Structural Design of a Building Essay
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 •Propped structures •Suspended structures •Traditional framed/caged structures •Cantilevered structures •Braced 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 TASK 2 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 industry.
Steel’s high strength, ductility, adaptation to prefabrication, speed of erection, etc. , have always been attractive characteristics to consultants and developers. In today’s “fast tracked” construction projects where time and schedule are of essence, these qualities become decisive in choosing the type of structure to be built. At present, Structural Steel Works, Inc. offers all of the advantages of steel as a building material at the most competitive price without sacrificing quality control. Advantages of using steel:- •Superior Strength and durability. •Precise measurements, perfect angles. •Resistant to pest. Great protection against the worst weather conditions. •Steel Components mean minimal material waste. •Installation is fast and simple. •Labour costs are minimal. •Steel is recyclable. •A cost Effective material. Structural steel building CONCRETE Reinforced concrete can be strengthened by using a number of different methods, such as -: •reinforcement bars •reinforcement grids •reinforcement plates •reinforcement fibers Concrete is very strong in compression but not in tension so these materials are there to help strengthen the concrete in tension. The term Ferro Concrete refers only to concrete that is reinforced with iron or steel.
Other materials used to reinforce concrete can be organic and inorganic fibers as well as composites in different forms. The most common method of strengthening concrete is to use reinforcement bars. For a strong, ductile and durable construction the reinforcement should have the following properties: •High strength •High tensile strain •Good bond to the concrete •Thermal compatibility •Durability in the concrete environment Advantages of using precast concrete:- •Column-Free Long Spans With fewer columns and more usable floor space, precast, prestressed concrete provides greater freedom for space utilization. Conserves Energy Prestressed concrete components can improve the thermal storage potential of a building. It effectively conserves energy required for heating and cooling. •Maintenance Free Precast concrete does not require painting and is free from corrosion. Its durability extends building life. •Resists Fire Durability and fire resistance mean low insurance premiums and greater personnel safety. Those who investigate life cycle costing will appreciate the precast concrete’s excellent fire resistance characteristics. •Rapid Construction precast concrete construction gets the job done sooner.
The manufacturing of prestressed members and site preparation can proceed simultaneously. Early occupancy provides obvious benefits to the client. •Versatility of Design Precast concrete buildings are not only functional but beautiful as well. Numerous panel configuration design possibilities are available. Structural concrete building As raw material prices differ, so does building design. During times of lower steel prices, more steel and less concrete is used, and vice versa, but both materials are typically used together. Concrete without steel reinforcement crumbles under tensile loads.
Steel on its own, without composite or reinforced concrete floors, is likewise not a preferred building method. While rebar is almost always steel, it is not considered structural steel and is described separately in the rebar and reinforced concrete articles. While both steel structures and Reinforced concrete cement(R. C. C)structures have their pros and cons, the steel structures have better strength to weight ratio than RCC, and can be easily dismantled(Steel structures, which have bolted connections can also be reused to some extent after dismantling).