Quicklinks ● ● ● ● ● ● April 2011 Seismic Design Provisions Seismic Test Methods Conclusion References About Architectural Testing Authors Design Provisions and Test Methods for Architectural Glass Subjected to Seismic Induced Building Movements Other Links ● The reference standards of the current building codes require the relative seismic displacement at glass fallout (∆fallout) of an individual glass panel be greater than the actual relative seismic displacement of the panel. Exceptions to this requirement are granted for: ATI Locations ● ● ● Glass with sufficient glass-to-frame clearances to accommodate seismic displacement; Fully tempered monolithic glass less than 10 feet above walking surfaces and; Single thickness laminated glass that is fully captured and wet glazed. Where the exceptions cannot be applied, the glass fallout shall be determined in accordance with AAMA 501.6 or through engineering analysis. Photo No. 1 Horizontal Racking Displacement using Hydraulic Actuator. Both test methods are routinely specified by architects. AAMA 501.4-09 is a static racking test method concerned with the serviceability of curtain wall and storefront glazing systems following a seismic event. This method requires companion air infiltration, water penetration and static load tests which typically require a chambered mockup. Thus, this testing is normally done in conjunction with a full air/water/structural performance mockup. AAMA 501.4 includes the following testing sequence: ● ● ● Photo No. 2 Dynamic Testing Apparatus. ● ● ● Baseline air leakage (ASTM E 283-91, Standard Test Method for Determining the Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen) Static water resistance (ASTM E 331-00, Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference) Structural performance at design wind pressure (ASTM E 330-02, Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights and Curtain Walls by Uniform Static Air Pressure Difference) Static horizontal racking displacement of design-specific value or default value of 0.01 x story height is applied with hydraulic actuators (see Photo No. 1) Repeat air leakage, static water resistance and structural performance Static horizontal racking displacement of 1.5x design value. AAMA 501.6-09, is a dynamic racking test method focusing on the seismic safety of architectural glass components within curtain wall and storefront wall systems. This test involves mounting individual, fully glazed wall panel specimens on a dynamic racking test apparatus (see Photo No. 2). The upper anchorage points move back and forth in sinusoidal motions at progressively higher racking amplitudes, as in a musical crescendo (see Figure 1). The bottom anchorage points remain fixed, thereby imparting a dynamic, in-plane story drift on the test specimen. Figure 1 Displacement History of Dynamic Racking Test (From AAMA 501.6 with permission). Dynamic racking frequencies are 0.8 Hz at lower racking amplitudes (< ±75 mm [3 in.]) and 0.4 Hz at higher racking amplitudes (> ±75 mm). The amplitude at which glass fallout is first observed for a given specimen is designated as ∆fallout for that test specimen. The lowest value of racking displacement causing glass fallout for three replicate specimens tested in accordance with AAMA 501.6 is the reported value of ∆fallout for that particular wall system glazing configuration. This value of ∆fallout must be greater than the actual relative seismic displacement of the panel for the specific project under consideration. Developed within the National Earthquake Hazards Reduction Program NEHRP, seismic design provisions for architectural glass were adopted in ASCE 7 and are now constituents of all major building codes. These provisions make reference to a specialized laboratory test method developed and published by AAMA. Together, the design provisions and laboratory test methods are intended to improve the life-safety performance of architectural glass components in earthquake-prone regions. ● ● ● AAMA 501.6-09, Recommended Dynamic Test Method for Determining the Seismic Drift Causing Glass Fallout from a Wall System. ASCE 7-05, Minimum Design Loads for Buildings and Other Structures. 2009 International Building Code. Architectural Testing continues to search for new ways to diversify our business using our broad capabilities and talented staff. Should you require any of our services or know of other unique opportunities where you can utilize our expertise, please don't hesitate to contact us. Travis Hoover Program Manager of Structural Systems Testing Joseph Reed PE Director of Engineering Mr. Travis Hoover has continual engineering experience since joining Architectural Testing in 1997. He oversees all AAMA 501.6 testing at Architectural Testing. He has Bachelor of Science in Mechanical Engineering Technology from The Pennsylvania State University. thoover@archtest.com Mr. Joseph Reed has continual engineering experience since 1988 and joined Architectural Testing in 2002. He is a Professional Engineer licensed in seven states. 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