321.2 Geotechnical Guidelines - Revision history

Hoskir: /* 321.2.4.4 Light Towers */

2024-07-19T18:20:51Z

321.2.4.4 Light Towers

← Older revision		Revision as of 13:20, 19 July 2024
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	[http://epg.modot.mo.gov/documents/321_p-y_Curve_Criteria.pdf P-Y Curve Parameters]		[http://epg.modot.mo.gov/documents/321_p-y_Curve_Criteria.pdf P-Y Curve Parameters]

	:1. K(f) = slope (variation) of linear subgrade modulus. From [[751.9 ~~LFD~~ Seismic\| EPG 751.9 ~~LFD~~ Seismic Design]] or “Soil Properties (Lpile & Com624P)”		:1. K(f) = slope (variation) of linear subgrade modulus. From [[751.9 Bridge Seismic Design\|EPG 751.9 Bridge Seismic Design]] or “Soil Properties (Lpile & Com624P)”

	:2. K(f)cyclic = for cyclic loading		:2. K(f)cyclic = for cyclic loading

	:3. E50 = strain at 50 % of the maximum difference in principal stresses, unitless, from Qu test and [[751.9 ~~LFD~~ Seismic\| EPG 751.9 ~~LFD~~ Seismic Design]] or “Soil Properties (Lpile ~~& Com624P~~)”		:3. E50 = strain at 50 % of the maximum difference in principal stresses, unitless, from Qu test and [[751.9 Bridge Seismic Design\|EPG 751.9 Bridge Seismic Design]] or “Soil Properties (Lpile)”

	Electro Chemical Parameters		Electro Chemical Parameters

Hoskir: /* 321.2.1.1 Geotechnical Organization of MoDOT */ updated link to Geotech Sharepoint page

2024-04-16T13:12:02Z

321.2.1.1 Geotechnical Organization of MoDOT: updated link to Geotech Sharepoint page

← Older revision		Revision as of 08:12, 16 April 2024
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	===321.2.1.1 Geotechnical Organization of MoDOT===		===321.2.1.1 Geotechnical Organization of MoDOT===

	Geotechnical functions in MoDOT are performed by personnel assigned to the Materials Engineering Unit, both in the district and at Central Office in Jefferson City. Each of the districts has a District Geologist or District Soils and Geology Technologist who reports to the District Operations Engineer. At the division/unit level, these functions are administered through the [~~http~~://sharepoint/~~systemdelivery~~/CM/~~geotechnical~~/~~default~~.aspx Geotechnical Section].		Geotechnical functions in MoDOT are performed by personnel assigned to the Materials Engineering Unit, both in the district and at Central Office in Jefferson City. Each of the districts has a District Geologist or District Soils and Geology Technologist who reports to the District Operations Engineer. At the division/unit level, these functions are administered through the [https://modotgov.sharepoint.com/sites/cm/SitePages/Geotechnical.aspx Geotechnical Section].

	The district geologist's most important job is the performance and reporting of the soil survey. Basic functions of the soil survey include typing soil and rock materials and determining their limits and engineering characteristics. Other important responsibilities are obtaining preliminary bridge foundation information and identification of potential foundation problems which should be investigated in more detail by division/unit level personnel assigned to the Geotechnical Section. These are referred to as, for lack of a better term, "Special Investigations."		The district geologist's most important job is the performance and reporting of the soil survey. Basic functions of the soil survey include typing soil and rock materials and determining their limits and engineering characteristics. Other important responsibilities are obtaining preliminary bridge foundation information and identification of potential foundation problems which should be investigated in more detail by division/unit level personnel assigned to the Geotechnical Section. These are referred to as, for lack of a better term, "Special Investigations."

Smithk: /* 321.2.4.4 Light Towers */ Per CM, updated "Site Manger" to "AWP"

2020-11-12T20:54:33Z

321.2.4.4 Light Towers: Per CM, updated "Site Manger" to "AWP"

← Older revision		Revision as of 15:54, 12 November 2020
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	Electro Chemical Parameters		Electro Chemical Parameters

	:Resistivity is a function of the chloride ion and sulfate ion content and most of the time we will not run this test. To run the test we need about half a materials sack and the sample is entered into ~~site manager~~.		:Resistivity is a function of the chloride ion and sulfate ion content and most of the time we will not run this test. To run the test we need about half a materials sack and the sample is entered into Per CM, updated "Site Manger" to "AWP".

	==321.2.5 Special Foundation Investigations==		==321.2.5 Special Foundation Investigations==

EPGsysop: /* 321.2.3.5 Practical Considerations */

2017-04-07T20:05:56Z

321.2.3.5 Practical Considerations

← Older revision		Revision as of 15:05, 7 April 2017
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	'''2. Construction Problems.''' In most cases, investigative techniques are clear cut and the scope of the investigation may be less detailed when only one type of foundation is feasible. However, the scope of investigation should be influenced by considerations of the possible consequences of a change in foundation type during construction. If spread footings on rock are anticipated but no rock is found at one column, then a pile driver must be brought in. If there is no bid item for that type of work, then the price must be negotiated. The contractor will likely ask for an additional working day and claim severe impact costs, etc. For these reasons, more thorough work (at least in numbers of borings) are needed where spread footings are anticipated than for most other foundation types. Of course, being shallow, the borings should be completed more quickly. The reverse circumstance is less critical. If piles are planned and a suitable bearing stratum for footings is found on one bent, it is a simple matter to form and pour the footing while under running the piles at that location. This also has implications with respect to the scope of the foundation investigation. There is often little risk in omitting holes when piles are the logical foundation type and subsurface conditions appear uniform.		'''2. Construction Problems.''' In most cases, investigative techniques are clear cut and the scope of the investigation may be less detailed when only one type of foundation is feasible. However, the scope of investigation should be influenced by considerations of the possible consequences of a change in foundation type during construction. If spread footings on rock are anticipated but no rock is found at one column, then a pile driver must be brought in. If there is no bid item for that type of work, then the price must be negotiated. The contractor will likely ask for an additional working day and claim severe impact costs, etc. For these reasons, more thorough work (at least in numbers of borings) are needed where spread footings are anticipated than for most other foundation types. Of course, being shallow, the borings should be completed more quickly. The reverse circumstance is less critical. If piles are planned and a suitable bearing stratum for footings is found on one bent, it is a simple matter to form and pour the footing while under running the piles at that location. This also has implications with respect to the scope of the foundation investigation. There is often little risk in omitting holes when piles are the logical foundation type and subsurface conditions appear uniform.

	'''3. Footings on Hard Rock.''' For most simple structures, spread footings on hard rock will be of some practical minimum size ~~such~~ that unit loads will usually be 10 tsf or less and almost never in excess of 20 tsf. This is one reason why strength tests on hard rock are usually rather pointless and judgments on hard rock allowable bearing capacities are subjective, sometimes involving building code tables, RQD, and other empirical means. Keep in mind that the discontinuities of rock (bedding planes, joints, etc.) and, in particular, any loss while coring represent the real bearing limitations of that rock. You must rely on the driller's judgment as to why you didn't recover core. If the drill stem dropped quickly with little or no resistance, you have a void, a clay seam, or other soft material.		'''3. Footings on Hard Rock.''' For most simple structures, spread footings on hard rock will be of some practical minimum size so that unit loads will usually be 10 tsf or less and almost never in excess of 20 tsf. This is one reason why strength tests on hard rock are usually rather pointless and judgments on hard rock allowable bearing capacities are subjective, sometimes involving building code tables, RQD, and other empirical means. Keep in mind that the discontinuities of rock (bedding planes, joints, etc.) and, in particular, any loss while coring represent the real bearing limitations of that rock. You must rely on the driller's judgment as to why you didn't recover core. If the drill stem dropped quickly with little or no resistance, you have a void, a clay seam, or other soft material.
	Footings on soft rocks such as clay shales, claystones and even some sandstones and siltstones are another matter. Here the normal allowable bearings may be within a much lower range, requiring substantial enlargement of footings. In such cases, fairly detailed test data (SPT, Qu, and even pocket penetrometer data) may be needed to make judgments about allowable footing loads.		Footings on soft rocks such as clay shales, claystones and even some sandstones and siltstones are another matter. Here the normal allowable bearings may be within a much lower range, requiring substantial enlargement of footings. In such cases, fairly detailed test data (SPT, Qu, and even pocket penetrometer data) may be needed to make judgments about allowable footing loads.

	===321.2.3.6 Philosophy ===		===321.2.3.6 Philosophy ===

Smithk: updated links

2016-06-14T14:50:15Z

updated links

← Older revision		Revision as of 09:50, 14 June 2016
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	===321.2.1.1 Geotechnical Organization of MoDOT===		===321.2.1.1 Geotechnical Organization of MoDOT===

	Geotechnical functions in MoDOT are performed by personnel assigned to the Materials Engineering Unit, both in the district and at Central Office in Jefferson City. Each of the districts has a District Geologist or District Soils and Geology Technologist who reports to the District Operations Engineer. At the division/unit level, these functions are administered through the [http://~~wwwi~~/~~intranet~~/cm/~~materials~~/~~Geotechnical~~.~~htm~~ Geotechnical Section].		Geotechnical functions in MoDOT are performed by personnel assigned to the Materials Engineering Unit, both in the district and at Central Office in Jefferson City. Each of the districts has a District Geologist or District Soils and Geology Technologist who reports to the District Operations Engineer. At the division/unit level, these functions are administered through the [http://sharepoint/systemdelivery/CM/geotechnical/default.aspx Geotechnical Section].

	The district geologist's most important job is the performance and reporting of the soil survey. Basic functions of the soil survey include typing soil and rock materials and determining their limits and engineering characteristics. Other important responsibilities are obtaining preliminary bridge foundation information and identification of potential foundation problems which should be investigated in more detail by division/unit level personnel assigned to the Geotechnical Section. These are referred to as, for lack of a better term, "Special Investigations."		The district geologist's most important job is the performance and reporting of the soil survey. Basic functions of the soil survey include typing soil and rock materials and determining their limits and engineering characteristics. Other important responsibilities are obtaining preliminary bridge foundation information and identification of potential foundation problems which should be investigated in more detail by division/unit level personnel assigned to the Geotechnical Section. These are referred to as, for lack of a better term, "Special Investigations."
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	===321.2.3.3 General Procedures ===		===321.2.3.3 General Procedures ===

	The first step after receipt of a request from the Bridge Unit or district is a file search for soil survey reports, preliminary bridge reports, and foundation reports for adjacent structures. A packet of information, which includes plans, correspondence, and prior reports is assembled for field use. Next, the district is consulted for advice as to field conditions, problems with utilities, crops, landowners, etc. If site access conditions are especially bad, someone from the [http://~~wwwi~~/~~intranet~~/cm/~~materials~~/~~Geotechnical~~.~~htm~~ Geotechnical Section] may visit the site to determine what equipment may be needed and how the site can be reached. As noted previously, either the Bridge Unit or the district's boring plan may be modified as appropriate given site conditions and constraints. Some of the considerations here include:		The first step after receipt of a request from the Bridge Unit or district is a file search for soil survey reports, preliminary bridge reports, and foundation reports for adjacent structures. A packet of information, which includes plans, correspondence, and prior reports is assembled for field use. Next, the district is consulted for advice as to field conditions, problems with utilities, crops, landowners, etc. If site access conditions are especially bad, someone from the [http://sharepoint/systemdelivery/CM/geotechnical/default.aspx Geotechnical Section] may visit the site to determine what equipment may be needed and how the site can be reached. As noted previously, either the Bridge Unit or the district's boring plan may be modified as appropriate given site conditions and constraints. Some of the considerations here include:

	:'''1. General knowledge of conditions in the physiographic or geologic area where the work is to be done.''' This strongly influences the kind of investigation which should be performed and how detailed it should be. For example, in the Springfield area, residual clay over heavily pinnacled rock is likely and the most important thing is to map the rock surface irregularities with a lot of auger borings to rock so that point bearing pile lengths can be determined. In the bootheel area, auger borings are virtually worthless and standard penetration test borings for design of friction piles are most important.		:'''1. General knowledge of conditions in the physiographic or geologic area where the work is to be done.''' This strongly influences the kind of investigation which should be performed and how detailed it should be. For example, in the Springfield area, residual clay over heavily pinnacled rock is likely and the most important thing is to map the rock surface irregularities with a lot of auger borings to rock so that point bearing pile lengths can be determined. In the bootheel area, auger borings are virtually worthless and standard penetration test borings for design of friction piles are most important.
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	'''3. The geotech should identify and investigate any geotechnical problems which may preclude or adversely affect the proposed design and be prepared to offer recommendations for alternative designs or design modification. '''		'''3. The geotech should identify and investigate any geotechnical problems which may preclude or adversely affect the proposed design and be prepared to offer recommendations for alternative designs or design modification. '''

	'''4. Retaining walls.''' The Bridge Unit or District is responsible for checking all aspects of structural (internal) stability and for evaluating external stability with respect to overturning, sliding (at the base of the wall) and bearing failure. The [http://~~wwwi~~/~~intranet~~/cm/~~materials~~/~~Geotechnical~~.~~htm~~ Geotechnical Section] is responsible for furnishing the data inputs necessary for the external stability checks and for evaluating overall or global stability included slopes for which the proposed wall may be a component.		'''4. Retaining walls.''' The Bridge Unit or District is responsible for checking all aspects of structural (internal) stability and for evaluating external stability with respect to overturning, sliding (at the base of the wall) and bearing failure. The [http://sharepoint/systemdelivery/CM/geotechnical/default.aspx Geotechnical Section] is responsible for furnishing the data inputs necessary for the external stability checks and for evaluating overall or global stability included slopes for which the proposed wall may be a component.

	'''5. Bridges.''' The Bridge Unit will design the foundation units in almost all cases but may ask for design assistance in certain instances. It is the geotech's responsibility to furnish data inputs of the type and quantity required to design those foundation types which are technically and economically feasible at each site. This infers that the geotech must have the capability and knowledge, and must have developed the information necessary to design the foundation if requested to do so. Keep in mind that a foundation cannot be designed in isolation. You can design an individual pile or footing but you must also know column and bent loads, group or cluster effects, embankment "drag loads", etc. and understand the interactions of the resulting stresses.		'''5. Bridges.''' The Bridge Unit will design the foundation units in almost all cases but may ask for design assistance in certain instances. It is the geotech's responsibility to furnish data inputs of the type and quantity required to design those foundation types which are technically and economically feasible at each site. This infers that the geotech must have the capability and knowledge, and must have developed the information necessary to design the foundation if requested to do so. Keep in mind that a foundation cannot be designed in isolation. You can design an individual pile or footing but you must also know column and bent loads, group or cluster effects, embankment "drag loads", etc. and understand the interactions of the resulting stresses.

Smithk: Per CM, removed EPG 321.2.10 soil survey info (terminology was no longer correct; it should be "preliminary geotechnical report"). Correct info is in EPG 320.1. Also, updated figs in EPG 320.2.10.6.

2012-06-25T18:46:45Z

Per CM, removed EPG 321.2.10 soil survey info (terminology was no longer correct; it should be "preliminary geotechnical report"). Correct info is in EPG 320.1. Also, updated figs in EPG 320.2.10.6.

Show changes

Smithk: References to ten districts and "District 3", etc. were removed.

2012-05-03T18:08:44Z

References to ten districts and "District 3", etc. were removed.

← Older revision		Revision as of 13:08, 3 May 2012
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	===321.2.1.1 Geotechnical Organization of MoDOT===		===321.2.1.1 Geotechnical Organization of MoDOT===

	Geotechnical functions in MoDOT are performed by personnel assigned to the Materials Engineering Unit, both in the district and at Central Office in Jefferson City. Each of the ~~ten~~ districts has a District Geologist or District Soils and Geology Technologist who reports to the District Operations Engineer. At the division/unit level, these functions are administered through the [http://wwwi/intranet/cm/materials/Geotechnical.htm Geotechnical Section].		Geotechnical functions in MoDOT are performed by personnel assigned to the Materials Engineering Unit, both in the district and at Central Office in Jefferson City. Each of the districts has a District Geologist or District Soils and Geology Technologist who reports to the District Operations Engineer. At the division/unit level, these functions are administered through the [http://wwwi/intranet/cm/materials/Geotechnical.htm Geotechnical Section].

	The district geologist's most important job is the performance and reporting of the soil survey. Basic functions of the soil survey include typing soil and rock materials and determining their limits and engineering characteristics. Other important responsibilities are obtaining preliminary bridge foundation information and identification of potential foundation problems which should be investigated in more detail by division/unit level personnel assigned to the Geotechnical Section. These are referred to as, for lack of a better term, "Special Investigations."		The district geologist's most important job is the performance and reporting of the soil survey. Basic functions of the soil survey include typing soil and rock materials and determining their limits and engineering characteristics. Other important responsibilities are obtaining preliminary bridge foundation information and identification of potential foundation problems which should be investigated in more detail by division/unit level personnel assigned to the Geotechnical Section. These are referred to as, for lack of a better term, "Special Investigations."

Smithk: Per CM, replaced MoDOT 50 Blow method with Split Spoon Test in Shale

2012-01-24T17:27:08Z

Per CM, replaced MoDOT 50 Blow method with Split Spoon Test in Shale

← Older revision		Revision as of 12:27, 24 January 2012
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	\|[http://epg.modot.mo.gov/documents/321_MoDOT_Field_Log_Protocol.pdf MoDOT Field Log Protocol]		\|[http://epg.modot.mo.gov/documents/321_MoDOT_Field_Log_Protocol.pdf MoDOT Field Log Protocol]
	\|-
	~~\|[[media:MoDOT 50 blow.doc\|MoDOT 50 Blow SPT Penetration Method]]~~
	\|-		\|-
	\|[http://epg.modot.mo.gov/documents/321_p-y_Curve_Criteria.pdf P-Y Curve Criteria]		\|[http://epg.modot.mo.gov/documents/321_p-y_Curve_Criteria.pdf P-Y Curve Criteria]
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	\|[http://epg.modot.mo.gov/documents/321_Seismic_Procedure.pdf Seismic Procedure]		\|[http://epg.modot.mo.gov/documents/321_Seismic_Procedure.pdf Seismic Procedure]
	\|-		\|-
	\|[[media:321 Soil and Rock Properties FHWA 2002.pdf \|Soil and Rock Properties, FHWA 2002]]		\|[[media:321 Soil and Rock Properties FHWA 2002.pdf \|Soil and Rock Properties, FHWA 2002]]
	\|-		\|-
	\|[http://epg.modot.mo.gov/documents/321_Soil_Profile_Type.pdf Soil Profile Type]		\|[http://epg.modot.mo.gov/documents/321_Soil_Profile_Type.pdf Soil Profile Type]
			\|-
			\|[[media:Split Spoon Test in Shale.doc\|Split Spoon Test in Shale]]
	\|-		\|-
	\|[http://epg.modot.mo.gov/documents/321_Subsurface_Inv_Manual_FHWA.pdf Subsurface Investigation Manual FHWA 1997]		\|[http://epg.modot.mo.gov/documents/321_Subsurface_Inv_Manual_FHWA.pdf Subsurface Investigation Manual FHWA 1997]

Smithk: Per Geotechnical; a general re-write and re-arrangement for EPG 321.

2011-03-31T20:03:08Z

Per Geotechnical; a general re-write and re-arrangement for EPG 321.

Show changes