B 88
[Subsidiary]
Distribution of concentrated load on solid slabs.
CAP. 123] Building (Construction) Regulations
[1985 Ed.
138. (1) Allowance shall be made for the bending moments due to concentrated loads, using methods based on the elastic theory.
(2)
(a) If a solid slab is simply supported on 2 opposite edges and carries 1 or more concentrated loads in a line in the direction of the span, it shall be designed to resist the maximum bending moment caused by the loading system. Such bending moment shall be assumed to be resisted by an effective width of slab (measured parallel to the supports) equal to the sum of the load width and 2.4 x (1-x/l) where x is the distance from the nearer support to the section under consideration and l is the span.
(b) Where the concentrated load is near an unsupported edge of a solid slab, the effective width shall not exceed the value in sub-paragraph (a), nor that value plus the distance of the centre of the load from the unsupported edge, as shown in Diagram 3.
DIAGRAM 3
Effective width of solid slab carrying a concentrated load near an unsupported edge
UNSUPPORTED EDGE
2x(1-x/l)
EFFECTIVE WIDTH
LOAD WIDTH
0.3 l
Trimming for openings.
Resistance to shear.
(3) Notwithstanding the provisions of regulation 127, distribution reinforcement of not less than 0.3 per cent of the gross cross-sectional area of the slab shall be provided over the full effective width resisting the bending moment due to the concentrated load.
139. When openings in floors or roofs are required, such openings shall be trimmed where necessary by special beams or reinforcement so that the designed strength of the surrounding floor is not impaired by the opening, due regard being paid to the possibility of diagonal cracks developing at the corners of openings.
140. (1) The shear stress q at any cross-section in a reinforced concrete beam or slab shall be calculated from the following equation:
B 88
[Subsidiary]
Distribution of concentrated load on solid slabs.
CAP. 123] Building (Construction) Regulations
[1985 Ed.
138. (1) Allowance shall be made for the bending moments due to concentrated loads. using methods based on the elastic theory.
(2)
(a) If a solid slab is simply supported on 2 opposite edges and carries 1 or more concentrated loads in a line in the direction of the span. it shall be designed to resist the maximum bending moment caused by the loading system. Such bending moment shall be assumed to be resisted by an effective width of slab (measured parallel to the sup- ports) equal to the sum of the load width and 2.4 x (1-x/f) where x is the distance from the nearer support to the section under consideration and / is the span.
(b) Where the concentrated load is near an unsupported edge of a solid slab the effective width shall not exceed the value in sub-paragraph (a),mor that value plus the distance of the centre of the load from the unsupported edge as shown in Diagram 3.
DIAGRAM 3
Effective width of solid slab carrying a concentrated load near/ an unsupported edge
UNSUPPORTED EDGE-
2x(1-2)-
EFFECTIVE WIDTH
LOAD WIDTH
0.3 1
Trimming for openings.
Resistance to shear.
(3) Notwithstanding the provisions of regulation 127, distri- bution reinforcement of not less than 0.3 per cent of the gross cross-sectional area of the slab shall be provided over the full effective width resisting the bending moment due to the concen- trated load.
139. When openings in floors or roofs are required such open- ings shall be trimmed where necessary by special beams or reinforce- ment so that the designed strength of the surrounding floor is not impaired by the opening, due regard being paid to the possibility of diagonal cracks developing at the corners of openings.
140. (1) The shear stress q at any cross-section in a reinforced concrete beam or slab shall be calculated from the following equation:
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