P. Muralidhar
National Institute of Construction Management And
Research, India
E-mail: pmuralidhar17@gmail.com
Submission: 21/06/2017
Accept: 08/03/2018
ABSTRACT
Operational efficiency in any
construction project is directly reflects the profitability of a project, It is
for benefit of a construction project. The current research paper
emphasized on high operational efficiency
by reducing waste, better layout planning, sound administration, business
practices and the review of existing facilities etc. Higher the operational
efficiency will enhance the profit by adding the value to the project in the
form of cost reduction in the areas of internal transportation, utilization of
existing facilities effectively. The current research study adopted the computerized relative allocation of facilities techniques (CRAFT)
and computerized relationship planning (CORELAP) algorithm to analyze the
operational efficiency of construction project site.
Keywords: Operational efficiency,
layout planning, CRAFT, CORELAP
1. INTRODUCTION
The construction projects are unique
compared to other projects and requires attention at all the stages of the
construction. Sound and effective communication is crucial for smooth
functioning of project activities, Which in turn leads to enhance the
operational efficiency and productivity.
Planning the layout of construction
project is crucial task and it has significant impact on construction cost, productivity
and safety. It involves positioning and dynamic relocation of temporary
facilities that were needed to support various construction activities on site
such as office, storage area, working area etc. Due to complexity of site
layout planning problems, construction managers used to perform the task using
previous experience, ad-hoc rules, first in first out(FIFO) approach which
leads to ambiguity and even to inadequate facilities in the project site.
In order to fulfill this complexity
several layout planning models are developed based on the suitable layout types
adopted by which operational efficiency is enhanced to higher extent. A well
designed layout may contribute to overall efficiency of operations in the
project site and may cut down the operating cost drastically.
To improve the operational
efficiency, the current study compares the transportation cost between the
departments and materials movement cost with in a project site. Computerized
relative allocation of facilities techniques (CRAFT) methodology is based on the heuristics approach and minimizes the
material handling cost.
Computerized relationship and layout
planning (CORELAP) attempts to find the near ness rating within the facility
constraints. CRAFT was utilized to compare the real cost involved in existing
layout and new layout.
2. LITERATURE REVIEW
A number of studies have been
conducted in order to improve operational efficiency in construction projects
by means of improving site layout planning thereby effectively reducing cost of
construction and simultaneously reducing the wastage in the site due to
inefficient layout management (CAI et al., 2012).
These studies adopted a wide range
of methodologies, development tools including neural networks, simulation,
knowledge-based systems, and genetic algorithms (BORDOLOI, 2014; PATIL; JOSHI,
2014).
According to the organizational
psychologists there are two ways to improve the productivity of employee’s i.e
performance: “financial” and “non‐fina ncial”
motivators. There must be uniform system for rewarding the employee performance
and the review of performance appraisal of employees (HANDIER, 1985).
The design of measurement of
performance of construction project employees should be different from the
performance appraisal of the manufacturing employees (JARKAS, et al., 2015).
The concept of index of complexity,
and work load indicator for designing the performance appraisal for
construction employees is essential. The index complexity is
a measurement of the congestion, around the tool and conditions for routing the
connections. The work load indicator is the product of the index complexity and
the number of connections of a certain type, such as piping, ductwork or
electrical (WIEZELALI, 2003).
Sometimes relocation of the
employees working in a critical operation in a simulated environment shows
reduction in cycle time and higher productivity (GNANAVEL et al., 2004). Ergonomically designed U-formed line layout is quite
useful in construction site for improving the productivity (ABDULAZIZ et al., 2009).
The small variation in operational efficiency helps to reduction of
20-40% in waste, may lead to reduce the
cost upto 80% (BURNS; MERZ, 2012). Identifying the On-site segregation of
recyclable and reusable materials may reduces the operating cost. It is
underlined that location isolation of
squanders is a successful route for augmenting site activities (DENNIS, 2001).
The previous studies on
sitelayout problems emphasized the
importance of waste reduction to
increase the operational efficiency, irrespective of type of construction (ELGENDI
et al., 2014; EI-RAYA ; SAID, 2009).
Zoning the various activities in the
project site will assist for enhancing
the operational efficiency (NESZMELYI;
VATTAI, 2013), categorizing the facilities in temporary as well permanent
manner is the basis to provide the facilities is the prime factor for selection
and designing the layout (ELBBELTAGI, 1983; CHARY, 2003; GOEL, 2010).
Several attempts have been made to
solve site layout planning issues using techniques like Genetic algorithm,
simulation modeling and ant colony optimization algorithm are used for site
layout planning. These techniques resulted that the facilities identified are
temporarily needed to support construction operations in the project but does
not from a part of the finished structure (SHETTY; DESHMUKH, 2013).
Evolution
Based models for site layout planning was also
considered for improving operational efficiency by using software for the site layout problems
(TOMMEELEIN; ZOUEIN, 1993). Properly Planned site layout facilities will improve the profitability,
safety and productivity to achieve the higher speed while performing the site
operations(SANAD et.al., 2013).
Better
site layout can be achieved easily by minimization of
travel time and removal of unnecessary movement of resources and proper
material handling techniques (KUMAR; SINGH, 2007). Computer Aided Drafting
(CAD) techniques are useful to improve the layout and will overcome the limitations of other
automated systems (ELBELTAGI et. al., 2004).
Many of the projects are not
successful because of the lack of accountability, poor integration of isolated
tasks, discrete functionality, lack of planning and controlling measures
(KUMAR; BANSAL, 2016). Based on the gaps identified from the literature review
has motivated to apply CORELAP and CRAFT techniques in the present study.
3. METHODOLOGY
The modular construction industry
has made significant advances in implementing processes and materials to build
and deliver more sophisticated and complex facility types. Many customers are
turning towards modular sytem for multi-story, steel framed structures, health
care facilities, educational structures, and also in large scale military
projects.
Always this system is known for its
time saving advantages, modular is now being recognized for being a more
resource-efficient and it is inherently a greener process. The present research
study has taken the building project
layout, and facilities are identified for the present site, relationship chart
was developed for 15 departments available in the project site using A, E, I,
O, U symbols. Proximity relation between
facility locations are also identified based on the relationship diagram.
A
= Absolutely Necessary that the two facility should be close (to be close)
B
= Especially Important that the two facility must be close
C
= Important that the two facility may be close
D
= Unimportant or no need to be close the two facility
E
= Undesirable or need to be far the two facility
3.1.
Craft
analysis
CRAFT is an improvement algorithm,
for the reallocation of available facilities. CRAFT algorithm, is developed by
Armour and Buffa. It starts with an initial layout and improves the layout by
interchanging the department pair wise so that the transportation cost is
minimized. The algorithm continues until no further interchanges are possible
to reduce the transportation cost. Centroid for each department is obtained
with the real dimensions of the plot using AUTOCAD software.
3.1.1. Distance
matrix
Matrix consisting of distances
between each and every department is formed. It is obtained in kilometers using
the formula: (X1 - X2) + (Y1 - Y2) Where X1 represents x coordinate of centroid of department A, X2
represents x coordinate of centroid of department B, Y1 represents y coordinate of centroid of department A, Y2
represents y coordinate of centroid of
department B.
3.1.2. Flow matrix
Matrix formed based on number of
flow of trips that a vehicle has to cover to travel between any two
departments. The content is subjective and based on subjective knowledge. Trip distance matrix is formed with values
calculated based on the number of trips (Flow matrix) and distance between two
departments (Distance matrix).
3.1.3. Cost matrix
Final determinable matrix calculated
using inputs from Trip distance matrix multiplied with assumed cost per km and
cost of operating a vehicle. Handling
cost: Handling cost associated with each and every department is calculated by
summation of all the costs in the department from Cost matrix along with
consideration of hiring charges.
3.2.
CORELAP
Is a constructive algorithm and
it deals the layouts by locating rectangular shaped departments. The
relationship chart provides the basis for the order in which different
departments are placed. The important step in CORELAP is learning about
adjacency. It generates a layout on the basis of total closeness rating (TCR) for
each department. Adjacency is a coefficient between two activities/spaces. The
range of adjacency is between 0 and 1.
There are three types of adjacency
as follows: Fully adjacent (side
contact), partially adjacent (point contact), and Non adjacent (no contact at
all). Fully adjacent has 1 value of coefficient; partially adjacent has 0.5
value of coefficient; and non-adjacent have 0 value of coefficient.
CORELAP
adapts this theory. The input requirements of CORELAP consist of
1.
Relationship
chart with weights for the departments, 2. Number & area of departments.
The implementation requires the user
to define weights in decreasing order A, E, I, O, U, and X. The ‘X’
relationship has to be assigned a negative weight. The same applies to cut-off.
The cut-off values convert the flow scores into equivalent relationship values
A, E, I, O, U, and X. Once the user has input the flows or the relationship
values he or she can update the spreadsheet.
4. APPLICATION OF CRAFT AND CORELAP- A CASE STUDY
The study was conducted at a
residential project spread over 29 acres and totally 15 departments are working
for the project. The entire site plan is made using AutoCAD with the exact
inputs from the site. The site is a residential project in Chennai, Tamilnadu.
The project is planned to build 1224
residential units. The supporting functional departments are setup to help
complete the execution and operation subjecting to the six residential blocks.
Cost matrix [cij] cell is formed. Figureure 1 depicts the pictorial representation
of layout plan of existing site. Block 1 to block 6 represents residential
blocks.
Other departments are the supporting
functional blocks placed around the major blocks. The existing site layout is
shown in Figure 1 and centroid between the
departments is shown in table 1. For the existing layout as shown in Figure
1 centroid for each and every department
is obtained using AutoCAD software and
centroid is calculated for every department portrayed in the Table 1.
Then the distance matrix, flow
matrix, is calculated in the Table 2 and Table 3 respectively. By using the
Table2 and Table 3 handling cost is calculated
for the existing site layout. As per the existing site layout average
kilo meters covered per week is 1.95 kilometers.
Figure 1: Site layout of exiting site
Table 1: Centroid of departments using
CRAFT
Department number |
Nomination |
Centroid |
Depart
ment number |
Nomination |
Centroid |
1 |
Block 1 |
(113,82) |
9 |
Steel scrap |
(265,368) |
2 |
Block 2 |
(113,115) |
10 |
Steel storage |
(202,230) |
3 |
Block 3 |
(113,145) |
11 |
Steel bending |
(202,160) |
4 |
Block 4 |
(113,190) |
12 |
Block 6 |
(265,192) |
5 |
Block 5 |
(113,220) |
13 |
Lorry stand |
(258,112) |
6 |
Store |
(102,310) |
14 |
Club house |
(225,18) |
7 |
Cement bag storage |
(152.5,342) |
15 |
Material scrap |
(202,113) |
8 |
Batching plant |
(213,335) |
|
|
|
Table 2: Distance matrix using
CRAFT
Table 3: Flow matrix using CRAFT
After
the calculation of handling cost for the existing site layout, the new site
layout has been formed as per Figure 2.Centroid of the departments are
calculated again using CRAFT for the newly formed site layout and represented in the Table 9. The trip
distance and flow matrix are formulated for the new site layout as shown in the
Figure 2. The distance covered per week is 1.67 kilometers for the newly formed layout using the CRAFT.
Table 4: Centroid of the newly
formed layout using CRAFT
Department number |
Nomination |
Centroid |
Department number |
Nomination |
Centroid |
1 |
Block 1 |
(163.07,88.39) |
9 |
Steel scrap |
(232.4,382.45) |
2 |
Block 2 |
(163.07,240.72) |
10 |
Steel storage |
(60.9,204.9) |
3 |
Block 3 |
(163.07,319.96) |
11 |
Steel bending |
(222.5,204.9) |
4 |
Block 4 |
(121.9,48.77) |
12 |
Block 6 |
(121.9,280.34) |
5 |
Block 5 |
(121.9,128.02) |
13 |
Lorry stand |
(129.5,382.45) |
6 |
Store |
(60.9,28.2) |
14 |
Club house |
(53.3,382.45) |
7 |
Cement bag storage |
(163.07,28.2) |
15 |
Material scrap |
(186.7,382.45) |
8 |
Batching plant |
(143,204.9) |
|
|
|
Figure 2: New site layout design using
CRAFT
Now
the distance is calculated for revised site layout using Corelap method and represented in the Table 6, Table 7,
Table 8 respectively.
Table 5: Relationship table
using CORELAP
Relationship |
Relationship values |
Corresponding values |
Absolutely
necessary |
A |
6 |
Especially
important |
E |
5 |
Important |
I |
4 |
Ordinary |
O |
3 |
Unimportant |
U |
2 |
Undesirable |
X |
1 |
Table 6: Relationship matrix
using CORELAP
Table 7: Total closeness rating
(TCR) using CORELAP
It is found that the distance
covered per week is 1.67 kilometers for the newly formed layout using the
CORELAP. As the distance is proportional to the cost and same was proven in the table 9.
Table 8: Assumptions for handling
Assumptions |
||
Fuel Cost |
INR 50/
litere |
|
Mileage |
6 km/liters |
|
Wages |
INR 250/ Km |
|
Hiring Charges |
Cranes |
INR 100/day |
Trucks |
800/day |
|
Transit
mixers |
600/day |
5. ANALYSIS OF RESULTS
Analysis has been done between the
existing and the new layout. As the distance is directly proportional to the
cost and the same was reflected in the cost estimation per week. The savings
are substantial with new layout compared to the existing layout in the project.
The results are tabulated in the Table 9.
Table 9: Cost associated with
old layout and new layout
Parameters |
Considerations |
Actual estimate using CRAFT(old layout) |
Actual estimate using CRAFT and CORELAP (New layout) |
Average kms
covered/week |
From CRAFT |
1.95kms |
1.67kms |
Transportation
Cost/km |
Assumed
value: wages – Rs.
250/km from table 8 |
INR. 258.3 |
NR. 258.3 |
Hiring
cost/week |
Assumed: 5 operating
days a week. |
INR. 12000 |
INR. 12000 |
Total
handling cost/week |
|
INR. 2,52,455 |
INR. 2,42,100 |
Estimated
duration of project |
Actual project
estimate |
200 weeks |
200 weeks |
Overall
handling cost associated with this site layout |
Calculation: Rs. 2,52,455
* 200 weeks for old layout Calculation:
Rs. 2,42,100 * 200 weeks For new
layout |
INR.
5,04,91,000 |
INR.
4,84,20,000 |
Savings per
week – INR. 10,355 |
|||
Estimated
saving – INR. 20,71,000 |
|||
% of saving
from overall handling cost – 23.38% |
6. CONCLUSIONS:
From the above analysis, it is
observed that an amount of INR 10,355 can be saved per week if the same project
has been done with newly formed layout using CRAFT and CORELAP. This tends to
prove that the site layout which has been adopted currently in the site
applying the expertise regarding the operational importance is not optimal and
the site layout which has been analyzed by using the application of CRAFT and
CORELAP software yield positive results.
Taking into consideration the
modified layout in the present scenario would save an amount of INR20, 71,000
for the estimated project duration the opportunity cost for the project
duration is estimated to be INR 6,42,010. The operational efficiency of a
construction site was analyzed by CRAFT and CORELAP techniques by considering
above case study of building project.
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