BS 227:1995 download.Specification for H-section steel arches for use in mines.
1 Scope
BS 227 specifies requirements for H-section steel arches for use in underground roadways in mines.
BS 227 applies to semi-circular and double radiused profile arches and cambered and flat-top arches.
BS 227 excludes H-section steel arches used in roadway junction structures.
In addition to the definitive requirements, BS 227 also requires the items detailed in 6.1, 6.2, 7.1 and 7.5 to be documented. For compliance with BS 227, both the definitive requirements and the documented items have to be satisfied.
NOTE Dimensions on figures are in millimetres.
2 Normative references
BS 227 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, only the edition cited applies; any subsequent amendments to or revisions of the cited publication apply to BS 227 only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments.
3 Definitions
For the purposes of this British Standard the following definitions apply.
3.1
mine
a facility established for extracting coal or other minerals from seams without removal of the overburden and accessed via a shaft or a drift tunnel
3.2
underground roadways
tunnels in mines for access, ventilation and extraction purposes
3.3
H-section steel arch
a structure made from lengths of hot rolled steel H-shaped section, manufactured specifically for the mining industry and used for supporting the sides and roof of underground roadways in mines. It comprises two or more side members or legs and one or more top members or beams or crowns to form a portal frame with an open base. The side members or legs may be splayed out at an angle
3.4
strut
a nominally horizontal structural member used to join adjacent arches to form a continuous structure along the length of the roadway as it is formed
3.5
strut hole
a hole placed centrally along the web of an arch member through which a bolt can be passed for the purpose of attaching struts
3.6
joint
the point at which mating members of an arch are joined during assembly
3.7
joint hole
a hole placed centrally along the web of a member to
enable two members to be joined end to end, to form
a butt joint by means of fishplates
3.8
fishplate
a plate used to join two members end to end to effect a butt joint. Fishplates are usually fitted in pairs between the flanges on each side of the web and bolted through with, usually, two bolts to each side of the joint. Fishplates can also be curved having the same curvature as the members in order to effect a continuously curved arch
3.9
fishplate holes
holes placed, usually in pairs. centrally along the web of the members to either side of a butt joint, through which bolts can be passed in order to join the members end to end using fishplates
3.10
fish bolts and nuts
bolts and nuts used to connect pairs of fishplates
3.11
cranked fishplate
a fishplate formed at an angle, usually 120° to 135°
3.12
corner brackets and clips
brackets and clips used to join members where the flange of the roof member is positioned to rest on the upper end of a side or leg member. The joint is effected using one or more bolts
3.13
single bolt joints
a type of joint used to join two members at an angle. They usually comprise mating lugs welded to the ends or sides of the members which can be bolted together to effect the joint using a single bolt
3.14
base width
the distance between the inside flanges of the H-section arch measured across the base
3.15
chord length
the distance measured in a straight line between the ends of an H-section member taken from the inside edges
4 Information and requirements to be agreed and to be documented
4.1 The following information to be supplied by the purchaser shall be fully documented. Both the definitive requirements specified throughout the standard and the following documented items shall be satisfied before a claim of compliance with the standard can be made and verified:
a) for double radiused arches, the support base width (see 6.2):
b) for cambered and flat top arches, the beam lengths and support heights (see 7.1).
4.2 The following item to be agreed between the contracting parties which are specified in the clauses referred to shall be fully documented. Both the definitive requirements specified throughout the standard and the following documented item shall be satisfied before a claim of compliance with the standard can be made and verified.
For all H-section members, the requirement, if any, for strut holes (see 6.1, 6.2 and 7.5).
5 Common requirements
5.1 General
Clauses 5.2 to 5.6 shall apply to all arches and members covered in clause 6 and clause 7 unless otherwise stated.
5.2 Material
The properties of the steel shall conform with Table 1 and shall be tested in accordance with Annex A.
5.5.2 Material testing
Fishplates made from any material other than in 5.2, or by any other method than that of 5.2. the joints made shall be type tested in accordance with Annex B.
5.5.3 Fishplate cross-section
Hot rolled and pressed steel fishplate cross-sections shall be in accordance with Figure 2 to Figure 4 as appropriate.
5.5.4 Fishplate holes
Fishplate holes shall be dimensioned and positioned in accordance with Figure 2 to Figure 4 as appropriate.
5.5.5 Fish bolts and nuts
Fish bolts shall have square heads and necks, and shall be of sufficient length to be used with a full hexagon nut which, when tightened down, shall leave 2 mm of bolt protruding. Bolts and nuts shall conform to Figure 5 and also strength grade designation 4.6 and all other requirements shall be in accordance with BS 4190. Threads shall be coarse pitch series in accordance with BS 3643.
5.5.6 Fishplated joints
Fishplated joints shall conform to Figure 2 to Figure 4 as appropriate.
5.6 Welding
All welding shall be compatible with the design and materials of construction and conform to BS 5135.
6 Semi-circular and double radiused
arches
6.1 Semi-circular arches
Semi-circular arches shall be of a semi-circular profile with parallel legs, or splayed legs inclined at between 6° and 6° 4’ to the vertical, and shall conform to the parameters specified in Table 3 and illustrated in Figure 6. They shall have joints positioned by reference to a) the number of members per arch, b) the crown angle and c) the chord length. all as specified in Table 3 and illustrated in Figure 6.
The requirement for strut holes in the semi-circular arch shall be by agreement between the supplier and purchaser (see 4.2). Where it is agreed that there shall be strut holes in the arch they shall be in accordance with 5.4 and shall be positioned by reference to Figure 7 to Figure 42 and Table 3. The holes shall be positioned along the centre line of the arch within the following tolerances:
strut hole centre to adjacent
strut hole centre ± 12 mm;
strut hole centre to joint end ± 2.5 mm.
Semi-circular arches of the refuge hole type shall be in accordance with Figure 43.
6.2 Double radiused arches
Double radiused arches shall be of a double radiused profile with parallel legs or splayed legs inclined at between 6° and 6° 45’ to the vertical as illustrated in Figure 44. They shall have a base width within ± 25 mm of that specified by the purchaser [see 4.1 a)1.
NOTE Preferred forms are given in Table 4.