S UPERIOR IV U NIVERSIDAD DE A LICANTE
D. Método indirecto de caudal de aire por unidad de superficie, para espacios no dedicados a ocupación humana permanente, que en este caso se han
6.3. ESTUDIO GENERAL DE LA DEMANDA TÉRMICA DEL EDIFICIO
6.3.3. DEMANDAS TÉRMICAS Y CARGAS PUNTA ANUALES
9) Methods of interconnection, other than the shear connectors covered in this chapter, may be used to effect the transfer of longitudinal forces between a steel member and the slab, provided the adequacy with regard to behaviour and strength is demonstrated by tests and supported by a conceptual model.
Depending on the type of shear connector, reference shall be made to European Standards or European Technical Approvals or, in their absence, to national documents. The design of the composite beam shall conform to be design of a similar member employing either studs or other shear connectors as included in this code, in so far as practicable
6.1.2 Deformation capacity of shear connectors
1) Ductile connectors are those with sufficient deformation capacity to justify the assumption of ideal plastic behaviour of the shear connection in the structure considered.
2) Headed studs with an overall length after welding not less than 4 times the diameter, and with a shank of diameter not less than 16 mm and not exceeding 22 mm, may be considered as ductile within the following limits for the degree of shear connection, which is defined by the ratio N/Nf.
Steel stress Bs
N/mm2 k 160 200 240 280 320 360 400
maximum bar spacing wk = 0.3 mm 250 200 160 110 use Table 5.1
(mm) wk = 0.5 mm 250 250 250 250 200 140 80
For steel sections with equal flanges:
For steel sections having a bottom flange with an area not exceeding 3 times the area of the upper flange:
3) The following shear connectors may be considered as having the same deformation capacity as headed studs with the dimensions given in 2):
a) friction grip bolts designed in accordance with 6.5;
b) other connections having a characteristic slip capacity of not less than 6 mm at the characteristic resistance, determined from push tests in accordance with 10.2.
4) Headed stud connectors may be considered as ductile over a wider range of spans than given in 2) above where:
a) the studs have an overall length after welding not less than 76 mm, and a shank of diameter not less than 19 mm and not exceeding 20 mm;
b) the steel section is a rolled I or H with equal flanges;
c) the concrete slab is composite with profiled steel sheeting that spans perpendicular to the beam and is continuous across it;
d) there is one stud per rib of sheeting, placed centrally within the rib;
e) for the sheeting, bo/hpU 2 and hpk 60 mm, where the notation is as in 6.3.3.1;
f) the force Fc is calculated by the method of 6.2.1.2 3).
Where these conditions are satisfied, the ratio N/Nf should satisfy:
L k 5 (6.1)
where L is the span in metres,
Nf is the number of shear connectors determined for the relevant length of beam in accordance with 6.2.1.1, and
N is the number of shear connectors provided within the same length of beam.
L k 10
6.1.3 Spacing of shear connectors
1) The shear connectors shall be spaced along the beam so as to transmit longitudinal shear and to prevent separation between the concrete slab and the steel beam, considering an appropriate distribution of design longitudinal shear force.
2) In cantilevers and negative moment regions of continuous beams, the shear connectors shall be spaced to suit the curtailment of tension reinforcement, ignoring the anchorage length of curtailed bars.
3) Stud connectors in accordance with 6.3.2 and 6.3.3 may be spaced uniformly over a length Lcr between adjacent critical cross-sections as defined in 4.1.2 provided that:
— all critical sections in the span considered are in Class 1 or Class 2,
— N/Nf satisfies the limit given by 6.1.2, when L is replaced by Lcr, and
— the plastic resistance moment of the composite section does not exceed 2.5 times the plastic resistance moment of the steel member alone.
4) If the plastic resistance moment exceeds 2.5 times the plastic resistance moment of the steel member alone, additional checks on the adequacy of the shear connection should be made at intermediate points
approximately mid-way between adjacent critical cross-sections.
5) The required number of shear connectors may be distributed between a point of maximum sagging bending moment and an adjacent support or point of maximum hogging moment, in accordance with the longitudinal shear calculated by elastic theory for the loading considered. Where this is done, no additional checks on the adequacy of the shear connection are required, unless the method of 4.4.4 7) for shear buckling resistance of a web is used.
6.2 Longitudinal shear force
6.2.1 Beams in which plastic theory is used for resistance of cross sections 6.2.1.1 Full shear connection
1) For full shear connection, the total design longitudinal shear V= to be resisted by shear connectors spaced in accordance with 6.1.3 between the point of maximum sagging bending moment and a simple end support shall be:
whichever is the smaller, and
and these areas relate to the cross-section at the point of maximum sagging bending moment.
V= = Fcf (6.6)
where
or
Aa is the area of structural steel,
Ac is the effective area of concrete, defined in 4.2.1 and 4.2.2, excluding any web encasement, Ase is the area of any longitudinal reinforcement in compression that is included in the calculation
of the bending resistance,
2) For full shear connection, the total design longitudinal shear V= to be resisted by shear connectors spaced in accordance with 6.1.3 between the point of maximum sagging bending moment and an intermediate support or a restrained end support shall be
and these areas relate to the cross section at the support, and Fcf is as defined in 1) above, and is taken as zero for a cantilever.
6.2.1.2 Partial shear connection with ductile connectors
1) If the connectors are ductile as defined in 6.1.2, it may be assumed that sufficient slip can occur at the