Precast Concrete Moment Frame Assemblies for Structural Testing at the NFRL

STATEMENT OF WORK Precast Concrete Moment Frame Assemblies for Structural Testing at the NFRL 1. Background The Structures Group in the Engineering Laboratory at the National Institute of Standards and Technology (NIST) researches and develops performance-based tools to enhance building resilience against extreme hazards like wind, fire, and earthquakes, providing technical data, structural standards, and failure analysis to mitigate disasters. The Structures Group is expanding upon a recently completed multi-year experimental research effort that focused on mitigating disproportionate collapse of buildings in the United States. First, prototype 10-story buildings were designed for seismic and gravity loads, with each building employing one of the following lateral load resisting systems at its perimeter: steel moment frame, reinforced concrete moment frame, or precast concrete moment frame. Next, moment frame assemblies representing a portion of these frames were tested at full scale under a middle column removal scenario to evaluate the disproportionate collapse resistance of each system. The precast concrete moment frame assemblies that were tested revealed potential vulnerabilities, which led to them being only marginally able to resist disproportionate collapse under a sudden column removal scenario. The moment connections in these assemblies were made by steel link plates that protruded from the beam ends and were fillet welded to plates embedded in the columns. Motivated by the suboptimal performance of these assemblies, NIST, in collaboration with an industry review committee of Precast/Prestressed Concrete Institute (PCI) members, developed five novel precast concrete beam-to-column moment connection concepts. Moment frame assemblies featuring these connection concepts were designed for moments arising from a middle column removal scenario in the exterior moment frame of a prototype precast concrete moment frame building. These assemblies were derived at five- eighths scale from the prototype building and were tested under a middle column removal scenario to characterize their robustness against disproportionate collapse. While all five of the tested connection concepts were shown to be viable for use in precast concrete construction to achieve robust performance against disproportionate collapse, their performance under seismic loads is unknown. NIST has selected two of the five connection concepts for further experimental study. The connections are called the threaded rod connection and the bar coupler connection. Moment frame assemblies featuring these two connection concepts will be subjected to fully-reversed cyclic loads, which are representative of what is expected to be felt by structural members during earthquake ground motion. These experimental tests will help to provide the technical basis for the development and improvement of codes, standards, and practices governing the design of precast concrete structures. 2. Purpose and Objective The purpose of this requirement is to obtain contractor services to fabricate and deliver a quantity of three (3) precast concrete moment frame assemblies to the National Fire Research Laboratory (NFRL) located in Building 205 at NIST in Gaithersburg, MD, with an option to procure up to two (2) additional precast concrete moment frame assemblies, for a total of five (5) assemblies. Each assembly shall consist of two precast concrete beams and one precast concrete column. The NIST Contracting Officer’s Representative (COR) will provide preliminary design drawings for the assemblies, which include details for the steel reinforcement and cast-in hardware. -- 1 of 14 -- Section 3.2 details the “Preliminary Design Drawings” as an attachment named “Full-Scale Flexure Specimens Preliminary Design Drawings.” The contractor shall deliver the individual components comprising the assemblies (i.e., the beams and columns) to NIST in accordance with the Deliverables table. Once at NIST, NIST staff will connect the precast concrete beams to the central precast concrete column using threaded rods for the threaded rod connection or reinforcing bar couplers for the bar coupler connection. PLACE OF PERFORMANCE The primary place of performance shall be at the Contractor’s place of business. All products required shall be delivered to NIST located in Gaithersburg, Maryland. PERIOD OF PERFORMANCE The Base Period of Performance shall be effective for 6 months from September 1, 2026 through February 28, 2027. Options to increase quantity are applicable to this requirement. Two (2) Optional Items, as described further below, if exercised at time of award or within the effective period of performance, shall each extend the performance period by an additional four (4) months. If one option is exercised, the performance period will be extended by four months from six months to 10 months. If the second option is exercised, an additional four months will be added to the performance period and extended from 10 to 14 months. The Period of Performance shall not exceed 14 months. 3. SPECIFIC REQUIREMENTS TASKS Task 3.1 The Contractor shall provide the equipment, materials, and labor necessary to fabricate and deliver the assemblies to the NFRL in Building 205 at the NIST campus in Gaithersburg, MD. As summarized in Table 1, this statement of work includes a base requirement of three precast concrete assemblies (i.e., six precast concrete beams and three precast concrete columns), with options for purchasing two additional assemblies (an assembly is comprised of two precast concrete beams and one precast concrete column) in increments of one. The optional additional precast concrete beams and columns may be purchased either at the time of award, or at any time within the effective period of performance (see Table 1 below). Specific requirements for each of these products are given in subsequent sections, as indicated in Table 1. In addition to the required products li…