Proceedings of the Institution of Civil Engineers - Construction Materials
DOI link: https://doi.org/10.1680/jstbu.171.9.661
As the only renewable construction material, and owing to the superior specific stiffnesses and strengths of the different species, timber has been used in major load bearing applications for thousands of years. The advent of waterproof adhesives during World War II and recent advances in manufacturing have combined to exploit the ease of forming and machining this material, leading to various forms of engineered timber including glulam, laminated veneer lumber (LVL) and cross-laminated timber (CLT). Manufactured in lightweight modules that are easily transported, then quickly craned into position and connected to produce eye-catching structures, engineered timber provides cost-effective alternatives (with minimal numbers and complexity of connections) to conventional materials for rapid construction of affordable residential and office spaces in busy city centres.
This report represents the results of the activities performed in working group 1, Basis of Design. The most important task of working group 1 was the defragmentation and harmonization of techniques and methods that are necessary to prove the reliable, safe and economic application of timber materials or products in the construction industry. This report is structured into five parts. At first general principles regarding the design formats are addressed (Part I). Afterwords timber specific aspects regarding code calibration (Part II) and serviceability (Part III) are summarized. In Part IV other demanding issues for the implementation into Eurocode 5 are addressed. Here also summaries of joint activities with other working groups on cross laminated timber and timber connections are presented. The report concludes with a guideline for data analysis (Part V).
The intention of this STAR is a more detailed summary of the relevant work, done during the last 20 years on the topic of CLT. Additional references not included in the documents of SC5.T1 were added highlighting also CLT relevant publications not directly addressing content of the CLT draft version for EC 5. Apart from providing additional references for all topics and chapters of SC5.T1 draft documents edited by WG 2 / TG 1 & TG 3 within this STAR, further necessary scoentific work was identified and listed.
Fire safety is widely perceived as a barrier to implementation of tall timber buildings, particularly for engineered mass timber buildings with significant areas of exposed timber and timber structural framing. This negative perception is exacerbated by a lack of scientific data or experimental evidence on a range of potentially important issues that must be properly understood to undertake rational, performance-based engineering design of such structures. With the goal of delivering fully engineered structural fire designs, this paper presents and discusses a framework for using scientific knowledge, along with fire engineering tools and methods, to enable the design of timber buildings such that, when subject to real fire loads, their performance is quantified. The steps in this framework are discussed with reference to the available literature, in an effort to highlight areas where additional knowledge and tools are needed.