shaft construction, that meet the modified slump requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. The Special Provision for Quality Control and Acceptance of Portland Cement Concrete, [http://mdotcf.state.mi.us/public/dessssp/spss_source/12SP-604B-05.pdf 12SP-604B-05], does not supersede these requirements.
		+
		+	If concrete for drilled shaft foundations does not meet the modified slump requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction it should not be allowed.

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← Older revision		Revision as of 14:46, 14 November 2014
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	[[Category:Construction Manual]]		[[Category:Construction Manual]]
−
−
−	~~<center><span STYLE="font: 60pt arial;">'''719'''</span></center>~~
−
−	~~<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center>~~
−
−	~~<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center>~~
−
−	~~==[[#General\|General]]==~~
−
−	~~Below is a list with definitions of common earth retaining structures utilized by MDOT:~~
−
−	*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.
−
−	*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.
−
−	*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.
−
−	*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.
−
−	*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.
−
−	*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).
−
−	*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.
−
−	~~Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.~~
−
−	~~==[[#Abutments\|Abutments]]==~~
−
−	~~MDOT utilizes the following types of abutments:~~
−
−	*Curtainwall Abutment (see rigid-gravity retaining wall below);
−
−
−	~~[[File:Fig719-1.png\|600px\|framed\|center\|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]~~
−
−
−
−	*Cantilevered Abutment (see semi-gravity retaining wall below)
−
−
−	~~[[File:Fig719-2.png\|600px\|framed\|center\|Figure 2. reinforced cantilever abutment wall]]~~
−
−
−
−	*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.
−
−	Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.
−
−	~~==[[#Anchored Wall\|Anchored Wall]]==~~
−
−	Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.
−
−
−
−	~~==[[#Mechanically Stabilized Earth Wall\| Mechanically Stabilized Earth Wall]]==~~
−
−	~~Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:~~
−
−	:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.
−
−	:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office.
−
−	:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.
−
−	:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.
−
−	:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement.
−
−	:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall.
−
−	:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.
−
−	:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.
−
−	:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.
−
−	:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.
−
−	:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.
−
−	:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.
−
−	~~MSE Wall Construction Considerations~~
−
−	*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.
−
−	*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.
−
−	*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.
−
−	~~[[File:Fig719-3.png\|600px\|framed\|center\|Figure 1. MSE wall]]~~
−
−	~~==[[#Non-Gravity Cantilevered Retaining Wall\| Non-Gravity Cantilevered Retaining Wall]]==~~
−
−	~~Examples of on-gravity cantilevered retaining walls are listed below:~~
−	*Tangent piles or drilled shafts;
−	*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);
−	*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).
−
−	~~==[[#Rigid-Gravity and Semi-Gravity Retaining Wall\|Rigid-Gravity and Semi-Gravity Retaining Wall]]==~~
−
−	~~[[File:Fig719-4.png\|600px\|framed\|center\|Figure 3. Reinforced concrete counterfort semi-gravity wall]]~~
−
−
−
−	~~[[File:Fig719-5.png\|600px\|framed\|center\|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]~~

← Older revision		Revision as of 19:36, 12 November 2014
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	:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office.		:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office.
		+
	:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.		:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.

@@ Line 372: / Line 372: @@
 Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:
-:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed.  Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.
+:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed.  Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.
-:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected.  If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit.  If they are not shop inspected then verification of project requirements is the responsibility of the project office.
+:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected.  If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit.  If they are not shop inspected then verification of project requirements is the responsibility of the project office.
-Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage.  The panels must also be properly stored on-site to prevent damage.
+:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage.  The panels must also be properly stored on-site to prevent damage.
 :C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction.  The walls end up being buried into the final structure and are not removed.  The wire facing panels in this temporary application are usually black steel due to the short duration of use.