Engineering and Construction

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During the CD stage, the architect and consultants prepare their own sets of drawings, referred to as   construction drawings . Thus, a project has architectural construction drawings, civil and structural construction drawings, MEPF construction drawings, landscape construction drawings, and so on.

Construction drawings are dimensioned drawings (usually computer generated) that  fully delineate the building. They consist of floor plans, elevations, sections, schedules, and  various large-scale details. The details depict a small portion of the building that cannot be  adequately described on smaller-scale plans, elevations, or sections.    

Construction drawings are the drawings that the construction team uses to build the  building. Therefore, they must indicate the geometry, layout, dimensions, types of materials, details of assembling the components, colors and textures, and so on. Construction drawings are generally two-dimensional drawings, but three dimensional isometrics are sometimes used for complex details. Construction drawings are also used by the contractor to prepare a detailed cost estimate of the project at the time of bidding.

Construction drawings are not a sequence of assembly instructions, such as for a bicycle. Instead, they indicate what every component is and where it will be located when the building is completed. In other words, the design team decides the “what” and “where” of the building. The “how” and “when” of the building are entirely in the contractor’s domain.

NOTE

Working Drawings and Construction Drawings The term working drawings was used until the end of the  twentieth century for what are now commonly referred to as construction drawings.

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Once the schematic design is approved by the owner, the process of designing the building in greater detail begins. During this stage, the schematic design is developed further—hence the term   design development  (DD) stage.

While the emphasis in the SD stage is on the creative, conceptual, and innovative aspects of design, the DD stage focuses on developing practical and pragmatic solutions for the  exterior envelope, structure, fenestration, interior systems, MEPF systems, and so forth.

This development involves strategic consultations with all members of the design team. Therefore, the most critical feature of the DD stage is decision making, which may range  from broad design aspects to details. At this stage, the vast majority of decisions about  products, materials, and equipment are made. Efficient execution of the construction documents depends directly on how well the DD is managed. A more detailed version of the specifications and probable cost of the project is also prepared at this stage.  

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The schematic design gives graphic shape to the project program. It is an overall design concept that illustrates the key ideas of the design solution. The major player in this stage is the architect, who develops the design scheme (or several design options) with only limited help from the consultants. Because most projects have strict budgetary limitations, a rough estimate of the project’s probable cost is generally produced at this stage.

The schematic design usually goes through several revisions, because the first design scheme prepared by the architect will rarely be approved by the owner. The architect communicates the design proposal(s) to the owner through various types of drawings—plans, elevations, sections, freehand sketches, and three dimensional graphics (isometrics, axonometrics, and perspectives). For some projects, a three-dimensional scale model of the entire  building or the complex of buildings, showing the context (neighboring buildings) within which the project is sited, may be needed.

With significant developments in electronic media technology, especially building information modeling (BIM), computer-generated imagery has become common in architecture and related engineering disciplines. Computer-generated walk-through and flyover simulations are becoming increasingly popular ways of communicating the architect’s  design intent to the owner and the related organizations at the SD stage.

It is important to note that the schematic design drawings, images, models, and simulations, regardless of how well they are produced, are not adequate to construct the building. Their objective is merely to communicate the design scheme to the owner (and to consultants, who may or may not be on board at this stage), not to the contractor.

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The    design phase   begins after the selection of the architect. Because the architect (usually a firm) may have limited capabilities for handling the broad range of building-design activities, several different, more specialized consultants are usually required, depending on the size and scope of the project.

In most projects, the design team consists of the architect, civil and structural consultants, and mechanical, electrical, plumbing, and fire-protection (MEPF) consultants. In complex projects, the design team may also include an acoustical consultant, roofing and waterproofing consultant, cost consultant, building code consultant, signage consultant, interior designer, landscape architect, and so on.

Some design firms have an entire design team (architects and specialized consultants) on staff, in which case the owner will contract with a single firm. Generally, however, the design team comprises several different design firms. In such cases, the owner typically contracts the architect, who in turn contracts the remaining design team members,  Figure 1.1. Thus, the architect functions as the prime design professional and, to a limited degree, as the owner’s representative. The architect is liable to the owner for his or her own work and that of the consultants. For that reason, most architects ensure that their consultants carry adequate liability insurance.

FIGURE 1.1 Members of a typical design team, and their interrelationships with each other and the owner in a traditional contractual setup. A line in this illustration indicates a contractual rela- tionship between parties. (“MEPF consultants” is an acronym for mechanical, electrical, plumbing and fire consultants.)

In some projects, the owner may contract some consultants directly, particularly a civil consultant (for a survey of the site, site grading, slope stabilization, and site drainage), a geotechnical consultant (for investigation of the soil properties), and a landscape architect (for landscape and site design),  Figure 1.2   . These consultants may be engaged before or at the same time as the architect.  

FIGURE 1.2 Members of a typical design team, and their interrelationships with each other and the owner in a project where some consultants are contracted directly by the owner. A solid line in this illustration indicates a contractual   relationship between parties. A dashed line indicates a communication link, not a contract.

Even when a consultant is contracted directly by the owner, the architect retains some liability for the consultant’s work. This liability occurs because the architect, being the prime design professional, coordinates the entire design effort, and the consultants’ work is influenced a great deal by the architectural decisions. Therefore, the working relationship between the architect and an owner-contracted consultant remains essentially the same as if  the consultant were chosen by the architect.

In some cases, an engineer or another professional may coordinate the design process.

This  generally occurs when a building is a minor component of a large-scale project. For example, in a  highly  technical project such as a power plant, an electrical engineer may be  the prime design professional.

In most building projects, the design phase consists of three stages:

  •     Schematic  design   stage
  •     Design  development   stage
  •     Construction  documents   stage