Eurocode 3 - Design of joints

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MMj,Rd j,RdM2/3 M j,Edj,RdMj,Ed S ηS /j,ini φφ j,ini0 ” 0 0 ” 0a) 2/3 b)j,Ed j,Rd j,Ed j,Rd)LJXUH5RWDWLRQDOVWLIIQHVVWREHXVHGLQHODVWLFJOREDODQDO\VLV7DEOH6WLIIQHVVPRGLILFDWLRQFRHIILFLHQWOther types of joints(beam-to-beamBeam-to-columnType of connection joints joints, beam splices,column base joints)Welded 2 3Bolted end-plate 2 3Bolted flange cleats 2 3,5Base plates - 3 5LJLGSODVWLFJOREDODQDO\VLV(1) The joints should be classified according to their strength, see 5.2.3.0(2) For joints connecting H or I sections is given in 6.2.j,Rd(3) For joints connecting hollow sections the method given in section 7 may be used.(4) The rotation capacity of a joint shall be sufficient to accommodate the rotations resulting from theanalysis.(5) For joints connecting H or I sections the rotation capacity should be checked according to 6.4. (ODVWLFSODVWLFJOREDODQDO\VLV(1) The joints should be classified according to both stiffness (see 5.2.2) and strength (see 5.2.3).6 φ0 is given in 6.2,

(1) The provisions given in 5.1.5 apply only to structures whose joints are verified according to section 7.

(2) The distribution of axial forces in a lattice girder may be determined on the assumption that the members are connected by pinned joints (see also 2.7).

(3) Secondary moments at the joints, caused by the rotational stiffnesses of the joints, may be neglected both in the design of the

(4) The moment rotation characteristic of the joints should be used to determine the distribution of internal forces and moments.

(5) As a simplification, the bi-linear design moment-rotation characteristic shown in Figure 5.2 may be obtained from Table 5.2.

(6) The method given in 6.3.1 and is given in 6.4.(2) For joints connecting H or I sections j,Rd j Cd

(7) For joints connecting hollow sections the method given in section 7 may be used.

(8) The stiffness modification coefficient SU(1 ( M jM j,Rd S /j,ini 1Cd)LJXUH6LPSOLILHGELOLQHDUGHVLJQPRPHQWURWDWLRQFKDUDFWHULVWLF *OREDODQDO\VLVRIODWWLFHJLUGHUV

members and in the design of the joints, provided that both of the following conditions are satisfied:

1. the joint geometry is within the range of validity specified in Table 7.1, Table 7.8, Table 7.9 or Table 7.20 as appropriate;
2. the ratio of the system length to the depth of the member in the plane of the lattice girder is not less than the appropriate minimum value. For building structures, the appropriate minimum value may be assumed to be 6. Larger values may apply in other parts of EN 1993.

(4) The moments resulting from transverse loads (whether in-plane or out-of-plane) that are applied between panel points, should be taken into account in the design of the members to which they are applied. Provided that the conditions given in 5.1.5(3) are satisfied:

• the brace members may be considered as pin-connected to the chords, so moments resulting from transverse loads applied to chord members need not be distributed into brace members, and vice versa;
• the chords may be

Considered as continuous beams, with simple supports at panel points.–(5) Moments resulting from eccentricities may be neglected in the design of tension chord members and brace members. They may also be neglected in the design of connections if the eccentricities are within the following limits:

íG ”H ”G ... (5.1a)– 0 0

íK ”H ”K ... (5.1b)– 0 0

where: H is the eccentricity defined in Figure 5.3; G is the diameter of the chord; K is the depth of the chord, in the plane of the lattice girder.

(6) When the eccentricities are within the limits given in 5.1.5(5), the moments resulting from the eccentricities should be taken into account in the design of compression chord members. In this case, the moments produced by the eccentricity should be distributed between the compression chord members on each side of the joint, on the basis of their relative stiffness coefficients, where is the system length of the member, measured between panel points.

(7)

When the eccentricities are outside the limits given in 5.1.5(5), the moments resulting from the eccentricities should be taken into account in the design of the connections and the compression chord members. In this case, the moments produced by the eccentricity should be distributed between all the members meeting at the joint, on the basis of their relative stiffness coefficients(8). The stresses in a chord resulting from moments taken into account in the design of the chord should also be taken into account in determining the factors m, n, and p connections, see Table 7.2 to Table 7.5, Table 7.10 and Table 7.12 to Table 7.14(9). The cases where moments should be taken into account are summarized in Table 5.3.

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Source of the bending moment

Type of component

Secondary effects

Transverse loading

Eccentricity

Compression chord

Yes

Tension chord

No

Not if 5.1.5(3) Yes is satisfied

Brace member

No

Connection

Not if 5.1.5(5) is satisfied SU(1 ( &ODVVLILFDWLRQRIMRLQWV *HQHUDO(1) The details of all joints shall fulfil the assumptions made in the relevant design method, withoutadversely affecting any other part of the structure.(2) Joints may be classified by their stiffness (see 5.2.2) and by their strength (see 5.2.3). &ODVVLILFDWLRQE\VWLIIQHVV *HQHUDO(1) A joint may be classified as rigid, nominally pinned or semi-rigid according to its rotational stiffness,6 with the classification boundaries given in 5.2.2.5.by comparing its initial rotational stiffness j,ini127(Rules 6 for joints connecting H or I sections are given in 6.3.1.for the determination of j,ini6 for joints connecting hollow sections are not given in thisRules for the determination of j,iniStandard.(2) A joint may be classified on the basis of experimental evidence, experience of previous satisfactoryperformance in similar cases or by calculations based on test evidence. 1RPLQDOO\SLQQHGMRLQWV(1) A nominally pinned

(1) A joint shall be capable of transmitting the internal forces, without developing significant moments which might adversely affect the members or the structure as a whole.

(2) A nominally pinned joint shall be capable of accepting the resulting rotations under the design loads.

(1) Joints classified as rigid may be assumed to have sufficient rotational stiffness to justify analysis based on full continuity.

(1) A joint which does not meet the criteria for a rigid joint or a nominally pinned joint should be classified as a semi-rigid joint.

(Semi-rigid joints provide a predictable degree of interaction between members, based on the design moment-rotation characteristics of the joints.

(2) Semi-rigid joints should be capable of transmitting the internal forces and moments.

(1) Classification boundaries for joints other than column bases are given in 5.2.2.1(1) and Figure 5.4.

(2) Column bases may be classified as rigid provided the

Le seguenti condizioni sono soddisfatte: nei telai in cui il sistema di controventatura riduce lo spostamento orizzontale di almeno l'80% e - dove gli effetti della deformazione possono essere trascurati - λ ” se ... (5.2a) - 0 λ λ6 • (, /se 0,5 < < 3,93 e - 1 ) / ; ... (5.2b) - j,ini c c0 0λ • 6 •(, /se e / . ... (5.2c) - j,ini c c0 6 •(, /altrimenti se / . ... (5.2d) - j,ini c cdove: λ è la slenderness di una colonna in cui entrambe le estremità sono considerate incernierate; 0 / , , sono come indicato nella Figura 5.4.c c 6 •N (, /Zona 1: rigida, se /j,ini b b bdove N = 8 per i telai in cui il sistema di controventatura riduce lo spostamento orizzontale di almeno l'80% N = 25 per gli altri telai, a condizione che in ogni b *)•. /. 0,1piano b cZona 2: semirigidaTutte le giunzioni nella zona 2 dovrebbero essere classificate come semirigide. Le giunzioni nelle zone 1 o 3 possono opzionalmente essere trattate come semirigide.φ 6 ” (, /Zona 3: nominalmente incernierata, se /j,ini b b*) .Per i telai in cui /. < 0,1 il

joints should be classified as semi-rigid.

Key:

• b is the mean value of // for all the beams at the top of that storey
• b is the mean value of // for all the columns in that storey
• c is the second moment of area of a beam
• b is the second moment of area of a column
• c/ is the span of a beam (centre-to-centre of columns)
• b/ is the storey height of a column

c )LJXUH&ODVVLILFDWLRQRIMRLQWVE\VWLIIQHVV &ODVVLILFDWLRQE\VWUHQJWK *HQHUDO(1)

A joint may be classified as full-strength, nominally pinned or partial strength by comparing its design0 with the design moment resistances of the members that it connects. Whenmoment resistance j,Rdclassifying joints, the design resistance of a member should be taken as that member adjacent to thejoint. 1RPLQDOO\SLQQHGMRLQWV(1)

A nominally pinned joint shall be capable of transmitting the internal forces, without developingsignificant moments which might adversely affect the members or the structure as a whole. SU(1 ( (2)

A nominally

A pinned joint shall be capable of accepting the resulting rotations under the design loads. 0 is not greater than (3) A joint may be classified as nominally pinned if its design moment resistance j,Rd is 0.25 times the design moment resistance required for a full-strength joint, provided that it also has sufficient rotation capacity.

The design resistance of a full strength joint shall be not less than that of the connected members. A joint may be classified as full-strength if it meets the criteria given in Figure 5.5.

A joint which does not meet the criteria for a full-strength joint or a nominally pinned joint should be classified as a partial-strength joint.

a) Top of column: 0 is the design plastic moment resistance of a beam; b,p is the design plastic moment resistance of a column.

b) Within column height: 0 is the design plastic moment resistance of a beam; b,p is the design plastic moment resistance of a column.

Key: 0 is the design plastic moment resistance of a beam; b,p is the design plastic moment resistance of a column.

I hope this helps!

To model the deformational behaviour of a joint, account should be taken of the shear deformation of the web panel and the rotational deformation of the connections. 00 and

Joint configurations should be