Posts by Kanwarjot Singh

Total number of connectors required to resist V_h is given by V_h/q
where q is the allowable shear for one connector, kip (kN) and its value is given in structural design guides.

Some keypoints should be considered
1. Required number of shear connectors should be placed uniformly in the section having zero to maximum moment.
2. Shear Connectors should have a minimum of 25.4mm (1inch) of concrete cover in all the directions.
3) Stud diameter should not exceed 2.5 times the beam-flange thickness. ( May increase only if studs are located directly over the web)

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In a composite construction, a concrete slab and steel beams act together to resist the load acting on beam and thus the slab acts as a cover plate. Due to this we use a lighter steel section in composite construction

What are the Two Methods of Composite Construction in Buildings?
Method 1. In the first method, we cast the steel beam entirely in the concretion i.e steel beam encased in the concrete. The steel concrete bond is the main reason for composite action. The beam is laterally braced therefore the allowable stress in the flanges is 0.66F_y, where F_y is the yield strength, ksi (MPa), of the steel.

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According to AISC, the cross sectional area of of bolts and threaded parts are designed for specified allowable unit tension and shear stresses. In case of seismic loads and wind loads in combination of gravity loads, we increase the allowable stresses by 1/3. Normally in case of direct tension, rivets are not recommended.

Bearing type connections are the most commonly used connection is building construction. In buildings, the allowable bearing stress F_p, ksi (MPa), on projected area of fasteners is
F_p=1.2 F_u
where
F_uis the tensile strength of the connected part in ksi (MPa).

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As per AISC guidelines, the combined effect of forces from moment and shear should be considered while designing fasteners or welds for end connections of girders, beams, and trusses. When flanges or moment connection plates for end connections of beams and girders are welded to the flange of an I- or H-shape column, a pair of column-web stiffeners having a combined cross-sectional area A_st not less than that calculated from the following equations must be provided whenever the calculated value of A_stis positive:

A_st = P_bf-F_yct_wc(t_b+5K) / F_yst
where
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Criteria for Buildings

The AISC specification for ASD for buildings places a limit on compressive stress in webs to prevent local web yielding. For a rolled beam, bearing stiffeners are required at a concentrated load if the stress f _a , ksi (MPa), at the toe of the web fillet exceeds F_a= 0.66F_yw , where F_yw is the minimum specified yield stress of the web steel, ksi (MPa). In the calculation of the stressed area, the load may be assumed distributed over the distance.

For a concentrated load applied at a distance larger than the depth of the beam from the end of the beam:

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By Kelly Baldwin

Published in Construction Canada, v. 98, no. 1, Jan./Feb., 1998, pp. 28-29

Abstract: Conductive concrete is a cement-based composite that contains electronically conductive components to attain stable and relatively high conductivity. Potential applications include electrical heating for de-icing of parking garages, sidewalks, driveways, highway bridges, and airport runways, as well as electrical grounding.

Résumé: Le béton conducteur est un composite à base de ciment contenant une certaine quantité d’éléments qui assurent une conductivité électrique stable et relativement élevée. Les applications possibles sont : le chauffage électrique pour dégivrer les garages de stationnement, les trottoirs, les voies d’accès, les ponts routiers et les pistes d’aéroport, et la mise à la terre électrique.
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