1、BSI Standards PublicationBS EN 16481:2014Timber stairs Structuraldesign Calculation methodsBS EN 16481:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 16481:2014.The UK participation in its preparation was entrusted to TechnicalCommittee B/543, Round and sa
2、wn timber.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2014. Published by BS
3、I StandardsLimited 2014ISBN 978 0 580 79693 7ICS 91.060.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 June 2014.Amendments issued since publicationDate Text
4、 affectedBS EN 16481:2014EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16481 June 2014 ICS 91.060.30 English Version Timber stairs - Structural design - Calculation methods Escaliers en bois - Conception de la structure - Mthodes de calcul Holztreppen - Bauplanung - Berechnungsmethoden This E
5、uropean Standard was approved by CEN on 17 April 2014. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
6、concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN membe
7、r into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, Fran
8、ce, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KO
9、MITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16481:2014 EBS EN 16481:2014EN 16481:2014 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Normative r
10、eferences 6 3 Terms and definitions, formula symbols and SI-units .7 3.1 Terms and definitions .7 3.2 Notation of formula symbols 7 3.3 SI-units . 11 4 Principles for verification of mechanical performance characteristics 12 4.1 Performance characteristics to be verified 12 4.2 Typical actions 12 4.
11、3 Significant action combinations . 12 4.3.1 General . 12 4.3.2 Action combinations relevant for verification of usability/serviceability . 13 4.3.3 Action combination for verification of the load-bearing capacity . 13 4.4 Bearing resistance within the verification of the load-bearing capacity 13 5
12、Determination of mechanical stress (stress resultants and deformations) . 14 5.1 General . 14 5.2 Static systems and cross-section properties for tread of stairs . 16 5.2.1 Parallel treads without riser . 16 5.2.2 Parallel steps with riser 18 5.2.3 Tapered treads 19 5.2.4 Kite winders . 22 5.3 Stati
13、c systems for stair strings and their cross-sectional characteristics . 24 5.3.1 Closed strings . 24 5.3.2 Cut string . 28 5.4 Calculation models for joints 32 5.4.1 General . 32 5.4.2 Modelling of tread-string connections . 33 5.4.3 Modelling of string-corner connections . 44 5.4.4 Modelling of con
14、nections to the construction . 46 5.5 Modelling of loads 49 5.5.1 Modelling of permanent loads . 49 5.5.2 Modelling of the variable, equally distributed vertical load qk,1. 49 5.5.3 Modelling of the variable and equally distributed horizontal load qk,250 6 Verification within the limit state of serv
15、iceability 52 6.1 General . 52 6.2 Limit values of deformations . 52 6.3 Verification of oscillation . 53 7 Verification within the limit state of load bearing capacity 53 7.1 General . 53 7.2 Verification of the load-bearing capacity of cross-sections 53 7.3 Verification of load-bearing capacity of
16、 the connections. 54 7.3.1 Verification of load-bearing capacity of tread-string connections 54 7.3.2 Verification of the load-bearing capacity of string-corner connections . 55 7.4 Verification of the load-bearing capacity of connections to the building. 57 Bibliography . 58 BS EN 16481:2014EN 1648
17、1:2014 (E) 3 Foreword This document (EN 16481:2014) has been prepared by Technical Committee CEN/TC 175 “Round and sawn timber”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endors
18、ement, at the latest by December 2014, and conflicting national standards shall be withdrawn at the latest by December 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for iden
19、tifying any or all such patent rights. This document takes into account the following standards: EN 1990; EN 1991-1-1; EN 1995-1-1. This document is addressed for structural designers to design timber stairs from a common European method; it should be useful for SMEs as an alternative to testing whe
20、re applicable. This European Standard takes into account the current state of the art regarding safety concept, loading assumptions, determination of stress resultants, as well as dimensioning in the field of wood engineering. The requirements and verification procedures essential for the verificati
21、on of mechanical performance characteristics, serviceability and load-bearing capacity of stairs and their components are compiled and described in the following clauses. The mechanical performance characteristics of stairs may be verified by using the following methods: testing of stairs as a whole
22、 or in part; mathematical verification on the basis of structural analysis following the principles of this European Standard; assessment based on experience: conventionally accepted performance (CAP) which should be defined in national documents. All methods are equally valid. This document needs t
23、o be read in conjunction with EN 15644. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yug
24、oslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 16481:2014EN 16481:2014 (E) 4 1 Scope Thi
25、s European Standard constitutes a frame standard for the design of timber stairs as well as wood and wood-based components used in stairs by calculation methods. Some calculation methods can be derived from testing results, for example CEN/TS 15680. This document specifies the design and the require
26、ments for materials and components to be used in these calculation methods. It may be complemented by national application documents based on this European Standard. This European Standard applies to coated and uncoated components. This document covers load-bearing components such as strings, treads
27、, risers, posts and guardrails. Requirements for a timber stair are defined in the product standard, EN 15644. This document does not cover stairs that contribute to the overall stability of the works or the strength of the structure. This European Standard is valid for the verification of mechanica
28、l performance characteristics, usability and load-bearing capacity and their related durability. Other requirements, e.g. requirements for acoustic properties, are not covered by this European Standard. For the design, calculation and determination of not solely resting actions, additional requireme
29、nts need to be taken into account (to be checked). For the dimensioning with special reference to resistance to fire and earthquake/seismic action, additional requirements may be taken into account. Without further verification, the methods in this European Standard are valid for different types of
30、stair structures and their components, as illustrated in Figure 1: a) Stair with closed string and riser BS EN 16481:2014EN 16481:2014 (E) 5 b) Stair with closed string without riser c) Stair with cut strings and riser BS EN 16481:2014EN 16481:2014 (E) 6 d) Stair with cut strings without riser e) Co
31、mbination of stairs with closed string and cut string with or without riser Figure 1 Types of stair structures and their components 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated re
32、ferences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 338, Structural timber Strength classes EN 1990, Eurocode Basis of structural design EN 1991-1-1:2002, Eurocode 1: Actions on structures Part 1-1: Ge
33、neral actions Densities, self-weight, imposed loads for buildings EN 1993-1-1, Eurocode 3: Design of steel structures Part 1-1: General rules and rules for buildings BS EN 16481:2014EN 16481:2014 (E) 7 EN 1995-1-1, Eurocode 5: Design of timber structures Part 1-1: General Common rules and rules for
34、buildings NOTE Eurocode includes its National Application Documents (NAD). EN 14076, Timber stairs Terminology EN 15644, Traditionally designed prefabricated stairs made of solid wood Specifications and requirements EN ISO 80000-1, Quantities and units Part 1: General (ISO 80000-1) 3 Terms and defin
35、itions, formula symbols and SI-units 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in EN 1990, EN 1995-1-1 and EN 14076 and the following apply. NOTE The general terms used in the context of actions and resistance as well as terms referring to the safet
36、y concept are given in EN 1990. The specific valid terms used in the field of wood construction are found in EN 1995-11. Specific terms regarding stair construction are given in EN 14076. 3.1.1 cross-bracing tie-bars system designed to provide torsional restraint to strings EXAMPLE Screws, nails, gl
37、ues. 3.2 Notation of formula symbols In most cases, the notation of formula symbols consists of a main symbol (main indicator) and one or more subscript indicators. The following list defines the most common notations. Explanations of further notations either follow immediately the formula in which
38、they appear or are described in the accompanying text. pitch partial safety factor for loads xtorsional angle around the x-axis ytorsional angle around the y-axis ztorsional angle around the z-axis Mpartial safety factor for a material property 0combination coefficient A cross-sectional area Aycross
39、-sectional shear area in the direction of the y-axis Azcross-sectional shear area in the direction of the z-axis Across-bracingcross-sectional area of the cross-bracing Astringcalculated cross-sectional area of the string BS EN 16481:2014EN 16481:2014 (E) 8 Astring,I-Ireal cross-sectional area of th
40、e string in section I-I Astring,III-IIIreal cross-sectional area of the string in section III-III Ay,stringcalculated shear area of the string in the direction of the y-axis Az,stringcalculated shear area of the string in the direction of the z-axis corner_i connecting rod, bottom string-corner sect
41、ion corner_i+1 connecting rod, top string-corner section Dmaxmaximum distance between lower edge of string and lower edge of housing Dmediumaverage value of Dmaxund DminDminsmallest distance between upper edge of string and upper edge of housing d cross-sectional thickness, subscript for rated value
42、 dhousingdepth of housing dtreadthickness of the tread dstringthickness of the string E modulus of elasticity e eccentricity EA stretch stiffness of a component Edvalue of influence regarding the verification EIybending stiffness around the y-axis EIzbending stiffness around the z-axis EIy,treadbend
43、ing stiffness of the tread around the y-axis EIz,treadbending stiffness of the tread around the z-axis etreaddistance of the plumb line of tread and the idealized plumb line of the cut string F force, point load f1fundamental frequency G rigidity modulus GAyrigidity stiffness of a component in the d
44、irection of the y-axis GAzrigidity stiffness of a component in the direction of the z-axis GIttorsional stiffness of a component Gkpermanent action of construction including all fasteners g going H acting horizontally live load h height of cross-section hbalustradedistance between horizontal rail lo
45、ad and tread hmaxreal maximum section height of the cut sting hminreal minimum section height of the cut sting hc,string,max real maximum distance between the plumb line of a cut string to lowest edge of the string hc,string,minreal minimum distance between the plumb line of a cut string to lowest e
46、dge of string hcutmaximum height of the cut string area (hcut= hmax hmin) hstringheight of the string BS EN 16481:2014EN 16481:2014 (E) 9 hhousingheight of the housing h*c,stringcalculated distance of the plumb line of a cut string to lowest edge of string h*stringcalculated height of the cut string
47、 H*stringorthogonal projection of the calculated height of the cut string H*c,stringorthogonal projection of the calculated distance of the plumb line of a cut string to lowest edge of string I moment of inertia Icross-bracing calculated moment of inertia of the cross-bracing by stairs with cut stri
48、ngs Ittorsional moment of inertia It,stringcalculated torsional moment of inertia from the string Iymoment of inertia around the y-axis Iy,stringcalculated moment of inertia of the string around the y-axis Iy,string, I-Ireal moment of inertia of the string around the y-axis in section I-I Iy,string,
49、III-IIIreal moment of inertia of the string around the y-axis in section III-III Izmoment of inertia around the z-axis Iz,stringcalculated moment of inertia of the string around the z-axis k spring stiffness kDtorsion spring stiffness kDytorsion spring stiffness in bending around the y-axis kDztorsion spring stiffness in bending around the z-axis kFstretch spring stiffness kmcoefficient kmodmodifications coefficient that takes into account the impact of the service class and load duration on the strength properties Kshapecoefficient
