Critical Path Method in Construction Industry - Revision history

Tkokotas at 15:34, 18 December 2018

2018-12-18T15:34:42Z

← Older revision		Revision as of 15:34, 18 December 2018
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			''Developed by Adam Dominik Pekala''


	'''Critical Path Method (CPM)''' is a project management method created in 1958 in American company DuPont to improve internal production processes. Since then the method is widely used in industries such as construction, aerospace, defense, engineering, research and many more. However, this article focuses on its use in civil engineering industry and construction. The method is suitable for all kind of construction projects that require many independent activities to be completed.		'''Critical Path Method (CPM)''' is a project management method created in 1958 in American company DuPont to improve internal production processes. Since then the method is widely used in industries such as construction, aerospace, defense, engineering, research and many more. However, this article focuses on its use in civil engineering industry and construction. The method is suitable for all kind of construction projects that require many independent activities to be completed.

Adam.pekala: /* Resource-Dependent Critical Path Method */

2015-09-28T22:22:09Z

Resource-Dependent Critical Path Method

← Older revision		Revision as of 22:22, 28 September 2015
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	== Resource-Dependent Critical Path Method ==		== Resource-Dependent Critical Path Method ==
	[[File:CPM Figure10a.PNG\|~~275px~~\|right\|thumb\|<center>Figure 5: RDCPM - Redundancy ''(source: own construction based on <ref name=RDCPM/>)</center>'']]Since as mentioned in Linear Resource Based CPM chapter it is impossible to identify corrects slacks and critical path which is resource based using regular CPM method, further studies were undertaken and 4-step resource dependent critical path method was created (RDCPM). This method, however, was constrained by assumption of maximum resources being available during the whole duration of a project. A new method was created and called Enhanced RDCPM<ref name=RDCPM>[https://www.jstage.jst.go.jp/article/jscejcei/69/2/69_I_110/_article]''”Enhanced Resource-Dependent Critical Path Method for Identifying Resource Dependencies in Variable Resource Constrained Project” Journal of Japan Society of Civil Engineers, Ser. F3 (Civil Engineering Informatics) Vol. 69 (2013) No. 2 p. I110-I120''</ref> - taking from the traditional CPM and Resource Constrained Scheduling. It is divided in 6 steps which are as follows:		[[File:CPM Figure10a.PNG\|240px\|right\|thumb\|<center>Figure 5: RDCPM - Redundancy ''(source: own construction based on <ref name=RDCPM/>)</center>'']]Since as mentioned in Linear Resource Based CPM chapter it is impossible to identify corrects slacks and critical path which is resource based using regular CPM method, further studies were undertaken and 4-step resource dependent critical path method was created (RDCPM). This method, however, was constrained by assumption of maximum resources being available during the whole duration of a project. A new method was created and called Enhanced RDCPM<ref name=RDCPM>[https://www.jstage.jst.go.jp/article/jscejcei/69/2/69_I_110/_article]''”Enhanced Resource-Dependent Critical Path Method for Identifying Resource Dependencies in Variable Resource Constrained Project” Journal of Japan Society of Civil Engineers, Ser. F3 (Civil Engineering Informatics) Vol. 69 (2013) No. 2 p. I110-I120''</ref> - taking from the traditional CPM and Resource Constrained Scheduling. It is divided in 6 steps which are as follows:
	# Performing CPM – standard analysis is performed with forward and backward pass to calculate ES, EF, LS, LF and floats for each of the activities.		# Performing CPM – standard analysis is performed with forward and backward pass to calculate ES, EF, LS, LF and floats for each of the activities.
	# Inserting Dummy Activities – if the project has varying resources during its execution it might be impossible to identify resource dependencies for activities. It is inserted in-between the periods where the availability of the resources varies – classic RCS can be easily used. Moreover dummy activities might help to establish resource links between activities so that the schedule is easily updateable.		# Inserting Dummy Activities – if the project has varying resources during its execution it might be impossible to identify resource dependencies for activities. It is inserted in-between the periods where the availability of the resources varies – classic RCS can be easily used. Moreover dummy activities might help to establish resource links between activities so that the schedule is easily updateable.

Adam.pekala: /* Resource-Dependent Critical Path Method */

2015-09-28T22:21:58Z

Resource-Dependent Critical Path Method

← Older revision		Revision as of 22:21, 28 September 2015
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	== Resource-Dependent Critical Path Method ==		== Resource-Dependent Critical Path Method ==
	[[File:CPM Figure10a.PNG\|~~250px~~\|right\|thumb\|<center>Figure 5: RDCPM - Redundancy ''(source: own construction based on <ref name=RDCPM/>)</center>'']]Since as mentioned in Linear Resource Based CPM chapter it is impossible to identify corrects slacks and critical path which is resource based using regular CPM method, further studies were undertaken and 4-step resource dependent critical path method was created (RDCPM). This method, however, was constrained by assumption of maximum resources being available during the whole duration of a project. A new method was created and called Enhanced RDCPM<ref name=RDCPM>[https://www.jstage.jst.go.jp/article/jscejcei/69/2/69_I_110/_article]''”Enhanced Resource-Dependent Critical Path Method for Identifying Resource Dependencies in Variable Resource Constrained Project” Journal of Japan Society of Civil Engineers, Ser. F3 (Civil Engineering Informatics) Vol. 69 (2013) No. 2 p. I110-I120''</ref> - taking from the traditional CPM and Resource Constrained Scheduling. It is divided in 6 steps which are as follows:		[[File:CPM Figure10a.PNG\|275px\|right\|thumb\|<center>Figure 5: RDCPM - Redundancy ''(source: own construction based on <ref name=RDCPM/>)</center>'']]Since as mentioned in Linear Resource Based CPM chapter it is impossible to identify corrects slacks and critical path which is resource based using regular CPM method, further studies were undertaken and 4-step resource dependent critical path method was created (RDCPM). This method, however, was constrained by assumption of maximum resources being available during the whole duration of a project. A new method was created and called Enhanced RDCPM<ref name=RDCPM>[https://www.jstage.jst.go.jp/article/jscejcei/69/2/69_I_110/_article]''”Enhanced Resource-Dependent Critical Path Method for Identifying Resource Dependencies in Variable Resource Constrained Project” Journal of Japan Society of Civil Engineers, Ser. F3 (Civil Engineering Informatics) Vol. 69 (2013) No. 2 p. I110-I120''</ref> - taking from the traditional CPM and Resource Constrained Scheduling. It is divided in 6 steps which are as follows:
	# Performing CPM – standard analysis is performed with forward and backward pass to calculate ES, EF, LS, LF and floats for each of the activities.		# Performing CPM – standard analysis is performed with forward and backward pass to calculate ES, EF, LS, LF and floats for each of the activities.
	# Inserting Dummy Activities – if the project has varying resources during its execution it might be impossible to identify resource dependencies for activities. It is inserted in-between the periods where the availability of the resources varies – classic RCS can be easily used. Moreover dummy activities might help to establish resource links between activities so that the schedule is easily updateable.		# Inserting Dummy Activities – if the project has varying resources during its execution it might be impossible to identify resource dependencies for activities. It is inserted in-between the periods where the availability of the resources varies – classic RCS can be easily used. Moreover dummy activities might help to establish resource links between activities so that the schedule is easily updateable.

Adam.pekala: /* Resource-Dependent Critical Path Method */

2015-09-28T22:21:36Z

Resource-Dependent Critical Path Method

← Older revision		Revision as of 22:21, 28 September 2015
Line 170:		Line 170:

	== Resource-Dependent Critical Path Method ==		== Resource-Dependent Critical Path Method ==
	Since as mentioned in Linear Resource Based CPM chapter it is impossible to identify corrects slacks and critical path which is resource based using regular CPM method, further studies were undertaken and 4-step resource dependent critical path method was created (RDCPM). This method, however, was constrained by assumption of maximum resources being available during the whole duration of a project. A new method was created and called Enhanced RDCPM<ref name=RDCPM>[https://www.jstage.jst.go.jp/article/jscejcei/69/2/69_I_110/_article]''”Enhanced Resource-Dependent Critical Path Method for Identifying Resource Dependencies in Variable Resource Constrained Project” Journal of Japan Society of Civil Engineers, Ser. F3 (Civil Engineering Informatics) Vol. 69 (2013) No. 2 p. I110-I120''</ref> - taking from the traditional CPM and Resource Constrained Scheduling. It is divided in 6 steps which are as follows:		[[File:CPM Figure10a.PNG\|250px\|right\|thumb\|<center>Figure 5: RDCPM - Redundancy ''(source: own construction based on <ref name=RDCPM/>)</center>'']]Since as mentioned in Linear Resource Based CPM chapter it is impossible to identify corrects slacks and critical path which is resource based using regular CPM method, further studies were undertaken and 4-step resource dependent critical path method was created (RDCPM). This method, however, was constrained by assumption of maximum resources being available during the whole duration of a project. A new method was created and called Enhanced RDCPM<ref name=RDCPM>[https://www.jstage.jst.go.jp/article/jscejcei/69/2/69_I_110/_article]''”Enhanced Resource-Dependent Critical Path Method for Identifying Resource Dependencies in Variable Resource Constrained Project” Journal of Japan Society of Civil Engineers, Ser. F3 (Civil Engineering Informatics) Vol. 69 (2013) No. 2 p. I110-I120''</ref> - taking from the traditional CPM and Resource Constrained Scheduling. It is divided in 6 steps which are as follows:
	# Performing CPM – standard analysis is performed with forward and backward pass to calculate ES, EF, LS, LF and floats for each of the activities.		# Performing CPM – standard analysis is performed with forward and backward pass to calculate ES, EF, LS, LF and floats for each of the activities.
	# Inserting Dummy Activities – if the project has varying resources during its execution it might be impossible to identify resource dependencies for activities. It is inserted in-between the periods where the availability of the resources varies – classic RCS can be easily used. Moreover dummy activities might help to establish resource links between activities so that the schedule is easily updateable.		# Inserting Dummy Activities – if the project has varying resources during its execution it might be impossible to identify resource dependencies for activities. It is inserted in-between the periods where the availability of the resources varies – classic RCS can be easily used. Moreover dummy activities might help to establish resource links between activities so that the schedule is easily updateable.
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	#*Strict Resource Precedence Relation – relation in which a delay in finish time pre-occurring activity results in delay in finish time of following activity		#*Strict Resource Precedence Relation – relation in which a delay in finish time pre-occurring activity results in delay in finish time of following activity
	#*Flexible Resource Precedence Relation – relation in which a delay in finish time of pre-occurring activity results in delay of start time only, in following activity		#*Flexible Resource Precedence Relation – relation in which a delay in finish time of pre-occurring activity results in delay of start time only, in following activity
	#Removal of redundant precedence relations – all of the redundant activities can be safely removed from the schedule. If an activity is preceded by two inter-dependent activities, one of the links can be safely removed. Example of link removal is presented ~~below~~.		#Removal of redundant precedence relations – all of the redundant activities can be safely removed from the schedule. If an activity is preceded by two inter-dependent activities, one of the links can be safely removed. Example of link removal is presented in Figure 5.
	<div style="clear: both"></div>		<div style="clear: both"></div>
	~~[[File:CPM Figure10.PNG\|800px\|center\|thumb\|<center>Figure 5: RDCPM - Redundancy ''(source: own construction based on <ref name=RDCPM/>)</center>'']]~~
	<div style="clear: both"></div>		<div style="clear: both"></div>

Adam.pekala: /* Example of CPM graph creation */

2015-09-28T22:07:41Z

Example of CPM graph creation

← Older revision		Revision as of 22:07, 28 September 2015
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	\|+<br>'''Dependencies graph'''		\|+<br>'''Dependencies graph'''
	\|-		\|-
	\|[[File:CPM Figure2.JPG\|450px\|center\|thumb\|Figure 2: Dependencies graph ''(source: own construction)'']]		\|[[File:CPM Figure2.JPG\|450px\|center\|thumb\|<center>Figure 2: Dependencies graph ''(source: own construction)''</center>]]
	\|}		\|}
	<div style="clear: both"></div>		<div style="clear: both"></div>

Adam.pekala: /* Example of CPM graph creation */

2015-09-28T22:07:01Z

Example of CPM graph creation

← Older revision		Revision as of 22:07, 28 September 2015
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	=== Example of CPM graph creation ===		=== Example of CPM graph creation ===
	{\| class="wikitable" style="float:~~right~~; margin-left: ~~10px~~;"		Based on a simplified one story building and reduced to basic number of activities a CPM method with CPM graph creation will be presented. First of all, following the methodology there is a need to point out all of the activities that are identyfied in the project and estimate their duration. In the example activity list from the table below will be used. Then, by analyzing inter-activity dependencies, a dependecy graph is drawn. As a rule of thumb the graph starts on the left side with starting activities (independent activity that happens in t=0) and finishes with last activity that is the last activity (followed usually by activities from the critical path).
			{\| class="wikitable" align: center; style="float:left; margin-left: 5px;"
			\|+'''List of activities'''
	\|-		\|-
	\|ID/Number		\|ID/Number
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	\|1		\|1
	\|}		\|}
	Based on a simplified one story building and reduced to basic number of activities a CPM method with CPM graph creation will be presented. First of all, following the methodology there is a need to point out all of the activities that are identyfied in the project and estimate their duration. In the example activity list from the table below will be used. Then, by analyzing inter-activity dependencies, a dependecy graph is drawn. As a rule of thumb the graph starts on the left side with starting activities (independent activity that happens in t=0) and finishes with last activity that is the last activity (followed usually by activities from the critical path).




	~~[[File:CPM Figure2.JPG\|450px\|right\|thumb\|Figure 2: Dependencies graph]]~~



			{\|align: right style="margin: auto;"
			\|+<br>'''Dependencies graph'''
			\|-
			\|[[File:CPM Figure2.JPG\|450px\|center\|thumb\|Figure 2: Dependencies graph ''(source: own construction)'']]
			\|}
	<div style="clear: both"></div>		<div style="clear: both"></div>
	There are two main steps to be performed based on the activities' duration provided in activity table - forward pass calculation and backwards pass calculation.		There are two main steps to be performed based on the activities' duration provided in activity table - forward pass calculation and backwards pass calculation.

Adam.pekala: /* Example of CPM graph creation */

2015-09-28T22:05:36Z

Example of CPM graph creation

← Older revision		Revision as of 22:05, 28 September 2015
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	~~{\|align: right style="margin: auto;"~~
	\|-
	\|[[File:CPM Figure2.JPG\|450px\|right\|thumb\|Figure 2: Dependencies graph]]		[[File:CPM Figure2.JPG\|450px\|right\|thumb\|Figure 2: Dependencies graph]]
	\|}

Adam.pekala: /* Example of CPM graph creation */

2015-09-28T22:05:08Z

Example of CPM graph creation

← Older revision		Revision as of 22:05, 28 September 2015
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	{\|align: right style="margin: auto;"		{\|align: right style="margin: auto;"
	~~\|+<br>'''Dependencies graph'''~~
	\|-		\|-
	\|[[File:CPM Figure2.JPG\|450px\|~~center~~\|Figure 2: Dependencies graph]]		\|[[File:CPM Figure2.JPG\|450px\|right\|thumb\|Figure 2: Dependencies graph]]
	\|}		\|}

Adam.pekala: /* Example of CPM graph creation */

2015-09-28T22:04:20Z

Example of CPM graph creation

← Older revision		Revision as of 22:04, 28 September 2015
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	=== Example of CPM graph creation ===		=== Example of CPM graph creation ===
			{\| class="wikitable" style="float:right; margin-left: 10px;"
	Based on a simplified one story building and reduced to basic number of activities a CPM method with CPM graph creation will be presented. First of all, following the methodology there is a need to point out all of the activities that are identyfied in the project and estimate their duration. In the example activity list from the table below will be used. Then, by analyzing inter-activity dependencies, a dependecy graph is drawn. As a rule of thumb the graph starts on the left side with starting activities (independent activity that happens in t=0) and finishes with last activity that is the last activity (followed usually by activities from the critical path).
	{\| class="wikitable" ~~align: center;~~ style="float:~~left~~; margin-left: ~~5px~~;"
	~~\|+'''List of activities'''~~
	\|-		\|-
	\|ID/Number		\|ID/Number
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	\|1		\|1
	\|}		\|}
			Based on a simplified one story building and reduced to basic number of activities a CPM method with CPM graph creation will be presented. First of all, following the methodology there is a need to point out all of the activities that are identyfied in the project and estimate their duration. In the example activity list from the table below will be used. Then, by analyzing inter-activity dependencies, a dependecy graph is drawn. As a rule of thumb the graph starts on the left side with starting activities (independent activity that happens in t=0) and finishes with last activity that is the last activity (followed usually by activities from the critical path).


	{\|align: right style="margin: auto;"		{\|align: right style="margin: auto;"

Adam.pekala: /* Example of CPM graph creation */

2015-09-28T22:01:48Z

Example of CPM graph creation

← Older revision		Revision as of 22:01, 28 September 2015
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	=== Example of CPM graph creation ===		=== Example of CPM graph creation ===
	{\| class="wikitable" style="float:~~right~~; margin-left: ~~20px~~;"
			Based on a simplified one story building and reduced to basic number of activities a CPM method with CPM graph creation will be presented. First of all, following the methodology there is a need to point out all of the activities that are identyfied in the project and estimate their duration. In the example activity list from the table below will be used. Then, by analyzing inter-activity dependencies, a dependecy graph is drawn. As a rule of thumb the graph starts on the left side with starting activities (independent activity that happens in t=0) and finishes with last activity that is the last activity (followed usually by activities from the critical path).
			{\| class="wikitable" align: center; style="float:left; margin-left: 5px;"
			\|+'''List of activities'''
	\|-		\|-
	\|ID/Number		\|ID/Number
Line 102:		Line 105:
	\|1		\|1
	\|}		\|}
	Based on a simplified one story building and reduced to basic number of activities a CPM method with CPM graph creation will be presented. First of all, following the methodology there is a need to point out all of the activities that are identyfied in the project and estimate their duration. In the example activity list from the table below will be used. Then, by analyzing inter-activity dependencies, a dependecy graph is drawn. As a rule of thumb the graph starts on the left side with starting activities (independent activity that happens in t=0) and finishes with last activity that is the last activity (followed usually by activities from the critical path).

			{\|align: right style="margin: auto;"
	{\|align: right style="margin: auto;"
	\|+<br>'''Dependencies graph'''		\|+<br>'''Dependencies graph'''
	\|-		\|-
	\|[[File:CPM Figure2.JPG\|450px\|~~right~~\|~~thumb\|<center>~~Figure 2: Dependencies graph ~~''(source: own construction)''</center>~~]]		\|[[File:CPM Figure2.JPG\|450px\|center\|Figure 2: Dependencies graph]]
	\|}		\|}


	<div style="clear: both"></div>		<div style="clear: both"></div>