Determination of Initial Stiffness of Timber–Steel Composite (TSC) Beams Based on Experiment and Simulation Modeling

Meng-Ting Tsai,Truong Le

doi:10.3390/su10041220

Abstract

Due to improvements in the use of recyclable materials in construction, timber–steel composite (TSC) beams demonstrate high potential for future construction. In this study, a proposed simulation modeling, which was adopted from the simulation modeling of a timber I-shape composite, was applied to estimate the initial stiffness of TSC beams. The strength of each beam could be determined once the initial stiffness was estimated. In addition, a series of experiments were performed to examine the accuracy of the proposed simulation modeling, including the effects of different shapes of steel members, fasteners, and applying and not applying a dowel connection. The results indicated that the simulation modeling could adequately determine strength at a deflection of 1/360 of the span. The ratio of difference between the experimental results and the simulation modeling results was less than 10% if a dowel connection at the web was applied. However, the ratio of difference reached 26% and 24% in the TSC beams without a dowel connection at the web that were fastened with screws and nails at the flange, respectively, revealing the importance of applying a dowel connection at the web. Moreover, the strength of the TSC beams with a dowel connection at the web that were fastened by screws was approximately 15% higher than that of TSC beams without screw fasteners. In conclusion, the proposed simulation modeling can provide designers with a method for estimating the initial stiffness and strength of TSC beams within a deflection of 1/360 of the span, supporting the future application of TSC beams in construction.

Highlights

Most buildings are constructed using different materials
The main objective of this study is to establish simulation modeling of timber–steel composite (TSC) beams assembled by local materials and determine their initial stiffness, which is defined as the strength when deflection exceeds 1/360 of the span, for future applications according to Design and Construction Specifications of Wood Construction for Buildings, Table 5-4.2 [8], for wooden structure designs in Taiwan
By determining the initial stiffness using available characteristics such as the shape of the steel member and the fasteners applied with a dowel connection, it is possible to obtain a reliable result for initial analysis when the deflection is limited to 1/360 of the span

Summary

Introduction

Most buildings are constructed using different materials. The most commonly used structural material is reinforced concrete, which is a composite of cement and steel rebars. In Europe, studies have examined the use of steel as a reinforced member for timber, especially for repairing and strengthening of the existing timber structure [4,5], while others focus on TSC beams for the development of multi-storey buildings [6]. TSC beams provide solutions to improve the structural stiffness for these retrofitted historical wooden buildings without distinct changes. The main objective of this study is to establish simulation modeling of TSC beams assembled by local materials and determine their initial stiffness, which is defined as the strength when deflection exceeds 1/360 of the span, for future applications according to Design and Construction Specifications of Wood Construction for Buildings, Table 5-4.2 [8], for wooden structure designs in Taiwan. The initial stiffness can be determined using Equation (7)

Objectives

Methods

Results

Discussion

Conclusion