MECHANISM OF BUILDING OPERSTIONS...LESSON TWO....

Mechanism of Building Operations is a method or means of carrying out construction activities by use of machines as plant or equipment.

LAYOUT OF PLANT AND EQUIPMENT

Refers to the physical arrangement of production facilities, it is the configuration of departments, work centres and equipment in the conversion process. It is a floor plan of the physical facilities, which are used in production.

Or layout of Plantis a plan of an optimum arrangement of facilities including personnel, operating equipment, storage space, material handling equipment and all other supporting services along with the design of best structure to contain all these facilities”.

Objectives of Layout of plant

The primary goal of the plant layout is to maximise the profit by arrangement of all the plant facilities to the best advantage of total manufacturing of the product.

The objectives of plant layout are:

1. Streamline the flow of materials through the plant.

2. Facilitate the building process.

3. Maintain high turnover of in-process inventory.

4. Minimise materials handling and cost.

5. Effective utilisation of men, equipment and space.

6. Make effective utilisation of cubic space.

7. Flexibility of building operations and arrangements.

8. Provide for employee convenience, safety and comfort.

9. Minimize investment in equipment.

10. Minimize overall production time.

11. Maintain flexibility of arrangement and operation.

12. Facilitate the organizational structure.

REASON FOR USING PLANTS AND EQUIPMENT’S DURING CONSTRUCTION PROCESS

§  High output

§  Quality of works

§  Economy

§  Nature of the work

CLASSIFICATION AND TYPES OF CONSTRUCTION PLANT AND EQUIPMENT BASED ON ITS USES

§  EXCAVATING PLANT

Dozer

Wheel Loader

Hydraulic Excavator

§  COMPACTING PLANT

Vibratory Compactor

§  CONCRETING PLANT

Batching Plants

Mixers

Concrete Pumps

Transit Mixers

Dumpers

Concrete Placers

§  WELDING EQUIPMENTS :

Generators

Transformers

Rectifiers

Submerged Arc Welding Unit

Automatic Welding Set

§  TRANSPORTING PLANT

Tractors Trailors

Trucks

Tipper

§  LIFTING PLANT PILING PLANT AND EQUIPMENT

Cranes 01-10 Ton

Cranes 11-20 Ton

Cranes 21-50 Ton

Cranes 51-75 Ton

Cranes 76-100 Ton

Cranes 101-150 Ton

Cranes 151-200 Ton

Cranes 201-250 Ton

Cranes 251-300 Ton

§  DRILLING PLANT AND EQUIPMENT

Piling Rigs

Rotary, Piling Rigs/Crane Mounted Rotary Piling Rigs

Piling Winch with Accessories

Pile Hammer

Boring Tools & Accessories for Piles of Different Diameters

Diaphragm Wall Rigs

Rectangular Grabs for Diaphragm Walls of Different Thickness

Tripod Type Bored Piling Equipment

Truck Mounted Direct Mud Circulation Type Bored Piling Rig

Vibratory Hammer

High Pressure Mud Pump

Bentonite Mixing and Generating Unit

During using these plants and equipment its evaluation on performance depends on:-

    i.        Volume of works it can perform on given time

   ii.        Technicalities involved during operating it

 iii.        Economy of such plant e.g. initial and operating cost.

Task: Different between plant and 

  EQUIPMENTS USED

        I.            Dump level: an instrument with a telescope having cross-hairs used for reading (determining) vertical distances (heights) of objects from the ground. It is free to turn 360⁰.

     II.            Cross-staff: a graduated bar usually 4 meters long from which heights of various features on the ground are read using cross-hairs of the telescope of the leveling machine. The staff is held vertically in order to get accurate desired results.

   III.            Tape measure: used to measure the length of profile (25m in this case) and other distances in cross-section including the horizontal distances.

  IV.            Field book frame: for booking, holding and holding data sheets.

     PROCEDURES

        I.            A profile 300metres long was established from a control point BM whose reduced level is 1650m running within the survey area.

     II.            The profile levels at a horizontal distance interval of 25m were determined using a leveling machine,staff, tape measure and tripod stand.

   III.            At each profile level, a cross-section 30metres wide was established, being 15metres in both sides of the profile and at each interval of 5metres the levels were determined and recorded.

  IV.            The levels which were visible were treated as intermediate sights and the one seemed to be invisible, was made a foresight and a back sight of the next change point.

    V.            The reduced levels (heights) of all established points as shown on field data sheet were determined and recorded. The closing of the leveling process was done back to the starting control point of reduced level 1650m.

The profile and cross-section drawings of point distribution and the field data sheet are shown on respectively.

       PROBLEMS:

(i)                 Lack of some required instruments for this survey work such as ranging poles,tape measure,hammer,pegs/iron pins and optical square  and foot plate from the survey office.

(ii)              Rainfall

(iii)            Large number of people in a group (28 people).

  DATA ANALYSIS

Data are shown on the field data sheet

ARITHMETIC CHECK:

 ∑BS= 13.514m

∑FS=13.519m,  ∑ BS - ∑FS= 13.514m - 13.519m = -0.005m

∑Rise = 20.450m

∑Fall = -20.455m,   ∑Rise - ∑Fall =20.450m - 20.455m = -0.005m

RL last = 1649.995m

RL first = 1650.000m, RL last – RL first = 1649.995m – 1650.000m= -0.005m

Since; ∑BS - ∑FS = ∑Rise - ∑Fall = RL last – RL first = -0.005m

Computations are correct.

MISCLOSURE:

Is the difference between the known reduced level of control point BMand that calculated reduced level during leveling of profile and cross-section .

RL known = 1650.000m, RL computed = 1649.995m

RL computed – RL known

MISCLOSURE =RL computed – RL known = 1649.995m – 1650.000m

= - 0.005m

The misclosure is tolerable

Error Distribution:

Error = misclosure/number of change points(n)

Misclosure = -0.005m,  n = 7

Error = -0.005m/ =-0.00071m

The error of -0.00071m was distributed accumulatively as shown on the field data sheet.

ERRROR ANALYSIS:

No	NAME	TYPE	SOURCE	PREVENTION
1	Instrumental error	Systematic	-Two foot screws for levelling machine were not working. -slow motion screw.	-inspection of the machine before using it -careful centering and adjustment of the level.
2	Personal error	Random	Wrong reading at the staff	Focusing to get a clear image of cross-hairs and the leveling staff
3	Personal/natural error	Random	Tilting of the level staff	A spirit bubble should be centered for the level staff to be vertically upright.
4	Natural	Environmental	Refraction, curvature of the earth and wet ground.	-taking short, equal fore sight and back sight distances -using stepping method for slopping areas.

RECOMMENDATION:

To get more accurate data, the leveling machine should be leveled with the spirit bubble centered, all screws should be working properly, well focused eye piece to get clear cross-hair and leveling staff images before taking measurements. Repeating the survey work and taking the mean value, it helps in minimizing errors.

CONCLUTION:

Data were well collected and the profile and cross-sections were drawn to show the terrain of the area.