There are 7 different forms of structural design used to form multi-storey buildings within the building industry today, They are:-
•Shear wall structures
•Hull core structures
•Traditional framed/caged structures
The two that are popular and most widely used are shear wall structuresand braced structures.
SHEAR WALL STRUCTURES
These are made up from Concrete continuous vertical walls that are used as both architecturally partitions and structurally to carry gravity and lateral loading. They are very high in plane stiffness and strength which makes them the ideal panels for bracing tall buildings; they also act as vertical cantilevers in the form of separate planar walls, and as non-planar assemblies of connected walls around elevator, stair and service shafts. This way of forming a building is well suited to hotel and residential buildings where the floor-by floor repetitive planning allows the walls to be vertically continuous and where they serve simultaneously as excellent acoustic and fire insulators between rooms and apartments. Advantages:-
•Tensile reinforcement for areas where tension stresses occur in •Walls when wind uplifts stresses exceed gravity stresses. •High strength concrete has enable wall thickness to be minimized, hence maximizing rentable floor space. •Technology exists to pump and to place high-strength concrete at high elevation. •Fire rating for service and passenger elevator shafts is achieved by simply placing concrete of a determined thickness. •The need for complex bolted or side-welded steel connections is avoided. •Well detail reinforce concrete will develop about twice as much damping as structural steel. Disadvantages:-
•Shear walls formed around elevator and service risers require a concentration of opening at ground level where stresses are critical. •Shear wall vertical movements will continue throughout the life of the building. •Construction time is generally slower than for a steel frame building. •The additional weight of the vertical concrete elements as compared to steel will induce a cost penalty for the foundations. •Regular survey check must be undertaken to ensure that the vertical and twist alignment of the shear walls are within tolerance. •In general it is difficult to achieve a good finish from slip-form formwork systems, and rendering or some other type of finishing may be necessary.
Shear wall Structures
BRACED FRAME STRUCTURES
Braced frames are cantilevered vertical trusses resisting laterals loads through the axial stiffness of the frame members. This is an effective way of building as the steel has a high ratio of stiffness; it is an ideal method to use in the production of multi-storey building. A braced frame is made completely from steel, this is because the diagonal steels are subjected to tension and lateral loading. Able to produce a laterally very stiff structure by using a minimum amount of additional materials makes it an economical structural form for any height of buildings. Advantages:-
•Girders only participate minimally in the lateral bracing action-Floor framing design is independent of its level in the structure. •Can be repetitive up the height of the building with obvious economy in design and fabrication. Disadvantages:-
•Obstruct the internal planning and the locations of the windows and doors; for this reason, braced bent are usually incorporated internally along wall and partition lines, especially around elevator, stair, and service shaft.-Diagonal connections are expensive to fabricate and erect.
Braced frame structures
There are many different materials that can be used to form a multi-story building, the two most common are steel and concrete this is due to both the strength and the cost of the materials. STEEL
The demand for steel as a building material is growing within the construction...