Traditional
Construction Procedures
As mentioned in Above,
construction under the traditional construction procedure is performed by
contractors. While they would like to satisfy the owner and the building
designers, contractors have the main objective of making a profit. Hence, their
initial task is to prepare a bid price based on an accurate estimate of
construction costs. This requires development of a concept for performance of the
work and a construction time schedule. After a contract has been awarded,
contractors must furnish and pay for all materials, equipment, power, labour,
and supervision required for construction. The owner compensates the
contractors for construction costs and services.
A general contractor
assumes overall responsibility for construction of a building. The contractor
engages subcontractors who take responsibility for the work of the various
trades required for construction. For example, a plumbing contractor installs
the plumbing, an electrical contractor installs the electrical system, a steel
erector structural steel, and an elevator contractor installs elevators. Their
contracts are with the general contractor, and they are paid by the general
contractor.
Sometimes, in addition
to a general contractor, the owners contracts separately with specialty
contractors, such as electrical and mechanical contractors, who perform a
substantial amount of the work required for a building. Such contractors are
called prime contractors. Their work is scheduled and coordinated by the
general contractor, but they are paid directly by the owner. Sometimes also,
the owner may use the design-build method and award a contract to an
organization for both the design and construction of a building. Such
organizations are called design-build contractors. One variation of this type
of contract is employed by developers of groups of one-family homes or low-rise
apartment buildings. The homebuilder designs and constructs the dwellings, but
the design is substantially completed before owners purchase the homes.
Administration of the
construction procedure often is difficult. Consequently, some owners seek
assistance from an expert, called a professional construction manager, with
extensive construction experience, who receives a fee. The construction manager
negotiates with general contractors and helps select one to construct the
building. Managers usually also supervise selection of subcontractors. During
construction, they help control costs, expedite equipment and material
deliveries, and keep the work on schedule (see Art. 17.9). In some cases,
instead, the owner may prefer to engage a construction program manager, to
assist in administrating both design and construction.
Construction contractors
employ labour that may or may not be unionized. Unionized craftspeople are
members of unions that are organized by construction trades, such as carpenter,
plumber, and electrician unions. Union members will perform only the work
assigned to their trade. On the job, groups of workers are supervised by crew
supervisors, all of whom report to a superintendent.
During construction, all
work should be inspected. For this purpose, the owner, often through the
architect and consultants, engages inspectors. The field inspectors may be
placed under the control of an owner’s representative, who may be titled clerk
of the works, architect’s superintendent, engineer’s superintendent, or
resident engineer. The inspectors have the responsibility of ensuring that
construction meets the requirements of the contract documents and is performed
under safe conditions. Such inspections may be made at frequent intervals.
In addition, inspections
also are made by representatives of one or more governmental agencies. They
have the responsibility of ensuring that construction meets legal requirements
and have little or no concern with detailed conformance with the contract
documents. Such legal inspections are made periodically or at the end of
certain stages of construction. One agency that will make frequent inspections
is the local or state building department, whichever has jurisdiction. The
purpose of these inspections is to ensure conformance with the local or state
building code.
During construction,
standards, regulations, and procedures of the Occupational Safety and Health
Administration should be observed. These are given in detail in ‘‘Construction
Industry. OSHA Safety and Health Standards (29CFR1926/1910),’’ Government
Printing Office, Washington, DC 20402.
Following is a
description of the basic traditional construction procedure for a multi-story
building:
After the award of a
construction contract to a general contractor, the owner may ask the contractor
to start a portion of the work before signing of the contract by giving the
contractor a letter of intent or after signing of the contract by issuing a
written notice to proceed. The contractor then obtains construction permits, as
required, from governmental agencies, such as the local building, water, sewer,
and highway departments.
The general contractor
plans and schedules construction operations in detail and mobilizes equipment
and personnel for the project. Subcontractors are notified of the contract
award and issued letters of intent or awarded subcontracts, then are given, at
appropriate times, notices to proceed.
Before construction
starts, the general contractor orders a survey to be made of adjacent
structures and terrain, both for the record and to become knowledgeable of
local conditions. A survey is then made to lay out construction.
Field offices for the
contractor are erected on or near the site. If desirable for safety reasons to
protect passers-by, the contractor erects a fence around the site and an
overhead protective cover, called a bridge. Structures required to be removed
from the site are demolished and the debris is carted away.
Next, the site is
prepared to receive the building. This work may involve grading the top surface
to bring it to the proper elevations, excavating to required depths for
basement and foundations, and shifting of utility piping. For deep excavations,
earth sides are braced, and the bottom is drained.
Major construction
starts with the placement of foundations, on which the building rests. This is
followed by the erection of load-bearing walls and structural framing.
Depending on the height of the building, ladders, stairs, or elevators may be
installed to enable construction personnel to travel from floor to floor and
eventually to the roof. Also, hoists may be installed to lift materials to
upper levels. If needed, temporary flooring may be placed for use of personnel.
As the building rises,
pipes, ducts, and electric conduit and wiring are installed. Then, permanent
floors, exterior walls, and windows are constructed. At the appropriate time,
permanent elevators are installed. If required, fireproofing is placed for
steel framing. Next, fixed partitions are built and the roof and its covering,
or roofing, are put in place.
Finishing operations
follow. These include installation of the following: ceilings; tile; wallboard;
wall panelling; plumbing fixtures; heating furnaces; air-conditioning
equipment; heating and cooling devices for rooms; escalators; floor coverings;
window glass; movable partitions; doors; finishing hardware; electrical
equipment and apparatus, including lighting fixtures, switches, outlets,
transformers, and controls; and other items called for in the drawings and
specifications. Field offices, fences, bridges, and other temporary construction
must be removed from the site. Utilities, such as gas, electricity, and water,
are hooked up to the building. The site is landscaped and paved. Finally, the
building interior is painted and cleaned.
The owner’s
representatives then give the building a final inspection. If they find that
the structure conforms with the contract documents, the owner accepts the
project and gives the general contractor final payment on issuance by the
building department of a certificate of occupancy, which indicates that the
completed building meets building-code requirements.