Structural Steel Design
Structural steel fabricator design is the process of determining the strength and weight of the material to be used in the construction of a structure. This includes the use of Allowable Strength Design, Foundations, Load and Resistance Factors, Rationalization, Beam Erection, and Cost Structures.
Allowable Strength Design
Allowable strength design is a technique used to identify the allowable stresses for steel members, in conjunction with permitted stresses specified in applicable standards. The allowed stress is calculated using the ratio of the nominal strength of the material to its safety factor. This translates into load factors for full scale structures.
While Allowable Stress Design (ASD) is still in use in some countries, Limit State Design (LRFD) has replaced it globally. Both methods may be used to keep the material stresses in a reasonable range. However, switching between methods can lead to disastrous results.
For the most part, the allowable strength design for structural steel is similar to LRFD. The difference is in the way it is applied.
Load and Resistance Factor Design
Load and Resistance Factor Design (LRFD) is a structural design philosophy that combines the modern probabilistic approach with limit state strength and serviceability design criteria. This method provides a high degree of safety for poorly defined loads and maximizes casing design. It is applicable to steel structures and can be incorporated into the 2006 International Building Code.
The LRFD method takes the assumption that a structure is designed with all possible actions during the design time. The LRFD factor of safety is calculated as a ratio of working stress to ultimate stress. For deterministic loads, such as wind or earthquake, the factor of safety is reduced. In the case of impact loads, the factor is increased.
Steel frame erection is a complex process that requires a lot of knowledge and safety procedures. The risks involved can vary based on the type and size of structure, the materials used, and the overall working conditions.
One of the major challenges in steel erection is determining the proper sequence of erection. There are four main tasks to consider: preparing the foundation, bolting the base plate, bolting the beams, and erecting the columns.
Having a comprehensive job hazard analysis will help you identify any potential hazards and create a safety plan. In addition to the proper tools and equipment, this plan should also contain a number of precautions to reduce the risk of injury.
Foundations are one of the most important parts of a building project. They set the pace for the construction process. It is vital to design foundations correctly, and to follow standard codes.
The main factors that affect the foundation design include soil type, climate, codes, and weight. In addition, foundations must be properly poured and maintained to minimize possible damage.
Typically, slab-on-grade foundations are placed on 2 to 3 inches of washed gravel. Slab-on-grade foundations are often covered with a 6 mil polyethylene vapor barrier to prevent moisture from wicking through the slab.
Other types of foundations include pile foundations and perimeter walls. These are commonly used in coastal flood zones and weak soils.
The rationalization of structural steel design is an important aspect of building construction. By rationalizing the steel in a building, it is possible to safely support the same loads with less material. This will help to reduce the amount of material required for the structure and hence reduce the cost.
Designing a new structure is a very costly process and it is not uncommon for architects to utilize the least expensive method. However, a more sophisticated design strategy can decrease the total amount of materials used.
One strategy is to reduce the number of joints and section sizes of the beams and columns. However, this requires a deeper understanding of the engineering processes involved.