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JWDD004-16 JWDD004-Halpin-v6 August 4, 2005 12:3
Chapter 16
Material Management
Fiber Reinforced Polymer Rebar
The Need
Reinforced concrete is a very common building material for the construction
of facilities and structures. As a complement to concreteÕs very limited tensile
strength, steel rebar has been an effective and cost-efficient reinforcement.
However, insufficient concrete cover, poor design or workmanship, and the
presence of large amounts of aggressive agents in the concrete as well as
environmental factors all can lead to cracking of the concrete and corrosion of
the steel rebar. For instance, in the United States, almost 40% of bridges are
structurally deficient or functionally obsolete largely due to cracking and
corrosion.
Dry Dock #4 Pearl Harbor, Hawaii.
The Technology
Composite materials made of fibers embedded in a polymeric resin, also known as
fiber-reinforced polymers (FRPs), have become an alternative to steel reinforcement for
concrete structures. Aramid fiber-reinforced polymer (AFRP), carbon fiber-reinforced
polymer (CFRP), and glass fiber-reinforced polymer (GFRP) rods are commercially
available products for use in the construction industry. They have been proposed for use in
lieu of steel reinforcement or steel prestressing tendons in nonprestressed or prestressed
concrete structures. The problems of steel corrosion are avoided with the use of FRPs
because FRP materials are nonmetallic and noncorrosive. In addition, FRP materials
exhibit several properties including high tensile strength, which make them suitable for
use as structural reinforcement. Fiberglass rebar may be a suitable alternative to steel
reinforcing in architectural concrete, in concrete exposed to de-icing or marine salts, and
in concrete used near electromagnetic equipment.
Caissons and port facilities.
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Figure 16.1 The ownerÐarchitectÐconstruction relationship.
16.1 MATERIAL MANAGEMENT PROCESS
In the traditional contractual relationship, the owner contracts with a general contractor or
construction manager to build his facilities and with an architect to perform the design.
The general contractor, through this contract with the owner, is obligated to perform the
work in accordance with the architectÕs instructions, specifications, and drawings. Thus, the
architect is the ownerÕs agent during the design and construction of a project. The lines of
communication between the three parties are established as shown in Figure 16.1.
The materials that comprise facilities in building construction are subject to review
by the architect or design professional. The contractor usually delegates responsibility for
some of the categories of work involved in the project to subcontractors and suppliers. This
delegation is accomplished through subcontracts and purchase orders. As a result of this
delegation, a distinct life cycle evolves for the materials that make up the project. The four
main phases of this cycle are depicted in Figure 16.2.
16.2 THE ORDER
When the contract for construction is awarded, the contractor immediately begins awarding
subcontracts and purchase orders for the various parts of the work. How much of the work is
subcontracted depends on the individual contractor. Some contractors subcontract virtually
all of the work in an effort to reduce the risk of cost overruns and to have every cost item
assured through stipulated-sum subcontract quotations. Others perform almost all the work
with their own field forces.
The subcontract agreement defines the specialized portion of the work to be performed
and binds the contractor and subcontractor to certain obligations. The subcontractor, through
the agreement, must provide all materials and perform all work described in the agreement.
The Associated General Contractors (AGC) of America publish the Standard Subcontract
Agreement for use by their members.
A sample of this agreement can be found in Appendix G. Most contractors either adopt
a standard agreement, such as that provided by theAGC, or implement their own agreement.
In most cases, a well-defined and well-prepared subcontract is used for subcontractingwork.
All provisions of the agreement between the owner and contractor are made part of
the subcontract agreement by reference. The most important referenced document in the
subcontract agreement is the General Conditions. Procedures for the submittal of shop
drawings and samples of certain materials are established in the General Conditions. The
General Conditions provide that ÒWhere a Shop Drawing or Sample is required by the
Figure 16.2 Material life cycle.
16.2 The Order 277
Figure 16.3 Field purchase order (courtesy of Henry C. Beck Co.).
Contract Documents. . . , any related Work performed prior to ENGINEERÕs review and
approval of the pertinent submittal will be at the sole expense and responsibility of the
CONTRACTOR.Ó
The purchase order is a purchase contract between the contractor and the supplier. This
document describes the materials to be supplied, their quantities, and the amount of the
purchase order.
Purchase orders vary in complexity and can be as simple as a mail order house (e.g.,
Sears) order form, or as complex as the construction contract itself. When complex and
specially fabricated items are to be included in the construction, very detailed specifications
and drawings become part of the purchase order. Some typical purchase order forms are
shown in Figures 16.3 and 16.4. Figure 16.3 shows a form for field-purchased items procured
from locally available sources. These items are usually purchased on a cash-and-carry basis.
The purchase order in this case is used primarily to document the purchase for recordkeeping
and cost accounting purposes (rather than as a contractual document). A more
formal purchase order used in a contractual sense is shown in Figure 16.4. It is used in the
purchase of more complex items from sources that are remote to the site.
Regardless of the complexity of the transaction, certain basic elements are present in
any purchase order. Five items can be identified as follows:
1. Quantity or number of items required.
2. Item description. This may be a standard description and stock number from a
catalog or a complex set of drawings and specifications.
3. Unit price.
4. Special instructions.
5. Signatures of agents empowered to enter into a contractual agreement.
278 Chapter 16 Material Management
Figure 16.4 Formal purchase order (courtesy of Henry C. Beck Co.).
For simple purchase orders, the buyer normally prepares the order. If the vendor is
dissatisfied with some element of the order, hemayprepare his ownpurchase order document
as a counterproposal.
The special instructions normally establish any special conditions surrounding the
sale. In particular, they provide for shipping and invoicing procedures. An invoice is a
billing document that states the billed price of shipped goods. When included with the
shipped goods, it also constitutes an inventory of the contents of the shipment. One item of
importance in the order is the basis of the price quotation and responsibility for shipment.
Price quotations normally establish an FOB location at which point the vendor will make
the goods available to the purchaser. FOB means Free On Board and defines the fact that
the vendor will be responsible for presenting the goods free on board at some mutually
16.2 The Order 279
Figure 16.5 Procurement documents and title transfer sequence.
agreed-upon point such as the vendorÕs sales location, factory, or the purchaserÕs yard or
job site. This is important because if the FOB location is other than the vendorÕs location,
the vendor is indicating that the price includes shipment. The vendor may quote the price
as cost, insurance, and freight (CIF). This indicates that the quoted price includes item cost
plus the shipment cost to include freight and insurance expenses to the FOB location.
In the event the vendor ships the goods, it is of interest to establish at what point in
time title of ownership passes from the vendor to the purchaser. This is established by
the bill of lading. The bill of lading is a contractual agreement between a common carrier
and a shipper to move a specified item or group of goods from point A to point B at a
contracted price. If ownership passes to the purchaser at the vendorÕs location, the contract
for shipment is made out between the purchaser and the common carrier. In cases in which
the vendor has quoted a CIF price, he acts as the agent of the purchaser in retaining a carrier
and establishing the agreement on behalf of the purchaser. The bill of lading is written
to pass title of ownership at the time of pickup of the goods by the common carrier at
the vendorÕs location. In such cases, if the common carrier has an accident and damages
the goods during transfer, the purchaser must seek satisfaction for the damage since he is
the owner.
If goods are to be paid cash on delivery (i.e., COD), the title of ownership passes at the
time of payment. In such cases, the bill of lading is between vendor and common carrier. If
damage should occur during shipment, recovery of loss falls to the vendor as owner.
The sequence of events in CIF and COD transactions is shown in Figure 16.5. This
figure also indicates the relationship between order, bill of lading, and invoice. A typical
bill of lading memorandum and invoice are shown in Figures 16.6 and 16.7.
The invoice normally states the payment procedures and establishes trade discounts that
are available to the purchaser if payment is made in a timely fashion. Trade discounts are
incentives offered by the vendor for early payment. If the purchaser pays within a specified
period, he must pay the stated price minus a discount. Failure to pay within the discount
period means that the full price is due and payable. Terminology relating to trade discounts
is as follows:
1. ROG/AOG: The discount period begins upon receipt of goods (ROG) or arrival of
goods (AOG).
2. 2/10 NET 30 ROG: This expression appearing on the invoice means 2% can be deducted
from the invoiced amount if the contractor pays within 10 days ofAOG/ROG.
Full payment is due within 30 days of AOG/ROG.
Figure 16.6 Typical bill of lading (courtesy of Augusta Meadow Steel Products, Inc.).
Date
280
Figure 16.6 (Continued).
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282 Chapter 16 Material Management
Figure 16.7 Typical invoice (courtesy of Bibb Steel & Supply Company).
3. 2/10 PROX NET 30: A 2% cash discount is available if invoice is paid not later
than the 10th of the month following ROG. Payment is due in full by the end of the
following month.
4. 2/10 E.O.M.: The discount (2%) is available to the 11th of the month following
ROG. Payment in full is due thereafter.
Trade discounts received are treated as earned income in financial statements.
The special conditions of the purchase order may include a Òhold harmlessÓ clause. Such
clauses protect one of the parties to the purchase order from liability arising out of damages
resulting from the conditions of the purchase order. A transit concrete mix company, for
instance, may have the contractor submit his orders on their forms holding the vendor
harmless for damages arising out of delivery of the concrete to the site. Thus, if the transit
mix truck should back across a gas main on the site, rupturing it during normal delivery,
liability for repair costs will accrue to the contractor since the concrete vendor is Òheld
harmless.Ó The converse could, of course, occur if the contractor uses his own purchase
order form, which holds him harmless in such an event. These situations are not covered
by normal liability insurance since such Òcontractually accruingÓ liability is considered to
be outside the realm of normal liability. If the language of the order is prepared by the
contractor, the hold harmless clause will operate to protect him. If the vendorÕs language is
used, the special conditions will hold him harmless in these damages situations.
16.3 Approval Process 283
For the contractorÕs protection, reference is made in complex purchase orders (requiring
special fabrication) to the contractor specifications and other documents that define the
materials to be supplied. Specifications detail the required shop drawings, product data,
and samples that must be submitted for approval prior to fabrication and delivery. The
provisions of the purchase order and the subcontract agreement require the subcontractor
and supplier to obtain approval for their materials.
16.3 APPROVAL PROCESS
The contract drawings prepared by the architect are generally not specific enough to facilitate
accurate fabrication of the materials involved. Therefore, to produce the necessary materials
for a project, subcontractors and suppliers must provide details that further amplify the
contract drawings. These details can be classified into three groups: (1) shop drawings, (2)
product data, and (3) samples.
Shop drawings are defined in the General Conditions as ÒAll drawings, diagrams,
illustrations, schedules, and other data or information which are specifically prepared or
assembled by or for CONTRACTOR and submitted by CONTRACTOR to illustrate some
portion of theWork.Ó The detailing, production, and supplying of shop drawings are the sole
responsibility of the contractor or the contracted agent. However, the design professional is
responsible for verification that the supplied shop drawings correctly interpret the contract
documents. Dimensions, quantities, and coordination with other trades are the responsibility
of the contractor. Approved shop drawings become the critical working drawings of a
project and are considered a part of the contract documents. Typically, shop drawings are
submitted for materials such as reinforcing steel, formwork, precast concrete, structural
steel, millwork, casework, metal doors, and curtain walls.
Product data may be submitted to illustrate the performance characteristics of the
material items described by the shop drawings or may be submitted as verification that a
standard product meets the contract specifications. Product data are illustrations, standard
schedules, performance charts, instructions, brochures, diagrams, and other information
furnished by the contractor to illustrate a material, product, or system for some portion of
thework. Mill test reports, concrete mix designs, masonry fire rating tests, curtainwall wind
test reports, and mechanical equipment performance tests are examples of product data.
Product data are particularly important when a subcontractor or supplier is submitting
data on a product that is a variance from the contract specifications. The architect carefully
analyzes the submitted data prior to rendering an approval of the substitution. Also, the
product data are used extensively to coordinate the materials used by the mechanical and
electrical subcontractors. The contractor must communicate the product data between these
major subcontractors to ensure proper performance of their portion of the work.
Samples usually involve the finishes of a project and are physical examples of materials
to be supplied. The architect may require samples of plastic laminate finishes for doors and
counters, flooring, wall coverings, paint, stucco, precast concrete, ceilings, and other items.
These are used by the architect in developing the overall building finish scheme.
The approval process involving shop drawings, product data, and samples has several
substages that are critical to the material life cycle. These are: (1) submission by the subcontractor
or supplier, (2) review of the submittal by the contractor, (3) review by the architect
or design professional, and (4) return of submittal to the subcontractor or supplier.
At the time of awarding subcontracts and purchase orders, the contractor usually establishes
the quantity, size, and other requirements for all submittals. In most cases, several
blue line prints (usually six) are required when shop drawings are submitted for approval.
The product data quantities required may range from three to six copies. The copies of
a submittal may vary depending on the number of other subcontractors or vendors that
must receive approved copies to coordinate their work. In all cases, careful planning of
284 Chapter 16 Material Management
the quantity of submittals will expedite the other substages by eliminating the handling of
unnecessary copies of submittals.
Timing of submittals is of utmost importance in the effective processing of material
submittals. Subcontracts and purchase orders often contain language such as Òall submittals
must be made immediatelyÓ or Òfifteen (15) days after execution of this agreement, all
submittals must be made.Ó In most cases, contractors do not preplan in detail the required
submittal data from a subcontractor or supplier. The result is a landslide of submittals, most
of which are not necessary, in the early stages of the project. Thus, field office personnel
waste time sorting and determining the most critical submittals. A well-planned approach
to scheduling submittals will ensure timely processing and better control of required
submittals.
Once a submittal is received by the contractor, the process of checking for conformance
with the intent of the contract documents is performed. A submittal, whether it is a shop
drawing, product data, or sample, is governed by the contract drawings and specifications.
The contractorÕs field or main office personnel in charge of submittals may make notations
and comments to the designer or his engineers to clarify portions of the submittal or to
correct the submittal. The submittal represents specific details of the project and is of primary
importance in coordination, as well as depicting exactly what a supplier or subcontractor
is providing. The contractor is required by the general conditions to clearly note to the
architect or design professional any variation from the contract documents.
The amount of time involved in the contractorÕs review of submittals may vary from
1 to 5 days, depending on the nature of the submittal and its correctness. Reinforcing
steel and structural steel shop drawings typically require the greatest amount of time. Also,
schedules such as doors, hardware, and door frames consume a great deal of time because of
the minute details that must be checked. However, the time expended in submittal processing
by the contractor can most easily be controlled at this substage. It must be remembered that
time spent in reviewing, checking, and coordinating submittals is one of the most effective
methods of ensuring a highly coordinated and smooth running project.
Once the contractor has completed the reviewof a submittal, the document is transmitted
to the architect for approval. The contractor may indicate on the transmittal the date when
approval is needed. Here again, the amount of time required for the architect to review a
submittal depends on its complexity and whether or not other engineers (i.e., mechanical,
electrical, or structural) must participate in the review. As a general rule, 2Ð3 weeks is a good
estimate for the time required by the architect to complete the reviewand return the submittal.
The period when a submittal is in the hands of the architect is probably the most critical
substage of the approval process for materials. During this critical substage, the contractorÕs
submittal can be Òlost in the shuffleÓ if the architectÕs activities are not monitored daily. The
most common method of monitoring submittals is through the use of a submittal log, which
indicates the date, description, and quantity of each submittal. From this log the contractor
can develop a listing of critical submittals to monitor on a daily basis. Once the submittal
leaves the contractorÕs control in the field office, its return must be followed constantly or
valuable time will be wasted.
The final substage of the approval process for a material item is the return of the
submittal to the supplier or subcontractor. The submittal may be in one of the following
four states when returned to the architect:
1. Approved.
2. Approved with noted corrections; no return submittal needed.
3. Approved with noted corrections; however, a final submittal is required.
4. Not approved; resubmit.
The first through third designations would release the vendor or subcontractor to commence
fabrication and delivery. The fourth stage would require that the approval process
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