Senin, 26 September 2011

Lecture 1A.4: The European Building Market

ESDEP WG 1A:
STEEL CONSTRUCTION:
ECONOMIC & COMMERCIAL FACTORS

Lecture 1A.4: The European Building

Market

OBJECTIVE/SCOPE

To explain both the need and the difficulty of harmonising construction in Europe in accordance with the Single European Act.

PREREQUISITES

None.

RELATED LECTURES

None.

SUMMARY

Construction in Europe is a complex and important industry. At present legal, regulatory and contractual frameworks vary significantly throughout the European Community. There are also considerable differences in procurement methods. The framework and timetable for harmonisation is presented, highlighting the importance of the Construction Products Directive. The role and development of the Eurocodes, European Standards and the CE mark are summarised. The future implications and development of harmonisation are postulated. Annex A provides a summary of current practice in some Member States.

1. INTRODUCTION

European construction is an extremely complex industry encompassing a wide range of activities and professions. It is also the largest employer in the European Community, employing 6,6% of the active population and accounting for 9,1% of gross domestic product (GDP) in 1985, when the last survey was conducted.
Major groups within the industry include public authorities such as local government or town planning authorities, and private clients, contractors, specialist sub-contractors, design and technical service professionals, consultants, building product manufacturers and specialists in the financial sector dealing with construction and property.
The ways in which these groups operate and the controls and procedures they use vary considerably throughout the European Community, according to a comprehensive study commissioned by the Commission of European Communities (CEC) [1]. The study was originally instigated in response to a resolution calling for the standardisation of contracts and controls in the construction industry and the harmonisation of responsibility and standards governing after-sales guarantees on housing; subsequently it was extended to encompass all building construction.
It has been widely recognised that construction presents the greatest challenge to European harmonisation. The Commission decided to tackle this most difficult task first. Successful harmonisation of the construction industry would be a major step towards the objectives of the Single European Act, which calls for a Unified European Market by the end of 1992. A special terminology has developed for harmonisation. Words are given specific meanings that may have legal significance. For this reason a glossary of terms is given in Annex A.

2. CURRENT SITUATION

The report of the study examined the Construction Industry across Europe and found that most Member States were in favour of harmonised controls and procedures [1]. Many also wished to see more precise definitions of the responsibilities and liabilities of the participating parties.
The report found that there was wide support for more measures to protect the buyer of the final product through an insurance scheme. This is consistent with the objectives of the Single European Act, which are not just confined to the establishment of a free market for the trading of goods and services, but also to improve consumer protection, health, safety and the environment throughout the Community.
Information sheets containing details of the present methods of procurement, form of contracts, controls and responsibilities used in the various Member States are given in Annex B. For these methods to be successfully harmonised the report listed 14 "elements" which should be considered in any common Community rules [1]. These elements included:

Definition of the role of the client and the task of the engineer,
Specific liability
Insurance (for professional liability)
Qualification of contractors,
Design codes and specifications
External inspections
Acceptance criteria
Contractual documents
Tenders

The Community already recognises the professional qualifications of its members under the Treaty of Rome. However, there is much diversity between Member States in the length of university courses and the amount of practical experience required to become a professional engineer. The requirements for architects, on the other hand, are less diverse and they may be the first profession to be fully harmonised within the Construction Industry.

3. LEGISLATIVE FRAMEWORK AND TIMETABLE FOR HARMONISATION

The European Parliament is at the top of the legislative framework. It debates all legislation and has the power to amend or add further details to the proposed action. A typical proposal passes through the following stages:

One of the 25 Directorates General of the Commission (CEC), or a sub-division of it responsible for the particular area of policy, e.g. DG III responsible for the Internal Market and Industrial Affairs, will draw up the measures required to implement the proposed action.
The Council of Ministers agrees the proposal, often only by a majority vote.
The European Parliament debates the proposed legislation.
After the inclusion of any amendments or additions resulting from the debate, the Council of Ministers agrees the legislation.
The Commission then implements the legislation through directives, which are then adopted by each Member State through legislation in their national parliaments and associated regulations, recommendations, guidelines or standards. This ensures that the autonomy of individual Member States is not threatened.

The way the Commission implements the removal of technical barriers to trade was dealt with by the European Parliament under the New Approach or "Nouvelle Approach" Resolution. It was conceived to accelerate the completion of the Single European Market and consists of a framework of directives that cover general principles only. This approach allows each Member State the freedom to use their own design and manufacturing traditions and skills which have often been developed from centuries of use.
The most fundamental directive affecting the Construction Industry is the Construction Products Directive. It was conceived under the New Approach Resolution and applies to construction products for permanent use in building or civil engineering works. A product is deemed fit for use and may carry the CE mark if it complies with the Directive.
The Directive is implemented by relying on the product's conformity with harmonised standards or, in the absence of such a standard, with European Technical Approvals (ETA) as proof of compliance with its essential requirements.
The harmonised standards and guidelines to establish European Technical Approvals are initiated as a mandate to CEN from the Commission's Standing Committee on Construction (SCC). They may be accompanied by interpretive documents to assist in the preparation of standards. It is at this stage that the first detailed technical requirements are considered. The preparation of harmonised standards is undertaken by the European Committee for Standardisation (CEN). It produces standards through the following structure:
Mandates for standards preparation are issued by the Commission of the European Communities (CEC) to the European Committee for Standardisation (CEN). The CEN Technical Board (responsible for controlling the standards programme and includes delegations from the CEN members, i.e. the natural standards organisations, establishes Technical Committees (TC's) (formed to prepare standards and includes representatives from the CEN members with relevant technical expertise) and Technical Working Groups (TWG's) (formed to undertake specific short term tasks for the committee and may include representatives from product manufacturers, trade associations and standards authorities).
The timetable for the harmonisation process and the key legal steps are summarised in Table 1.

4. THE ROLE AND DEVELOPMENT OF THE EUROCODES

The Eurocodes and their associated European Standards provide a framework for the implementation of the Construction Products Directive and the award of the CE mark. This is the reason for their urgent introduction and their ENV status.
They will only be given full EN status after a period of trial use in Member States and incorporation of comments through the Technical Committee. The timetable for the issue of the Eurocodes as EN is not yet established but it is likely that the principal Eurocodes will achieve EN status during the period 1995-1998.
The framework of European Standards will take a similar time to implement. In the interim, Provisional Guides are available as Annexes to the main Eurocodes, e.g. Annex T to Eurocode 3: Fabrication of Structural Steelwork - Provisional Guide.
During the ENV phase, it is intended that the Eurocodes are implemented in Member States by National Application Documents. These documents provide national values of partial safety factors and also incorporate any specific material requirements. For example:

In the UK the requirements for providing minimum ties to ensure adequate structural integrity and resistance to accidental damage are maintained.
In France, there are certain clarifications on the detailed application of rules for calculating the semi-rigid action of connections.

The Eurocodes present best available European design practice. They offer the opportunity of superseding and improving upon traditional practices. They should therefore improve the overall economy of construction as well as offering more consistent safety and reliability.

5. THE CE MARK

The CE mark may be used on products that comply with European Standards, or in the absence of such standards, European Technical Approvals as demonstration of compliance with the Construction Products Directive (CPD). The objective behind this approach is to ensure compatibility between design, execution procedures and products. In the transitional stages before the full harmonisation of standards, certain technical specifications which are recognised by the Community may also provide compliance. In exceptional cases, certification of conformity by an approved body or a declaration of conformity by the manufacturer (provided certain conditions are met involving approved bodies during the testing) is acceptable.
The use of the CE mark implies compliance with the essential requirements of the CPD which relate to:

mechanical resistance and stability
safety in case of fire
health, hygiene and the environment
safety in use
protection against noise
energy economy and heat retention

The use of the CE mark is not a guarantee of performance, only of minimum acceptable compliance with the essential requirements listed above. Compared to other marks of quality it may well be a levelling down to a lowest acceptable, safe quality. Other marks of quality, particularly those relating to performance beyond the essential requirements are therefore likely to remain in operation throughout Europe. However the situation is intended to be sufficiently transparent for the individual purchaser to be able to weigh up quality versus price for a particular product or structure.

6. THE FUTURE FOR CONSTRUCTION IN THE UNIFIED EUROPEAN MARKET

The emphasis on quality, even the lowest acceptable quality implied by the CE mark, gives greater priority to the wishes of both the building owner and his tenant. For the designer and constructor it is likely to lead to the development of minimum guarantees and associated provisions for damages. Differential insurance premiums may develop, favouring more reputable contractors and offering tangible benefit from quality. For the owner there will be responsibilities for `fair play' towards both his contractors during construction and his tenants during the service life of the building.
Harmonised standards imply larger potential markets and greater opportunities for economies of scale. Trade should be simpler with reduced certification, documentation and administration. Minimum standards imply better consumer protection which should lead to greater consumer confidence; this should act as a direct stimulus to investment.
Of course the greater formality of harmonised, regulated construction is likely to create some problems, especially for small and medium enterprises. Generally, the cost of entry into steelwork construction will increase because of the need to be conversant with the details of European legislation prior to trading. To the benefit of the owner and tenant it will be more difficult to cut corners either in product standards or in safety in execution.
There could be a concern that the introduction of harmonised construction may lead to a reduction in the range and individuality of construction. In reality all the regulations are so general in nature that they are unlikely to inhibit individuality or innovation in any way. What may happen is that the establishment of a common design base makes it easier to export and import forms of construction. Thus the only individual forms of construction at risk are those which are inherently uneconomic and deserve to become extinct from commercial pressures.

7. CONCLUDING SUMMARY

European construction in a complex and important industry, accounting for 9% of Europe's GDP.
Harmonisation of European construction is an important but difficult part of the establishment of the Unified European Market.
Currently there are significant differences in technical, legal, regulatory and contractual frameworks between Member States.
The Single European Act in 1987 and the implementation of the Construction Products Directive in 1991 were important steps in the creation of the Unified European Market, notionally to be established by December 1992.
The Eurocodes and their associated European Standards provide the framework for the implementation of the CPD and the award of the CE mark.
A harmonised construction market is expected to improve minimum standards of quality and assist the transfer of best construction practice throughout Europe.

REFERENCES[1] Mathurin, C. Controls, Contracts, Responsibilities and Insurance in Construction in the European Community, Commission of the European Communities, 1988.

Date	Event	Objective/Outcome
1957	Treaty of Rome	EEC Established.
26.07.71	Public Works Directive	Co-ordination of procedures for the award of public works contract.
07.05.85	New Approach to Technical Harmonisation and Standards	Proposals to accelerate the completion of the Single European Market.
10.07.85	Architects Directive	Mutual recognition of qualifications.
01.07.87	Single European Act	Removal of internal barriers to trade. Majority voting introduced.
01.10.88	Resolution calling for Standardisation in the Construction Industry	Standardisation of contracts and controls. Harmonisation of responsibility and standards governing guarantees.
21.12.88	Construction Products Directive (CPD)	Removal of technical barriers to trade. Essential requirements to establish fitness for use.
12.07.89	Safety at Work Directive	Encourage improvement in health and safety at work.
18.07.89	Public Works Directive	Amendment to 1971 Directive.
21.10.89	Testing and Certification	Regulations & Approved Bodies.
27.07.91	CPD in force	Implemented by Member States.
31.12.92	Deadline for Unified European Market

TABLE 1 - Timetable for harmonisationANNEX A: QUESTIONNAIRE - BUILDING PROCUREMENT IN EUROPERepresented here are the following countries:
Austria
Belgium
Finland
France
Germany
Greece
Ireland
Italy
Luxembourg
Spain
Sweden
United Kingdom
AUSTRIA

1. INTRODUCTION

Technical Standards are generally complete and coherent. Requirements for certification and quality marks sometimes could cause expensive implications.
There is a good framework for planning and controlling the maintenance of structures during their lifetime.

2. CONTROLS

Town planning regulations are tightly controlled. Obtaining planning permission can sometimes delay construction for a long time.
National technical building standards, e.g. ONORM and other rules and guidelines prepared by such organisations as OIAV, OSTV in some cases are established by federal law.
There are different building laws "Bauordnungen" in the Austrian Federal Countries and some Towns covering administrative regulations and execution of construction. In those laws, there are additional directives for certain types of construction such as schools, warehouses, car parks, theatres, etc. and for some actions, e.g. fire.
In addition to compulsory special rules for energy supply, environmental protection, technical and mechanical services and installations, there are industrial guidelines which only have to be followed when contractually agreed.
Where materials and components are not generally used, special federal country government approval or test marks are required. In addition, formal quality assurance is necessary for some materials and components that are incorporated into permanent works. Government approval, test marks and quality assurance have to be executed by authorised organisations such as technical institutes, consulting engineers, etc.

3. CONTRACTS

General

Public sector contracts always adopt specified standard forms. In the private sector modifications to those standard forms are usual. The principal standard form is regulated in ONORM A 2050 and consecutive standards. Multi-storey-buildings relate to the LB-H "Leistungsbeschreibung Hochbau".
Pre-qualification is only adopted for large, complex or unusual projects in order to check the capability and craftsmanship of contractors. It is used in conjunction with the restricted tender procedures.

Forms of Contract

(a) Unit Price Contract
Unit price contracts require a description of works with detailed technical specifications and a bill of quantities. Fixed quantities are defined for all items on the bill.
(b) Lump Sum Contract
Lump sum contracts require a general description of the works with a programme of execution. This type of contract is used in order to find the best technical, economic and functional solution.

4. MAIN METHODS OF PROCUREMENT

Separation of Design and Construction is usual
(a) Individual Contracting
The client places separate contracts with the designer and several package contractors, in order to separate design and construction responsibilities.
(b) General Contracting
(i) Design and construction arranged separately by the client. The general contractor is responsible for the execution of the total scope of work and undertakes the main parts of the work itself. He also places individual packages to subcontractors. Detailed design is sometimes the responsibility of the general contractor.
(ii) 'Design and Build' construction: the general contractor takes responsibility for the complete design and construction. He places several individual package contracts with subcontractors and carries out the main part of the work himself.
(c) Management Contracting
The management contractor undertakes responsibility for all design and execution works, but does not do any work directly. The work is carried out by a series of contractors who are contractually bound to the management contractor.
The most popular forms in Austria are (a) and (b i).

5. RESPONSIBILITIES

There are general clear divisions of responsibilities.
The client is responsible for contract award, taking over the works when they are completed and payments.
The architect or the master-building ("Baumeister") is responsible for pre-design, detailed design and drawings, obtaining planning permission, defining bills of quantities, tendering and site management including architectural and technical supervision. He has the principal responsibility for quality, safety and compliance with the law.
Consulting engineers are responsible for the technical input in their specialised fields, such as structural design, etc. The responsibilities cover detailed design, drawings, tendering and supervision.
The contractor is responsible to the client for carrying out the work, warranties, maintaining programme and for some aspects of detailed design and shop drawings.

6. INSURANCE AND GUARANTEES

It is not general practice to insure against damage during execution. However, architects and consulting engineers are constrained to carry professional insurance.
Generally, the client is offered a guarantee on the completion of the works for three to five years. Grave defects can be asserted in thirty five years.

7. FUTURE IMPROVEMENTS

Unification of different building laws should be the main target for Austria.
BELGIUM

1. INTRODUCTION

Technical Standards are generally complete and coherent. However, requirements for certification and quality marks are sometimes requested. Specifications are not always updated as frequently as is desirable.

2. CONTROLS

The procedure of obtaining building permits can sometimes delay construction for a long period of time.
National building standards, e.g. NBN, EN, ENV, and guidelines prepared by such organisations as CSTC, Technical Agreement (Union Belge pour l'Agrement technique dans la Construction) have to be respected.
For some buildings, special requirements in relation with workers safety have to be respected.
Testing by regional Authorities can be required in some cases (Charpy, welding tests ...).

3. CONTRACTS

Public Sector

Private Sector

Forms of contract

(a) Unit Price Contract
Unit price contracts require a description of works with detailed technical specifications and a bill of quantities. Fixed prices are defined for all items on the bill. The risk on quantities is with the client.
(b) Lump Sum Contract
Lump sum contracts require a general description of the works with a programme of construction. The risk on quantities is with the contractor. This type of contract is normally used for 'turnkey' projects by general contractors in order to find the best technical, economic and functional solution.

4. MAIN METHODS OF PROCUREMENT

(a) Individual Contracting
The client places separate contracts with the designer and several package contractors. Design and construction responsibilities are separate.
(b) General Contracting
Usually the contracts are lump sum and fixed price.
The general contractor takes responsibility for the complete design and construction. He places several individual package contracts with subcontractors and carries out the main part of the work himself.
(c) Project Manager Contracting
The Project Manager undertakes responsibility for all design and construction works, but does not do any work directly. The work is carried out by a series of contractors who are contractually bound to the project manager who is acting on behalf of the client. Sometimes, these contracts are on a percentage of global cost.
The most popular forms of contract are (a) and (b).

5. LIABILITIES

Contractors

(a) Liability Before Acceptance ("reception")
All contractors are subject to the principles of contractual liability in ordinary law.
Example: completion of execution within the contractual deadline.
(b) Liability After Acceptance
The contractor is liable for:
- Decennial liability
Civil code provides for a special liability of 10 years (for stability aspects only).
This liability is public policy which means that it is forbidden to attenuate it by conventional clauses.
· So-called latent defects considered minor which are not discovered at the time of acceptance. The defects listed in this category are those which do not affect the stability of a building or of a construction.
This liability if not public policy.
Conditions for liability are:
· a contract referring to the "gros oeuvre" must exist.
· a serious defect affecting the solidity or the stability of a building must be pointed out.

Architects

Architects are subject to liability under ordinary law applicable to contractors as well as to decennial liability.
They are not liable for tasks assigned to a specialised design office (design and planning which is outside their normal qualification) except for the incorporation of these designs into the entire plan.

Sharing out of liabilities

The architect is the project leader, in charge of designing the building. In principle, any design defect is, therefore, the exclusive liability of the architect.
The contractor is responsible for any defects which stem from the implementation of the plans drafted by the architect, or defects linked with the execution of the construction project.

Sub-contracting

Architects and contractors are solely liable to the contracting authority for any errors made by their sub-contractors.
Sub-contractors are only liable to the contracting authority if a contractual relationship exists between them.

6. INSURANCE AND GUARANTEES

Architects and contractors ordinarily subscribe to an insurance policy designed to cover their commitments in connection with the decennial liability. Furthermore, the contractors are required to subscribe to a civil liability insurance covering "company risks".
In the case of construction projects carried out on behalf of the State and for the majority of important construction projects, the contracting authority specifies in its tender that two additional policies have to be subscribed:
· An "all risks at the work site" insurance policy covering any risks inherent in a construction site. It includes:
· financial compensation for damages incurred to insured property
· civil liability towards third parties
· proximity disturbances, i.e. any damage incurred by adjacent buildings
This insurance takes effect at the beginning of execution and ends when the building is occupied or with the provisional acceptance.
It is ordinarily subscribed by the general contractor on his behalf and on behalf of the sub-contractors. However, it may also be subscribed by the contracting authority or the developer.
· So-called "liability insurance and inspections" guaranteeing compensation for damage to the building which occurs within the ten-year period following acceptance of the building irrespective of the subscriber of the policy (contractor, sub-contractors, architects, engineers, contracting authorities).
The guarantee of the liability insurance and inspections may be implemented only on the condition that the construction work which is the object of the guarantees is submitted for inspection to an independent body - the SECO Bureau - which is in charge of inspecting design and execution of works.
FINLAND

1. INTRODUCTION

Contractual methods have been long established, but their relative importance is changing. Construction management agreements are becoming more popular and system unit procurement is being introduced as a method of procurement.
In product approval, a change of policy is taking place. Rules that demanded an approval by one specific body are being abolished in preparation for the European Economic Space Agreement. This is most notably the case in electric appliances but also elsewhere.

2. CONTROLS

Every building needs a building permit admitted by the local authorities before it can be built. The local authorities check that the building is designed in accordance with the valid technical and city planning regulations. Hierarchically the highest level of regulation is incorporated into the Building Law and Byelaw, which cover both the technical and city planning rules.
The technical regulations are given in the National Building Code, which the Ministry of the Environment issues. The Building Code includes two kinds of regulations: requirements that are compulsory and guidelines, which present one approved solution to a specific problem In practice, the guidelines are semi-compulsory because it may be difficult to persuade the local authorities to approve a solution not presented in the guidelines although they have the right to do so if the solution satisfies the compulsory requirements.
Several ministries and National Boards (e.g. the National Board for Housing) have their own technical rules governing special types of buildings (housing, hotels, etc.). These rules, however, are being abolished and all technical regulations will be presented in the National Building Code.
The guidelines in the Building Code do not give guidance to all problems that arise in building. In these cases it is customary to refer to recommendations issued by various industrial organisations or to standards issued by SFS, the Finnish Standards' Organisation.
The local authorities can also make local rules additional to the national regulations. The local rules mostly cover subjects related to city planning: the architecture of buildings, the size of building site, sewage treatment, fire protection, etc. City plans have lagged behind in many major cities, which has been an obstacle to building in these areas.
The Building Code specifies standards (SFS-standards) for several products that have to be met before a product can be approved. Such materials are, for instance, heat insulation and fire protection materials. The guidelines also specify quality control systems for steel, concrete and glued timber structures. The producer has to be accepted and inspected by a special quality control organisation (TLT for steel structures) or the satisfactory quality has to be proved by quality control documents in every single case.

3. CONTRACTS

The standard form used in most contracts is the Contract Agreement (RT 16-10193) prepared by the Association of Employers of Finland together with several other organisations. This form is used together with General Contract Conditions (YSE 1983) prepared by the same organisations.

4. MAIN METHODS OF PROCUREMENT

(a) Traditional Contracting
Design and building are separated in this form of procurement. The client has separate agreements with architects, engineers and contractors. The main contractor is responsible for carrying out the actual building work, procurement of labour and materials and for co-ordinating the work of sub-contractors and material suppliers. The sub-contractors can have their contracts either directly with the client or with the main contractor.
This form of contracting is the most widely used at the moment, but it is losing ground both to management contracting and system unit procurement.
In traditional contracting, the contractor is payed either on a lump sum or unit price basis. Unit price contracts are often used in industrial buildings and repair works, where the full extent of work is not exactly known when the contract agreement is signed.
(b) Management Contracting
In this form of contracting, the client has an agreement with the management contactor who is responsible for co-ordinating the design of the project and for co-ordinating the actual construction work, which is carried out by sub-contractors. The sub-contractors are contractually bound to the management contractor.
The management contractor is usually paid on a cost plus fee basis.
(c) Design and Build
The contractor is responsible both for the design and construction of the building.
The contractor may also enlarge his responsibilities to the procurement of the building site and marketing of the building, in which case he becomes a developer. This is often the case in office buildings and housing projects.
(d) System Unit Procurement
The disadvantage of traditional methods of procurement, where the work is carried out according to detailed plans prepared by the client and his consultants, is that they do not fully utilise the building component producers' and sub-contractors' know-how in developing the most cost-effective solutions for a specific building project. A new form of procurement called "System Unit Procurement" has been developed to overcome this disadvantage. In this form of procurement the client gives functional specifications for the building units to be procured and the material supplier or sub-contractor is responsible for the design and erection of the unit.

5. RESPONSIBILITIES

See items 4 and 6.

6. INSURANCE AND GUARANTEES

Unless the documents state otherwise, the contractor is obliged to take out a fire insurance that covers the building materials, supplies and components that can be damaged by fire.
He is also obliged to given the client a guarantee for fulfilling the contract and refunding advance payments. If not stated otherwise, the guarantee is 10% of the contract sum during the building operations and 2% during the guarantee period.
The guarantee period is one year if not stated otherwise in the documents. The contractor is, after the guarantee period, still responsible for such defects, omissions, inconveniences or incomplete work that the client could not reasonably notice during the handing-over inspection or guarantee period. This responsibility terminates 10 years after the handing-over inspection. There is a tendency for the courts of law to include an increasing amount of defects within this extended period of guarantee.
The law or the General Contract Conditions for Consultants (KSE 1983) do not require a professional insurance for the architects and engineers. It is common practice for them to take a voluntary professional insurance.
The upper limit of the damages a consultant may have to pay for professional omissions is equal to the consultants fee, if not stated otherwise in the contract documents. His responsibility covers the same periods of time according to the same principles as those of the contractors.
FRANCE

1. INTRODUCTION

All buildings are subject to standards, technical instructions, standardised technical documents, professional rules of application, or any other statutory tests which enable all the building clauses to be defined.

2. INSPECTIONS

The construction of new buildings is subject to a building license being obtained, which is issued today by the mayor of the district^* where the project is located. The license application must contain a description of the project (purpose, number of M² ...) as well as the main architectural aspects (type of structure, architectural concept ...).
After obtaining the licence, the main building contractor draws up a user file on the technical specifications and the drawings of the operation. In this context the materials are chosen according to:
· standards for the products, e.g. steel sections
· technical instructions or standardised technical documents (DTU) for building systems, e.g. curtain wall elevations, matching sheet with trapezoidal corrugations for flat floors and ceilings
· particular specifications for certain types of building (energy, buildings with public access)
· regional requirements for certain products, e.g. thatched roofing, bricks, etc.
For all public-sector contracts (Government, communes, departments and regions) there is a "public-sector contracts code" giving the statutory reference texts, for example the computational regulations.
Certification (or label adoption) is not very widespread in France, except for certain products and industries (e.g. nuclear power stations).

3. CONTRACT

General

(a) Public-sector Contract
All public-sector contracts are subject to a "public-sector contracts code". Furthermore, certain managements or national enterprises (SNCF^*, EDF^**) have issued their own technical specifications and material inspection procedures (stipulation of approved suppliers, administrative documents, quality assurance procedure, qualifying firms).
The opening up of the European market means that today foreign firms are able to tender for this type of contract, which was often not possible before.
(b) Private Contract
There is a "private contracts code" which defines relations between customers and firms. The clauses of the contract are drawn up by the main building contractor in agreement with the building owner. It is possible to issue only one call to tender to a limited number of firms, but it is also possible to negotiate with only one firm (a so-called order "by private contract".

Form of Contract

Contracts usually include price review clauses defined by official formulae and indices. It is possible, however, to come across contracts with firm, non-renewable prices. This is true for small, short-term sites.

4. MAIN METHODS OF OBTAINING CONTRACTS

There are mainly three types of contract entered into:

General Firm

A firm commits itself to the building price and deadline. It is responsible for the whole site, sub-contracts certain works to other firms and ensures co-ordination throughout.
It is an easy solution for the end customer and the architect because they only have dealings with a single manager. In return, this gives the firm considerable power in negotiating with sub-contractors for certain technical and economic choices and enables him in the end to increase his margin through negotiation with sub-contractors. This type of contract corresponds to "turnkey" contracts.

Contract in Separate Lots

The building owner and architect define lots of works for which they issue separate calls to tender to firms. This formula means that the most advantageous prices can often by obtained for each lot. It requires in return great co-ordination on the site, which the architects are not always able to ensure since there are a number of managers.
There are formulae which limit the number of lots and, therefore, the number of firms.
Moreover, general building firms are increasingly involved in property development. They buy land on which they construct a building for a customer. This formula generally gives them better margins.

5. RESPONSIBILITIES

As a rule, responsibilities are clearly defined.
The building owner, who is often the building's customer, is responsible for paying the firms and the main building contractor (architect + BBT^*). He generally calls on an inspection office (e.g. Veritas, Socotec) for the technical aspects to check that the building complies with regulations.
There are different types of tasks for the architect, but he is generally responsible for choosing and following-up technical solutions. He chooses a BBT* who is responsible for the calculation of the works, the technical design (electricity, fluids, etc.).
Finally, firms are responsible for performance on the site. They are responsible for assembly in compliance with the rules and often for implementing the site plans (a task which can be devolved to the architect in some cases).

6. INSURANCE AND GUARANTEE

In general, the customer is insured for damage during building. In addition, the architect and the BBT* underwrite insurance covering risks associated with the design of the work.
One specifically French detail is the existence of the "ten-year" guarantee affecting certain parts of the building. This guarantee period is the result of a law voted in 1978. The various guarantee periods are, therefore, as follows (as from the date of acceptance of the works to the end of building):
· two years for parts which come under the design and completion of the building (e.g. paper wall covering)
· ten years for the entire framework and functions of use of the building (roofing, floors)
· thirty years for parts which involve people's safety (balconies, structural elements)
This is a so-called "public liability" guarantee.
Furthermore, there is a one-year guarantee after acceptance of the works on the entire building called a flawless completion guarantee. In fact, the situation is a complex one because the ten-year guarantee affects both the assembly firms and the manufacturers of the materials.
In the event of disputes, the guarantees can be transferred from the firm to the manufacturer. Manufacturers of products may, therefore, be responsible for the use of their own product.

7. FUTURE CHANGES

The future enactment of the European Construction Products Directive will change guarantee and manufacturers' liability criteria.
In this instance, it is possible that the architects may be obliged to have a more technical vision of the use of materials because their responsibility will be more heavily involved.
Finally, problems of maintenance, life cycle and demolition of future buildings will have to be considered when building, which will bring about changes in building techniques.
GERMANY

1. INTRODUCTION

Technical standards are generally complete and coherent. However, requirements for certification and quality marks sometimes have expensive implications. Specifications are not always updated as frequently as is desirable.
There is a good framework for planning and controlling the maintenance of structures during their life.

2. CONTROLS

Town planning regulations are tightly controlled. Obtaining planning permission can sometimes delay construction for a long period of time.
National technical building standards, e.g. DIN, and other rules and guidelines prepared by such organisations as DASt, DAf, StB, IfBT, Argebau and STLB are established by government edict.
There are also state building laws covering administrative regulations and execution of construction. There are additional directives for certain types of construction such as schools, warehouses, garages, assembly halls, etc.
In addition to compulsory special rules for energy supply, environmental protection, technical and mechanical services and installations, there are industrial guidelines, e.g. AGI, VDI, ISO, which only have to be followed when contractually agreed.
Where materials and components are not generally used special government approval or test marks are required. In addition, formal quality assurance is necessary for some materials and components that are incorporated into permanent works. Materials and components that require test marks or quality assurance are listed in relevant government regulations. Government approval, test marks and quality assurance have to be executed by authorised organisations such as technical institutes or acknowledged academic experts.

3. CONTRACTS

General

Public sector contracts always adopt specified standard forms. In the private sector modifications to these standard forms are possible. The principal standard form is the "Verdingungsordnung fur Bauleistungen" (VOB). Part A defines the procedures prior to award of contract. Parts B and C provide general conditions of contract and the technical requirements for construction.
Pre-qualification procedures are only adopted for large, complex or unusual projects in order to check the capability and craftsmanship of contractors. They are used in conjunction with tender procedures.

Forms of Contract

Unit Price Contract

Lump Sum Contract

4. METHODS OF PROCUREMENT

Individual Contracting

General Contracting

Management Contracting

5. RESPONSIBILITIES

6. INSURANCE AND GUARANTEES

7. FUTURE IMPROVEMENTS

GREECE

1. INTRODUCTION

2. CONTROLS

3. CONTRACTS

Unit Price Contract

Lump Sum Contract

4. MAIN METHODS OF PROCUREMENT

Individual Contracting

General Contracting

Management Contracting

5. RESPONSIBILITIES

6. INSURANCE AND GUARANTEES

7. FUTURE IMPROVEMENTS

IRELAND

1. INTRODUCTION

2. CONTROL

3. CONTRACTS

Abbreviations

4. MAIN METHODS OF PROCUREMENT

5. RESPONSIBILITIES

6. INSURANCES AND GUARANTEES

7. FUTURE DEVELOPMENTS

ITALY

1. INTRODUCTION

2. CONTROLS

General

Public sector contracts always adopt specified standard forms. In the private sector modifications are frequent. The principal standard form is the "Capitolato generale e speciale per l'appalto dei Lavori pubblici". The first part defines procedures prior to the award of the contract. The second and third parts provide general conditions of contract and technical requirements for construction.
The weak point of many contracts concerns the requirements for drawings and the description of the scope of work which are often imprecise. This lack of precision causes claims, delays, etc.
Pre-qualification procedures are widely adopted. In Italy there is a specific "Builders List" - "Albo Nazionale dei Costruttori" - where the companies are included in relation to their capability to undertake in different works, such as reinforced concrete, earth movements, buildings, etc. and in relation to their financial means.

Forms of Contract

(a) Unit Price Contract
Unit price contracts require a description of works with detailed technical specifications and a rough bill of quantities. The risk on quantities is with the client. Programme of execution is required.
(b) Lump Sum Contract
Lump sum contracts require a description of works with detailed technical specifications. A programme of execution is also required. The risk on quantities is with the contractor.
(c) A variant of the second type is the lump sum contract related to a bill of quantities with unit prices. Variations required by the client are regulated in conformity to unit fixed prices: otherwise the risk on quantities is with the contractor.

3. MAIN METHODS OF PROCUREMENT

(a) Individual Contracting
The client places separate contacts with the designers and several package contractors. Design and construction responsibilities are separated
(b) General Contracting
There are unit prices and lump sum contracts, depending on the scope of works.
(i) Design and Construction Arranged Separately by the Client
The general contractor is responsible for the execution of the total scope of work and undertakes the main parts of the works himself. He also places individual packages to subcontractors. Workshop design is often the responsibility of the contractor.
(ii) 'Design and Build' Construction
The general contractor takes responsibility for the complete design and construction. He places several individual package contracts with sub-contractors and carries out the main part of the work himself. This is the main field of application of industrial buildings.
(iii) Management Contracting
Rarely used in Italy
The most popular forms of contract are (a) and (bi)

4. RESPONSIBILITIES

Italian laws and regulations give a clear division of responsibilities. Problems arise with the instructions for a complete, finished work. Often, in fact, drawings and specifications are incomplete and not detailed enough; this causes, as mentioned before, controversies among the parties and delays.
The client is responsible for the contract award, tendering, taking over the works when they are completed, and payments.
The architect is responsible for pre-design, detailed design and architectural drawings, obtaining planning permission, architectural and technical supervision, quality, compliance with the law relating to his role (architectural).
The clerk of works, often an engineer, has the responsibility for the site management and the erection of the building according to the approved drawings, the control of the bill of quantities, the control of the programme, safety and compliance with the law relating to his role.
The engineers are responsible for the technical inputs in their specialised fields, such as structural design, services, etc.
The contractor is responsible to the client for carrying out the work, warranties, maintaining the programme, and for shop drawings. The contractor is responsible to the client for the subcontractors.

5. INSURANCES AND GUARANTEES

Contractors are required to be insured against damage during the construction and for responsibilities under civil law.
Architects and engineers are not required to carry professional insurance (if not carried by the contractor).
The contractor must offer a guarantee valid for ten years as far as serious defects of the construction are concerned.

6. FUTURE DEVELOPMENTS

Many changes are foreseen and requested in the future, as outlined below:
· Drawings and specifications must be ready " for construction" at the time of the award, in order to avoid claims and disputes during execution and further delays and damages.
· Architects and engineers must be insured against damages.
· For public works, an independent surveyor dedicated to the control of quality and the bill of quantities is strongly required.
LUXEMBOURG

1. CONTROLS

Apart from building permits, administrative approvals for building products are not required in Luxembourg. As Luxembourg has no building standards, reference is normally made to Euronorms (EN) and Eurocodes or to the standards of neighbouring countries. Quality certificates from an acknowledged foreign testing institute are often requested.

2. CONTRACTS

Pubic sector contracts always adopt specific standard forms. In the private sector modifications to these standard forms are possible. The German standard form "Verdingungsordnung fur Bauleistungen" is commonly used as a basis for contracts.
Usually contracts are awarded in the form of unit price contracts. Lump sum contracts are rather an exception.

3. MAIN METHODS OF PROCUREMENT

In public works, individual contracting is the rule. The private sector may use general contacting as a method of procurement.

4. RESPONSIBILITIES

The architect and the engineer are responsible for the design and the bill of quantities.
The contractor is responsible for the executed work or the delivered equipment according to specifications, drawings and bill of quantities.

5. INSURANCE AND GUARANTEES

In addition to the insurance for responsibility under civil law, major contracts are executed under an all-risks insurance, covering damage during construction.
Guarantees are at two levels, a two-year guarantee for secondary work and a ten-year guarantee for the structural part of buildings.
SPAIN

Controls

Planning and Approvals

The seventeen autonomous communities (comunidad autonoma) or regional governments, not the State, have ultimate responsibility for planning and control of construction. The powers are exercised by the local authorities (ayuntamientos), of which there are some 8000 grouped into fifty-two provinces. The responsibilities were set out in Law 19 of 2 May 1975.
All local authorities of over 50,000 inhabitants have to produce a structure plan (plan general), which is approved by the planning commission of the autonomous communities. All urban areas each have a more detailed town plan (plan parcial), which is approved by the local authority as and when new areas are developed.
Each local authority grants building permits but does not exercise direct technical control. Control of building regulations and initial control in the light of the structure plan and town plan are exercised entirely by the architect via the local college of architects.
The building permit (licencia de construccion) is a legal requirement before construction can begin, and is required before gas, water and electricity connection can be made. It is only given when the developer or client presents the project documents together with a permit (visado) issued by the college of architects.
As well as checking from the point of view of urban planning, the local authority also verifies where appropriate that fire regulations, health regulations, or other specific local regulations are satisfied, particularly for public buildings.
At the end of construction, the architect signs the acceptance certificate, which must be stamped by the college of architects after the client has paid the architect's fees in full to the college. The certificate is then submitted to the local authority for the occupation licence (licencia de apertura).

Standards and Regulations

Building regulations in Spain are passed principally by the national government, but since 1980 the autonomous communities also have the power to do so.
The legislation has been divided since 1977 explicitly into two classes:
· The basic norms (normas basicas de la edificacion) (NBEs) which are the only obligatory standards.
· The technical norms (normas technologicas de la edificacion) (NTEs) which are advisory but not obligatory.
An index to the legislation on building, the Indice de Disposiciones Relacionadas con la Edificacion (latest edition 1987), is published by MOPU.
The Directorate-General of Architecture and Building Technology of MOPU produces or approves codes of practice (Soluciones Homologadas de Edificacion) (SHEs) whose use guarantees meeting the minimum requirements of the NBEs.
Product standards in Spain, for all industries, are set by the Spanish Association for the Normalisation of Certification (Asociacion Espanol de Normalisacion y Certificacion) (AENOR).
There is, in general, no legal requirement to use approved products, and no import restriction on products which do not meet or are not approved to UNE standards.
Testing for certification of suppliers and product approval is carried out by approved laboratories. In 1986 a new accreditation system for laboratories was set up asRed Espanola de Laboratorios de Ensayo (RELE).

Contract Forms

por ajuste alzado global y precio cerrado

por precio determinado en funcion de la unidad y cantidad

por administracion

Ley de Contratos del Estado

Regulacion General de Contratos del Estado

Pliego de Clausulas Administrativas Generales

PROCUREMENT PROCEDURES

Private Sector Procurement

The selection of a contractor by a private developer may often by influenced by the complex inter-relationships of Spanish business.

Public Procurement

Further new legislation will need to be introduced to adopt the new EC directives on public procurement. The existing EC directives were incorporated in decree 2528/1986. Existing procedures are set out in the legislation on State contracts described in the previous section.
The existing legislation (as modified in 1986) specifies three types of tendering procedure as follows:
· Subasta (auction) in which the tender documents include a fully priced bill of quantities.
· Concurso (competition) in which the bill of quantities is unpriced or not included, and the contract is awarded to the 'most advantageous offer'.
· Contratacion directa (negotiation) in which the price is negotiated directly with a candidate selected on general technical criteria.

Responsibilities

Architects Responsibilities

The architect is totally responsible for ground investigations, design and site supervision and advises on the appointment of a contractor.

Technical Architects Responsibilities

A technical architect is normally responsible for the bills of quantities, cost estimates, detailed budgets and control of payments in the architect's service.

Insurance and Guarantees

The Spanish Civil Code adopted a simple approach to construction liability, similar to the Napoleonic Code. The code is based on the following two basic principles.
· Ten-year strict liability for serious defects.
· Responsibility shared between the main contractor and two independent professionals acting in a personal capacity - the architect and the technical architect, oraparejador.
Both architects and technical architects have public liability insurance arranged through their colleges.
There is no obligation to carry insurance cover, and some professionals who are not in independent practice or have low workloads do not bother to insure.
SWEDEN

1. INTRODUCTION

The Swedish contractual situation within the building sector is standardised and well established between the various parties. In 1992 a new general regulation, called AB 92, was established (the former was AB 72).
There is a good framework for planning and maintenance of buildings during their lifetime.

2. CONTROLS

Planning regulations are tightly controlled by state and municipalities. Obtaining planning permission can sometimes delay construction for a very long period of time.
Examples of various Swedish building-regulations and codes are "Boverkets nybyggnadsregler" (regulations and general recommendations), BBK (concrete structures), BSK (steel structures), etc.
There are also state building laws covering administrative regulations and execution of construction. There are also additional laws and directives for certain types of constructions and installations.
There is a strong movement in Sweden to give the industry a higher degree of responsibility for its products and works.
In addition to compulsory special regulations for energy supply, environmental protection and mechanical services and installations, there are also industrial guidelines.
Where materials and components are not generally tested and used special government approval or test marks are required. In addition, formal quality assurance is necessary for some materials and components that are incorporated into permanent construction. Materials and components that require test marks or quality assurance are listed in relevant government regulations. Testing and approvals have to be executed by authorised bodies.

3. CONTRACTS

General

Public sector contracts always adopt specified standard forms according to the new "AB 92" (general regulations for contractual works). The principal standard form is the "AB 92".
Pre-qualification procedures are seldom used for projects in order to check capability and craftsmanship of contractors. They are now used in conjunction with restricted tender procedures and their use will increase in the next few years.

Forms of Contract

Lump Sum Contract

Unit Price Contract

Cost-plus Contract

Methods of Procurement

(a) Divided Contract
Here the client places separate contracts with the designer and several package contractors. Design and construction responsibilities are separate.
(b) General Contracting
Contracts are lump sum and fixed price with or without price adjustment.
(i) Design and construction is arranged separately by the client. The general contractor is responsible for the execution of the total scope of work and undertakes the main parts of the work himself. He also places individual packages to subcontractors. Detailed design is often the responsibility of the general contractor.
(ii) 'Design and Build' Construction
Here, the general contractor takes total responsibility for the complete design and construction. He places several individual package contracts with subcontractors and carries out the main part of the work himself.
(iii) 'Design, Build and Operate' Construction
This is an extension of 'Design and Build' Construction where the contractor is also responsible for the management of the finished building.
(c) Management Contracting
The contractor takes responsibility for all design and construction works, but does not do any work directly. The work is carried out by a series of contractors who are contractually bound to the main contractor, who fulfils the role of the client. Sometimes these contracts are on a cost plus fee basis.

4. RESPONSIBILITIES

There are generally clear divisions of responsibilities. The client is responsible for contract award, taking over as the works are completed, and payments.
Engineers are responsible for the technical input in their specialised fields such as structural design. The responsibilities cover detailed design, drawings, tendering and supervision by the rule of "YOKEL 72".
The contractor is responsible to the client for carrying out the work, warranties, maintaining programme and some aspects of detailed design and shop drawings. Sub-contractors have equal responsibilities.

5. INSURANCES AND GUARANTEES

Sometimes contractors insure against damage during construction, e.g. "Contractors all risk".
Generally, the client is offered a two-year guarantee on completion of the work. It is under discussion to establish an eight-year responsibility assurance for contracts, which is expected to increase contract costs by 1-2%.

6. FUTURE IMPROVEMENTS

Means are being sought to make contractors more responsible, see above.
More emphasis will be given to providing a practical education for designers and builders.
UNITED KINGDOM

1. INTRODUCTION

The market is well developed with suitable technical standards available. There are various routes used for building procurement depending on the size and type of building and the client preference. In the particular case of steel frames, responsibility for frame design and the detail design of connections is often split between different organisations. A Consulting Engineer is often employed for the frame design, including selection of sections, while the Fabricator will normally detail design the connections to resist the loads provided by the Designer. There are, therefore, separate contracts involved for the different operations. An increasing number of jobs are carried out through the "Design & Build" method where responsibility for the whole rests with one organisation. Some sub-contracting is normal.

2. CONTROLS

In addition to the overall requirement to obtain planning permission for the whole works, it is necessary to satisfy the Building Regulations. These regulations are administered by the local authority where the building is to be built. For structural frames, this work will involve a check of the calculations to ensure the regulations have been satisfied. This is normally achieved by conforming to the appropriate European or national standard but exceptionally, the Building Control Officer can accept alternatives.
For products for which the codes are not appropriate, test results verified by the British Board of Agreement or other reputable independent bodies, such as Universities, will usually be accepted.

3. CONTRACTS

Most structural steelwork is carried out as a subcontract to the main or management contractor. The form of contract is usually JCT 80, although many variants are used. Where the steelwork is measured, as opposed to a lump sum arrangement, then the measurement will usually be to SMM7 (RICS Standard Method of Measurement 7th edition).
One of the problems in the industry is the lack of a standard approach and contract. Care must be taken to understand the legal and technical requirements of each contract. The publication of the "National Structural Steelwork Specification" assists this process.

4. MAIN METHODS OF PROCUREMENT

The three main procurement routes are:

Traditional

In this method, the building is designed by the client's professional team who then select a main contractor who organises the work and appoints his
Sub-contractors. The sub-contractors may be pre-selected and nominated by the Design Team.

Management Contracting

In this arrangement, a Management Contractor is appointed by the client in the early phases of the work. He works alongside the Design Team and advises on the practical aspects of the design as well as ensuring this work proceeds to programme. He also appoints and manages the work of the various Sub-contractors.
The specialist Sub-contractors, of which the Steelwork Supplier is one, are responsible for the detail design, fabrication and erection of the various work packages.
The steel sub-contract includes the frame and secondary members and, depending on the type of work, the cladding, floors, hand railing, etc.

On Site Design and Build

The client provides, with professional assistance, an outline scheme and a performance specification. The remainder of the design and its construction are then put out to competitive tender.
It is the job of each tendering contractor to manage the work. The structural steel frame is usually provided by a subcontractor as before but with the additional responsibility for the frame design in addition to the normal detail design, fabrication and erection.

5. RESPONSIBILITIES

The professional team, involving architects, engineers, quality surveyors are responsible for producing the overall design of the building, How far they proceed with the detail design depends on the form of contract being employed and the types of specialist sub-contractors.
The main or management contractor is responsible for organising the work on site, safely and to programme, and for coordinating the various subcontractors. He is responsible to the client for their work.

6. INSURANCES AND GUARANTEES

There are statutory insurance requirements such as Public Liability to cover damage and injury to personnel. The completed work is subject to a contractual maintenance period, often of 12 months. After that, responsibilities are covered by the law.
Guarantees of performance, particularly corrosion of some components, are sometimes requested but are not normal.

7. FUTURE IMPROVEMENTS

The major improvements are likely to come from a less adversarial approach to construction. This change is inhibited by the litigatious attitude of Contractors and
Sub-contractors at present, and the temptation to increase profits through claims.
A greater understanding by Designers and Quantity Surveyors of modern construction and fabrication techniques would assist.

Previous | Next | Contents

ESDEP WG 1B
STEEL CONSTRUCTION:
INTRODUCTION TO DESIGN

Lecture 1B.1: Process of Design

OBJECTIVE/SCOPE

To introduce the challenge of creative design and to explain approaches by which it may be achieved.

PREREQUISITES

A general knowledge of basic applied mechanics is assumed and prior encouragement should be given to read J E Gordon's three books [1,2,3].

RELATED LECTURES

Since this lecture deals with the process of design in general terms almost all other lectures are related to it in some way. Those sections which are most closely associated with it are 1B:Introduction to Design, 14: Structural Systems: Buildings, 15A: Structural Systems: Offshore, 15B: Structural Systems: Bridges, and 15C: Structural Systems: Miscellaneous

SUMMARY

The lecture begins by considering a definition of design and some objectives. It discusses how a designer can approach a new problem in general and how a structural designer can develop a structural system. It concludes by considering differences of emphasis in design approach for different classes of structure.

1. DESIGN OBJECTIVES

The results of successful design in structural engineering can be seen and used by everyone, see Figure 1.

The question is: how can professional designers be developed and eventually produce better designs than those previously encountered, to benefit and enhance the performance of human activities? In particular how can steel be utilised effectively in structures for:

travelling more easily over awkward terrain, requiring bridges.
enabling basic industrial processes to function requiring, for example, machinery supports, docks and oil rig installations.
aiding communications, requiring masts.
enclosing space within buildings, as in Figure 2.

Design is 'the process of defining the means of manufacturing a product to satisfy a required need': from the first conceptual ideas, through study of human intentions, to the detailed technical and manufacture stages, with the ideas and studies communicated with drawings, words and models.
'Designers'? All people are capable of creative conceptual ideas - they are continuously processing information and making conscious imaginative choices, e.g. of the clothes they wear, of the activities they engage in, and the development of ideas they pursue, causing changes.
In structural design, prime objectives are to ensure the best possible:

unhindered functioning of the designed artefact over a desired life-span.
safe construction system, completed on time and to the original budget cost.
imaginative and delightful solution for both users and casual observers.

These points could possibly be satisfied by either:

simply making an exact copy of a previous artefact, or,
're-inventing the wheel', by designing every system and component afresh.

Both these extreme approaches are unlikely to be entirely satisfactory. In the former case, the problem may well be slightly different, e.g. the previous bridge may have stimulated more traffic flow than predicted, or vehicle weights may have increased. Economic and material conditions may have changed, e.g. the cost of labour to fabricate small built-up steel elements and joints has increased compared to the production cost of large rolled or continuously welded elements; also, corrosion resistant steels have reduced maintenance costs relative to mild steel. Deficiencies of performance may have been discovered with time, e.g. vibrations may have caused fatigue failures around joints. Energy consumption conditions may have changed, e.g. relating to the global discharge of certain chemicals, the cost of production of certain materials, or the need for greater thermal control of an enclosed space. Finally, too much repetition of a visual solution may have induced boredom and adverse cultural response, e.g. every adjacent building is produced in the "Post Modern Style".
With the latter approach, 'life is often just too short' to achieve the optimal solution whilst the client frets.... Civil and structural engineering projects are usually large and occur infrequently, so a disenchanted client will not make a second invitation. Realisation of new theoretical ideas and innovations invariably takes much time; history shows this repeatedly. Thus methodical analysis of potential risks and errors must temper the pioneering enthusiast's flair.
Positive creative solutions must be achieved for all aspects of every new problem. The solutions will incorporate components from the extremes above, both of fundamental principles and recent developments. However, throughout the Design Process it is prudent to maintain a clear grasp of final objectives and utilise relatively simple technical means and solutions.

2. HOW DOES THE DESIGNER APPROACH HIS NEW TASK?

At the outset of a new task an "instant of blind panic" may occur. There are a variety of Design Methods to help progress [4, 5] with the new task, but the following methodical approach is suggested:

Recognise that a challenge exists and clearly define the overall objectives for a design, see Figure 3.
Research around the task and investigate likely relevant information (Analysis).
Evolve possible solutions to the task (Synthesis).
Decide on, and refine, the best solution (Evaluation), establishing clear priorities for action (in terms of manufacture, construction, operation and maintenance).
Communicate decisions to others involved in the task.

At the outset, these five phases appear as a simple linear chain; in fact the design process is highly complex, as all factors in the design are interdependent to a greater or lesser degree. Hence there will be many steps and loops within and between the phases, as seen in Figure 4. The first rapid passage through phases 1, 2 and 3 will decide if there is 'any problem', e.g. is the likely traffic flow adequate to justify a convenient but high cost bridge?

All factors and combinations must be explored comprehensively from idea to detail, with many compromises having to be finely balanced to achieve a feasible solution. Ideas may be developed: verbally, e.g 'brainstorming' or Edward de Bono's 'lateral thinking' approaches [6], graphically, numerically or physically. Always qualitative assessment should proceed quantitative evaluation.
The starting point for Analysis may thus be the designer's current preconceived notion or visual imagination, but the Synthesis will reveal the flexibility of his mind to assimilate new ideas critically, free of preconception.
A designer can prepare himself for the compromises and inversions of thought and interaction with other members of the Design Team leading to successful synthesis, through 'Roleplay Games', e.g. see 'The Monkey House' game, in Appendix 1.

3. HOW DOES THE DESIGNER DEVELOP HIS STRUCTURAL SYSTEM?

An example of structural design, and the various decision phases, will be briefly considered for a simple two-lorry garage building with an office, toilet and tea room, shown completed in Figure 2. It is assumed in this hypothetical case that an initial decision has already been made by the client to have this set of requirements designed and built.

3.1 Pose an Initial Concept that may well Satisfy the Functions

It is invariably the best idea to start by looking at the functions (performance) required and their relationships. Make a list of individual functions; then generate a 'bubble' (or flow) diagram of relationships between different functional areas to decide possible interconnections and locations, see Figure 5. Find, or assume, suitable plan areas and minimum clear heights of each three-dimensional 'volume of space'. A possible plan layout may then be indicated, noting any particular complications of the site, e.g. plan shape, proximity of old buildings, slope or soil consistency.

Many other plan arrangements will be possible and should be considered quickly at this phase.
The requirements of each 'volume of space' and its interfaces must be examined for all functional, cost and aesthetic criteria, e.g. what structural applied live loads must be resisted; what heating, ventilating, lighting and acoustic requirements are likely to be desired, see Figure 6.

The main criteria can easily be recognised and then followed up and tested by numerical assessment. Incompatibilities may be 'designed out' by re-arranging the planned spaces or making other compromises, see Figure 7, e.g. would you accept an office telephone being very close to the workshop drill or lorry engine, without any acoustic insulation?

Prepare a set of initial assumptions for possible materials and the structural 'Frame', 'Planar' or 'Membrane' load-bearing system [7] that might be compatible with the 'volumes of space' as shown in Figure 8. These assumptions will be based on previous knowledge and understanding of actual constructions[8-13] or structural theory, see Figure 9 a, b, as well as the current availability of materials and skills. Initial consultations may be needed with suppliers and fabricators, e.g. for large quantities or special qualities of steel.

Steelwork, with its properties of strength, isotropy and stiffness, and its straight and compact linear elements, lends itself to 'Frame' systems, see Figure 9 c-e, which gather and transfer the major structural loads as directly as possible to the foundations, as a tree gathers loads from its leaves through branches and main trunk to the roots.
Next (and continuously) elucidate and test your ideas by making quick 3D sketches, or simple physical models, to explore the likely compatibility and aesthetic impact.
A range of stimulating evocative patterns viewed at different distances from, all around, and inside the buildings must be developed:

Long range	the skyline silhouette or "landscape" pattern
Middle distance	when the whole built object can be seen
Close up	when a detail is clearly seen
Very close	when the texture of the materials can be seen.

All these conditions should be satisfied, and especially for very large buildings for most of the time. Deficiencies may be made up in some people's minds if their social conditions change for the better or natural or changing phenomena occur, e.g. the rays of the setting sun suddenly give a completely different colour appearance or after sunset the interior lighting creates patterns previously unnoticed.
Form, colour, warmth and definition can be achieved with skilful use of steel, especially with "human scale" elements though repetition will soon induce boredom; but only as part of the complete sensory experience which must include elegant solutions to all aspects - especially those easily visible - of the total building design.
It is very important that all principal specialists (architects, engineers for structure and environmental services, and also major suppliers and contractors who should all have common education and understanding of basic design principles) collaborate and communicate freely with each other - also with the client - at this conceptual design phase. Bad initial decisions cannot subsequently be easily and cheaply rectified at the more detailed design phases.
Be prepared to modify the concept readily (use 4B pencils) and work quickly. Timescale for an initial structural design concept: seconds/minutes. But hours will be needed for discussion and communication with others in researching an initial complete design idea.

3.2 Recognise the Main Structural Systems and Contemplate the Necessary Strength and Stiffness

Consider the applied live loads from roofs, floors or walls, and trace the 'load paths' through the integral 3D array of elements to the foundations, see Figure 10.

If the roof is assumed to be profiled steel decking, the rainwater should run to the sides, and a manufacturers' data table will indicate both the slope angle to be provided (4° - 6° minimum) and the secondary beam (purlin) spacing required, e.g. commonly 1,4m - 2,6m. The purlins must be supported, e.g. commonly 3m - 8m, by a sloped main beam or truss, usually spanning the shorter direction in plan, and supported by columns stabilised in three dimensions.
Wind loads on the longer side of the building can be resisted by cladding that spans directly to the main columns, or onto sidewall rails spanning between columns. The columns could resist overturning by:

cross-bracing (in this case the large entry door would be impeded).
or rigidly fixing the columns to the foundation bases ("linked cantilevers"); can the soil resist the extra overturning effect at the base?
or rigidly fixing the tops of the columns to the main beams (creating 'portals') and giving smaller, cheaper "pin" base foundations.

Wind loads on the open short side of the building can be resisted by the opening door spanning top or bottom, or side to side. At the closed short side the wind loads can be resisted by cladding that either spans directly between secondary end wall columns, or onto rails to these columns.
At both ends of the building, longitudinal forces are likely to be induced at the tops of the columns. Trussed bracing can be introduced, usually at both ends of the roof plate, to transfer these loads to the tops of a column bay on the long side - which must then be braced to the ground.
Identify the prime force actions (compression C; tension T; bending B) in the elements and the likely forms of overall and element deflections for all applied loadings both separately and when combined.
It is always useful to have the elements drawn to an approximate scale, which can be done using manufacturers' data tables for decking and cladding, from observations of existing similar buildings, or using 'Rules of Thumb', e.g. the span/depth ratio for a simply-supported beam equals about 20 for uniform light roof loading, see Figure 11.

At this phase the structural design becomes more definite (use B pencil) and takes longer. Timescale: minutes.

3.3 Assess Loads Accurately and Estimate Sizes of Main Elements

Establish the dead load of the construction and, with the live loads, calculate the following, see Figure 12:

beam reactions and column loads (taking half the span to either side of an internal column).
maximum bending moments, e.g. wL²/8 for a simply supported beam, under uniform load.
maximum shearing forces in beams.
deflection values, e.g. 5/384 wL⁴/EI for a simply supported beam with uniform load.

The size of columns carrying little moment can be estimated from Safe Load Tables by using a suitable effective length. Significant bending moments should be allowed for by a suitable increase, i.e. twice or more, in section modulus for the axis of bending.
Beam sizes should be estimated by checking bending strength and stiffness under limiting deflections. Structure/service duct or pipe integration may require beams to be as shallow as possible, or deeper and with holes in the web.
Likely jointing methods must be considered carefully: is the beam to be simply supported or fully continuous and what are the fabrication, erection and cost implications?
Structural calculations are now being performed (use HB pencil with slide rule, simple calculator or computer) and the time involved is more significant. Timescale: minutes/hours.

3.4 Full Structural Analysis, using Estimated Element Sizes with Suitable Modelling of Joints, Related to Actual Details

Carry out a full structural analysis of the framework, either elastically or plastically. A computer may well be used, though some established 'hand' techniques will often prove adequate; the former is appropriate when accurate deflections are required, see Figure 13.

For the analysis of statically indeterminate structures, an initial estimate of element stiffnesses (I) and joint rigidity must be determined by the third phase above, before it is possible to find the disposition of bending moments and deflections. If subsequent checking of the design of elements leads to significant changes in element stiffness, the analysis will have to be repeated. The role of the individual element flanges and web in resiting local forces within connections must also be considered very carefully when determining final element sizes. Excessive stiffening to light sections can be prohibitively expensive.
The analysis cannot be completed without careful structural integration and consideration of the compatibility of the entire construction system including its fabrication details.
Element joints will usually be prepared in the factory using welding, with bolts usually completing joints of large untransportable elements at site. Bracings, deckings and claddings will usually be fixed on site with bolts or self-tapping screws. It is important to remember that failures most frequently arise from poor jointing, details and their integration.
The structural calculations and details are now progressing (use HB pencil with slide rule, calculators and computers). Timescale: hours/days.
Iteration of phases 1-4 above will undoubtedly be required, in particular to ensure that the early structural decisions are compatible with the subsequent investigations concerning the functional, environment, cost and aesthetic aspects. The effect of any change must be considered throughout the complete design. Changes usually necessitate a partial 're-design'.

3.5 Communicate Design Intentions through Drawings and Specifications

Prepare detail drawings and specifications for contractors' tenders, see Figure 14. Iteration of the design may again be necessary, due to variations in contractors' prices and/or preferred methods, e.g. welding equipment available, difficulties in handling steelwork in the fabricating shop or for transportation and erection. Changes and innovations in the design must be communicated and specified very carefully and explicitly.

In many cases it is common practice for a Consulting Structural Engineer to prepare preliminary designs with choice of main sections, leaving a Steelwork Fabricator to complete the detailed design and jointing system, before checking by the Consultant.
The structural design is now being finalised (use 2 to 4 H pencils and pens, or computers). Timescale: days/weeks.

3.6 Supervise the Execution Operation

Stability of the structure must be ensured at all stages of the execution, see Figure 15. High quality components and skilled erectors must be available at the right place and time, calling for very careful organisation. If 'all goes to plan' every piece will fit into the complete jigsaw.

The design ideas are now being put into operation (use gumboots). Timescale: weeks/months.

3.7 Conduct Regular Maintenance

Only regular maintenance already thoroughly planned into the design will be needed, with occasional change and renovation needed with change of use or occupation. Correction of design faults due to innovation and errors should not be needed.
This is the operation phase. (Use a serene outlook on life!) Timescale: years/decades.

3.8 Differences of Emphasis in Design Approach Compared to that of a Medium Sized Building

3.8.1 Single houses

Most "traditionally" built timber and masonry houses include some standard steel elements, e.g. hot-rolled steel beams to span larger rooms and support walls, hollow section columns for stair flights, cold-rolled lintels over window openings, stainless steel wall ties and straps, also nails, screws and truss-rafter nail plates.
Cold-rolled galvanised or stainless steel sections can be made up into truss-rafters and replace timber in repetitive conditions. Similar sections can be made up as stud walls, but fire protection of the thin-walled sections will require careful attention, especially for multi-storey houses.
A main steel structural frame may be used for houses, but integration of services, thermal control, fire protection in multi-storeys, corrosion and fabrication costs of elegant jointing must be designed appropriately. Various types of profiled or composite panel cladding can be used for the exterior.

3.8.2 Bridges

The magnitudes of gravity loading are often relatively greater in bridges, and particular load patterns need to be assessed; also trains of moving wheel loads will occur giving marked dynamic effects. Dynamic effects of wind loading are significant in long-span structures. Accessibility of site, constructability of massive foundations, type of deck structure and regular maintenance cost will govern the system adopted. Aesthetics for users and other observers are important; long distance scale should be appropriately slender but psychologically strong; careful attention is needed for fairly close viewing of abutments and deck underside.

3.8.3 Offshore oil rigs

The scale of the whole operation will be very many times that of an onshore building. Gravity loading, wind speeds, wave heights and depth of water are significant design parameters for structure size and stability (here larger elements cause larger wind and wave loads). The scale of the structure also poses special problems for fabrication control, floating out, anchorage at depth by divers and, not least, cost, see Figure 1. Later when the design life is complete, the problems of dismantling should be easy, if considered during the initial design.

4. CONCLUDING SUMMARY

This lecture introduces the challenge of creative design and suggests a holistic strategy for designing structural steelwork. It seeks to answer questions about what a designer is trying the achieve and how he can start putting pen to paper. It illustrates how a successful design is iterated, through qualitative ideas to quantitative verification and finally execution.
Creative and imaginative design of structures is most challenging and fun - now try it and gain confidence for yourself. Do not be afraid of making mistakes. They will only be eliminated by repeating and exploring many other solutions. Make sure the design is right before it is built, using your own personal in-built checking mechanisms.

5. REFERENCES

[1] Gordon, J. E. 'The New Science of Strong Materials', Pelican.
[2] Gordon, J. E. 'Structures', Pelican.
[3] Gordon, J. E. 'The Science of Structures and Materials', Scientific American Library, 1988.
[4] Jones, J. C. 'Design Methods', Wiley 2nd Edition 1981.
A good overview of general design methods and techniques.
[5] Broadbent, G. H. 'Design in Architecture', Wiley, 1973.
Chapters 2, 13, 19 and 20 useful for designing buildings.
[6] De Bono, E. eg: 'Lateral Thinking' or 'Practical Thinking' or 'The Use of Lateral Thinking', Pelican.
[7] LeGood, J. P, 'Principles of Structural Steelwork for Architectural Students', SCI, 1983 (Amended 1990).
A general introduction and reference booklet to buildings for students.
[8] Francis, A. J, 'Introducing Structures, Pergamon, 1980.
A good overview text, especially Chapter 11 on Structural Design.
[9] Lin, T. Y. and Stotesbury, S. D, 'Structural Concepts and Systems for Architects and Engineers', Wiley, 1981.
Chapters 1-4 give a very simple and thoughtful approach to total overall structural design, especially for tallish buildings.
[10] Schodek, D. L, 'Structures', Prentice Hall, 1980.
Good clear introductory approach to structural understanding of simple concepts, also especially chapter 13 on structural grids and patterns for buildings.
[11] Otto, F, 'Nets in Nature and Technics', Institute of Light Weight Structures, University of Stuttgart, 1975.
Just one of Otto's excellent booklets which observe patterns in nature and make or suggest possible designed forms.
[12] Torroja, E, 'Philosophy of Structures', University of California Press, 1962.
Still a unique source book.
[13] Mainstone, R. J, 'Developments in Structural Form', Allen Lane, 1975.
Excellent scholarly historical work, also chapter 16 on 'Structural Understanding and Design'.
APPENDIX 1'The Monkey House' roleplay game for a group of students at a seminar, Figure 16

Between 10 and 12 acting roles are created, one for each student in the group, to consider design requirements and interactions. Each actor sees an outline sketch plan of a possible building and has about 3 minutes to prepare his role's requirements, likes and dislikes. These requirements are propounded for about 2/3 minutes to his uninterrupting fellow participants, who note points of agreement/disagreement. When all actors have spoken, the many conflicts are then generally discussed and explored by the actors for about 30 minutes. Then the chairperson seeks a conclusion - who is The Monkey House really for?

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