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College Algebra 9th Edition by Michael Sullivan. Calculus G. Michael R. Lindeburg - Seismic design of building structures - 8th edition. The 3rd edition of these conditions was published in He has many duties similar to those of the Engineer under the ICE Measurement Version and is required to behave impartially in regard to certain decisions Clause 2 6.

However, care is needed if work is re-measured against billed rates, since the contractor could then choose to adopt forms of design that suit the more profitable bill rates he has quoted. The contractor can therefore start construction as soon as he has enough design ready. But where a project offers a wide range of design options, a design and construct contract may not offer an employer the best service because the options chosen by the contractor may tend to be those which suit his plant and workforce best, rather than the interests of the employer.

It should be the aim of the par- ties prior to award of contract to arrive at an agreed scheme and specification for the works. Since this form of contract requires extensive input by tenderers their number should be limited to three or four only. This new form, based on the ICE 7th edition and issued in , sets out a background contract which stays in place for a prescribed term of years and under which the Engineer can instruct packages of works to be undertaken as necessary.

Works are ordered through a Works Order which defines what is required and supplies any drawings or specifications not already in the contract. Payment is made by measurement from a schedule of rates in the contract or other agreed means. The administration and supervision requirements usually follow those of the Measurement Version and will thus be familiar to most engineers.

This form can provide a welcome flexibility for employers in procuring irregular items of work or carrying out services which can be called up as and when needed and at short notice. The form may be suitable for some types of framework arrangement see Section 1.

The main construction contract was developed and renamed the Engineering and Construction Contract ECC which went into a second edition in A short form for minor works and a short sub-contract form are also available.

The contract requirements are defined in separate sets of data — Works Information and Site Information supplied by the Employer, and Contract Data which set out various pieces of information depending on which options have been chosen. A project manager appointed by the employer administers the contract on behalf of the employer, assisted by a supervisor on site. A separate adjudicator is appointed to whom the contractor but not the employer can take disputes with the project manager or the supervisor for adjudication.

The contract attempts to overcome some old problems by several new approaches, but the latter may present some new difficulties. A list of eighteen Compensation Events is prescribed, each of which entitles the contractor to claim extra payment and delay. They include the usual matters of claim such as vari- ation of work, unforeseen conditions, etc.

This definition could give rise to problems of interpretation and may lead to claims even when the weather causes no delay. The problems with this approach are discussed in Section Strict time limits of 2 weeks apply to stages of action and response by both contractor and project manager in respect of such quotations and other submissions. These times are tight and may cause difficulties; failure of the project manager to reply within a specified time limit being itself a compensation event!

The stated intent of the drafters of the ECC contract is to stimulate good management. This seems to be achieved by requirements for meetings in a variety of situations, so as to seek advantageous solutions to potential prob- lems, and the tight timetables for responses between the parties. The addendum acts as an addition to individual contracts, which may be of any type, and allows for revision as partners leave or are added to a project.

Contract conditions used for civil engineering work 45 4. They take the same form as the ICE conditions, but with some variations and simplifications to allow for work outside the UK.

Additions can be made to cover local needs and different procedures for payment including payment in different currencies. The 4th edition — sub- stantially revising the 3rd — incorporated changes resulting from consult- ations within the international construction industry and with major international lending agencies.

These conditions were accepted by the major lending agencies who recommend or require their use together with addi- tional clauses and amendments proposed by the agencies. The first is a Contract for Construc- tion to replace the Red Book.

Much of the text and the concepts have remained but the whole is re-organized into what was considered a more logical sequence of clauses. As the title suggests this is intended both for plant supply and installation and for use where much of the civil works may also be designed by the contractor. This contract again uses an independent engineer to monitor design and construction against the requirements and has the DAB to decide disputes.

They are, in con- sequence, widely used and are available in a number of different forms, for example, for payment by priced bills of quantities, lump sum, schedule of rates, or for design and construct, or supply only contracts. The contract is adminis- tered by a project manager or supervising officer who may be given powers similar to those of the engineer under the ICE conditions, but this depends on the policy of the government department concerned and type of work undertaken.

The employer i. Different departments may adopt different approaches in using the conditions, and new methods of contract administration have been tried out from time to time. Earlier editions of these conditions were felt to leave too much of the risk of construction with the con- tractor; for example by allowing neither extra time nor money in the event of bad weather.

Buildings will, of course, include many significant elements of civil construction, such as deep foundations or reinforced concrete structures such as a multi-storey car park. A range of standard forms of conditions provides for different types of employer and for payment by lump sum or quantities. Usually an architect or contract administrator supervises construction and issues certificates for payment, but a civil engineer may carry out these duties for structural works. Quantity surveyors, advisory to the architect, draw up bills of quantities and produce valuations and estimates.

Unlike civil engineering work, items in the bills contain descriptions of what is required in addition to any specification included in the contract documents, and the work has to be carried out in accordance with the bills and the draw- ings.

Much of the work is carried out by sub-contractors appointed by the main contractor or sub-contractors nominated by the employer through the architect. The need for nomination arises so that the architect can obtain exactly the finishes, etc. This tends to result in an increased possibility of disputes arising. A Clerk of Works may be appointed to supervise work on site for the employer but with very limited powers under the contract.

It is thus possible for there to be three separate appointments — architect, quan- tity surveyor and clerk of works — taking part in supervision and this splitting of responsibilities and duties can lead to problems.

A Management form of JCT Contract was introduced in under which the onus for carrying out the work is placed upon a management contractor: that is, a firm of builders or civil engineers whose primary input is to manage and co-ordinate the inputs of sub-contractors see Sections 1.

The form is still in use especially in its modified G90 form in the water industry despite the introduction of MF1 see below. The contract allows for definition of what is required in outline and by specification, the contractor being responsible for the design and manufacture or procurement. The total plant required for a project is often procured by issue of contracts covering separate specialities, such as pumps and motors, switchgear, or instrumentation selected to suit the capabilities of tenderers.

Provision for any associated civil works included in the contract is elementary: if they are required it is best they should be included as a fully designed package that can be sub-let. Payment terms are usually lump sum, but interim payments and some items of re-measure can be included. The terms provide for restricted liability of the contractor for defects other than during the first year of maintenance. The first edition was published in but further revisions with amendments have been issued, Revision 4 being issued in Among other matters, payment terms have to be decided and details added.

The 3rd edition is a substantially altered and improved version of the 2nd edition. Again it is intended for work worldwide so it allows for additions to cover local needs. The contractor carries the main responsibility for design but must comply with any requirements set out in the contract. He arranges all procurement including any civil, mechan- ical, electrical and instrument work, etc. Performance tests are required to prove that the effective- ness of the plant is as specified in the contract.

Provisions for dealing with claims and variations are not extensive; the expectation being that, prior to the award of contract, the parties will have agreed in detail the specific items of plant to be provided, so that little change is needed.

The project manager is not fully independent, though required to be impartial in some actions; the purchaser is bound by the decisions made by his project manager and cannot dispute them in arbitration. Provision is made for an independent expert to be called in to decide some technical or valuation matters. Since there is little allowance for unforeseen constructional problems, the conditions may not be suitable for major associated civil engineering works.

The contract can be on the basis of cost plus a percentage fee rarely used or cost plus a fixed fee, or a target cost. Payment terms have to define which costs are reimbursable and which are covered by any lump sum payments. This amounts to payment in advance. A project manager adminis- ters the contract but he does not have a fully independent status, although he is required to act impartially in some matters.

The purchaser is responsible for the actions of the project manager and cannot dispute his decisions. These I Chem E conditions have been used occasionally for certain civil engineering works, primarily because they form a framework on which to base a cost reimbursement contract. These agreements are compatible with the standard ICE forms of contract but are also intended for use alongside any of the major forms of construction con- tract setting out the obligations and liabilities of the consultant and defining his duties.

Forms are also available for use with GCWorks 1. The sub-contractor is deemed to have full knowledge of the main contract and many provisions such as for payment, claims and variations are intended to reflect the terms of the main contract. Mechanisms for dealing with dis- putes also reflect the standard ICE conditions and provision is made for these to be dealt with jointly where the matter in dispute affects both contracts. From these considerations it should be possible to decide on the content of each contract as to the scope of works, whether or not the contractor is to carry out any design or whether designs will be provided complete for construc- tion.

These together with any financial requirements should enable a choice to be made of the conditions of contract likely to be most suitable for the works see Chapter 4. One of the main aims in these decisions will be to try to ensure that contracts are packaged to suit the capabilities of the tenderers likely to be invited.

Preparing contract documents 51 5. Their roles are defined in the contract. However, because there is a need for day-to-day supervision of civil engineering construction, the two parties may agree that a third person should carry out such duties. This third person can have varying powers under the contract and this is reflected in his designation. The roles of these participants are described briefly below; the use of a capital letter in their designation being discontinued except where necessary for clarity.

He sets down what he requires and specifies this in the tender documents, which he issues to firms of con- tractors to seek their offers to carry out the works. His obligations include ensuring that the works are legally acceptable and practical, and that the site for them is freely available. He may also need to arrange that associated needs, such as the supply of power, drainage and the like which he is providing, are available.

Having set up these basic elements he must, above all, ensure that he can meet his obligation to pay the contractor in accordance with the con- tract.

If any dispute remains unresolved under the contract, the employer must decide what action to take; either to negotiate some settlement or, per- haps, take the dispute to adjudication, arbitration or the courts. The contractor takes on the obligation to construct the works.

In his offer to the employer he puts himself forward as being able to build the works to the requirements set out in the tender documents. In order to do this he will have studied the documents and any geotechnical or other information provided or otherwise available, visited the site and checked the availability of such labour, plant and materials as may be needed.

Once his offer is accepted and the contract is formed the contractor takes on the obligation of doing all and anything needed to complete the works in accordance with the contract, regardless of difficulties he may encounter.

He is responsible for all work done by his sub-contractors and suppliers, and any design work the contract requires him to undertake. He is not a party to the contract; but he is named in it with duties determined by the parties. Although he is appointed and paid by the employer, he has to supervise the construction of the works as an independent person, making sure they accord with the specified require- ments.

He also acts as an independent valuer of what should be paid to the contractor, and as a decider of issues arising in the course of construction. Given efficient contract documents and completion of the designs before construction starts, the appointment of an independent engineer to adminis- ter the contract encourages contractors to submit their keenest prices. Many contractors will seek out the reputation of such an engineer for his experience and ability to apply fair dealing, and will adjust their prices accordingly.

This benefits both the employer and contractor since it gives assurance that their interests will be protected. Few civil engineering contracts handled in this manner need settlement by resort to arbitration or a court of law.

A project manager holds a different appointment from the independent engineer described above. He may carry out many similar duties as the engineer under the traditional form of contract, but he is not fully independent. The specific content of the contract will define the limit of his powers to act independently. Decisions made by the project manager on matters that are subject to assent by the employer will commit the employer, who will not be able to dispute them. If the contractor is to offer his lowest prices he has to be assured the terms of the contract will be interpreted impartially; for this reason an adjudicator is appointed to whom the contractor can take his disputes with the project manager.

The supervisor under the ECC has a role which is mostly restricted to watching over construction and attending tests, etc. His main role, however, is to ensure the works are carried out as required by the contract. The contract thus binds the contractor to construct the works as defined, and the employer to pay for them in the manner and timing set out.

As civil engineering works are often complex, involving the contractor in many hundreds of different operations using many different materials and manu- factured items, including employment of a wide variety of specialists, the documents defining the contract are complex and comprehensive.

The task of preparing them for tendering therefore warrants close attention to detail and uniformity of approach, so as to achieve a coherent set of documents which forms an unambiguous and manageable contract. A typical set of documents prepared for tendering will include the following. Instructions to tenderers These tell the contractor where and when he must deliver his tender and what matters he must fill in to provide information on guarantees, bond, proposed methods for construction, etc.

The instructions may also inform him of items which will be supplied by the employer, and sources of materials he should use e.

The particular conditions adopted may contain amendments or additions that the employer wishes to make to the standard con- ditions. Usually the standard conditions which are available in printed form are not reproduced in the tender documents but they will be named by specific reference and a schedule will show what changes have been made to them. The specification This describes in words the works required, the quality of materials and workmanship to be used, and methods of testing to be adopted to ensure compliance.

The specification usually starts with a description of the works to be constructed, followed by all relevant data concerning the site, access, past records of weather, etc.

Further details are given in Section 5. Bill of quantities or schedule of prices These form an itemized list covering the works to be constructed, against each item of which the tenderer has to quote a price. This permits re-measure according to the actual quantity done under each item.

Some bills contain many hundreds of items, classified by trade or accord- ing to a standard method of measurement; other bills contain a less number of items see Chapter A schedule of prices may comprise a series of lump sums or it may call for rates only, but can list provisional quantities which are estimated, that is, uncertain. They would be used, for instance, for a contract for sinking boreholes, items being provided for boring in stages of depth, the total depth to which any hole has to be sunk not being known in advance.

The appendices to tender will contain other matters defining the contract terms and which the tenderer confirms he accepts in making his offer, such as time for completion of the works, damages for failure to complete on time, minimum amount of insurances, completion of bond, etc.

There may be other matters concerning the basis of his offer he is required to supply, such as cur- rency exchange rates for international contracts or sources of materials. The contract drawings These should provide as complete a picture as possible of all the works to be built. The more complete the contract drawings are, the more accurately the contractor can price the work, and the less likelihood there is that variations and extra payments will be necessary.

However, it is not necessary at tender stage to provide every detailed drawing that will ultimately be required such as all concrete reinforcement drawings so long as the contract drawings pro- vided to tenderers show quite clearly what is required.

On small jobs all the foregoing documents may be combined in one volume; but on most jobs at least two and sometimes three or more volumes will be necessary. A tenderer is usually sent a second copy of the instructions to ten- derers, bill of quantities, tender and appendices, so that he can keep one copy of what he has bid. When preparing contract documents a number of matters of contractual import- ance must be considered.

For the standard ICE conditions entries will be required in the appendix to the Form of Tender but for the ECC conditions it will be necessary to decide which options are to be included as part of the con- ditions of contract as well as making appropriate entries in the Contract Data. The Defects Correction Period must be stated.

This is the period during which the contractor must repair any defects in the works resulting from his workmanship. The period is usually 52 weeks for major construction but may be more or less depending on whether there is running plant involved or how soon defects may become apparent.

A Performance Bond is usually required where the employer feels he needs financial protection against a contractor failing to complete the works either due to lack of resources or financial instability. The size of the bond should cover having to re-tender and any extra costs to complete. The value should thus be chosen to suit the work but should not generally exceed 10 per cent of the value of works.

Bonds are, however, relatively expensive to supply and thus put up prices and so may be considered unnecessary if the contractor is substantial, or part of a large group who can supply a parent company guarantee. Insurance against third party risks needs to have a value set with reference to the likely risks of damage.

In a rural area this may be small, but works near a major industrial complex may need a higher level of cover. Normally it is the contractor who provides insurance cover both for the works and third parties but sometimes employers prefer to provide these insurances to save costs. This can lead to problems when the cover provided does not fully represent the risks which arise. The Time for Completion of the works should be set at a reasonable period given a proper level of resources.

In many cases there will be a need for sec- tions of the works to be defined and separate times for completion to be set for each of these. Sections may be needed if other contractors are to have access to the site e. Since the employer will be kept from using his works and may incur other costs if the contractor fails to complete on time it is usual to set liquidated damages to compensate him for his loss. These must be calculated as a genuine pre-estimate of the loss based on the value of the works output and other costs anticipated.

Most contracts provide that a portion of the money due to a contractor each month be retained by the employer. This retention has to be set and is usually a percentage often 5 per cent of the value of works certified up to a limit.

The intention is to provide cover for defects and outstanding work but retention is unpopular with contractors who point out that bonds and money yet to be certified for payment provide funds should this be necessary. An inconsistency in the documents can give rise to a major dispute under the contract, having a serious effect on its financial out- come. Some guiding principles are as follows.

These need plan- ning out beforehand. It is not easy to achieve an error-free specification. It is of considerable assistance to copy model clauses that, by use and modification over many previous contracts, have proved satisfactory in their wording. Such model clauses can be held on computer files so they are easy to reproduce and mod- ify to make relevant to the particular project in hand. Copying whole texts from a previous specification which can result in contradictory requirements should not be adopted.

Entirely new material is quite difficult to write and will almost certainly require more than one attempt to get it satisfactory. Under the first an informative description is given of what the contractor is to provide and all special factors, limitations, etc. Under the second the detailed requirements are set out. The extent of detail adopted should relate to the quantity and importance of any particular type of work in relation to the works required. Thus the specification for concrete quality may be very exten- sive where much structural concrete is to be placed; but it may be quite short if concrete is only required as bedding or thrust blocks to a pipeline.

Repetition of requirements should be avoided. If requirements appear in two places, ambiguity or conflict can be caused by differences of wording. Also there is a danger that a late alteration alters one statement but fails to alter its repetition elsewhere. Some methods may need to be specified, such as the requirements con- cerning the handling and placing of concrete, but these and similar matters should be specified under workmanship and materials clauses.

Other direc- tions on method should be given only if essential for the design. For instance, if it is necessary to under-pin or shore up an existing structure, the exact method used should not be specified for, if the contractor follows the method and damage ensues, the liability for damage may lie on the designer.

Usually there is no need to specify a particular method, but there may be a need to rule out certain methods; for example, that the contractor is not to use explosives.

The drafter might think it covers any rock encountered but it does not if the geological data supplied with the contract or reasonably available to the contractor provides no evidence of the existence of rock. If there is evidence that rock might be encountered, a definition of it is required as discussed in Section Details and dimensions of the plant will be required to permit design of structures to proceed.

Thus the employer has to let contracts for the supply of such plant in time for delivery of the plant to occur when the construction needs to incorporate it. Figure 5. A plan of this kind is needed for many types of project. However, because the employer orders the plant he becomes liable for any delay caused to the civil contractor if he does not place an order in time, or the plant supplier defaults on his promised delivery period.

Although this may result in plant being ready before the construction contractor needs it, this is the best policy to follow. T Manufacture Supply First buildings ready 3. T All buildings ready Manufacture 4. T Supply Start delivery 2 months safety margin Substantial completion — do. T on time Civil wks 6. T Civil wk 7. T Civil construction Works Finishing sub — c Manufacture 8. Process plant 4. Pipe supply 6. Site preparation Electrical subc. Swing bridge 7. Main civil works 2. Site investigations Plant 8.

Pumping plant 3. Valve supply Civil subc. Instrumentation Fig. Planning the co-ordination of contracts for a water supply project the cost of getting the construction contractor to temporarily store some plant on site — will be less than the cost of delaying construction.

An alternative is for the employer to pass to the construction contractor the responsibility for arranging delivery of plant as he needs it. This was done on the Mangla dam project in Pakistan where eight major suppliers for hydro- electric plant, gates, valves and other large equipment were involved. The civil contractor was required to take over the plant supply contracts and arrange delivery to suit his construction programme, after such plant had been tested to the satisfaction of the employer.

This kind of approach, however, is only practicable where the project is so large, as at Mangla, that construction takes several years to complete. Site preparation contracts An employer may also let a separate civil engineering contract for site- preparation, which covers building of access roads, bulk excavation, and pro- viding electrical, water, and sewerage services to the site. This contract can be let while detailed design of the project is still ongoing, and can therefore contribute to early project com- pletion.

Other advantages are that some excavation can be left open for the civil works tenderers to view, so minimizing the risk of claims for unforeseen ground conditions, and arrangements can be made for temporary storage of pipes and valves, etc.

However a site contract must be completed before the main civil engineering contract is let. Co-ordination requirements When separate plant supply contracts are let, the main civil contract must include all details of what the civil contractor must do in connection with such plant.

The contract drawings should show how the latter has to be done, and who is to be responsible for positioning any such item correctly. On a large scheme where several teams of engineers work on differ- ent parts of the design, checking that the interface between their separate parts match, is equally important. Under the first, the specification should provide a brief but reasonably compre- hensive description of the works to be built.

The elements making up the whole project should be mentioned, together with their principal sizes or, where rele- vant, outputs. This is of assistance to those who might wish to use the priced contract later for the purpose of analysing costs. The services which the con- tractor is to provide may need description, particularly if he is to design any part of the works. Explanation should be given of the industry or national standards used on the project, and in what circumstances alternatives may be allowed.

The geological and hydrological data presented is of crucial contractual signifi- cance. The employer should thus supply to tenderers any information he has which can be considered relevant to the works. Choice of this information can present serious problems.

There may be a large amount of such data, and it may be of variable reliability due to use of dif- ferent methods of procurement, testing samples, etc. But to hold any data back on the basis of its doubtful validity would be dangerous; it could turn out to be highly relevant to troubles the contractor might encounter.

Yet to comment on the reliability of data, would be equally dangerous. Therefore the data included in, or supplied with, the tender documents must be chosen with care by the geotechnical engineer in charge of such matters and no interpretation or comment on such data should be given. However factual descriptions of the methods used for obtaining data should be given because this is relevant infor- mation which can indicate variations of data reliability. The dates when investi- gations took place and their exact locations are also essential information.

The fourth section defines any requirements or restrictions in respect of the programme for construction and the completion of the contract, including details of sections of the works required to be completed early. If any bonus is to be allowed for completion of all, or some part of the works by a given date, this should be defined. Details should be given of all other contractors who will have rights to enter the site, what work they will undertake and what facil- ities they will need.

Lists of contractors supplying materials to be incorporated in the works need to be given, together with expected times of delivery. Tests stipulated before work can be accepted and should also be detailed.

It is usual to specify a material and its associated workmanship together in the same section. If workmanship is described separately from materials there is a risk that some workmanship requirement may be overlooked by tenderers.

The specification is normally divided into classes of work or trade. An alternative is to list trades, both in the specification and bill of quantities, in the order in which they will be used. This is more logical, helps drafting and makes sure matters are not missed. In the 17th Century A. His discoveries and theories laid the foundation for much of the progress in the science. Newton also formulated 3 laws of motion, and from them the universal law of Gravitation.

Starting about , at the age of 23, newton enunciated pronounce, speak the principles of mechanics, formulated the law of Gravitation; viz. Newton developed the Laws of Inertia and motion which become the fundamental principles used in Structural Analysis. By the middle of the 19th century, much progress had been made in this area. A French physicist Charles Augustine Coulomb and a French engineer-mathematician Louis Marie Henri Navier , are said to have founded the science of mechanics of materials, and often considered to be the founder of modern structural analysis.

Andrea Palladio , an Italian architect, is thought to have been the first person to use modern trusses. After his time trusses were forgotten for years, until they were reintroduced by Swiss designer. Montagnana building designed by Andrea Palladio.

Tesina Stone Bridge, designed by Palladio It was actually in , the first rational method of analyzing jointed trusses was introduced by Squire Whipple of United States. This was the first significant American contribution to structural theory. Several excellent methods for calculating deflections were published in the s and s which further accelerated the rate of structural analysis development.

He has become known as the father of Iron Bridge building in America. Bridge -NY-mohawk design by Squire Whipple, students, observers on top of the bridge.

E Clapeyron of France for the Three-Moment theorem in See reference link. For nearly 15 years, until the introduction of Moment Distribution, Slope Deflection was the popular method used for the Analysis of continuous beams and frames in the United States of America.

A very common method used for the approximate analysis of continuous concrete structures, was the Moment and Shear Coefficient developed by the H. Westergaard and W. Slater a member of the American Concrete Institute in Also, prior to this, moments and stresses in slabs was published by Westergaard and Slater in a Proceedings of American Concrete Institute in Another simple method of analyzing building frames for Lateral Loads is the Cantilever method presented by A.

Wilson in engineering record, These methods are said to be satisfactory for buildings with height not in excess of 25 to 35 stories. In the first half of the 20th century A. Jack C.