Review Category : Structural Systems

A modified speedcore system.

The composite plate shear wall-concrete filled (C-PSW/CF) system, also referred to as the SpeedCore system, is a modular construction system where wall modules are composed of two steel faceplates, concrete infill, and tie bars connecting the face plates. While the system is somewhat similar to the system previously introduced by Corus (now TATA steel) in the early-mid 2000s and marketed in the United Kingdom (UK) as CoreFast, the SpeedCore system has significant differences from CoreFast. The key feature of the CoreFast system is that the elements are shop-fabricated using a patented friction stir welding process to connect the tie bars to the inside of the face plates, whereas SpeedCore is a nonproprietary system (Huber et al., 2021). Although CoreFast was not widely used outside of the UK, the SpeedCore system is emerging as an alternative to conventional reinforced concrete (RC) shear walls in the US. This is due to both constructability advantages for steel buildings, research undertaken by the nuclear industry, and, more recently, the research led by Purdue University and the University at Buffalo. The SpeedCore system is now addressed in the American Institute of Steel Construction’s AISC 360-22 Specification for Structural Steel Buildings, AISC 341-22 Seismic Provisions for Structural Steel Buildings.” and AISC Design Guide 38 “SpeedCore Systems for Steel Structures.” This article presents alternative approaches to connecting Speedcore modules to simplify construction.

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An Alternative to Traditional Podium Levels

Developers are always looking for new and innovative ways to make buildings more profitable and financially efficient. Traditionally, a multi-story bearing wall building over one to two levels of steel or concrete, also known as a podium structure, has filled this need by offering high-density residential units at the upper levels and parking or retail spaces at the lowest floors. For multi-story residential buildings, wood construction is generally considered the most cost-efficient form of construction, followed by cold-formed steel (CFS) bearing walls and then heavy steel or concrete framing. Because of this, developers have sought to maximize the number of wood-framed floors over the podium level before switching to more costly materials.

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Per ACI 318-19 and ASCE 7-22

This article provides background on the recognition of ductile coupled shear wall systems of reinforced concrete in ASCE 7-22 Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE 2022) Table 12.2-1, Design Coefficients and Factors for Seismic Force-Resisting Systems. The system itself is defined in ACI 318-19 Building Code Requirements for Structural Concrete (ACI 2019).

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Overview of Structural Behavior, Challenges, and Opportunities

Reciprocal frames (RF) are a family of structures that increasingly are attracting interest from many participants in the construction industry. They offer architectural opportunities through their expressive form and structural advantages due to their specific configuration. This article describes what makes this type of structure so different from other systems.

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The Role of Architectural and Structural Elements in Facility Fire-Protection Schemes

When most people think of fire protection, their minds go straight to fire alarm systems and sprinkler systems. In reality, these two systems are just small pieces of a larger puzzle. Fire protection encompasses a “system of systems” that work together to provide occupant and facility protection in a fire or other emergency. These systems often include many other building systems that are generally not at the top of mind when considering Fire Protection. For example, if a facility has duct smoke detection, HVAC controls may shut down air handling equipment to prevent the spread of smoke. In low-light environments, such as theaters and nightclubs, lighting controls that automatically turn on lights may be part of the life safety systems to ensure occupants have adequate light to evacuate. Fire-resistance-rated construction to provide compartmentation, exit separation, and protected egress paths are also part of these systems, which make up the facility’s fire-protection envelope. Other passive fire-protection systems include the facility’s structural aspects.

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Multi-unit residential construction continues to see an increasing demand for living units above a one- or two-story podium. The demand is primarily driven by maximizing residential unit density within permissible building heights for a particular construction type. Architecturally, the podium’s primary purpose is a horizontal separation between different occupancies, creating open space for parking, retail, or amenity space on the lower floor(s). Yet, for the structural engineer, the podium level is expected to transfer significant loads from the density of the program above the podium to a different structural system below. While “stick-built” construction is historically wood-framed, the prevalence of cold-formed steel is increasing the structural demands on the podium level due to the ability to construct as many as ten stories of residential (Figure 1). While the design focus is often the structural efficiency of the residential units, due consideration is required for a properly designed, detailed, and constructed podium structure.

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STRUCTURE magazine published Structural Design and Coordination of ICC 500 Tornado Shelters in July 2020, summarizing when a storm shelter is required, design criteria, and lessons learned. The authors of the July 2020 article provide guidance on design criteria, including the significantly increased basic wind speed, the increased internal pressure coefficient which presumes a breach in the building envelope, the increased directionality factor, and increased minimum roof live load, among other design criteria. To supplement the information in the previous article and illustrate the implications of storm shelter design criteria, the Table summarizes and compares wind load design parameters for a fictitious building used conventionally or as a storm shelter.

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Cross-Laminated Timber (CLT) panels are becoming increasingly common as a roof or floor deck system in mass timber buildings. The roof and floor deck systems need to be carefully engineered and detailed to serve as diaphragms resisting wind and seismic loads. The diaphragm transmits lateral loads to the vertical lateral load resisting elements – usually shear walls or braced frames.
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