15-01-2013, 04:01 PM
DESIGN CONCEPT OF PRE ENGINEERED BUILDING
[attachment=47032]
ASTRACT:
The pre-engineered steel building system construction has great advantages to the single storey buildings, practical and efficient alternative to conventional buildings, the System representing one central model within multiple disciplines. Pre-engineered building creates and maintains in real time multidimensional, data rich views through a project support is currently being implemented by Staad pro software packages for design and engineering.
1. INTRODUCTION
A tall steel building is not more in the total number of tall steel structures that are built around the world. A large steel structures being built are only single storey buildings for industrial purpose. Secondary structural members span the distance between the primary building frames of metal building systems. They play a complex role that extends beyond supporting roof and wall covering and carrying exterior loads to main frames. Secondary structurals, as these members are sometimes called, may serve as flange bracing for primary framing and may function as a part of the building’s lateral load–resisting system. Roof secondary members, known as purlins, often form an essential part of horizontal roof diaphragms; wall secondary members, known as girts, are frequently found in wall bracing assemblies. The majority of steel structures being built are only low-rise buildings, which are generally of one storey only. Industrial buildings, a sub-set of low-rise buildings are normally used for steel plants, automobile industries, light, utility and process industries, thermal power stations, warehouses, assembly plants, storage, garages, small scale industries, etc. These buildings require large column free areas. Hence interior columns, walls and partitions are often eliminated or kept to a minimum. Most of these buildings may require adequate headroom for use of an overhead traveling crane. A third type of secondary framing, known by the names of eave strut, eave purlin, or eave girt, acts as part purlin and part girt—its top flange supports roof panels, its web, wall siding. Girts, purlins, and eave struts exhibit similar structural
behaviour. Since most secondary members normally encountered in metal building systems are made of cold-formed steel, our discussion starts with some relevant issues in design of cold-formed steel structures.
Pre-Engineered Buildings
The scientific-sounding term pre-engineered buildings came into being in the 1960s. The buildings were ―pre-engineered‖ because, like their ancestors, they relied upon standard engineering designs for a limited number of off-the-shelf configurations. Several factors made this period significant for the history of metal buildings. First, the improving technology was constantly expanding the maximum clear-span capabilities of metal buildings. The first rigid-frame buildings introduced in the late 1940s could span only 40 ft. In a few years, 50-, 60-, and 70-ft buildings became possible. By the late 1950s, rigid frames with 100-ft spans were made, ribbed metal panels became available, allowing the buildings to look different from the old tired corrugated appearance. Third, collared panels were introduced by Strand-Steel Corp. in the early 1960s, permitting some design individuality. At about the same time, continuous span cold-formed Z purlins were invented (also by Strand-Steel), the first factory-insulated panels were developed by Butler, and the first UL-approved metal roof appeared on the market.1st And last, but not least, the first computer-designed metal buildings also made their debut in the early 1960s. With the advent of computerization, the design possibilities became almost limitless. All these factors combined to produce a new metal-building boom in the late 1950s and early 1960s. As long as the purchaser could be restricted to standard designs, the buildings could be properly called pre-engineered. Once the industry started to offer custom-designed metal buildings to fill the particular needs of each client, the name pre-engineered building became somewhat of a misnomer. In addition, this term was uncomfortably close to, and easily confused with, the unsophisticated prefabricated buildings, with which the new industry did not want to be associated. Despite the fact that the term pre-engineered buildings is still widely used, and will be often found even in this book, the industry now prefers to call its product metal building systems.
Dynamic / Seismic Analysis
Mass modeling, Extraction of Frequency and Mode shapes.
Response Spectrum, Time History Analysis.
Modal Damping Ratio for Individual Models.
Harmonic Load Generator.
Combination of Dynamic forces with Static loading for subsequent design.
Secondary Analysis
Forces and Displacements at sections between nodes.
Maximum and Minimum force Envelopes.
Load Types and Load Generation:
Loading for Joints, Members/Elements including Concentrated, Uniform, Linear, Trapezoidal, Temperature, Strain, Support Displacement, Prestressed and Fixed-end Loads.
Global, Local and Projected Loading Directions.
Uniform or varying Element Pressure Loading on entire or selected portion of elements.
Floor/Area Load converts load-per-area to member loads based on one-way or two-way actions.
Automatic Moving Load Generation as per standard AASHTO or user-defined loading.
UBC 1997.AIJ/IS 1893/Cypriot Seismic Load Generation.
Automatic Wind Load Generation.
[attachment=47032]
ASTRACT:
The pre-engineered steel building system construction has great advantages to the single storey buildings, practical and efficient alternative to conventional buildings, the System representing one central model within multiple disciplines. Pre-engineered building creates and maintains in real time multidimensional, data rich views through a project support is currently being implemented by Staad pro software packages for design and engineering.
1. INTRODUCTION
A tall steel building is not more in the total number of tall steel structures that are built around the world. A large steel structures being built are only single storey buildings for industrial purpose. Secondary structural members span the distance between the primary building frames of metal building systems. They play a complex role that extends beyond supporting roof and wall covering and carrying exterior loads to main frames. Secondary structurals, as these members are sometimes called, may serve as flange bracing for primary framing and may function as a part of the building’s lateral load–resisting system. Roof secondary members, known as purlins, often form an essential part of horizontal roof diaphragms; wall secondary members, known as girts, are frequently found in wall bracing assemblies. The majority of steel structures being built are only low-rise buildings, which are generally of one storey only. Industrial buildings, a sub-set of low-rise buildings are normally used for steel plants, automobile industries, light, utility and process industries, thermal power stations, warehouses, assembly plants, storage, garages, small scale industries, etc. These buildings require large column free areas. Hence interior columns, walls and partitions are often eliminated or kept to a minimum. Most of these buildings may require adequate headroom for use of an overhead traveling crane. A third type of secondary framing, known by the names of eave strut, eave purlin, or eave girt, acts as part purlin and part girt—its top flange supports roof panels, its web, wall siding. Girts, purlins, and eave struts exhibit similar structural
behaviour. Since most secondary members normally encountered in metal building systems are made of cold-formed steel, our discussion starts with some relevant issues in design of cold-formed steel structures.
Pre-Engineered Buildings
The scientific-sounding term pre-engineered buildings came into being in the 1960s. The buildings were ―pre-engineered‖ because, like their ancestors, they relied upon standard engineering designs for a limited number of off-the-shelf configurations. Several factors made this period significant for the history of metal buildings. First, the improving technology was constantly expanding the maximum clear-span capabilities of metal buildings. The first rigid-frame buildings introduced in the late 1940s could span only 40 ft. In a few years, 50-, 60-, and 70-ft buildings became possible. By the late 1950s, rigid frames with 100-ft spans were made, ribbed metal panels became available, allowing the buildings to look different from the old tired corrugated appearance. Third, collared panels were introduced by Strand-Steel Corp. in the early 1960s, permitting some design individuality. At about the same time, continuous span cold-formed Z purlins were invented (also by Strand-Steel), the first factory-insulated panels were developed by Butler, and the first UL-approved metal roof appeared on the market.1st And last, but not least, the first computer-designed metal buildings also made their debut in the early 1960s. With the advent of computerization, the design possibilities became almost limitless. All these factors combined to produce a new metal-building boom in the late 1950s and early 1960s. As long as the purchaser could be restricted to standard designs, the buildings could be properly called pre-engineered. Once the industry started to offer custom-designed metal buildings to fill the particular needs of each client, the name pre-engineered building became somewhat of a misnomer. In addition, this term was uncomfortably close to, and easily confused with, the unsophisticated prefabricated buildings, with which the new industry did not want to be associated. Despite the fact that the term pre-engineered buildings is still widely used, and will be often found even in this book, the industry now prefers to call its product metal building systems.
Dynamic / Seismic Analysis
Mass modeling, Extraction of Frequency and Mode shapes.
Response Spectrum, Time History Analysis.
Modal Damping Ratio for Individual Models.
Harmonic Load Generator.
Combination of Dynamic forces with Static loading for subsequent design.
Secondary Analysis
Forces and Displacements at sections between nodes.
Maximum and Minimum force Envelopes.
Load Types and Load Generation:
Loading for Joints, Members/Elements including Concentrated, Uniform, Linear, Trapezoidal, Temperature, Strain, Support Displacement, Prestressed and Fixed-end Loads.
Global, Local and Projected Loading Directions.
Uniform or varying Element Pressure Loading on entire or selected portion of elements.
Floor/Area Load converts load-per-area to member loads based on one-way or two-way actions.
Automatic Moving Load Generation as per standard AASHTO or user-defined loading.
UBC 1997.AIJ/IS 1893/Cypriot Seismic Load Generation.
Automatic Wind Load Generation.