Advances on structural design with timber in Uruguay: Towards a proposal for a National Annex to Eurocode 5

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2 Advances on structural design with timber in Uruguay: Towards a proposal for a National Annex to Eurocode 5 Presenter: Andrea Cardoso Corresponding author: ldaguiar@fing.edu.uy Vanesa Baño Leandro Domenech Gonzalo Cetrangolo Hugo O Neill Laura Moya

3 1. Uruguayan forestry Uruguayan forestry The Uruguayan forestry sector has had a significant increase in wood volume during the last thirty years as a result of a government policy to promote forest plantations

4 1. Uruguayan forestry Uruguayan forestry The Uruguayan forestry sector has had a significant increase in wood volume during the last thirty years as a result of a government policy to promote forest plantations The main industrial use of eucalyptus species is the production of pulp, while pine and part of the eucalyptus are used for construction products

5 1. Uruguayan forestry Uruguayan forestry An important volume of wood (1.7 million m 3 of pine and 0.4 million m 3 of eucalyptus) have not current industrial destination

6 1. Uruguayan forestry Uruguayan forestry An important volume of wood (1.7 million m 3 of pine and 0.4 million m 3 of eucalyptus) have not current industrial destination The Uruguayan government has impulse the incorporation of timber for structural use, which implies the need for a national system of codes for timber products and for design and construction with timber

7 2. Design process 2.1. Stages in structural design Design process of a structure Structural planning Definition of external loads Determination of internal forces Design of structural members Detailing, drawing and preparation of schedules

8 2. Design process 2.1. Stages in structural design Design process of a structure Structural planning Definition of external loads Determination of internal forces Design codes Design of structural members Detailing, drawing and preparation of schedules Introduction of security

9 2. Design process 2.1. Stages in structural design Design process of a structure Structural planning Definition of external loads Determination of internal forces Design of structural members Detailing, drawing and preparation of schedules Design codes Introduction of security ASD or LRFD

10 2. Design process 2.2. ASD and LRFD methods ASD and LRFD methods ASD: Allowable Strength Design LRFD: Load and Resistance Factor Design

11 2. Design process 2.2. ASD and LRFD methods ASD and LRFD methods ASD: Allowable Strength Design LRFD: Load and Resistance Factor Design The LRFD method accounts separately for the predictability of applied loads through the use of load factors and for material and construction variability through resistance factors. The ASD method combines the two factors into a single factor of safety.

12 2. Design process 2.2. ASD and LRFD methods ASD and LRFD methods ASD: Allowable Strength Design LRFD: Load and Resistance Factor Design The variable factor of safety associated with the LRFD method is considered to be more consistent with probability since structures that have highly predictable loads (predominately dead load for example) do not require the same factor of safety as structures subjected to loads that are not very predictable (live and wind loads for example).

13 3. Codes 3.1. United States Codes in the United States In the USA the ASD method has been gradually replaced by the LRFD method

14 3. Codes 3.1. United States Codes in the United States In the USA the ASD method has been gradually replaced by the LRFD method LRFD was introduced for: reinforced concrete structures in 1970 (ACI 318:1970)

15 3. Codes 3.1. United States Codes in the United States In the USA the ASD method has been gradually replaced by the LRFD method LRFD was introduced for: reinforced concrete structures in 1970 (ACI 318:1970) steel structures in 1986 (AISC 360:1986)

16 3. Codes 3.1. United States Codes in the United States In the USA the ASD method has been gradually replaced by the LRFD method LRFD was introduced for: reinforced concrete structures in 1970 (ACI 318:1970) steel structures in 1986 (AISC 360:1986) timber structures in 2005 (NDS 2005)

17 3. Codes 3.1. United States Codes in the United States In the USA the ASD method has been gradually replaced by the LRFD method The most recent editions of the United States codes for the design of timber and steel structures was developed in a dual format LRFD was introduced for: reinforced concrete structures in 1970 (ACI 318:1970) steel structures in 1986 (AISC 360:1986) timber structures in 2005 (NDS 2005)

18 3. Codes 3.2. Europe What Eurocodes are? The Eurocodes are a set of European standards with the objectives of the elimination of technical obstacles to trade and the harmonization of technical specifications

19 3. Codes 3.2. Europe What Eurocodes are? The Eurocodes are a set of European standards with the objectives of the elimination of technical obstacles to trade and the harmonization of technical specifications Purposes of the Eurocodes: a means to prove compliance with the requirements for mechanical strength and stability and safety in case of fire established by European Union law

20 3. Codes 3.2. Europe What Eurocodes are? The Eurocodes are a set of European standards with the objectives of the elimination of technical obstacles to trade and the harmonization of technical specifications Purposes of the Eurocodes: a means to prove compliance with the requirements for mechanical strength and stability and safety in case of fire established by European Union law a basis for construction and engineering contract specifications

21 3. Codes 3.2. Europe What Eurocodes are? The Eurocodes are a set of European standards with the objectives of the elimination of technical obstacles to trade and the harmonization of technical specifications Purposes of the Eurocodes: a means to prove compliance with the requirements for mechanical strength and stability and safety in case of fire established by European Union law a basis for construction and engineering contract specifications a framework for creating harmonized technical specifications for building products

22 3. Codes 3.2. Europe European Committee for Standardization (CEN) - Members

23 3. Codes 3.2. Europe European Committee for Standardization (CEN) - Affiliates

24 3. Codes 3.2. Europe European Committee for Standardization (CEN) - Partner Standardization Bodies

25 3. Codes 3.2. Europe EN Eurocodes Parts Eurocode 0 (EN 1990) Basis of structural design Eurocode 1 (EN 1991) Eurocode 2 (EN 1992) Eurocode 3 (EN 1993) Eurocode 4 (EN 1994) Eurocode 5 (EN 1995) Eurocode 6 (EN 1996) Eurocode 7 (EN 1997) Eurocode 8 (EN 1998) Eurocode 9 (EN 1999)

26 3. Codes 3.2. Europe EN Eurocodes Parts Eurocode 0 (EN 1990) Eurocode 1 (EN 1991) Actions on structures Eurocode 2 (EN 1992) Eurocode 3 (EN 1993) Eurocode 4 (EN 1994) Eurocode 5 (EN 1995) Eurocode 6 (EN 1996) Eurocode 7 (EN 1997) Eurocode 8 (EN 1998) Eurocode 9 (EN 1999)

27 3. Codes 3.2. Europe EN Eurocodes Parts Eurocode 0 (EN 1990) Eurocode 1 (EN 1991) Eurocode 2 (EN 1992) Design of concrete structures Eurocode 3 (EN 1993) Eurocode 4 (EN 1994) Eurocode 5 (EN 1995) Eurocode 6 (EN 1996) Eurocode 7 (EN 1997) Eurocode 8 (EN 1998) Eurocode 9 (EN 1999)

28 3. Codes 3.2. Europe EN Eurocodes Parts Eurocode 0 (EN 1990) Eurocode 1 (EN 1991) Eurocode 2 (EN 1992) Eurocode 3 (EN 1993) Design of steel structures Eurocode 4 (EN 1994) Eurocode 5 (EN 1995) Eurocode 6 (EN 1996) Eurocode 7 (EN 1997) Eurocode 8 (EN 1998) Eurocode 9 (EN 1999)

29 3. Codes 3.2. Europe EN Eurocodes Parts Eurocode 0 (EN 1990) Eurocode 1 (EN 1991) Eurocode 2 (EN 1992) Eurocode 3 (EN 1993) Eurocode 4 (EN 1994) Eurocode 5 (EN 1995) Design of timber structures Eurocode 6 (EN 1996) Eurocode 7 (EN 1997) Eurocode 8 (EN 1998) Eurocode 9 (EN 1999)

30 3. Codes 3.2. Europe EN Eurocodes Parts Eurocode 0 (EN 1990) Eurocode 1 (EN 1991) Eurocode 2 (EN 1992) Eurocode 3 (EN 1993) Eurocode 4 (EN 1994) Eurocode 5 (EN 1995) Eurocode 6 (EN 1996) Eurocode 7 (EN 1997) Geotechnical design Eurocode 8 (EN 1998) Eurocode 9 (EN 1999)

31 3. Codes 3.2. Europe EN Eurocodes Parts Eurocode 0 (EN 1990) Eurocode 1 (EN 1991) Eurocode 2 (EN 1992) Eurocode 3 (EN 1993) Eurocode 4 (EN 1994) Eurocode 5 (EN 1995) Eurocode 6 (EN 1996) Eurocode 7 (EN 1997) Eurocode 8 (EN 1998) Design of structures for earthquake resistance Eurocode 9 (EN 1999)

32 3. Codes 3.2. Europe Eurocode 0 (EN 1990): Basis of structural design Eurocode 1 (EN 1991): Actions on structures Structural safety, serviceability and durability Actions on structures Eurocode 2 (EN 1992): Concrete Eurocode 3 (EN 1993): Steel Eurocode 4 (EN 1994): Composite Eurocode 5 (EN 1995): Timber Eurocode 6 (EN 1996): Masonry Eurocode 9 (EN 1999): Aluminum Design and detailing Eurocode 7 (EN 1997): Geotechnical design Eurocode 8 (EN 1998): Seismic design Geotechnical and seismic design

33 3. Codes 3.2. Europe Eurocode 5: Design of timber structures Part 1 - General Part 1-1: Common rules and rules for buildings (EN :2004) Part 1-2: Structural fire design (EN :2004) Part 2 Bridges (EN :2004)

34 3. Codes 3.2. Europe Eurocode 5: Design of timber structures LRFD Part 1 - General Part 1-1: Common rules and rules for buildings (EN :2004) Part 1-2: Structural fire design (EN :2004) Part 2 Bridges (EN :2004)

35 3. Codes 3.2. Europe What National Annexes (NA) are? Technical documents of national implementation with the objectives of the definition of the Nationally Determined Parameters (NDP) and, optionally, Non-Contradictory Complementary Information (NCCI) to Eurocodes

36 3. Codes 3.2. Europe What National Annexes (NA) are? Technical documents of national implementation with the objectives of the definition of the Nationally Determined Parameters (NDP) and, optionally, Non-Contradictory Complementary Information (NCCI) to Eurocodes Parameters that stay open in the Eurocodes for the election of one national option, either because they are ignored in the Eurocodes or because they depend directly on the country

37 3. Codes 3.2. Europe What National Annexes (NA) are? Technical documents of national implementation with the objectives of the definition of the Nationally Determined Parameters (NDP) and, optionally, Non-Contradictory Complementary Information (NCCI) to Eurocodes Parameters that stay open in the Eurocodes for the election of one national option, either because they are ignored in the Eurocodes or because they depend directly on the country Information that helps the user to apply the Eurocode and the National Annexes

38 3. Codes 3.3. Nearby countries Codes in nearby countries

39 3. Codes 3.3. Nearby countries Codes in nearby countries Argentina CIRSOC 601 (2013) ASD

40 3. Codes 3.3. Nearby countries Codes in nearby countries Argentina CIRSOC 601 (2013) ASD Chile NCh 1198 (2006) ASD

41 3. Codes 3.3. Nearby countries Codes in nearby countries Argentina CIRSOC 601 (2013) ASD Chile NCh 1198 (2006) ASD Brazil NBR 7190 (2010) LRFD

42 3. Codes 3.4. Uruguay Codes in Uruguay Actions on structures UNIT 33 (1991) General actions on buildings UNIT 50 (1984) Wind actions on structures

43 3. Codes 3.4. Uruguay Actions on structures UNIT 33 (1991) General actions on buildings UNIT 50 (1984) Wind actions on structures Concrete design Codes in Uruguay UNIT 1050 (2005) Design and construction of concrete structures

44 3. Codes 3.4. Uruguay Actions on structures UNIT 33 (1991) General actions on buildings UNIT 50 (1984) Wind actions on structures Concrete design Codes in Uruguay UNIT 1050 (2005) Design and construction of concrete structures Steel and timber design IE3-53 (1953) Design of steel structures IE4-50 (1950) Design of timber structures

45 3. Codes 3.4. Uruguay Codes in Uruguay There is not a national code for the design of timber structures in Uruguay

46 3. Codes 3.4. Uruguay Codes in Uruguay There is not a national code for the design of timber structures in Uruguay This can cause inconsistencies between the determination of mechanical properties of the material and the method used for the design by engineers or architects

47 3. Codes 3.4. Uruguay Codes in Uruguay There is not a national code for the design of timber structures in Uruguay This can cause inconsistencies between the determination of mechanical properties of the material and the method used for the design by engineers or architects There is not a common criterion for all materials regarding deflection limits, acceptable vibration frequencies or time required of mechanical resistance in fire

48 3. Codes 3.4. Uruguay Codes in Uruguay There is not a national code for the design of timber structures in Uruguay Objective of the work Design a code for timber structures for Uruguay whether developing an own code or adopting an existing one

49 4. Methodology Research project: Technical documents for standardization of timber structures and buildings

50 4. Methodology Research project: Technical documents for standardization of timber structures and buildings Lines of work 1) Determining the physical and mechanical properties of timber in Uruguay

51 4. Methodology Research project: Technical documents for standardization of timber structures and buildings Lines of work 1) Determining the physical and mechanical properties of timber in Uruguay 2) Design a code for timber structures for Uruguay The results of this second line are presented in this work.

52 4. Methodology Research project: Technical documents for standardization of timber structures and buildings Lines of work 1) Determining the physical and mechanical properties of timber in Uruguay 2) Design a code for timber structures for Uruguay Tasks performed Analysis of international codes for the design of timber structures The results of this second line are presented in this work.

53 4. Methodology Research project: Technical documents for standardization of timber structures and buildings Lines of work 1) Determining the physical and mechanical properties of timber in Uruguay 2) Design a code for timber structures for Uruguay Tasks performed Analysis of international codes for the design of timber structures Discussion about whether to develop an own code or adopt an existing one The results of this second line are presented in this work.

54 4. Methodology Research project: Technical documents for standardization of timber structures and buildings Lines of work 1) Determining the physical and mechanical properties of timber in Uruguay 2) Design a code for timber structures for Uruguay The results of this second line are presented in this work. Tasks performed Analysis of international codes for the design of timber structures Discussion about whether to develop an own code or adopt an existing one Drafting of a proposal for the Uruguayan National Annex to Eurocode 5

55 5. Results 5.1. Nationally Determined Parameters EN : Nationally Determined Parameters (NDP) (2)P: Assignment of loads to load-duration classes (1)P: Assignment of timber constructions to service classes (1)P: Partial factors for material properties 6.4.3(8): Tensile stresses in double tapered, curved and pitched cambered beams 7.2.(2): Limiting values for deflections of beams 7.3.3(2): Vibrations in residential floors (4): Lateral load-carrying capacity of nails in end grain (7): Species sensitive to splitting in nailed joints (7): Racking resistance of wall diaphragms (1): Modification factors for bracing systems (3): Erection tolerances for trusses: maximum bow (4): Erection tolerances for trusses: maximum deviation from vertical alignment

56 5. Results 5.1. Nationally Determined Parameters EN : Nationally Determined Parameters (NDP) (2)P: Assignment of loads to load-duration classes (1)P: Assignment of timber constructions to service classes (1)P: Partial factors for material properties 6.4.3(8): Tensile stresses in double tapered, curved and pitched cambered beams 7.2.(2): Limiting values for deflections of beams 7.3.3(2): Vibrations in residential floors (4): Lateral load-carrying capacity of nails in end grain (7): Species sensitive to splitting in nailed joints (7): Racking resistance of wall diaphragms (1): Modification factors for bracing systems (3): Erection tolerances for trusses: maximum bow (4): Erection tolerances for trusses: maximum deviation from vertical alignment

57 5. Results 5.1. Nationally Determined Parameters EN : Nationally Determined Parameters (NDP) 2.1.3(2): Maximum temperature rise for separating function in parametric fire 2.3(1)P: Partial factor for material properties in fire 2.3(2)P: Partial factor for mechanical resistance of connections in a fire situation 2.4.2(3): Reduction factor for combinations of actions 4.2.1(1): Procedure for determining cross-sectional properties

58 5. Results 5.1. Nationally Determined Parameters Partial factors for material properties Quality control of the timber Quality control of the construction Factor for material properties Fundamental combinations Accidental combinations Normal Normal 1,60 Intense 1,45 Intense Normal 1,45 Intense 1,30 Normal - 1,10 Intense - 1,00

59 5. Results 5.1. Nationally Determined Parameters Partial factors for material properties Quality control of the timber Quality control of the construction Factor for material properties Fundamental combinations Accidental combinations Normal Normal 1,60 Intense 1,45 Intense Normal 1,45 Intense 1,30 Normal - 1,10 Intense - 1,00 Quality control of the timber: certification Quality control of the construction: judgment of the designer (relevance of the building, structural complexity, etc.)

60 5. Results 5.1. Nationally Determined Parameters Partial factors for material properties Quality control of the timber Quality control of the construction Factor for material properties Fundamental combinations Accidental combinations Normal Normal 1,60 Intense 1,45 Intense Normal 1,45 Intense 1,30 Normal - 1,10 Intense - 1,00 Eurocode 0 (EN 1990) Annex 3 About 200 specimens of Uruguayan Pinus elliottii/taeda

61 5. Results 5.1. Nationally Determined Parameters Limiting values for deflections of beams Integrity of the constructive elements Criteria Floors with brittle partitions Floors with ordinary partitions Other cases With ceiling or false plasterboard ceiling Without ceiling or false plasterboard ceiling Limiting values w act l/500 w act l/400 w act l/300 w act l/200 User comfort Floors and beams of floors w inst l/350 Appearance of the building work w net,fin l/300

62 5. Results 5.2. Non-Contradictory Complementary Information Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 External forces and load combinations Definitions for calculation of vertical and horizontal deflections Procedure for verification of floor vibrations

63 5. Results 5.2. Non-Contradictory Complementary Information Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 External forces and load combinations Definitions for calculation of vertical and horizontal deflections Procedure for verification of floor vibrations

64 5. Results 5.2. Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 UNIT 50 (1984): Wind actions on structures Proposed methods: 1) Establish the wind actions on structures according to UNIT 50.

65 5. Results 5.2. Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 UNIT 50 (1984): Wind actions on structures Proposed methods: 1) Establish the wind actions on structures according to UNIT 50. 2) Convert the characteristic wind velocity (v k ), defined by UNIT 50, in the basic wind velocity (v b ), defined by Eurocode 1, and establish the wind actions on structures according to Eurocode 1.

66 5. Results 5.2. Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 UNIT 50 (1984): Wind actions on structures Proposed methods: 1) Establish the wind actions on structures according to UNIT 50. 2) Convert the characteristic wind velocity (v k ), defined by UNIT 50, in the basic wind velocity (v b ), defined by Eurocode 1, and establish the wind actions on structures according to Eurocode 1. v b = 0,858 0,676 1,149 v k = 0,667 v k

67 5. Results 5.2. Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 UNIT 50 (1984): Wind actions on structures Proposed methods: 1) Establish the wind actions on structures according to UNIT 50. 2) Convert the characteristic wind velocity (v k ), defined by UNIT 50, in the basic wind velocity (v b ), defined by Eurocode 1, and establish the wind actions on structures according to Eurocode 1. v b = 0,858 0,676 1,149 v k = 0,667 v k Ground roughness

68 5. Results 5.2. Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 UNIT 50 (1984): Wind actions on structures Proposed methods: 1) Establish the wind actions on structures according to UNIT 50. 2) Convert the characteristic wind velocity (v k ), defined by UNIT 50, in the basic wind velocity (v b ), defined by Eurocode 1, and establish the wind actions on structures according to Eurocode 1. v b = 0,858 0,676 1,149 v k = 0,667 v k Ground roughness Sampling interval

69 5. Results 5.2. Non-Contradictory Complementary Information Relationship between UNIT Actions Codes and Eurocode 1 UNIT 50 (1984): Wind actions on structures Proposed methods: 1) Establish the wind actions on structures according to UNIT 50. 2) Convert the characteristic wind velocity (v k ), defined by UNIT 50, in the basic wind velocity (v b ), defined by Eurocode 1, and establish the wind actions on structures according to Eurocode 1. v b = 0,858 0,676 1,149 v k = 0,667 v k Ground roughness Sampling interval Return period

70 5. Results 5.3. Research topics Future research topics Study of the embedment strength for the design of connections

71 5. Results 5.3. Research topics Future research topics Study of the embedment strength for the design of connections Determination of the sensitivity to splitting of local cultivated species

72 5. Results 5.3. Research topics Future research topics Study of the embedment strength for the design of connections Determination of the sensitivity to splitting of local cultivated species Study of the charring rates of local cultivated species

73 5. Results 5.3. Research topics Future research topics Study of the embedment strength for the design of connections Determination of the sensitivity to splitting of local cultivated species Study of the charring rates of local cultivated species Determination of the physical and mechanical properties of sawn timber and engineered wood products. Develop an UNIT standard for visual grading and establish the correlation with the strength classes

74 6. Conclusions Conclusions Eurocode 5 parts 1-1 and 1-2 were proposed to be used in Uruguay for the design of timber structures. The adoption of the Eurocode 5 establishes a precedent in Uruguay for other construction materials

75 6. Conclusions Conclusions Eurocode 5 parts 1-1 and 1-2 were proposed to be used in Uruguay for the design of timber structures. The adoption of the Eurocode 5 establishes a precedent in Uruguay for other construction materials A National Annex to Eurocode 5 was proposed. This document contains the Nationally Determined Parameters and Non-Contradictory Complementary Information to Eurocode 5 for the Uruguayan conditions of timber design

76 6. Conclusions Conclusions Eurocode 5 parts 1-1 and 1-2 were proposed to be used in Uruguay for the design of timber structures. The adoption of the Eurocode 5 establishes a precedent in Uruguay for other construction materials A National Annex to Eurocode 5 was proposed. This document contains the Nationally Determined Parameters and Non-Contradictory Complementary Information to Eurocode 5 for the Uruguayan conditions of timber design In order to complete the National Annex to Eurocode 5 with information about local cultivated species and local conditions a list of research topics was recommended