CIVIL ENGINEERING FORMULAS

BUILDING AND STRUCTURES FORMULAS 227

least 1 in (25.4 mm) of concrete cover in all directions; and unless studs are
located directly over the web, stud diameters may not exceed 2.5 times the
beam-flange thickness.
With heavy concentrated loads, the uniform spacing of shear connectors
may not be sufficient between a concentrated load and the nearest point of
zero moment. The number of shear connectors in this region should be at least

(9.69)

where Mmoment at concentrated load, ftkip (kNm)
Mmaxmaximum moment in span, ftkip (kNm)
N 1 number of shear connectors required between Mmaxand zero moment
Str/SsorSeff/Ss, as applicable
Seffeffective section modulus for partial composite action, in^3 (mm^3 )

Shear on Connectors

The total horizontal shear to be resisted by the shear connectors in building con-
struction is taken as the smaller of the values given by the following two equations:

(9.70)

(9.71)

whereVhtotal horizontal shear, kip (kN), between maximum positive moment
and each end of steel beams (or between point of maximum posi-
tive moment and point of contraflexure in continuous beam)
specified compressive strength of concrete at 28 days, ksi (MPa)
Acactual area of effective concrete flange, in^2 (mm^2 )
Asarea of steel beam, in^2 (mm^2 )

fc

Vh

AsFy

2

Vh

0.85fcAc

2

N 2 

N 1 [(M/Mmax)1]

 1

a

Concrete

slab

C≤^1 Span CC

8

a

≤^1 a

2

FIGURE 9.5 Limitations on effective width of concrete slab

in a composite steel-concrete beam.