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Project activities lead and lag

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lead is the process of acceleration of conducting successor activity by starting the successor activity before the finish of previous activity, this can be done if there are no physical or technical constraints on starting with successor activity before completion the precedent activity, this will occur in FS type of activities. an example of this is the fixing of formwork and casting of 50 columns for a building, fixing formwork required 4 days. instead of waiting for 4 days, to begin with, casting, we will start casting from day one. skilled engineers will always utilize all the available manpower and equipment. also, they will reduce the time of performing the job by overlapping the activities as much as possible without reducing the quality of the work. 

Figure 1











lag is the delay of successor activity after the completion of the precedent activity. lag represents the time before the second activity can start. Lag may be found in activities with all relationship types: finish-to-start, start-to-start, finish-to-finish, and start-to-finish.. suppose we finish casting our bridge deck and post-tensioning is the second activity, post-tensioning can't start until the concrete attains the required strength so in this case second activity delayed after the completion of the first activity and this is the lag.
Figure 2



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My name is Mohammad Hamdan, and I am a Civil/bridge Engineer with extensive professional background and experience in the field of construction. I have 10+ years of experience in the construction field. During my professional career, my emphasis has been placed on structural projects, mainly bridges, infrastructure and roads. Reading and practicing the design of structures is my passion.i was lucky to be a part of a big team that executed major highway interchanges. I believe in spreading the knowledge, thus, i compose these courses to share my experience and knowledge. My course focuses on the practical side of construction field. On other word, i am sharing some of what new engineers need to know about construction field. Beside working on construction field, i love writing some articles on my website ( curious civil engineer) Moreover, i wrote some engineering papers, you can check them  by searching my name on Google (Mohammad mamon Hamdan)