Schmidt M.K.,Elstner Associates Inc.
Challenging Glass 2 - Conference on Architectural and Structural Applications of Glass, CGC 2010
Heat-strengthened glass with residual surface compressive stresses above those allowed by ASTM C1048 was installed in a curtain wall in the mid-Atlantic region of the United States. To address building ownership's concerns regarding postbreakage glass fallout, fragmentation tests were performed using a protocol adapted from EN 1863. Consistent with previous research, no significant difference in fragmentation was noted between samples with residual surface compressive stresses conforming to ASTM C1048 and those with residual surface compressive stresses well beyond the established ASTM limits. Simplistic analyses revealed that, under certain modes of failure, risk of glass fallout is comparable for conforming and nonconforming heat-strengthened glass. The completed testing also has implications for glass quality control processes. Copyright © with the authors. All rights reserved. Source
Horst M.,Elstner Associates Inc.
ASTM Special Technical Publication
Exterior insulation and finish systems (EIFS) can provide a durable, waterresistant covering for a variety of building types. However, as with any cladding material, considerations during design and workmanship during construction are the primary factors in determining the success of an EIFS-clad building. Among the important factors to consider in the design of EIFS cladding is that the EIFS is only one component of the overall building enclosure system, which includes roofing, windows, sealants, possibly other cladding materials, and many other elements. During the design phase of a project, careful consideration must be given to the compatibility of other enclosure components with the EIFS. In addition, detailing of the interfaces between the EIFS and these components, typically referred to as integration details, is critical in achieving the expected building performance and durability of the exterior cladding assembly. During the construction phase, coordination of various trades, including the EIFS installer, is essential to ensuring successful installation of these integration details. Over the past 15 years, the author has had the opportunity to evaluate a variety of EIFS-clad buildings that exhibit successes and failures of these integration details. More recently, the author has performed peer reviews for design architects and has provided consulting services to assist contractors with potential compatibility issues and with developing integration details. In this paper, the author will discuss several common problematic interfaces between EIFS and adjacent construction. Design principles and other considerations for improving the function of the exterior building enclosure at these interfaces will be explored. Several case studies, including positive and negative examples of design and construction details, will be used to illustrate concerns with their integration. In addition, the paper will identify and discuss facets of several of the standards that have been developed by ASTM International (ASTM) to assist designers, consultants, and contractors in the development of integration details and the determination of their compatibility. © Copyright 2016 by ASTM International. Source
Kehoe B.E.,Elstner Associates Inc.
9th US National and 10th Canadian Conference on Earthquake Engineering 2010, Including Papers from the 4th International Tsunami Symposium
There are a number of standards and methodologies available for the seismic evaluation of existing buildings. Some of these standards are intended to be used for specific building types, such as unreinforced masonry buildings, while other standards are intended to be applied to more general types of buildings. ASCE 31-03 has evolved over time through a series of earlier guidelines and is a standard that has been developed to be applied to a variety of building types. Each seismic evaluation method that has been developed has a specific purpose and audience for which it has been targeted. As such, these methodologies have advantages and limitations. While some limitations are obvious, others are more fundamental and not as apparent. Some of these fundamental limitations with respect to ASCE 31-03 are discussed. In addition to limitations in the applicability of the methodology within the ASCE 31-03 standard, there are issues with how the standard correlates with other design and evaluation standards that are currently in use. Recommendations are made to changes in the basic concept of ASCE 31-03, which relies on standard building types based on material and lateral force resisting system, to a methodology that focuses primarily on seismic behavior. The characteristics that affect seismic behavior include height, lateral force resisting system, materials, and configuration. Different techniques can then be used to evaluate the performance of buildings for each of the behavior types. Source
Reins J.D.,Elstner Associates Inc.
Journal of Performance of Constructed Facilities
This paper discusses the partial collapse of John Purdue Block, a historic masonry structure in Lafayette, Indiana. The collapse occurred while the structure was being renovated and modified to prepare it for a new occupancy and usage. Prior to the start of the project, masonry strengths were not assessed or even estimated, and the primary structural elements were not analyzed for the proposed changes in loading and geometry. Relatively modest loads on the masonry walls and columns, coupled with a long-term performance without distress, may have provided a false sense of confidence that the structure could safely withstand comparatively minor changes in geometry and loading. Subsequent testing and analysis revealed the cause of the failure to be localized compressive stresses that exceeded the ultimate capacity of the brick masonry. © 2014 American Society of Civil Engineers. Source
Kehoe B.E.,Elstner Associates Inc.
NCEE 2014 - 10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering
Seismic design of nonstructural components using ASCE 7-10 considers the interaction between the response of the nonstructural component and the response of the building by means of a component amplification factor, ap, that accounts for the dynamic interaction between the nonstructural component and the response of the building. ASCE 7-10 provides tables of architectural, mechanical, and electrical components that specify values for ap. The values in the tables are either 1.0 or 2.5 for components considered rigid or flexible, respectively. ASCE 7-10 provides a definition for determining whether a component is rigid based on the component's period of vibration. The tabulated values of nonstructural amplification factors may not adequately characterize the actual seismic behavior of some nonstructural components since the values do not consider the actual properties of the nonstructural components and the effect of actual support and bracing. While ASCE 7-10 provides a formula for determining the actual period of mechanical and electrical components, this formula is seldom used in actual practice. Determining the period of vibration of a nonstructural component does not provide all of the information needed to assess how a nonstructural component will respond during an earthquake since it does not consider the predominant periods of vibration of the building. The vibrational periods for some common nonstructural components are tabulated based on considerations of material properties and dimensions. Data from component testing are also summarized and compared to calculated values. The influence of support conditions are also described. Recommendations for changes to building code requirements are presented. Source