SIST EN 16481:2014
(Main)Timber stairs - Structural design - Calculation method
Timber stairs - Structural design - Calculation method
EN 16481 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 requirements for materials and components to be used in these calculation methods. It may be complemented by national application documents based on this standard. This European Standard applies to coated and uncoated components. This document covers load-bearing components such as strings, steps, risers, newels, handrails and balustrades. This document provides examples of calculations in part 2 (or Annex, see separate document N 283). The 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 mechanical performance characteristics, usability and load-bearing capacity and their related durability. Other requirements, e.g. requirements for acoustic properties, are not covered by this standard. For the design, calculation and determination of not solely resting actions, additional requirements 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.
Holztreppen - Bauplanung - Berechnungsverfahren
Dieser Europäische Norm-Entwurf legt ein Berechnungsverfahren für die Konstruktion von Holztreppen sowie für Bauteile aus Holz und Holzwerkstoffen, die für Treppen verwendet werden, in einer Rahmennorm fest. Einige Berechnungsverfahren können von Prüfergebnissen abgeleitet werden, z. B. CEN/TS 15680. Dieses Dokument legt die Konstruktion von und die Anforderungen an Werkstoffe(n) und Bauteile(n) fest, die in diesen Berechnungsverfahren zu verwenden sind. Sie kann durch Nationale Anwendungsdokumente ergänzt werden, die auf dieser Norm beruhen.
Dieser Europäische Norm-Entwurf gilt für beschichtete und unbeschichtete Bauteile. Dieses Dokument behandelt tragende Bauteile wie Wangen, Stufen, Setzstufen, Pfosten, Handläufe und Umwehrungen. Dieses Dokument enthält Berechnungsbeispiele in Teil 2 (oder Anhang, siehe das separate Dokument N 283). Die Anforderungen an eine Holztreppe sind in der Produktnorm EN 15644 festgelegt. Dieses Dokument behandelt keine Treppen, die zur allgemeinen Standsicherheit von Bauwerken oder zur Festigkeit der Konstruktion beitragen.
Dieser Europäische Norm-Entwurf gilt für den Nachweis mechanischer Leistungseigenschaften, Gebrauchs-tauglichkeit, Tragfähigkeit und der damit verbundenen Dauerhaftigkeit. Weitere Anforderungen, z. B. Anforde-rungen an akustische Eigenschaften, werden in dieser Norm nicht behandelt.
Für die Konstruktion, Berechnung und Bestimmung von nicht nur stützenden Einwirkungen müssen zusätz¬liche Anforderungen berücksichtigt werden. (Zu überprüfen).
Für die Bemessung mit besonderer Verweisung auf Brandverhalten/Beständigkeit gegen Erdbeben/seis-mische Einwirkungen können zusätzliche Anforderungen berücksichtigt werden.
Die folgende Information gilt ohne weiteren Nachweis für verschiedene Arten von Treppenbauten und ihrer Bauteile, wie in den Bildern 1 folgt:
Escaliers en bois - Conception de la structure - Méthode de calcul
Le présent document constitue une norme cadre pour la conception, par des méthodes de calcul, des escaliers en bois ainsi que des éléments en bois et à base de bois utilisés dans les escaliers. Certaines méthodes de calcul peuvent être issues de résultats d’essai, par exemple la CEN/TS 15680. Le présent document spécifie la conception et les exigences relatives aux matériaux et aux éléments à utiliser dans ces méthodes de calcul. Il peut être complété par des documents d’application nationaux fondés sur la présente norme.
Le présent document s’applique aux éléments revêtus et non revêtus. Le présent document couvre les éléments porteurs tels que limons, marches, contremarches, poteaux, mains courantes et balustrades. Le présent document fournit des exemples de calculs dans la partie 2 (ou une annexe, voir le document séparé N 283). Les exigences relatives à un escalier en bois sont définies dans la norme de produit EN 15644. Le présent document ne traite pas des escaliers qui contribuent à la stabilité générale de l’ouvrage ou à la résistance de la structure.
La présente norme est valable pour la vérification des caractéristiques de performances mécaniques, la facilité d’usage et la capacité portante ainsi que la durabilité associée. Les autres exigences, par exemple les exigences relatives aux propriétés acoustiques, ne sont pas traitées dans la présente norme.
Pour la conception, le calcul et la détermination des actions qui ne sont pas uniquement des actions de repos, des exigences supplémentaires doivent être prises en compte (à vérifier).
Pour le dimensionnement avec une référence particulière à la résistance au feu et à l’action sismique, des exigences supplémentaires peuvent être prises en compte.
Sans vérification supplémentaire, les informations suivantes sont valables pour différents types de structures d’escaliers et leurs éléments, tels qu’illustrés dans les Figures 1 suivantes :
Lesene stopnice - Dimenzioniranje konstrukcij - Računska metoda
Standard EN 16481 predstavlja okvirni standard za načrtovanje lesenih stopnic in lesenih sestavnih delov ali sestavnih delov na osnovi lesa, ki se uporabljajo v stopnicah, s pomočjo računskih metod. Nekatere računske metode je mogoče izpeljati iz preskusnih rezultatov, na primer CEN/TS 15680. Ta dokument določa načrtovanje in zahteve za materiale in sestavne dele, ki jih je treba uporabiti v teh računskih metodah. Dopolnjujejo ga lahko nacionalni izvedbeni dokumenti, ki temeljijo na tem standardu. Ta evropski standard velja za premazane in nepremazane sestavne dele. Ta dokument zajema nosilne sestavne dele, kot so notranja lica, stopnice, ličnice, sredinski drogovi, stopniščne ograje in podestne ograje. Ta dokument v delu 2 (ali dodatku, glejte poseben dokument N 283) zagotavlja primere izračunov. Zahteve za lesene stopnice določa proizvodni standard EN 15644. Ta dokument ne zajema stopnic, ki prispevajo k splošni stabilnosti konstrukcije ali trdnosti strukture. Ta evropski standard velja za verifikacijo lastnosti mehanske zmogljivosti, uporabe in nosilnosti ter z njimi povezano trajnost. Druge zahteve, npr. zahteve po akustičnih lastnostih, niso zajete v tem standardu. Za načrtovanje, izračunavanje in določanje ostalih ukrepov je treba upoštevati dodatne zahteve. (bo preverjeno naknadno). Za dimenzioniranje s posebnim poudarkom na požarni odpornosti in potresom se lahko upošteva dodatne zahteve.
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Holztreppen - Bauplanung - BerechnungsverfahrenEscaliers en bois - Conception de la structure - Méthode de calculTimber stairs - Structural design - Calculation method91.060.30Stropi. Tla. StopniceCeilings. Floors. StairsICS:Ta slovenski standard je istoveten z:EN 16481:2014SIST EN 16481:2014en,fr,de01-september-2014SIST EN 16481:2014SLOVENSKI
STANDARD
SIST EN 16481:2014
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16481
June 2014 ICS 91.060.30 English Version
Timber stairs - Structural design - Calculation methods
Escaliers en bois - Conception de la structure - Méthodes de calcul
Holztreppen - Bauplanung - Berechnungsmethoden This European 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 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 member 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, France, 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
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR 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 ESIST EN 16481:2014
EN 16481:2014 (E) 2 Contents Page Foreword .3 1 Scope .4 2 Normative references .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 4.3 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 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 Static 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 connections 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,2 . 50 6 Verification within the limit state of serviceability . 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 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
SIST EN 16481:2014
EN 16481:2014 (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 endorsement, 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 identifying 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 where 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 verification 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 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 to 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 Yugoslav 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. SIST EN 16481:2014
EN 16481:2014 (E) 4 1 Scope This 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 requirements 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, 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 mechanical 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 requirements 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 stair structures and their components, as illustrated in Figure 1:
a) Stair with closed string and riser SIST EN 16481:2014
EN 16481:2014 (E) 5
b) Stair with closed string without riser
c) Stair with cut strings and riser SIST EN 16481:2014
EN 16481:2014 (E) 6
d) Stair with cut strings without riser
e) Combination 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 references, 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: General 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 SIST EN 16481:2014
EN 16481:2014 (E) 7 EN 1995-1-1, Eurocode 5: Design of timber structures — Part 1-1: General — Common rules and rules for 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 definitions, 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 safety concept are given in EN 1990. The specific valid terms used in the field of wood construction are found in EN 1995-1–1. 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, glues. 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 they appear or are described in the accompanying text. . pitch
partial safety factor for loads 3x torsional angle around the x-axis 3y torsional angle around the y-axis 3z torsional angle around the z-axis M partial safety factor for a material property 0 combination coefficient A cross-sectional area Ay cross-sectional shear area in the direction of the y-axis Az cross-sectional shear area in the direction of the z-axis Across-bracing cross-sectional area of the cross-bracing Astring calculated cross-sectional area of the string SIST EN 16481:2014
EN 16481:2014 (E) 8 Astring,I-I real cross-sectional area of the string in section I-I Astring,III-III real cross-sectional area of the string in section III-III Ay,string calculated shear area of the string in the direction of the y-axis Az,string calculated shear area of the string in the direction of the z-axis corner_i connecting rod, bottom string-corner section corner_i+1 connecting rod, top string-corner section Dmax maximum distance between lower edge of string and lower edge of housing Dmedium average value of Dmax und Dmin Dmin smallest distance between upper edge of string and upper edge of housing d cross-sectional thickness, subscript for rated value dhousing depth of housing dtread thickness of the tread dstring thickness of the string E modulus of elasticity e eccentricity EA stretch stiffness of a component Ed value of influence regarding the verification EIy bending stiffness around the y-axis EIz bending stiffness around the z-axis EIy,tread bending stiffness of the tread around the y-axis EIz,tread bending stiffness of the tread around the z-axis etread distance of the plumb line of tread and the idealized plumb line of the cut string F force, point load f1 fundamental frequency G rigidity modulus GAy rigidity stiffness of a component in the direction of the y-axis GAz rigidity stiffness of a component in the direction of the z-axis GIt torsional stiffness of a component Gk permanent action of construction including all fasteners g going H acting horizontally live load h height of cross-section hbalustrade distance between horizontal rail load and tread hmax real maximum section height of the cut sting hmin real 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,min real minimum distance between the plumb line of a cut string to lowest edge of string hcut maximum height of the cut string area (hcut = hmax – hmin) hstring height of the string SIST EN 16481:2014
EN 16481:2014 (E) 9 hhousing height of the housing h*c,string calculated distance of the plumb line of a cut string to lowest edge of string h*string calculated height of the cut string H*string orthogonal projection of the calculated height of the cut string H*c,string orthogonal 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 strings It torsional moment of inertia It,string calculated torsional moment of inertia from the string Iy moment of inertia around the y-axis Iy,string calculated moment of inertia of the string around the y-axis Iy,string, I-I real moment of inertia of the string around the y-axis in section I-I Iy,string,III-III real moment of inertia of the string around the y-axis in section III-III Iz moment of inertia around the z-axis Iz,string calculated moment of inertia of the string around the z-axis k spring stiffness kD torsion spring stiffness kDy torsion spring stiffness in bending around the y-axis kDz torsion spring stiffness in bending around the z-axis kF stretch spring stiffness km coefficient kmod modifications coefficient that takes into account the impact of the service class and load duration on the strength properties Kshape coefficient according to the cross-sectional shape L length of cross-section or length of system La calculated support length at the wall side of a kite winder before the corner Lb calculated support length at the wall side of a kite winder after the corner Lc calculated support length at the outer side of a kite winder before the corner Ld calculated support length at the outer side of a kite winder after the corner Lcantilever calculated length of the overhang of a cut tread Lcut maximum length of cut string area Lload length of the actual line load Lstair length stair Ltread calculated span of tread M moment, bending moment, point load Mk,1 net mass of the structure, including all fasteners Mk,2 single mass Mrail,k bending moment for the computational modelling of the rail load SIST EN 16481:2014
EN 16481:2014 (E) 10 Mx,d,corner i governing torsional moment around the x-axis before the corner due to the load combinations Mx,d,corner_i+1 governing torsional moment around the x-axis after the corner due to the load combinations Mx,Rd,corner_i determined by tests in the link design value of the torsional recordable Mx,d,tread governing torsional moment at the beginning of the tread or end result of the load combination Mx,Rd,tread by test or calculation determined design value of recordable torsion in the tread My,d,corner_i governing bending moment around the y-axis before the corner due to the load combinations My,corner_i+1 governing bending moment around the y-axis after the corner due to the load combinations My,Rd,corner_i rated value of the absorbable bending moment in the connection around the y-axis, determined by tests (corner) My,d,tread governing bending moment around the y-axis at the beginning of the tread or end due to the load combinations My,Rd,tread rated value of the absorbable bending moment in the connection around the y-axis, determined by tests (tread) Mz,d,corner_i governing bending moment around the z-axis before the corner due to the load combinations Mz,corner_i+1 governing bending moment around the z-axis after the corner due to the load combinations Mz,Rd,corner_i rated value of the absorbable bending moment in the connection around the z-axis, determined by tests (corner) Mz,d,tread governing bending moment around the z-axis at the beginning of the tread or end due to the load combinations Mz,Rd,tread rated value of the absorbable bending moment in the connection around the z-axis, determined by tests (tread) mlower lower margins mupper upper margins o overlap Q variable action, point load Qk,1 concentrated point load q variable action, uniformly distributed load qk,1 equally distributed vertical load qk,2 equally distributed horizontal load qk,left maximum value of variable line load to be applied on a winder tread qk,right minimum value of variable line load to be applied on a winder tread r rise Td,cross-bracing governing tension force in the cross-bracing as a result of load combinations TRd,cross-bracing rated value of the tension force absorbable in the cross-bracing traction, determined by tests or calculation u, v, w deformation, deflexion w width section, SIST EN 16481:2014
EN 16481:2014 (E) 11 w1 outer side real tread width w1,id idealized outer side step width w2 wall side real tread width w2,id wall side idealized tread width wi_stair internal width of the stair wav,id average value of idealized tread widths wstair width of flight wtread tread depth wG vertical deformation due to permanent action wq,k1 vertical deformation due to variable uniformly distributed vertical load wQ,k1 vertical deformation due to vertical point load of size 2 kN in an unfavourable position X property of building material Xk characteristic value of a material property XRd design value of material property x, y, z coordinates xcross-bracing local x-axis of the cross-bracing ycross-bracing local y-axis of the cross-bracing zcross-bracing local z-axis of the cross-bracing xstring local x-axis of the string ystring local y-axis of the string zstring local z-axis of the string xtread local x-axis of the tread ytread local y-axis of the tread ztread local z-axis of the tread 3.3 SI-units SI-units shall be applied in accordance with EN ISO 80000-1. For calculations, the following units shall be applied: — forces and loads: kN, kN/m, kN/m2; — bulk density: kN/m3; — density: kg/m3; — tension, stress and stability: N/mm2 (=MN/m2 or MPa); — elasticity and rigidity modulus: N/mm2 (= MN/m2 or MPa); — moments (bending moment): kNm. SIST EN 16481:2014
EN 16481:2014 (E) 12 4 Principles for verification of mechanical performance characteristics 4.1 Performance characteristics to be verified The fulfilment of the following mechanical performance characteristics shall be verified. a) Serviceability – a stair is deemed to satisfy this requirement when: 1) under the actions applied, the deformation of the stair as a whole and/or its parts (e.g. steps and strings) shall not at any point exceed the preset maximum deformation values defined in EN 1995-1-1 (Eurocode 5) and National Application Document (NAD) when applicable, 2) under the action applied, the fundamental frequency of the stair as a whole shall fulfil the value defined in EN 1995-1-1 (Eurocode 5) and National Application Document (NAD) where applicable. b) Load-bearing capacity - a stair is deemed to satisfy this requirement when 1) the existing use of the stair as a whole or of one of its single parts under the applied actions shall not exceed at any point the nationally set maximum values with regard to admissible use. The fulfilment of both performance characteristics shall be verified. For the purpose of evaluating the results, the most unfavourable case is significant. Stairs assessed based on experience, e.g. conventionally accepted performance (CAP) may be accepted according to national decisions. 4.2 Typical actions Types and sizes of actions to be applied follow indications found in EN 1991-1-1 and are combined with relevant national regulations. In order to verify the mechanical performance characteristics of stairs, the following action types shall be considered: — Gk Dead load of construction including all fasteners according to EN 1991–1–1:2002, Clause 5. — qk,1 Equally distributed vertical load [kN/m2] according to EN 1991–1–1:2002, 6.3. Without a further national value, the default value should be applied as, qk,1 = 3 kN/m2. — Qk,1 Concentrated single load [kN] according to EN 1991–1–1:2002, 6.3. Without a further national value, the default value should be applied as, Qk,1 = 2 kN. — qk,2 Equally distributed horizontal load [kN/m] according to EN 1991–1–1:2002, 6.4. Without a further national value, the default value should be applied as qk,2 = 0,5 kN/m. — Mk,1 Permanent mass of construction including the mass of all fasteners. — Mk,2 Single mass for fundamental frequency. Without a further national value, the default value should be applied as Mk,2 = 1 kN . 4.3 Significant action combinations 4.3.1 General Types and sizes of applied action combinations are chosen on the basis EN 1991-1-1 in combination with relevant national regulations. In order to verify the mechanical performance characteristics of a prefabricated stair or of one of its parts, the following typical action combinations shall be examined. SIST EN 16481:2014
EN 16481:2014 (E) 13 Without national values, the default values should be applied as given below. 4.3.2 Action combinations relevant for verification of usability/serviceability The verification of usability/serviceability shall be carried out by using three action combinations. 1) Action combination “Deformation_qk,1” The significant actions Ed consist of: {}k,11,01,0EEGq=⋅+⋅dk (1) 2) Action combination “Deformation_Qk,1” The significant actions Ed consist of: {},11,01,0EEGQ=⋅+⋅dkk (2) 3) Action combination “Fundamental frequency_Mk,2” The significant actions Ed consist of: {}121010EEMM=⋅+⋅dk,k,,, (3) 4.3.3 Action combination for verification of the load-bearing capacity The verification of the load-bearing capacity shall be carried out by using two action combinations. 1) Action combination “Rupture Load_qk,1” The significant actions Ed consist of: {}{},10,2,1,21,351,51,51,351,51,05EEGqqEGqq=⋅+⋅+⋅⋅=⋅+⋅+⋅ψdkkkkkk (4) 2) Action combination “Rupture Load_Qk,1” The significant actions Ed consist of: {}113515EEGQ=⋅+⋅dkk,,, (5) 4.4 Bearing resistance within the verification of the load-bearing capacity The properties of building materials are indicated by characteristic values, Xk. For wood and wood-based materials, and in the absence of relevant national directives, the assessment values XRd used within the limit state of the load-bearing capacity result from: kXX⋅=γmodkRdm (6) SIST EN 16481:2014
EN 16481:2014 (E) 14 For example using solid timber in service class 2 or 1, use kmod =
0,9 and m = 1,3. For steel parts, the assessment values XRd used within the limit state of the load-bearing capacity shall be taken from EN 1993-1-1 in the absence of relevant national directives. In the absence of relevant national directives, the characteristic stress, stiffness and bulk density indices shall be taken from EN 1995-1-1. In the absence of relevant national directives, the characteristic rupture load, Xk, is used as the lowest value derived from tests with relevance to components resistance based on three identical component tests. For rupture loads derived from components tests, and in the absence of relevant national directives, the assessment values XRd used within the limit state of the load-bearing capacity result from: 15XXX==γkkRdm, (7) Without a further national value, the default value m shall be applied as 1,5 where a minimum of 3 tests have been conducted and this value can be changed to 1,3 where 10 or more tests have been carried out (see ETAG 008). 5 Determination of mechanical stress (stress resultants and deformations) 5.1 General a) In principle, this European Standard allows the determination of mechanical stress (stress resultants and deformations) in two different ways, as follows: 1) separate determination of mechanical stress of treads or strings, respectively, with the help of structural frame analysis, either on plan or spatial, as well as static systems for all single parts independent from each other; 2) interrelated determination of mechanical stress of treads and strings with the help of spatial structural frame analysis and a spatial static system of the stair as a whole. b) The separate determination of mechanical stress is valid for: 1) all forms of single treads, 2) straight stairs with vertical support in places described in the following manner (see Figure 2),
Figure 2 — Ground plan of straight stairs SIST EN 16481:2014
EN 16481:2014 (E) 15 3) turning stairs (winding stairs) with vertical support in all places in which the string changes direction (see Figure 3).
Figure 3 — Ground p
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