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q);

of the adjacent brace members, see Figure 1.3(a);

the overall in-plane depth of the cross-section of member i (i = 0, 1, 2 or 3); a factor defined in the relevant table, with subscript g, m, n or p ; the buckling length of a member;

the length of the projected contact area of the overlapping brace member onto the face of the chord, in the absence of the overlapped brace member, see Figure 1.3(b);

the length of overlap, measured at the face of the chord, between the brace members in a K or N joint, see Figure 1.3(b);

the root radius of an I or H section or the corner radius of a rectangular hollow section;

the flange thickness of an I or H section;

the thickness of a plate;

the web thickness of an I or H section;

a factor defined in the relevant table;

the included angle between brace member i and the chord (i = 1, 2 or 3);

a factor defined where it occurs;

a factor defined in the relevant table;

the angle between the planes in a multiplanar joint.

The integer subscripts used in section 7 are defined as follows: is an integer subscript used to designate a member of a joint, i = 0 denoting a chord and i = 1, 2 or 3 the brace members. In joints with two brace members, i = 1 normally denotes the compression brace and i = 2 the tension brace, see Figure 1.4(b). For a single brace i = 1 whether it is subject to compression or tension, see Figure 1.4(a);

i and j are integer subscripts used in overlap type joints, i to denote the overlapping brace member and j to denote the overlapped brace member, see Figure 1.4(c).

The stress ratios used in section 7 are defined as follows:

the ratio (coWfyo) ! 7vin (used for RHS chords);

the ratio {rjv \t\lfy0) / yM5 (used for CHS chords);

the maximum compressive stress in the chord at a joint;

the value of cr0,Ed excluding the stress due to the components parallel to the chord axis of the axial forces in the braces at that joint, see Figure 1.4.

(6) The geometric ratios used in section 7 are defined as follows:

p is the ratio of the mean diameter or width of the brace members, to that of the chord:

for KT joints:

d1 + d2 + d 3 d1 + d2 + d3 b1 + b2 + b3 + h1 + h2 + h3 ■ or

y is the ratio of the chord width or diameter to twice its wall thickness:

tj is the ratio of the brace member depth to the chord diameter or width:

/.,,-, is the overlap ratio, expressed as a percentage (lov = (q/p) x 100%) as shown in figure 1.3(b). (7) Other symbols are specified in appropriate clauses when they are used. NOTE: Symbols for circular sections are given in Table 7.2.

a) Joint with single brace member

b) Gap joint with two brace members

Figure 1.4: Dimensions and other parameters at a hollow section lattice girder joint c) Overlap joint with two brace members

Figure 1.4: Dimensions and other parameters at a hollow section lattice girder joint

2 Basis of design

2.1 Assumptions

(1) The design methods given in this part of EN 1993 assume that the standard of construction is as specified in the execution standards given in 2.8 and that the construction materials and products used are those specified in EN 1993 or in the relevant material and product specifications.

2.2 General requirements

(1) All joints shall have a design resistance such that the structure is capable of satisfying all the basic design requirements given in this Standard and in EN 1993-1-1.

(2) The partial safety factors yM for joints are given in Table 2.1.

Table 2.1: Partial safety factors for joints

Resistance of members and cross-sections

7mo , Tmi and ym see EN 1993-1-1

Resistance of bolts

7m2

Resistance of rivets

Resistance of pins

Resistance of welds

Resistance of plates in bearing

Slip resistance

- for hybrid connections or connections under fatigue loading

- for other design situations

7M3 7m3

Bearing resistance of an injection bolt

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