SETTING OUT.docx.pdf - SETTING OUT 1.0 Scope of setting out...

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SETTING OUT 1.0 Scope of setting out Setting out is the transfer of measurements from working drawings to the building plot. Also, Setting out can be defined as the physical transfer into the ground what was initially on plan or in paperwork. For example, transferring the building professionals drawing plan onto the ground is a process of setting out. Pegs and profiles are set out to mark the positions of corners, walls and foundations. Most working drawings show separate measurements for individual features for example walls, windows and doors. Constructional Surveys Constructional surveys are surveys that deal with the tasks of marking the positions of the proposed infrastructure on the ground. They are also referred to as Location surveys. The features to be located can either be manmade or artificial such as Linear features - Trenches - Conduits - Buildings - Road centre line - Power line Curved features - Rounded kerbs (gutters) - Road centre lines - Roundabouts - Circular staircases Terms used in the constructional survey i) Bench mark This is a survey point whose height above a datum is already known and has been fixed accurately by the survey means. ii) Gradient This is the degree of slope used on the features as the pipe lines, sewer lines etc J. OMEKE 2021 EECQ 2233 ENG. SURVEYING 1B Lecture 2 1
iii) Section This is representation of the structure as it were cut from top to the bottom and looked from the side. iv) Trench / formation level This is the level to which the existing ground is worked by the constructional methods. The optimum position for the formation level is usually found by drawing the longitudinal section with the mass haul diagrams. v) Invert level This is the level of the inside bottom surface of a pipe in a trench. Purpose of the constructional surveys The constructional surveys are for i. Establishing on the ground a system of grades or markers both in plan and elevation from which measurements of earthworks and structures can be taken ii. Giving line and grade as needed either to replace stakes disturbed by the construction or reach additional points on the structure itself. iii. Making measurements necessary to verify the location of the completed parts of the structure Setting out procedures There are three distinct elements to setting out the task: i. Provision of horizontal control to ensure that the new works are in the correct place, ii. Provision of vertical control to ensure that they are at the correct level, iii. And provision of vertical alignment to ensure that multi storey or underground construction is plumb. J. OMEKE 2021 EECQ 2233 ENG. SURVEYING 1B Lecture 2 2
The setting out principles and point marking The information to be transferred from the paper should be in the format that is understood by all the people working on the site. The points or markers used are in three orders, namely i) Primary markers These are stations on the control traverse or triangulation. They are permanent ii) Secondary markers

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