cost efficient construction

1. Debre Berhan University
Institute of Technology
College of Engineering
Department of CoTM
C o st Efficient Construction (CoTM5282 )
Organized by Asemamaw D. & Habtamu G.
Sunday, January 15, 2023
C H A P T E R T WO
PL A N N I N G A N D CO S T E F FC I E N T D E S I G N

2. 2.1. Concept of Planning and Design
The Engineering Design Process involves the following
CHAPTER TWO
PLANNING AND COST EFCIENT DESIGN

3.  Is it the Lowest First-Cost Structure that meets the program?
 Is it the design with the Lowest Operating and Maintenance costs?
 Is it the building with the Longest Life Span?
 Is it the facility in which users are most productive?
 Is it the building that offers the greatest return on investment?
Design planning Requirements

4. Con …
Conceptual stage
 At the conceptual stage coordination among professionals is very
crucial.
 The following professionals could be involved in the design:
o Architect
o Structural Engineer
o Sanitary Engineer
o Electrical engineer
o Electro mechanical engineer
o Sociologist
o Environmentalist

5. Con …
Preliminary and Final Design Stage
 Nail down enough design details so that a decision can be made

6. Con …

7. Con …

8. Con …

9. Preliminary and Detailed Design should consider
 Geometery and planning
 Single or multi-story
 Simplicity and Repetition
 Economies of Scale
 New or existing work
 Number of amenity areas
 Amalgamating services
Preliminary and Detailed Design
Geometery and planning
 simple roof geometry minimizes junctions and materials
 reduce circulation space can maximize the usable area
 minimize wasted space
Single or multi-story
 Single story construction is always cheaper
 formwork and transporting material increase as story increase
 extra beams and support required as additional floor constructed

10.  simple structural elements repeated throughout a project can
 Duplicating elements can reduce costs because fabrication can
be done in bulk.
Simplicity and Repetition
Amalgamating services
 Locating bathrooms kitchens and laundry’s etc adjacent
or above each other, can reduce the cost of length of
concealed pipe work and conduit is reduced.
 Similarly amalgamating several services in the same
trench or duct can reduce costs.
Number of amenity areas
 Kitchens, laundries and bathrooms are more expensive due to
intensive use of plumbing, electrical ,fixtures and fittings.
 A good way to reduce cost is to minimize the number of amenity
areas

11.  Project site information
 Site characteristic/ terrain
 Orientation, neighborhood structure
 Climate
 Culture – communal, work and construction.
 Local resources – building, human, environmental and
technology
Initial considerations for a cost-efficient design in a rural or
urban setting
 Type and scale of the project
 Residential
 Communal
 Commercial
 Manufacturing, etc.
 Financial Constraints
 Resident developer
 Community investment
 Government
 Donors

12. 2.2. Detailed planning
 Adequate time and information should be available to perform
detail planning and design
 Examples of details design aspect which result in low-cost construction:
o Increasing the quality of concrete/steel – needs benefit/cost analysis
o Reinforcement cuts : in beams and slabs (proper reinforcement cutting
schedule)
o In high rise buildings lower story columns have higher load carrying capacity
=>they might not need much increased section (concrete, steel)
o Steel truss systems: all members need not be of the same cross section, proper
orientation of members

13.  Building construction basically involves four stages including
conceptual, preliminary design, final design and execution.
 Cost minimization could be achieved through close and serious
consideration at all stages
2.3. Integrated Planning
 Fragmented in nature, resulting in poor communication
between project stakeholders and leading to inefficiency and
low productivity in construction project delivery.
 In the conventional design process, the design is developed in a
segregated way with minimal interaction between the design
team members.

16. Traditional team model
Integrated design team model

17.  The Architect designs the building shape, orientation and
envelope and then transmits the drawings to the structural,
sanitary, mechanical and electrical engineers for their design.
 The traditional design process has a mainly linear structure due to
the successive contributions of the members of the design team.
 There is a limited possibility of optimization during the traditional
process, while optimization in the later stages of the process is
often troublesome or even impossible.

18. 2.4. Documentation
 It is always important for the designers to make sure that their
design ideas are properly conveyed to the ones who would be
executing project.
 Therefore, documents prepared during design should be clear
enough so that ambiguities are avoided during the actual
construction phase.
 The following is list of some of the documents produced by the
designers:
 Drawings including details
 Models
 Statical Calculation Reports
 Technical Specifications
 Bill of quantities
 Work schedules
 Contract Documents
 Guide Lines and manuals

19. Low cost building systems
 building systems that reduce the use of materials and or save in
construction time can provide a significant savings
 Designing in mind with standard dimension can reduce cutting and wastage
 Standard sizes are always cheaper than custom made sizes
1. Standard dimension
2. Prefabrication
 Fabricating items in a factory is always faster and cheaper than on site.
 No supply of shelter, materials, specialized machinery and labor on site
3. Variations
 Whilst it may be undesirable to avoid all variations, they should be minimized if
you want to reduce the cost
4. Accuracy of Documents
 The completeness and proper coordination of contract can affect the accuracy
of tendering and the likelihood of changes to the design or variations to the
building contract.

20. Building Cost can expressed in:
Per m2
Total construction cost
Life cycle cost analysis
Life Cycle Cost Analysis (LCCA)
Life cycle cost analysis (LCCA) is a method for assessing the total
cost of facility ownership.
It takes into account all costs of acquiring, owning, and disposing
of a building or building system.

21. Life Cycle Cost Analysis Con …
Designing new and renovated
buildings with maintenance and
operating costs in mind can result
in significant savings.
 The long-term cost implications
of building projects, ranges far
beyond initial design and
construction expenses.
 Life Cycle Cost Analysis /LCCA/ whole cost accounting / total cost of ownership
is a process of evaluating the economic performance of a building over its entire
life.
It balances initial monetary investment with the long-term expense of owning
and operating the building.

22. LCCA is based upon the assumptions that;
 Multiple building design options can meet programmatic needs,
and
 Achieve acceptable performance, and that these options have
differing initial costs, operating costs, maintenance costs, and
possibly different life cycles.
By comparing the life cycle costs of various design configurations,
LCCA can explore trade-offs;
 between low initial costs and long-term cost savings, identify the
most cost-effective system for a given use, and determine how
long it will take for a specific system to “pay back” its incremental
cost.

23.  Alternatives can be summarized in terms of the ratio of total
benefits to total cost (benefit-cost ratio) or equivalently, the total
net benefits(net present value, NPV).
Life cycle cost analysis con..
The Economic Analysis Process
Objective Alternative Assumptions Cost/Benefit
Compare
Cost/Benefit
Steps to estimate the economic consequences of a decision :
1. Define the problem and the objective.
2. Identify feasible alternatives for accomplishing the objective,
taking into account any constraints.
3. Determine whether an economic analysis is necessary, and if so,
the level of effort which is warranted.

24. 4. Select a method or methods of economic analysis.
5. Select a technique that accounts for uncertainty and/or risk if the
data to be used with the economic method are uncertain.
6.Compile data and make assumptions called for by the economic
analysis method(s) and risk analysis technique.
7.Compute a measure of economic performance.
9.Compare the economic consequences of alternatives and make a
decision.
Con..
 After identifying all costs by year and amount and discounting
them to present value, they are added to arrive at total life-cycle
costs for each alternative:

25. LCC = I + Repl. - Res + E + W + OM&R + O
• LCC = Total LCC in present-value (PV) of a given alternative
• I = PV investment costs
• Repl. = PV capital replacement costs
• E = PV of energy costs
• W = PV of water costs
• Res = PV residual value (resale value, salvage value) less disposal costs/
• OM&R = PV of non-fuel operating, maintenance and repair costs
• O = PV of other costs (e.g., contract costs)
Con..
Evaluation Criteria
 Lowest LCC (for determining cost-effectiveness)
 Highest NPV (for determining cost-effectiveness)

26. 2.5 Material Selection

27. MATERIAL SELECTION
 Building materials account for ~60 to 65% of the cost of housing
construction.
 A constant rise in cost of conventional building materials.
 Construction cost is way beyond the affordable limits of the
majority.
 Leading modern (conventional building materials): cement,
concrete, steel, bricks and wood.
 Alternative (low cost) materials and technologies are sought

28. Con …
Approaches
 Alternative construction materials E.g.. Cement replacement, Hydra
form…
 Use of locally available materials
 Reduced transportation cost, use of locally available labor/ workmanship.
 Construction materials and products should be used based
on evaluating characteristics such as:
 Reused and recycled-content;
 Zero or low off-gassing of harmful air emissions;
 Zero or low toxicity;
 Sustainable harvested highly recyclable materials;
 Durability;
 Longevity; and
 Local production.