BUILDING SYSTEM INTEGRATION BASIC ARCHITECTURE TUTORIALS

In theory, it is entirely possible to design and construct a building made of totally independent components. The separate pieces of such a building could be designed in isolation, each part having an autonomous role to play.

Someone who proposes this idea may note that a beam is a beam and a duct is a duct, after all, and there is no need to confuse one for the other. For every function or role to be performed in a building, there are a host of competing and individualized products to choose from. As long as the final assembly has already been worked out, the independent pieces can fulfill their single-purpose roles simply by fitting in place and not interfering with other pieces.

Most architects would quickly denounce this isolationist approach to design. Where, they would ask, is the harmony, the beauty, or even the practicality in such an absurdly fragmented method? Surely there is some sympathy and order among the parts that lead to a comprehensive whole?

Architects are, in fact, inherently prone to take exactly the opposite approach: Starting with carefully considered ideas about the complete and constructed building, they would then explore inward, working through intricate relationships between all the parts and functions. But how far does this concern for relationships go, and how inclusive is the complete idea?

Equally important, what sort of thinking is required to comprehend and resolve all the issues that arise in the process? This is where the topic and discipline of integration fits in—providing an explicit framework for selecting and combining building components in purposeful and intentional ways.

Integration among the hardware components of building systems is approached with three distinct goals: Components have to share space, their arrangement has to be aesthetically resolved, and at some level, they have to work together or at least not defeat each other. These three goals are physical, visual, and performance integration The following sections serve as a brief overview of how these goals are attained.

PHYSICAL INTEGRATION

Building components have to fit. They share space and volume in a building, and they connect in specific ways. CAD drawing layers offer a useful way to think about how complicated these networks of shared space and connected pieces can become. Superimposing structure and HVAC (heating, ventilating, and air-conditioning) layers provides an example: Are there problems where large ducts pass under beams? Do the reflected ceiling plan and furniture layouts put light fixtures where they belong?

Physical integration is fundamentally about how components and systems share space, how they fit together. In standard practice, for example, the floor-ceiling section of many buildings is often subdivided into separate zones: recessed lighting in the lowest zone, space for ducts next, and then a zone for the depth of structure to support the floor above.

These segregated volumes prevent “interference” between systems by providing adequate space for each individually remote system. Meshing the systems together, say, by running the ducts between light fixtures, requires careful physical integration. Unifying the systems by using the ceiling cavity as a return air plenum and extracting return air through the light fixtures further compresses the depth of physical space required. If the structure consists of open web joists, trusses, or a space frame, then it is possible that all three systems may be physically integrated into a single zone by carefully interspersing ducts and light fixtures within the structure.

Connections between components and among systems in general constitute another aspect of physical integration. This is also where architectural details are generated. The structural, thermal, and physical integrity of the joints between different materials must be carefully considered. How they meet is just as important as how they are separated in space.

VISUAL INTEGRATION

Exposed and formally expressive components of a building combine to create its image. This is true of the overall visual idea of the building as well as of the character of rooms and of individual elements, down to the smallest details.

The manner in which components share in a cumulative image is decided through acts of visual integration. Color, size, shape, and placement are common factors that can be manipulated in order to achieve the desired effect, so knowledge of the various components’ visual character is essential to integrating them.

Visual harmony among the many parts of a building and their agreement with the intended visual effects of design often provide some opportunities for combining technical requirements with aesthetic goals. Light fixtures, air-conditioning, plumbing fixtures, and a host of other elements are going to have a presence in the building anyway.

Ignoring them or trying to cover them with finishes or decoration is futile. Technical criteria and the systems that satisfy those functional demands require large shares of the resources that go into building. It follows that architects should be able to select, configure, and deploy building elements in ways that satisfy both visual and functional objectives.

PERFORMANCE INTEGRATION

If physical integration is “shared space” and visual integration is “shared image,” then performance integration must have something to dowith shared functions. A load-bearing wall, for example, is both envelope and structure, so it unifies two functions into one element by replacing two columns, a beam, and the exterior wall. This approach can save cost and reduce complexity if it is appropriate to the task at hand.

Performance integration is also served by meshing or overlapping the functions of two components, even without actually combining the pieces. This may be called “shared mandates.” In a direct-gain passive solar heating system, for example, the floor of the sunlit space is sharing in the thermal work of the envelope and the mechanical heating system by providing thermal storage in its massive heat capacity, which limits indoor temperature swings from sunlit day to cold starry night. The envelope, structure, interior, and services are integrated by the shared thermal mandate of maintaining comfortable temperatures.

THE USE OF PILES FOR LATERAL LOAD BEARING BASICS AND TUTORIALS

In practice one has to make a choice between the use of vertical piles used singly or in groups to carry such loads or of groups incorporating at least some piles installed to an angle of rake. The capacity of a pile as a structural unit to carry shear loads at its head depends on the strength of the section, and when the forces become high, one is impelled to find some structurally acceptable solution which keeps stresses within reasonable limits.

However, in choosing the possible option of raking piles one should be aware of the problems and limitations that may be involved. Some of the factors involved are as follows:

1 Raking piles are usually more expensive than vertical piles. This is partly involved with extra time taken to set up and maintain the equipment in position, the less efficient use of hammers in the case of driven piles, and the difficulties of concrete placing in bored piles.

2 The standards of tolerance that can be maintained in the installation of raking piles are not as good as for vertical piles. Most analyses of pile groups of this kind ignore the effect of tolerances, but if tolerances are properly taken into account they can have a significant effect on calculated pile loads, depending on pile grouping and numbers, with small groups being usually most sensitive.

3 Where the upper part of a raking pile is embedded in a soil that is likely to suffer time-dependent settlement, the pile will in due course be subject to bending stresses unrelated to the structural design load conditions. This may require increase of strength of the section, which is in turn reflected in costs.

4 Many machines used for pile installation carry the pile driving or forming equipment on a long mast, so that they become intrinsically less stable, particularly as the line of the pile gets further from the vertical position. In certain cases, when working close to river banks or railway lines, for example, there is a major limitation on how machinery can be positioned to produce the desired end result.

5 Design of groups involving raking and vertical piles and with loads that are both vertical and horizontal should have regard to the constancy of the relationship between these. If, for example, the vertical load is near constant, but the horizontal force varies greatly, then it is better to employ groupings with rakers balanced in two opposed directions rather than to have an arrangement of vertical piles plus piles raking in one direction only. This is simply to minimize the shears in the

heads of the piles when horizontal load falls to a minimum value.

6 The use of raking piles to ‘spread’ load under vertically loaded foundations, where the piles are fully embedded in the soil mass and where the whole foundation is expected to undergo significant consolidation/creep settlement, must lead to large bending stresses being developed in the piles. In certain cases this can lead to such stress levels in the piles that the section will suffer damage, which may in turn lead to severe problems in the supported structure.

It should, however, be said that where groups of raking piles derive their axial capacity from strata that are hard and relatively non-deformable, they provide a stiffness in terms of laterally applied forces which can be very desirable. The main issue in design is to avoid large and unquantifiable secondary stresses, and provided this can be achieved all will be well.

Where there are very heavy lateral loads to be carried and neither raking piles nor single piles other than perhaps those of very large diameter are suitable, then diaphragm piers or ‘barrettes’ have a useful potential application. They can be given high stiffness in the direction of applied horizontal loading without fear of the problem of major secondary stresses.