High Rise Structural Systems

By1.Mohamed Ayman2.Mohamed Ali 3.Mohamed Atef 4.Mohamed El Sayed

Under Supervision of

Dr. Ahmed Kamal Abd El Zaher

LOADS ON THE HIGHRISE STRUCTURES.

• Vertical Loads.

• Horizontal Loads.

• Unexpected Deflections.

• Wind Loads.

• Earthquake Loads.

– Definition.– Earthquake.– Seismic Waves.– Pressure waves.– Shear waves.

Types of High rise structures

• Braced Frame.– Braced frames are cantilevered vertical trusses.

Advantages

Disadvantages

• Rigid Frame Structure– Consist of columns and girders joined by

moment resistant connections.Advantages

Disadvantages

• In-filled Frame Structure.

–Most usual form of construction for tall Buildings up to 30 stories in height Column and girder framing of reinforced concrete.

• Flat Plate and Flat Slab Structure.– Is the simplest and most logical of all structural

forms in that it consists of uniforms slabs, connected rigidly to supporting columns.

– Particularly appropriate for hotel and apartment construction where ceiling space is not required and where the slab may serve directly as the ceiling.

• Shear wall structure.– Concrete or masonry continuous vertical walls

may serve both architecturally partitions and structurally to carry gravity and lateral loading.

Action to be considered.

Problem associated with formwork systems.

• Coupled wall structure.

– Consist of two or more shear walls in the same plane, or almost the same plane, connected at the floor levels by beam or stiff slabs.

• Wall-frame structure.– The walls and frame interact horizontally to

produce stiffer and stronger structure.

– Appropriate for the building in the 40 –60 story range

– The frames consist of 6-12 ft (2-4m) between centers, joined by deep spandrel girders.

– Gravity loading is shared between the tube and interior column or walls.

• The trussed tube.– Relatively broad column spacing can resulted large clear spaces for windows, a particular characteristic of steel buildings.

– The trussed tube system represents a classic solution for a tube uniquely suited to the qualities and character of structural steel.

• Tube in tube or Hull core structure.– This variation of the framed tube consists of an outer

frame tube, the “Hull,” together with an internal elevator and service core.

– The Hull and core act jointly in resisting both gravity and lateral loading.

– The structural tube usually adopts a highly dominant role because of its much greater structural depth.

• Bundled tube structure.– The concept allows for wider column spacing

in the tubular walls than would be possible with only the exterior frame tube form.

– The spacing which make it possible to place interior frame lines without seriously compromising interior space planning.

• Core and Outriggers system.–Outrigger serve to reduce the overturning

moment in the core that would otherwise act as a pure cantilever.

– In high-rise building this same benefit is realized by a reduction of the base core over-turning moments and the associated reduction in the potential core uplift forces.

• Advantages:– The outrigger systems may be formed in any

combination of steel, concrete, or composite construction.

• Disadvantages

• Hybrid Structure.– A Combination of two or even more of basic

structural forms.

– Hybrid structures are likely to be the rule rather than the exception for future very tall buildings.

– High-strength concrete, consist of stiffness and damping capabilities of large concrete elements.