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INTRODUCTION A. PURPOSE OF REPORT - The purpose of this report is to provide federal agencies with practical procedures for evaluating the need for through-building expansion joints in structural framing systems and with guidelines for designing expansion joints for those systems when they are required. B. SCOPE The term "expansion joint" as used throughout this report refers to the isolation joints provided within a building to permit the separate segments of the structural frame to expand and contract in response to temperature changes without adversely affecting the building's structural integrity or serviceability. This report is limited to the investigation of expansion joints that permit movement in the horizontal direction only. All types of building and all climatic conditions experienced in the United States are considered. Prob- lems such as those associated with vertical movement of the structural frame, dimensional changes of cladding, relative motion of cladding to frame, shrinkage of concrete, manufacturing errors in the length of members, and differential settlement of foundations are not considered. C. CONDUCT OF STUDY The study on which this report is based was carried out under the direction of the Federal Construction Council Standing Committee on Structural Engi- neering. The Committee first examined in detail an unpublished report in which horizontal changes in dimension in nine federal buildings were observed and related to recorded temperature changes. Additionally, the Committee studied the current practices of federal agencies regarding expansion joint criteria. To enchance its understanding of the distribution of stresses and associated deformation in frames subjected to uniform temperature change, the Committee formulated and conducted an analytical study of the effects of uniform tem- perature change on typical two-dimensional elastic frames. A theoretical 1
computer model was developed for this purpose. Observed dimensional changes caused by temperature changes were correlated with data obtained from the computer analysis. The results of the Committee's study and analysis, as well as its collective experience and judgment, served as the bases for this report. D. ORGANIZATION OF REPORT . . This report includes two main sections in addition to this Introduction: Section II, Recommendations, in which the Committee presents its recommenda- tions without detailed discussion, and Section III, Discussion, in which the Committee presents the data and rationale upon which the recommendations are based and on which attention is focused on the nature of the problems asso- ciated with temperature changes and their effects on structural integrity and building serviceability. The computer printout of an elastic analysis that illustrates the effects of temperature changes on horizontal dimen- sional movements and a compilation of temperature data for various cities in the United States are included as appendixes.
