Dissertation Master in Civil Ingeneering - Building Constructions DESIGN OF WOOD CONNECTIONS WITH DOWEL TYPE FASTENERS Luis Enrique Chávez Rubio Leiria, July of 2018 i This page was intetionally left blank ii Dissertation Master in Ingeneering and Building Construcction DESIGN OF WOOD CONNECTIONS WITH DOWEL TYPE FASTENERS Luis Enrique Chávez Rubio Dissertation developed under the supervision of Doctor Florindo José Mendes Gaspar, professor at the School of Technology and Management of the Polytechnic Institute of Leiria and co-supervision of Master Wilson Santiago Medina Robalino, professor at the Facultad de Ingeniería Civil y Mecánica of the Universidad Técnica de Ambato. Leiria, July of 2018 iii This page was intetionally left blank iv My most sincere acknowledgements to Doctor Florindo Gaspar who as a tutor, with his great human qualities, ability, support and knowledge has given me his conditional help to successfully complete this research project. To Ing. MSc. Santiago Median who has given me his support during the tutoring process and who has always been ready for any question. To all my friends who gave me all their support and who helped me improve every day. To all my family, especially my parents Enrique and Isabel, and my brother Xavier who were always in all the good or bad situations to support me and give me strength from the moment I left my country to study. Regardless of the distance, they knew how to transmit all the unconditional love and concern they had towards me so that my studies end with success. v This page was intetionally left blank vi Este trabalho tem como objetivo descrever os diferentes tipos de conectores e fixadores que são feitos para o dimensionamento e dimensionamento de conexões em estruturas de madeira. Para qual, uma descrição de cada um deles e suas características principais é feita. A seguir, é descrito o uso do programa com as planilhas e como usá-lo para inserir as informações e como os resultados são apresentados usando o Eurocódigo 5. Neste explica a seqüência que deve ser seguida e as diferentes seções da planilha para dimensionamento conexões com diferentes conectores do tipo tarugo. Além disso, indica as variáveis envolvidas no dimensionamento, que é utilizado para descrever os diferentes tipos de conexões a serem analisadas. O trabalho conclui apresentando todos os resultados da capacidade de resistência dos diferentes tipos de conexões através de tabelas de gráficos e porcentagens que ajudam a perceber como diferentes fatores intervêm na resistência da conexão. Palavras-chave: ligacões, estruturas de madeira, Eurocódigo 5, ligadores tipo cavilha, dimensionamento. vii This page was intetionally left blank viii This work aims to describe the different types of connectors and fasteners that is made for the design and dimensioning of connections in wooden structures. For which, a description of each of them and their main characteristics is made. Next, the use of the program with the spreadsheets is described, and how to use it to enter the information and how the results are presented using the Eurocode 5. It explains the sequence that must be followed and the different sections of the spreadsheet for dimensioning connections with different dowel-type connectors. In addition, it indicates the variables involved in the dimensioning, which is used to describe the different types of connections to be analysed. The work concludes, presenting all the strength capacity results of the different types of connections through graphs and percentages tables that help to perceive how different factors intervene in the resistance of the connection. Keywords: connections, wooden structures, Eurocode 5, dowel-type fasteners, dimensioning. ix This page was intetionally left blank x Acknowledgements ......................................................................................................... v Resumo .......................................................................................................................... vii Abstract .......................................................................................................................... ix Table of Contents ........................................................................................................... xi List of Figures ............................................................................................................... xv List of Tables ............................................................................................................... xvii List of Acronyms .......................................................................................................... xix 1. Introduction ............................................................................................................ 1 1.1. Background ........................................................................................................ 1 1.2. Objectives .......................................................................................................... 2 1.3. Structure of Dissertation .................................................................................... 3 2. Connections in Wooden Structures....................................................................... 5 2.1. Beam Connectors ............................................................................................... 5 2.1.1. Concealed Connectors ................................................................................ 5 2.1.2. Not Concealed Connectors ......................................................................... 6 2.2. Column to Base Connections ............................................................................. 9 2.3. Dowel Type Connectors .................................................................................. 10 2.3.1. Nails .......................................................................................................... 10 2.3.2. Screws ....................................................................................................... 11 2.3.3. Bolts .......................................................................................................... 13 2.3.4. Dowels ...................................................................................................... 14 3. Design of Wood Connections ............................................................................... 17 3.1. Embedment Strength ........................................................................................ 18 3.2. Fastener Yield Moment.................................................................................... 19 3.3. Johansen Equations .......................................................................................... 19 xi 3.3.1. Friction effects and Axial Withdrawal of the fastener ............................. 20 3.4. Nailed Connection ........................................................................................... 21 3.5. Screwed Connection ........................................................................................ 22 3.6. Bolted Connections .......................................................................................... 23 3.7. Dowelled Connection....................................................................................... 24 3.7.1. Wooden Dowelled Connection ................................................................. 25 3.8. Effective number of fasteners .......................................................................... 29 3.8.1. Principal factors affecting the connection strength .................................. 30 3.9. Comparison between the European and the American method ....................... 32 3.10. Numerical Models in Timber Connections .................................................. 33 3.11. Design for Durability ................................................................................... 34 3.11.1. Project Phase: ........................................................................................ 34 3.11.2. Manufacturing Phase: ........................................................................... 37 3.11.3. Maintenance Phase: .............................................................................. 37 4. Methodology .......................................................................................................... 39 4.1. Introduction ...................................................................................................... 39 4.2. Excel Spreadsheet ............................................................................................ 39 4.2.1. Spreadsheet for Metal Dowel-Type Fasteners.......................................... 41 4.2.2. Spreadsheet for Wooden Dowels ............................................................. 44 4.3. Materials and design ........................................................................................ 46 4.3.1. Type of Connection .................................................................................. 48 4.3.2. Dowel Type Fasteners .............................................................................. 49 5. Results and Discussion ......................................................................................... 53 5.1. Timber – Timber Connection........................................................................... 53 5.1.1. Influence of Splice Piece Thickness ......................................................... 53 5.1.2. Influence of Fastener Type ......................................................................