Reinforcement methods for compression perpendicular to grain in top/bottom plates of light timber frames

Abstract

Relatively low load-bearing capacity of top and bottom plates in light timber framed structures under compression perpendicular to grain and the consequential shortening of vertical elements have resulted in their limited applications in construction of mid-rise buildings. Solutions for the enhancement of the compression perpendicular to grain need to be further developed to tackle this problem. This paper investigates the contribution of excessive deflection of horizontal members to the vertical shortening of light timber frames due to compression perpendicular to the grain and evaluates the effectiveness of some different reinforcement techniques for improving the bearing strength of these members. A comprehensive experimental investigation of light timber framed members under compression perpendicular to the grain, provides information on different mechanical properties, different types of reinforcement methods and their effects on the load carrying capacity of a range of structural timber elements. For this purpose, 750 practical tests are carried out to evaluate the effectiveness of the solutions. The techniques include applying timber on timber and steel on timber connections, use of additional reinforcing materials and mechanical fasteners. The results indicate that the bearing capacity under compression perpendicular to grain can be considerably improved by applying some of these solutions; the level of improvement varies for each solution though.