Steel frame construction methods and applications

Steel Frame Construction

Bibliography and Further Information

Appendix a An Analysis of the Selection, Application or Installation of Materials and Building Components Used in Steel Frame Construction Today

An increasing number of commercial and residential structures are using steel frame construction techniques today. The increased popularity of this building technique has grown from its early beginnings in Chicago a century and a half ago to become the building method of choice for many urban settings today. This increased use is directly attributable to a number of key advantages that steel frame construction has been shown to have over other construction techniques. For example, according to Fanjoy (2006), "While a versatile building material, lumber can pose a number of challenges to builders and remodelers: sudden and sizeable fluctuations in price, for example, or rot and dimensional instability due to exposure to moisture, either at the building site or after installation. But there is an alternative: steel framing" (3). This author reports that steel frame construction provides a number of advantages over other construction techniques, including its relative stable price, high strength and durability, light weight, minimal waste and resistance to infestation and rot; the installed cost of steel framing, though, is typically higher because of increased labor and other installation factors (Fanjoy 4). Because resources are by definition scarce, it is therefore important to recognize when and where steel frame construction is an appropriate choice, and what factors should be taken into account when making this determination.

Purpose of Study.

The purpose of this study is to develop a best practices model for the selection and application or installation of materials and building components for steel frame construction purposes based on a critical review and analysis of the relevant peer-reviewed and organizational literature.

Importance of Study.

Beyond the need to ensure that a building conforms to a wide range of regulatory requirements from federal, state and local authorities, there is a more fundamental need to meet the needs of all stakeholders in the construction of new buildings in the United States today. In most cases, these stakeholders include virtually every resident in a given municipality, and given the economic impact of high rise buildings in particular to the national and global economy (witness the World Trade Center destruction of September 11, 2001), identify appropriate building materials and construction techniques for steel frame construction purposes has assumed increasing importance today.

Scope of Study.

The primary focus of this study will remain on contemporary applications, properties, strengths and limitations of steel frame construction techniques, based on the theory that emerged from the technique's early beginnings with the Home Insurance Building in Chicago (see graphic at Appendix A) to identify driving forces behind innovations and alternative construction techniques. The scope of the study will be defined by the following research questions:

What is the guiding theory behind steel frame construction today?

What is the current code of standard practice for steel frame construction?

What are the material selection considerations that should be taken into account?

What are the primary strengths of steel frame construction?

What are the primary limitations of steel frame construction?

Rationale of Study.

While every construction setting is unique, it is possible to identify some best practice guidelines to determine when and why steel frame construction techniques are a superior choice, and to use these guidelines as a starting point for further analysis and development.

Overview of Study

This study employed a three-section approach to Section 1 provides an introduction to the topic under consideration, a statement of the problem, the purpose of the study and its importance, as well as the study's scope and rationale. Section 2 provides a description of the research methodology used and why it was selected, and Section 3 provides a discussion and analysis of the material developed during the research process. A bibliography and sources for additional reading are followed by an appendix with relevant graphics.

Section Two: Methodology

Overview of Section Two.

This section provides a discussion of the research design and sample, the data analysis technique used, and a description of steps taken to ensure the reliability and validity of the approach; in addition, a discussion of the assumptions and limitations of the methodology for the study is followed by a summary of the chapter.

Research Design.

A review of the available research methodologies indicated that a grounded theory approach using a critical review of relevant peer-reviewed, organizational and governmental resources would provide the best well-rounded answers to the above-stated guiding research questions. In this regard, Wood and Ellis (2003) identified the following as important outcomes of a well conducted literature review in a construction industry context:

It helps describe a topic of interest and refine either research questions or directions in which to look;

It presents a clear description and evaluation of the theories and concepts that have informed research into the topic of interest;

It clarifies the relationship to previous research and highlights where new research may contribute by identifying research possibilities which have been overlooked so far in the literature;

It provides insights into the topic of interest that are both methodological and substantive;

It demonstrates powers of critical analysis by, for instance, exposing taken for granted assumptions underpinning previous research and identifying the possibilities of replacing them with alternative assumptions;

It justifies any new research through a coherent critique of what has gone before and demonstrates why new research is both timely and important.

The literature review proceeded using a number of sources, including university and public libraries, as well as reliable online sources such as EBSCO, Questia, federal governmental Web sites and where appropriate, organizational Web sites of major national and international building materials suppliers and vendors. Searches for relevant material in these settings included the use of phrases such as "steel frame construction," "building material selection criteria," "cold formed," etc. In addition, serendipitously identified resources were incorporated where appropriate.

Summary of Research Findings.

The research showed that steel frame construction techniques have evolved from their beginnings with the Home Life Building in Chicago in the mid-19th century to a wide range of commercial and residential structures today. The research was consistent in showing that the choice of steel framing can provide a number of advantages over other construction techniques, but there are some constraints to its use as well as some cost factors that must be taken into account when making the decision to use one construction approach over another. Finally, the research showed that unless specified to the contrary in the construction contract documents, the trade practices defined in the American Iron and Steel Institute Committee on Framing Standards Code of Standard Practice for Cold-Formed Steel Structural Framing control the design, fabrication and installation of cold-formed steel structural framing in the United States (Code of Standard Practice for Cold-Formed Steel Structural Framing 10).

Section Three: Discussion and Analysis

Theory.

The theory behind steel frame construction has become accepted practice today, and is based on the fundamental concepts first identified through the construction of the world's first skyscraper, the Home Insurance Building in Chicago (Pietig 177). According to this author, "The innovative method of support used to construct this building eliminated the need for foundations, and thus he suggests a new metaphor for teacher education: What was remarkable about it was that this ten-story skyscraper did not rest on a firm foundation. The architects invented a new form of support. Instead of heavy foundations and bearing walls, they built a steel skeleton, a scaffolding that was internal to the building" (Pietig 178). Contractors initially erected the scaffolding, and then effectively hung the skyscraper on that steel frame skeleton. "That system of girders and skeletal scaffolding remains to this day the technology for building skyscrapers. It is much more powerful than a solid foundation because it is integral to the structure. It weaves itself through it; it becomes part of the very structure it is trying to support" (Pietig 178).

In a report by Marsden (2005), the point is made that the Home Insurance Building was actually the product of two events, the Great Chicago Fire of 1871 and the invention of the elevator. "On the evening of Sunday, October 8, 1871, a fire began in Chicago which burned so fiercely that it took several days before it was brought under control. Almost 300 people were killed and 100,000 made homeless as 18,000 buildings were destroyed. The city fathers decided that the city would rise again, only this time more emphasis would be placed on building regulations" (Marsden 78). The engineer responsible for developing the theory behind the first steel frame construction was former Civil War Union Army engineer Major William Le Baron Jenney (1832-1907) (Marsden, 78).

According to Marsden, "While designing the 138-foot, ten-story Home Insurance Building, he incorporated a steel frame construction for the top four floors - thus enabling the building to be taller than normal for the city and inadvertently building the world's first skyscraper. This enthused many other architects, who soon began constructing most of their buildings with steel frame skeletons" (78). According to Montgomery (2003), "Higher floors of buildings tended to rent at a substantial discount, due to the need to climb several flights of stairs to reach one's workplace or residence. Otis's invention of the safety elevator at mid-century heralded the end of this constraint on vertical real estate development" (495). Likewise, Masden notes that the increasingly confident use of the relatively new ' elevators' also fueled demand for more steel frame structures; such new steel-framed buildings were known during this early period as "elevator buildings" instead of skyscrapers, a term that was first coined in 1883 (Marsden 78).

The underlying theory behind steel frame construction during its early use, though, fueled some well-intentioned but misguided efforts that adversely influenced future applications, selection of building materials, site selection and other salient factors involved in construction. In this regard, Mumford (1959) reports that, "Unfortunately, the skyscraper was an almost automatic response to land speculation: mechanization was subservient to the desire to achieve profitable congestion; and the architects as a profession did not oppose with any conception of public interests the private and shortsighted rapacity of the businessman" (20). The fact that most of these early steel frame projects were as effective as they were in their respective settings appears to be a matter of good fortune rather than any predetermined effort by the design team: "The architects of Chicago were technically adventurous, but socially timid: since they cheerfully accepted land speculation and congestion as if they were laws of nature, it was only by a happy accident that their site plans would turn out to be sound" (Mumford 20). By sharp contrast, steel frame applications today must take into account all of these factors as well as many more that have emerged in recent years in support of a unified building code and efforts to minimize new construction's impact on the environment continue to gain momentum and some of these initiatives are described further below.

Applications.

According to Montgomery (2003) "A revolution in building techniques was under way due to steel-frame construction methods, new fire-resistant technologies, and related innovations, paving the way for the construction of far taller buildings" (495). The development of new technologies for the construction of steel frame buildings resulted in a number of such structures in various sections of the city. Over the years, higher steel-frame buildings were built with many in Chicago; for example, the Masonic Temple (1892) of Daniel Burnham and John Root in Chicago reached 22 stories (91 meters or 302 feet); however, New York City also sported a 26-story Manhattan Life Building by 1894 (Swenson and Chang 82). The Singer Building (1907) designed by architect Ernest Flagg reached 47 stories (184 meters or 612 feet), and Cass Gilbert's Woolworth Building (1913) reached a height of 238 meters (792 feet) at 55 stories (Swenson and Chang 82). Relegated to the second-tallest building in New York until 2001, Shreve, Lamb & Harmon's 102-story steel-frame Empire State Building (1931) was an enormous 381 meters (1,250 feet) (Swenson and Chang 82). The Great Depression and World War II, though, stopped most efforts at steel frame construction until the late 1940s (Swenson and Chang 82).

Thereafter, steel frame construction applications took on some alternative configurations that no longer focused strictly on height that changed many of the structural and building component requirements. For example, in Volume 2 of his work, Encyclopedia of 20th Century Architecture, Stennott (2004) reports that the first work commissioned to Ludwig Mies van der Rohe (1886-1969) in the United States was the campus of the Illinois Institute of Technology (IIT) in Chicago. According to Stennott, this building.".. represents the fullest embodiment of modernist planning principles applied to the renovation of the city at mid-century. The campus is also notable as a site for Mies' development of industrial building techniques in the service of modernist spatial principles. Ultimately, IIT's most enduring significance is as a site for the direct architectural expression of steel-frame construction applied across scales from the individual structural member to the overall urban plan" (667). This author suggests that the entire campus and accompanying 22 original structures completed by Mies between 1939 and 1956 represent the seminal works of 20th-century architecture and planning in the Western Hemisphere (Stennott 667).

Mies' final plans for the larger campus as partially implemented by 1940 used a 24-by-24-foot steel frame planning module as an organizing element for the entire site (Stennott 667). According to Stennott, "The 24-foot dimension was selected for its economy and utility as a structural spanning dimension in steel-frame construction as well as its flexibility as an interior-planning dimension for classrooms, offices, and labs. This modular dimension system related interior and exterior spaces and ensured the integration of individual building components, such as columns and beams, with the overall planning strategy of the campus" (667). The first building completed on the campus was the Minerals and Metals Research Building (1942-43); this project demonstrated Mies' focus on articulating a language of building construction that was based on the expression of the structural steel frame (Stennott 667).

According to Stennott, "The precise relation of steel column, fireproofing, representational steel mullion, brick panels, and glass curtain wall posed a series of architectonic and technical questions that Mies and architects of the Second Chicago School would work to articulate and solve for three decades" (667). Subsequent work for the unrealized Library and Administration Building Project (1944) extended this research to Mies' continuing interest in using steel frame construction techniques for spanning lengthy spaces; these first two projects developed the repertoire of regularly dimensioned steel-frame buildings that would influence the Institute Buildings (1945) as well as the exceptionally proportioned long-span structures that characterized Mies' work (Stennott 667). According to Stennott, Mies' masterpiece, Crown Hall (1950-56), was designated a National Historic Landmark in 2001 and is shown in Figure 1 below (667).

Figure 1. Crown Hall (1956), Illinois Institute of Technology.

Source: Stennett 668.

Crown Hall was conceived as a single interior volume completely enclosed by glass and devoid of any interior structural members. As an expression of direct construction, the clarity of its spatial volume and subtlety of its structural system reinforce each other to produce the site's single most powerful architectonic statement and one of Mies' most important works. In a series of significant deviations from the majority of buildings on the campus, Crown Hall was developed as a hierarchically important exception to, as well as an ultimate reinforcement of, Mies' overall strategy for the campus and has been considered his most valued commission at IIT (Stennott 667).

Following the development of the curtain wall, new forms of structure appeared in high-rise buildings in the mid-20th century that used steel frame construction to its maximum advantage; other innovations in technology and their added expense both fueled the drive toward steel frame construction as well efforts to minimize the costs associated with these techniques. For example, environmental control systems increased in cost, economic pressures worked to produce more efficient structures (Swenson and Chang 82). Likewise, the 60-story Chase Manhattan Bank Building, designed by Skidmore, Owings & Merrill and constructed in 1961, had a standard steel frame with rigid portal wind bracing, which required 275 kilograms of steel per square meter (55 pounds of steel per square foot), almost the same as the Empire State Building of about 30 years earlier (Swenson and Chang 82).

Today, the following categories in Figure 2 represent the primary steel frame applications in use throughout the United States and reflect the rapid growth in popularity of these techniques in recent years.

Figure 2. Steel Framing by Application: 1997-2002.

Source: Based on data in Fanjoy 6.

Properties.

Properties of economy of structure in tall buildings was demonstrated early on with the John Hancock Building in Chicago in 1970; this building used a system of exterior diagonal bracing to form a rigid tube devised by the engineer Fazlur Khan (Swenson and Chang 82). While the Hancock building is 100 stories, or 343 meters (1,127 feet), high, its structure is so efficient that it required only 145 kilograms of steel per square meter (29 pounds per square foot) (Swenson and Chang 82). The framed tube that Khan developed for concrete structures was also applied to other tall steel buildings; for instance, Khan used a steel system of nine bundled tubes of different heights -- "each 22.5 meters (75 feet) square with columns spaced at 4.5 meters (15 feet) -- "to form the structure of the 110-story, 442-metre (1,450-foot) Sears Tower (1973), also in Chicago (Swenson and Chang 82).

Today, unless otherwise specified to the contrary in the contract documents, the trade practices that are defined in the American Iron and Steel Institute Committee on Framing Standards Code of Standard Practice for Cold-Formed Steel Structural Framing [Code of Standard Practice] govern the design, fabrication and installation of cold-formed steel structural framing in the United States (Code of Standard Practice for Cold-Formed Steel Structural Framing 10). For example, the Code of Standard Practice codifies the requirements for lateral force resisting systems: "The design responsibilities of the structural engineer-of record include but are not limited to design of roof/floor diaphragms, lateral load transferring elements (sometimes referred to as shear transfer bracing), main lateral force resisting elements and foundations, as well as compliance of the overall structure with applicable building codes" (Code of Standard Practice 16). Furthermore, in those cases where the design of lateral load transferring elements is to be performed by a specialty designer or component designer, the structural engineer-of-record is required to specify the following: