LECTURE1 Composite Structures

8/10/2019 LECTURE1 Composite Structures

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STE 402Composite Structures

Dr. Hesham Fawzy Shaabn

Professor,

Zagazig University


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What Composite Structures

Means?

The cross section of the element composed

of more than one material.

Examples:-

RC structures: Steel & Concrete (steel ratio=?)

Wood & Steel

Concrete & Steel

Concrete & FRP

Concrete, Steel & FRP


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Composite floor system

Components of a typical modern composite-floor system


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Composite floor system (cont.)

Components of a typical modern composite-floor system


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Advantages of Composite

Structures

Composite steel deck

Can use as permanent form and also external

reinforcement

Reduce labor cost

Faster construction resulting

Faster construction resulting From elimination of from work (shored and

unshored).


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Disadvantages of Composite

Structures

Low fire resistance

Skilled labor

Compared to RC labor

Relative high cost

Construction time

Suitable span (economic for large span)


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Historical (Early) Applications

of composite Structures

Early applications of the steel concrete composite

beams involved concrete-encased steel beams for

which the concrete served primarily as fire

protection.

However, it was recognized that both the strength

and stiffness of the encased member

Thegreatest application for composite constructionwas the development of the welded headed stud inthe 1950s


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Types of Composite Structures

Composite slab

corrugated steel deck and concrete

Composite beam

Steel section, shear connector & solid slab

Steel section, shear connector & composite slab

Composite column & frames Steel pipe filled with concrete.

Steel section encased with concrete column


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Composite slabs

a) fluted deck (b) embossed deck

The deck is cold-formed steel sheet, and some means of ensuring

mechanical interlock with the hardened concrete is provided.


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Composite slab (cont.)

steel deck serves temporarily as a construction

platform and as formwork to support the fresh

concrete

After the concrete hardens, the deck provides part

or all of the positive moment reinforcement for the

one-way slab

Properly attached deck also serves as lateralbracing for the compression flange of the beams

and girders during construcion


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Shear connectors

The most widely used type of shear connectors is the

headed stud. The stud shear connector is a short length of

round steel bar welded to the steel beam at one end and

having an anchorage provided in the form of a round head

at the other end.

The most common diameters are

16, 19 and 22mm


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Shear connectors (cont.)

The length is dependent on the depth of metal deck and shouldextend at least 40mm above the top of the deck. The studs are

normally welded to the beam with an automatic welding gun.


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Shear connectors (cont.)

The advantages of stud connectors are:

1. The welding process is rapid.

2. They provide little obstruction to reinforcement in the

concrete slab.

3. They are equally strong and stiff in shear in all directionsnormal to the axis of the stud.


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Shear connectors cont.

Other types of connector with higher strength have been

developed, primarily for use in bridges.


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Composite Beams

The coupling between steel beam and concrete slab assures both

economical and structural benefits, because of the quick

construction typical of the steel structures, and the large increment

in stiffness due to the presence of the concrete flange.

The reinforced concrete slab can be either solid or composite,

when cast on profile steel sheeting.


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Composite Beams cont.


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Examples of Composite

Structures

Bridges


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Examples of Composite

Structures

Tall Buildings

Documents

LECTURE1 Composite Structures