LEAN WORK STRUCTURING USING SYSTEM DYNAMICS MODELING
DR. MOHAMED A. EL-GAFY
DR. TARIQ ABDELHAMID
Discrete Event Simulation has been advanced in the construction
literature as a tool to design construction operations while incorporating
performance variability to arrive at more realistic durations and
cost estimates. This tool can enable Lean Construction work
structuring (LWS), which is concerned with the selection and
sequencing of work methods during the product design stage. LWS
is "thinking production process during the product design stage".
This paper introduces system dynamics as a quantitative approach
for LWS wherein an operation is designed and analyzed for effectiveness
of production strategies before implementation. System Dynamics
evaluates the actions in terms of dependencies and feedback loops
among process variables. It is also possible to represent the effect
of qualitative and latent variables. The proposed modeling approach
is demonstrated using a bricklaying operation to illustrate the
benefits of using system dynamics. Significant differences in
resource utilizations, operation cycle times, and overall time of
operations resulted from inclusion of soft factors into the modeling
process. The results also underscore the importance of sacrificing
utilization of local resources for an overall system gain as indicated
by lean construction. The major contribution of adding SD modeling
to the arsenal of LWS tools is that SD facilitates more realistic
designs of production systems.
Lean Construction, Lean Work Structuring, Discrete Event Simulation,
Dynamic System Modeling, Simulation
Download
Research Articles
FORMULATION OF MIX DESIGN PROCEDURE FOR SLAG CEMENT CONCRETE
DR. K. C. PAZHANI
DR. M. SEKAR
MR. G. T. KOTEESWARAN
Slag is obtained as a by-product in the manufacture of iron from
steel industries. It is a very fine, less permeable and light colour
product, which is used to replace cement in making high performance
concrete. Its heat of hydration is very low. Hence it is used for
mass concreting. The use of slag in the construction industry is
on rise because of its durability properties and cost effectiveness.
But, there is no standard design procedure available for the concrete
incorporating slag. In this project, an effort is made to formulate
the mix design procedure for slag cement concrete based on IS
method by making corrections in the target mean strength and the
water content for the required grade of concrete in the normal
mix design procedure. This is done by comparing the properties
such as strength and workability of the conventional concrete and
slag cement concrete. This paper involves the mix design procedure
for normal strength concrete with slag replacement levels of 15%,
30% and 45%.
Slag, Rate of Slump Loss, Multiplication Constant, Slag Cement
Concrete; Fineness, Specific Gravity, Compressive strength, Water
absorption, Early Age Strength
Download
Research Articles
ECONOMIC ANALYSIS OF DELHI METRO RAIL PROJECT, PHASE-I
DR. M. S. RANDIVE
MR. SHARAD TANPURE
India's population is increasing rapidly with higher growth in its
rate of urbanization. Being the national capital, Delhi is most
populated city in the country. Therefore growing demand for
public transport has damaged the ecosystem. Hence environmental
friendly urban transport system like Delhi Metro Rail Project proves
to be the need of time.
Herein attempt will be to find various possible sectors of economical
benefits due to Delhi Metro Rail Project-Phase-I. It provides the
benefits like saving in time, reduction in pollution, reduction in
fuel demand, reduction in travel time, increase in average speed
of the vehicles etc. The break even analysis for the cost is done
taking into account the present data and future projections of all
possible sectors of benefits.
Delhi Metro is exempted from the payment of income tax, capital
gain tax and property tax and custom duty on export. It is not
considered the today's worth of money irrespective of any interest
rate or inflation rate and escalation. The project will recover a total
construction cost by means of cost of savings (benefits) and will
achieve the break even (when benefits will more than that of
construction cost) of the cost of Phase-I in between 2011-2012.
This paper concludes with the result that Delhi Metro Rail Project,
Phase-I is economically feasible.
Delhi Metro Phase-I, Breakeven Analysis, Economical Feasibility,
Environmental Benefits
Download
Research Articles
CONSTRUCTION BUSINESS IN INDIA - QUALITATIVE ASSESSMENT
OF RISKS IN CONTRACT DOCUMENT FROM CONTRACTOR'S PERSPECTIVE
MR. R.C. WALKE
DR. PROF. VINAY TOPKAR
MRS. SEEMA PATIL
Construction is a pre-requisite to any development - may it be the
industrial power generation, irrigation for agriculture, health, defense,
sports, hospitals, schools, townships, offices, houses, and other
buildings; urban Infrastructure (including water supply, sewage
drainage), highways, roads, ports, railways, airports and environmental
projects. Construction projects are unique in character and do not
lend themselves to standardizations. Number of contractors are
involved in execution of these projects. Owners/Clients of the
construction projects want to complete it with minimum cost to
them and with minimum hassles and responsibilities. The contractors
want to accomplish the work by making as much as profit as
possible with least amount of hassles. Hence, in order to establish
duties, obligations, rights and responsibilities amongst client and
contractors, construction contracts are made. This establishes
mutual relationship and understanding to execute the work. In
India, Indian Contract Act 1872 forms the basis of many a construction
contracts. These construction contracts, through contract conditions
and specifications impose many risks on the contractors. It is
important for contractors to assess these risks so that they are
aware of the extent of risk exposure or the risks they may need
to deal with while executing the construction projects.
In this paper, an approach for qualitative assessment of risks from
contractor's perspective is proposed for the risks inherent in a
contract document, more specifically in conditions of contract and
specifications. The assessment shall help contractors to be aware
of various risks and of the risk responsibilities implied in the
contract document. This assessment shall also be a pre-requisite
to risk quantification and a quantitative risk assessment for a
project under consideration. Proposed approach is explained through
a case study where qualitative assessment of risks in the conditions
of contract and specifications in the contract document of Municipal
Corporation of Greater Mumbai (MCGM) for cement concrete road
work, from contractor's perspective. Scope of this approach is
limited to identification, classification and qualitative assessment
of these risks.
EXPERIMENTAL INVESTIGATION ON THE STABILIZATION OF BLACK COTTON SOIL USING CEMENT, FLY ASH AND LIME
R. SATHISH KUMAR
The objective of this paper is to upgrade black cotton soil as a
construction material using cement, fly ash and lime. Remolded
black cotton soil was blended with cement, lime and fly ash and
strength as well as CBR tests were conducted.
Shear test by direct shear test shows that the safe bearing
capacity increased by 75%, 101% and 110% respectively when the
additives content were increased from 0 to 20% in the order fly
ash, lime and cement, while the CBR improved enormously. The
optimum value for fly ash was found to be 20% the same is
recommended for strengthening the black cotton soil.
Soil stabilization, Shear test, California Bearing Ratio test (CBR),
Atterberg limits.
Download
Research Articles
CLEAN DEVELOPMENT MECHANISM FOR MUNICIPAL SOLID WASTE
Ms. Viju M. Sirsath, Dr. P. H. Sawant
The treatment of solid waste has been a
great challenge to the Municipal authorities.
Most of them just dump the solid wastes
without following any scientific method of
treatment. However, with Clean
Development Mechanism (CDM) of the Kyoto
Protocol, a new source of finance has emerged
and this is encouraging many municipal
authorities to undertake the municipal solid
waste (MSW) treatment projects where the
twin objectives of treatment as well as energy
generation are met. As the finance is
available both from the sale of energy and
CDM, these projects are becoming
economically viable. By reducing the global
warming and treating the solid wastes in
a scientific manner these projects are also
contributing to global and local
environmental benefits and sustainable
development. This paper discusses a case
study of existing Bio-methanation plant at
Thane, Maharashtra State to avail the
benefits of carbon credit.
Clean Development Mechanism
(MSW), Technological options for treatment
of Municiple Solid Waste (MSW)
Download
Research Articles
CUSTOMER SERVICE AND ITS EFFECTS ON CUSTOMER RETENTION AND DEFECTION
Prof. Monika Mahajan
The area of customer service has received
significant attention throughout research in
marketing. This paper reports the relationship
between customer service and customer
defection and retention from organizations.
These primary issues are explored:
1. A conceptual framework of service
quality.
2. Behavioral and financial consequences
of service quality.
3. Favorable and unfavorable customer
intentions.
4. An empirical study focusing on the
relationship between service quality
and customer behavioral intentions.
customer service and customer defection and retention, conceptual framework, Behavioral and financial consequences
Research & Publications Department 