Determining the dynamic increase factor for glued-laminated timber beams

Citation:

Lacroix, D. , & Doudak, G. . (2018). Determining the dynamic increase factor for glued-laminated timber beams. Journal of Structural Engineering, 144, 04018160. American Society of Civil Engineers. Retrieved from https://www.scopus.com/record/display.uri?eid=2-s2.0-85046899598&origin=inward&txGid=e75bbaf642b3fed6499c093c8d4a0422

Abstract:

This paper presents the results from an experimental program that investigated the flexural behavior of glulam beams subjected to dynamic loading. A total of thirty-eight beams consisting of three different cross-sections were tested destructively under both static and dynamic loads. The analysis resulted in a dynamic increase factor (DIF) of 1.14 for strain-rates ranging between 0.14 and 0.51 s-1, however, the increase was only observed when the outer tension laminate did not include continuous finger-joints (single laminate width) or closely aligned finger-joints (multiple laminates width) in the high moment region causing a straight fracture across the width. No increase due to high strain-rate effects was found when a continuous failure across the width due to finger-joints (FJs) were present in the outer tension laminate, and thus if continuous laminates, uninterrupted by FJs cannot be guaranteed, a dynamic increase factor of unity is suggested for design. Since the beams exhibited little to no ductility, it is recommended that a linear-elastic resistance curve be used to generate the dynamic resistance curve. An equivalent single-degree-of-freedom (SDOF) model accounting for high strain-rate effects using the derived DIF, where appropriate, captured the displacement at failure, time to failure, and displaced shape with reasonable accuracy. 

Notes:

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Last updated on 02/11/2021