The core of these systems is to present a way of working that either prevents problems arising, or if they do arise, identifies and rectifies them effectively and cheaply. In the next section, an overview of the ISO quality system will be presented. Another culture of quality management is the dedication to continual improvement. Such a commit- ment requires accurate measurement and analysis of the performance of the processes from the viewpoint of the customer.
This can take the form of a trend chart showing the trend of the problem. Control charts are also useful to highlight out-of-control conditions. A flowchart or process flow diagram will put the problem in the perspective of the whole operation. Histograms, scatter diagrams, and pareto analysis are other tools that may be used to identify and present the problem. Mears gave a good account of these and other techniques that have been used for quality improvement.
The problem has to be analyzed to identify the root cause. A common and useful technique is the fishbone diagram, also called the cause- and-effect diagram.
This and some other improvement techniques will be presented later. The action plan and monitoring of the implementation are the other two steps to complete the improvement process as shown in Fig. The action plan describes the action to be taken, assigning responsibility and time lines. Monitoring would confirm that the conditions have improved. Quality System Underlying the concept of quality management is a quality system.
It is becoming increasingly common for the ISO Standards certification to be necessary for tendering in big projects. The Standards provide the framework for developing the quality system. ISO excludes design and is the most appropriate choice for controlling the operations of a contractor. This is also adequate to cover design and build projects, provided that the design is bought-in. ISO carries an additional clause 4. The standards only provide the key elements in a quality system.
Evidently, there can be no standardized quality system because the specific choice of quality measures depends on factors such as the main fields of activity, the operational procedures, and the size and structure of the company. Nevertheless, there is a hierarchy of documents making up the quality system see Fig. The quality manual according to Part 1 of ISO defines an outline structure of the quality system and serves as a permanent reference in the implementation and maintenance of the system.
This is supported by the procedures and instruc- tions common to the whole organization at the company level. There are also quality documentation comprising forms and checklists, procedures, and work instructions that are more project specific, in order to operate effectively in the unique circumstances of the project. A brief synopsis of some of the pertinent clauses follows. Clause 4. TABLE 7. Review is necessary to ensure the integrity of the system and continual improvement.
It describes the implementation of a quality manual and the documentation necessary to operate the system. Quality planning is also a requirement in the clause, demonstrating how the system will be implemented and consistently applied. It also comprises the quality plans that set out the required good quality practices according to the specific requirements of the contract.
It ensures that they are adequately defined and understood, and any ambiguities or contradictions are resolved. This clause also includes a docu- mentation of the results of the process.
Design and development planning, and organization and technical interfaces relate to the resources and organizational aspects of the design process. The input and output elements deal with compliance with customer and statutory requirements and mode of output.
The remaining elements relate to the management of the design, comprising design review, verification, and validation, to ensure that the design actually meets requirements and original intention, and design changes, ensuring that revisions are adequately communicated and versions are adequately recorded.
The procedures ensure that the proper documents would be used, that there would be uniform documentation, and that revisions and obsolete documents would be properly handled.
The clause covers the evaluation of subcontractors and suppliers, standardization and specification of purchasing data, and verification of the purchased product.
Related procedures must also be in place to ensure that customer client supplied services or products, including information, also comply with quality standards Clause 4.
There are related procedures controlling product identification by marking or by accompanying docu- mentation Clause 4. The remaining clauses deal with process control, inspection and testing matters, handling and storage issues, quality records, audits, training, servicing, and statistical techniques.
The servicing clause deals with after-sales service and may not be appropriate in every construction company. Quality Improvement Techniques Mistakes and problems that arise provide opportunities for learning and continual improvement. There are numerous tools that have been used in this context. These range from simple checklists, flowcharts, scatter diagrams, and pareto analysis, to fishbone diagrams and more sophisticated tools such as bench- marking, customer needs mapping, and quality functional deployment QFD.
Essentially, they collect data so that the problem can be identified and aid in finding the cause and developing solutions to improve the situation. In this section, only the fishbone diagram, customer needs mapping, and QFD will be briefly presented. The reader may refer to Mears and McCabe for other techniques available. Fishbone Diagram The fishbone diagram was first developed by Karou Ishikawa. Essentially, it is a cause and effect analysis used to identify the root causes of a particular problem.
The final diagram resembles the skeleton of a fish as shown in Fig. The ribs on the minor spines are the causes within the main areas and can make up a chain of causes. The last rib in the chain is the fundamental root cause that is specific enough to take action on. Cause and effect analysis is usually used in a brainstorming setting, in which all members of the group should be familiar with the nature of the problem.
The analysis begins with a clear definition of the problem, defining its symptom or effect. The major areas have been grouped according to the major project players. In the case of process-related problems, the major groupings can usually be categorized according to resource and methods, such as tools, components, production methods, people, and environment.
In larger operations, the groupings could include the major processes making up the whole operation. The major categories are then refined to determine the root causes.
A plan of action is then formulated based on the root causes that have been uncovered according to a priority ranking system. Customer Needs Mapping Customer needs mapping is a technique that analyzes the effectiveness of the internal processes to meet customer requirements or needs.
It is based on a matrix approach, as shown in Fig. The customer in the analysis could be an internal customer, especially in the case of support activities such as inventory control and the IT department.
The left-hand column of the matrix makes up the customer needs. An importance rating on a scale of 1 least important to 5 most important is assigned to each item. The top row of the matrix identifies the internal processes required to meet these needs.
Only the major processes are necessary so as not to be bogged down by the details of a complex operation. To complete the matrix, the effectiveness of each process in meeting customer needs is evaluated. The evaluation is obtained through customer interviews and is based on the following scale: high H , medium M , and low L. With this mapping, the quality improvement team can now identify internal processes that need to be enhanced to improve quality delivery.
A customer need with high importance is one point of focus. An internal process that is not effective in meeting any customer needs should also draw attention, for example, internal process 3 of Fig. Another benefit of the mapping is the identification of customer requirements that have been neglected, such as customer need 2. A detailed flowchart of the whole operation usually accompanies the mapping so that improvement plans can be developed as a result of the analysis.
Since then, it has gone through several stages of development and has been used in various applications, not only in manufacturing, but also in the AEC industry. QFD uses a matrix structure in the form of the house of quality see Fig. The house of quality comprises six main sections, as shown in Table 7. The product characteristics or processes are the technical counterparts that must be deployed to meet customer requirements.
These technical counterparts are often related, and their interactions are shown using symbols as shown in Fig. The relationship matrix is the main matrix of the house. It shows the relationship between the customer requirements and the technical counterparts. Symbols as shown in the figure are also used to indicate the strength of their relationships. It is usual to denote their importance on a 5-point scale where 5 represents the highest importance.
Alternatively, the analytical hierarchical approach AHP referred to in the earlier section on value engineering can be used to rank their importance Akao, This section of the house of quality also comprises the competitive evaluation of competitors to highlight their strengths and weaknesses to meet their customer needs. If a numerical score is given to the relationship matrix, the technical rankings or process importance weights can be derived as shown in Fig.
The rankings show the importance of the internal processes in achieving the quality of the finished mold for the casting crew, an internal customer of the whole precast operation. The house of quality can be modified by incorporating an improvement ratio as shown in Fig.
The technical rankings obtained in this way would have taken into consideration the current deficiencies in the technical counterparts in meeting the customer requirement. Implementation Developing a Quality System The quality system is an essential aspect of the concept of quality management.
It is not the work of an individual appointed from within the organization, in addition to their other duties, as is frequently done. The process can become too long drawn, with the accompanying consequence of loss of impetus or of even having the whole process stalled.
Otherwise, there may be a compromise on the depth of coverage, resulting in an ineffective system. It is insufficient to develop the system. Full implementation, as shown in Fig. After development, the system has to be tested before it can be implemented, and auditing is required to maintain the system. Of these phases, the analysis is perhaps most crucial in determining the success of the quality system.
Typically, the analysis will reveal deficiencies in the present organization that need to be redressed, such as procedures being ignored or modified for a variety of reasons and contradictory and outdated procedures.
Information is gathered through a combination of interviews, questionnaires, review of existing forms and documents, and observation. Effective control can be formulated only if there is sufficient depth in the analysis. Successful implementation also entails a balance of the need for knowledge of quality management and an understanding of the organization and processes.
The use of QA consultants fulfills the first requirement but falls short of the need for company knowledge. Developing a Quality Culture The other aspect of successful implementation is developing a quality culture in which everyone is encouraged to be concerned with delivering quality in his or her own work. Instead of merely adopting the quality system as the way things should be done, the quality system will have to become the way things are actually done.
Because it requires things to be done differently, a clear and strong commitment from senior management is not an option. Though it starts from the top, this quality culture must be communicated to the worker level. It also provides the mechanism for selecting quality improvement projects for developing, forming, and assisting the quality teams, and following up on their implementation. Without such a structure, good improvement ideas suggested by workers, which goes beyond a single department, are usually not followed through because of the lack of authority.
Typically, the council is headed by a senior VP of the organization. Another necessary change is realizing employee participation because such quality initiatives may require the workers to change the way things are done. Along with this is the concept of employee empowerment. Clutterbuck also suggested some techniques for empowerment.
Employee empow- erment is an important key to continuous improvement because they are most involved in line operations and would be most familiar with problems. Quality circles Lillrank and Kano, center on the line workers whose day-to-day observation of the process is crucial to continuous improvement. There are overlaps in their objectives, but their approaches are distinct. Nevertheless, to achieve any significant success, the implementation of any of these concepts must be strongly supported by senior management of the organization and communicated through the organization.
Moreover, they cannot be practiced on an ad-hoc basis. A corporate program with clear policies has to be developed, wherein employee activities are integrated into the other activities of the organization.
It has been demonstrated that the application of these concepts will lead to great benefits to the organization, such as reduced costs, increased value, better designs, improved performance, and enhanced quality. Before concluding this chapter, there should be a brief mention of lean construction, which is an emerging concept also focused on value improvement.
The concepts of lean construction are applicable to design and field operations and are based on the new production philosophy in manufacturing that has been called by various terms, such as lean production, just-in-time JIT , and world class manufac- turing. It is believed that just as the new production philosophy has made significant impact on produc- tion effectiveness and has led to dramatic changes in production management in manufacturing, lean construction can have similar effects in the construction industry.
The new production philosophy originated from plant floor developments initiated by Ohno and Shingo at the Toyota car factories in Japan in the s, but only analyzed and explained in detail in the s. It was only in that the possibility of applying this new production philosophy in construction was mooted and put into a report Koskela, Since then, the application of this philosophy in construction has been termed lean construction.
Many of the concepts are still in their germination stages, but they are generally based on adopting a flow production view of construction instead of the traditional activities perspective. By focusing on the flow of production, the nonvalue activities can be identified and minimized, while the value adding activities can be enhanced Koskela, Each licensed professional who seals a work product shall be the Professional of Record POR for the work product bearing the seal.
A change or modification to a work product that requires a POR seal must be approved by the POR or an authorized licensed professional who will be responsible for the change. Changes not requiring approval of a licensed professional are not covered under this policy. Your browser is out-of-date! It has known security flaws and may not display all features of this and other websites.
Learn how. Skip to main content. Translate this page. These constraints, however, can lead to poor cost and value ratios, and if left unchallenged, can lead only to suboptimal solutions. In a project for the construction of a wafer fabrication multistory building, for example, the process engineer laid out their process plans for the various floors. The sub-fab facilities were arranged so precariously on one of the floors that the main fabrication area above this level could not be laid out symmetrically with respect to the building.
As customary, this was presented as a constraint to the structural engineers and vibration consultants of which the author was a member. The objective of the design was a waffle floor system that would ensure that the vibration level in the main fabrication area under ambient conditions would not exceed some extremely low threshold criteria with velocity limits not exceeding 6.
With the original layout, the design would demand some elaborate system of beam girders to take advantage of the shear walls at the perimeter because no shear walls are allowed in any area within the perimeter and still would suffer from unnecessary torsional rotation due to the eccentricity of the floor system. It was only after several deliberations that the process engineers finally agreed to modify their layout so that a symmetric design could be accommodated.
This resulted in significant savings in terms of con- struction costs and improved vibration performance. It is common that the initial specifications conflict with basic function of the design, which in this case, is a vibration consideration, leading to poor and expensive solutions, if left unchallenged.
Just as the extent of solutions can be curtailed if some poorly defined constraints are left unchallenged, the scope of alternatives can also be severely limited if the value engineering team comprise only the same designers of the system. These designers become so intimate with their designs that they fail to detect areas of unnecessary costs.
The approach is to form a multidiscipline team that cuts across the technical areas of the study, comprising one or two members in the major discipline with the others in related fields. In this way, the alternatives tend to be wider ranging and not limited by the experience of a single group. Greater consideration can also be given to the impact of these alternatives on the system as a whole.
As with any program, the VE program has to be well managed with the support of top management in all practical ways. Visible support will entail their presence in many of the review meetings of VE projects, their support with the necessary budget and staff training and participation, and their time to discuss problems associated with the program and implementation of the alternatives.
In the construction industry, it is usual to place the VE group with the purchase or design function of the organization. The success of the VE program also largely depends on the leader of the VE group. Nevertheless, he must be able to follow organizational culture to gain acceptance of management and colleagues, yet has to have the necessary qualities to bring about changes for the better.
His ability to control the dynamics of the group is important if he is to initiate and direct the program successfully. It is also not merely making construction methods more efficient after the project has been mobilized.
Instead, the concept of constructability arises from the recognition that construction is not merely a production function that is separated from engineering design, but their integration can result in signif- icant savings and better project performance.
Construction input in design can resolve many design- related difficulties during construction, such as those arising from access restrictions and incompatible design and construction schedules.
Construction input includes knowledge of local factors and site conditions that can influence the choice of construction method and, in turn, the design. The effects of an engineering bias to the neglect of construction input are discussed by Kerridge The highest ability to influence cost comes at the conceptual phase, where the decisions at that time could greatly affect the project plan, site layout and accessibility, and the choice of construction methods.
Full integration will require that the contractor or construction rep- resentative be brought into the project team at the same time as the designer. Thus, the choice of the contractual approach can be critical in determining early construction involvement in a project.
Another important consideration for meaningful construction input to design is the commitment to preconstruction planning. Conceptual Planning The key issues in this phase relate to evaluating construction implications to project objectives, developing a project work plan, site layout, and selecting major construction methods Tantum, Construction-related issues at this stage can have major impacts on budget and schedule.
The project objectives must be clearly established so that alternatives in various decisions can be effectively evaluated.
The implications from the construction perspective may not be readily apparent to the planning team, unless there is a member experienced in field construction. An effective work plan requires that work be adequately packaged and programmed so that design information and essential resources and materials required for each package can arrive in a timely fashion.
Without construction input, the packaging and availability of design may not allow desirable work packaging or construction sequence. Moreover, the problems or opportunities from local factors and site conditions may be missed. Construction knowledge is also necessary for developing a feasible schedule. It is usual for the building and site layouts to be determined solely on plant, process, and business objectives. Too often, construction implications are not considered with resulting severe limitations on construction efficiency due to inadequate space for laydown areas, limited access, and restrictions on choice of construction methods.
Construction knowledge is essential in the selection of major construction methods that will influence the design concepts. The possibility of modularization and the degree of prefabrication, for example, are construction issues that must be considered in this early stage.
Engineering and Procurement The following are some key ideas that are generally applicable for guiding the constructability initiatives during the engineering and procurement phase of the project. With respect to design per se, the general principle is to provide design configurations and concepts that reduce the tasks on site, increase task repeatability, and incorporate accessibility. This will reduce unnecessary delays in the field caused by resource and information unavailability.
Boyce presented some inter- esting principles in this aspect of designing for constructability. This will lead to fewer errors in the field, improved productivity through repetitive work, and advantages in managing the supply chain of fewer differing components. Focus instead is given to delivery, lifting, and assembly in the field. An accessibility checklist may be useful for this.
Computerized simulation CAD models are also used in this regard. Field Operations There are constructability issues remaining during field operations.
These pertain to task sequencing and improving construction efficiency and effectiveness. Contractors can still reap the benefits of constructability, which can be quite substantial if the decisions are taken collectively. Many innovations have been made in the use of temporary construction systems, use of hand tools, and construction equipment.
The advantages have been obvious: reduced erection and setup times, improved quality in products delivered, and increased construction productivity in related tasks. Many construction problems on site can be resolved quite easily with proper task sequences. Tasks can be better sequenced to minimize work site congestion with its consequent disruptions of work. Unnecessary delays can be avoided if tasks are properly sequenced to ensure that all prerequisites for a task are available before commencement.
Effective sequencing can also take advantage of repetitive tasks that follow each other for learning-curve benefits. Sharing of equipment and systems is also an important consideration in tasks sequencing. Implementation As in all value methods, to be effective, constructability has to be implemented as a program in the organization and not on an ad-hoc basis.
In this program, the construction discipline, represented by constructability members, becomes an integral part of the project team and fully participates in all design planning decisions.
A special publication prepared by the Construction Industry Institute Constructability Implementation Task Force CII, presented a clear step-by-step roadmap to provide guidance for implementing the constructability program at the corporate and project levels. Although there cannot be a single unique constructability program that can suit all companies, invariably, the commitment to a constructability program must come from senior management and be communicated clearly through the organization.
Successful and consistent implementation also requires a single point executive sponsor of the program, whose primary role is to promote its awareness and to be accountable for its success. Another important consideration in the program is to adopt a forward integration planning approach, rather than a backward constructability review of fully or partially completed designs. In the latter approach, the constructability team is excluded from the design planning process, thus preventing early construction input integration.
Any changes to be made after the review will usually be taken in an adversarial perspective, in which the designer becomes defensive and takes them to be criticisms. More- over, the design reworks are unnecessary and make the process inefficient and ineffective.
In the forward integration as shown in Fig. The outcome is obvious: improved design quality and reduced design reworks. As depicted in Fig. The first contains the feedback on the constructability program documenting specific lessons learned along the way. When the project terminates, each functional design should be evaluated and added to the lessons-learned file.
The discussions of constructability concepts can be guided by a checklist of the constructability concepts at each phase or by using a Constructability Applications Matrix see Fig. More ideas for constructability can also be obtained from suggestions by other personnel involved in the project. The project constructability team leads the constructability effort at the project level. The construc- tability team comprises the usual project team members and additional construction experts. If the contractor has not been appointed, an appropriate expertise with field experience has to be provided.
The specialists, for example, rigging, HVAC, electrical, and instrumentation, are only referred to on an ad-hoc basis, when their area of expertise is needed for input. A constructability coordinator is also needed, whose role is to coordinate with the corporate constructability structure and program.
Before concluding this section on constructability, it is important to realize that constructability is a complex process, and the constructability process itself is unstructured. Four-dimensional models McKinny and Fischer, , that is, three-dimensional CAD models with animation, are pro- viding the visualization capabilities to enhance communication between the designers and the construc- tors. Other models have also been developed for various aspects of constructability, for example, a constructability review of merged schedules checking for construction space, information, and resource availability Chua and Song, , and a logical scheduler from the workspace perspective Thabet and Beliveau, Specifications are written into contracts to ensure that the owner gets from the main contractor a product with the type of quality he envisaged.
Being able to deliver this is not something that can be left to chance. It will require management. Quality management has progressed through four stages, beginning with inspection and quality control QC , and has now arrived at quality assurance QA and total quality management TQM Dale et al.
Inspection is the activity that assesses by measurement or testing whether an element has con- formed to specifications. Corrective work is then ordered to rectify any nonconformance in the element. QC builds upon the inspection efforts and relies largely on statistical techniques to determine trends and detect problems in the processes. Such techniques are being used routinely in manufacturing.
With respect to the construction industry, concrete cube testing is one rare example. Instead of merely detecting the errors for remedial measures, QA and TQM are based on a quality system, with the objective of reducing and ultimately eliminating their occurrences. The customer perspective in TQM is derived from the process viewpoint. At every stage of a process, there are internal customers.
They belong to the group of people who receive some intermediate products from another group. For example, in an on-site precast operation depicted in Fig. The mold crew is the internal customer of the assembly process.
In turn, the casting crew is the internal customer of the mold assembly process, while the Land Transport Authority is the external customer of casting. Each of these crews will require that the intermediate product they receive meets the quality standards to avoid rework. The concept of internal customers ensures that quality permeates through the total operation, and thus by addressing the internal processes in this way, total quality improvement can be achieved. To ensure that customers get what they want, there is a need to fully understand their requirements and to communicate this throughout the organization.
This is at the heart of quality management and is the goal of the quality system. The quality system comprises quality manuals providing the templates to guide the worker in the performance of each particular task. These templates ensure management that proper work has been performed and provide confirmation to the owner that the work has met his requirements.
The core of these systems is to present a way of working that either prevents problems arising, or if they do arise, identifies and rectifies them effectively and cheaply. In the next section, an overview of the ISO quality system will be presented. Another culture of quality management is the dedication to continual improvement.
Such a commit- ment requires accurate measurement and analysis of the performance of the processes from the viewpoint of the customer. This can take the form of a trend chart showing the trend of the problem. Control charts are also useful to highlight out-of-control conditions. A flowchart or process flow diagram will put the problem in the perspective of the whole operation. Histograms, scatter diagrams, and pareto analysis are other tools that may be used to identify and present the problem.
Mears gave a good account of these and other techniques that have been used for quality improvement. The problem has to be analyzed to identify the root cause. A common and useful technique is the fishbone diagram, also called the cause- and-effect diagram. This and some other improvement techniques will be presented later. The action plan and monitoring of the implementation are the other two steps to complete the improvement process as shown in Fig. The action plan describes the action to be taken, assigning responsibility and time lines.
Monitoring would confirm that the conditions have improved. Quality System Underlying the concept of quality management is a quality system. It is becoming increasingly common for the ISO Standards certification to be necessary for tendering in big projects. The Standards provide the framework for developing the quality system.
ISO excludes design and is the most appropriate choice for controlling the operations of a contractor. This is also adequate to cover design and build projects, provided that the design is bought-in. ISO carries an additional clause 4.
The standards only provide the key elements in a quality system. Evidently, there can be no standardized quality system because the specific choice of quality measures depends on factors such as the main fields of activity, the operational procedures, and the size and structure of the company.
Nevertheless, there is a hierarchy of documents making up the quality system see Fig.
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