The prospective buyer of a pre-engineered metal building is offered more choices in the design, appearance, and value of a building then ever before. Enabling the customer to select a metal building system that provides the performance characteristics that best meets specific their metal building requirements. Our prefabricated metal building systems options includes:
Gable Symmetrical: A double slope building where the ridge of the roof is in the center of the building. This is the type of metal building that can be configured, priced, all through our online design system.
Gable Unsymmetrical: A double slope building where the ridge of the roof is off-center. This type of building requires a custom quote.
Single Slope: A sloping roof in one plane. The slope is from one sidewall to the opposite sidewall. This type of building requires a custom quote but we are adding this to our dealer’s online design system.
Lean-To: Ideally suited to give you that extra space you need alongside your building. The lean-to attaches at or below the eave of your building, and can provide shelter for a variety of uses, from just a covered area to a completely enclosed addition to your building. This type of addition requires a custom quote.
Hybrid Structures: Hybrid structures blend the advantages of metal building system construction with the conventional steel or wood members. Hybrid structures meet heavy loading requirements by providing the most effective design possible – the best of both worlds. The advantages include:
- Design flexibility
- Single source responsibility
- Fast, easy construction
- Cost effectiveness
The designs and engineering available allows virtually any requirement for hybrid structures, no matter how large or complex. When it comes to large, tough construction jobs, the hybrid building approach provides a cost conscious alternative.
Crane Buildings: With the use of metal building systems dominated by the manufacturing, industrial, and warehousing sector, building cranes as part of the structure has become an important element. We recognize the need to properly integrate the design of the metal building system with the building crane specifications. The building crane is a complex structural system consisting of the crane with trolley and hoist, cranes rails, crane runway beams, structural supports, stops, and bumpers.
The cranes typically found in metal building systems top running bridge cranes. Although there are many other types;
- Underhung
- Monorail
- Jib
- Stacker
- Gantry
We can provide each metal building and crane support system to meet the specific requirements of your project with either subs for rails for the crane to run on or point loads on the structure for different industrial uses, ie conveyers, chain lift.
Aviation Facilities: Aircraft hangars are individually engineered to meet specific requirements and are flexible enough to satisfy even the most complex aviation need. The steel aircraft storage hangars may be designed using gable symmetrical, gable unsymmetrical, or single slope structural systems. But for the easiest design it is best to place he hangar rood on the endwall parallel with an endwall frame to hang the stub columns from.
These cost effective, metal aircraft hangar designs have many advantages:
- Design flexibility
- Fast, easy construction
- Reduced maintenance costs
- Most important – we detail the hangar door engineering into the structure
The clearspan design provides column-free interiors for wide-open floor space and eave heights that can accommodate today’s larger aircrafts. The structures allow for a variety of door options including bi-fold, hydraulic one piece doors, bi-parting, and stack leaf designs.
By combining the metal building system with conventional exterior materials such as brick, stone, precast concrete, or glass, the structure can be aesthetically appealing while providing the perfect solution to aviation needs.
Construction Material Requirements
Consider some of the key factors that influence the selection of construction materials by the manufacturer, the designer, and the user.
STRENGTH is a very important factor.
AVAILABILITY the timing of materials influence its selection, cost of material, and final in-place cost.
WEIGHT and BULK becomes important from a handling and shipping standpoint.
DURABILITY of the finished product is measured in terms of its resistance to wear and destruction from all causes. Nothing much last longer then steel.
Materials must be capable of presenting a pleasing APPEARANCE.
Steel is used extensively in many segments of construction. The primary advantage of steel is its strength. The material, as it comes from the mills, has very exacting specifications, enabling engineers to design structures with a high degree of accuracy. In addition, steel is a plentiful and a well-accepted material. It has a high degree of workability because it can be cut, welded, shaped, and formed to meet a great variety of needs. Steel can also take a great deal of abuse and wear.
The greatest disadvantage of steel is that it will rust when exposed to the elements. This is prevented, however, by the application of protective coatings. At the factory they punch the holes and bend the pieces first then paint the pieces including inside the holes and edges. This provides a great advantage preventing rust.
Although steel will not burn, it is not classified as fireproof because it can become distorted, lose its structural strength, or even melt, depending on the intensity of the heat. Nevertheless, compared to many materials, steel offers a great deal of fire resistance due to the large amount of heat needed to cause any damage.
Fundamental Factors Affecting Building Design
Buildings provide shelter for persons and property. A building must have many desirable characteristics such as an attractive appearance, long life, flexibility of use, and economy. Protection though is one of the most important qualities in a building.
You might analyze this further and consider two kinds of protection.
1. Protection against forces or loads that may be exerted upon the building. Unless the structure can offer adequate resistance against various loading conditions, the safety of persons and the value of property are endangered. This is where sound design consideration must be given as to the strength of the metal building and particularly to the structural system.
2. Protection is protection against rain, wind, heat, and cold. Any of these can contribute to the discomfort of persons and cause a decrease in the value of contents. The degree of protection is determined by the weather tightness and thermal efficiency of a building. These things, of course, greatly influence the design of roofs and walls, also known as the covering system.
Design Loading
If you were to ask an engineer to design a prefabricated metal building of a certain size, he/she would first have to know what type and magnitude of the loads that would be imposed upon the building. Only with this basic information will he/she be able to design a building that will meet the prospective customer’s exact needs for loading conditions, it is important that you have a basic understanding of design loading.
A load is a force exerted upon a structure or one of its members. There are many different kinds of loads that must be taken into consideration in various situations, but only those that are of prime importance will be covered here.
Dead Load: The weight of the metal building system, such as roof, framing, and covering members.
Live Load : Any temporary load imposed on a building that is not wind load, snow load, seismic load, or dead load. A few examples of a live load are workers, equipment, and materials.
Snow Load : The vertical load induced by the weight of snow, assumed to act on the horizontal projection of the roof of the structure.
Ground Snow Load : Ground snow load is a calculation of a combination of slope roof snow and many other factors. Ground snow load is usually a higher value then roof snow load and two should be confused as the same.
(Note: Very wet snow 6″ deep is equal to one inch of water. One inch of water on a square foot of surface weighs five pounds.)
Wind Load: The forces imposed by the wind blowing from any direction. For a pre-engineered metal building the wind mph is translated into pounds per square foot and the converted load is allied to the building.
Seismic Load: The load(s) acting in any direction on a structural system due to the action of an earthquake.
Auxiliary Loads: All dynamic live loads such as cranes and material handling systems. This could also include point load for curbs or HVAC units for example.
Collateral Load : The weight of additional permanent materials, other than the weight of the metal building system, such as sprinklers, mechanical/electrical systems, and ceilings.
Resistance of Material to Forces
Loading has been defined as a force exerted on a building. Such forces are transmitted through joints and connections to individual parts or components. This eventually leads to a consideration of the properties of materials to resist forces in order to provide the engineer with a basis for subsequent design calculations.
Stress:The force acting on a member divided by its area.
Tension: Stresses acting away from each other that produce a uniform stretching of a member.
Compression: Stresses acting toward each other that causes a member to compress.
Shear: Stress that tends to keep two adjoining planes of a material from sliding on each other, under two equal and parallel forces acting in opposite directions.
Column Reactions
Any structure placed on a foundation causes a load to be imposed on that foundation. All buildings have these loads imposed by the columns on the foundation. These loads are called column reactions.
Column reactions are often expressed using the term “kip.” A kip is a commonly used engineering term for 1,000 pounds, derived from the contraction of the words “kilo” (1,000) and “pound”.
Framing structures exert a load on a foundation both vertically and horizontally. The vertical load is the result of the dead weight of the structure, and other loads such as snow on the roof, wind loads, crane loads, or seismic loads.
The horizontal load is the result of wind loads or seismic loads, and also produces the tendency of the base of rigid frame columns to spread apart under vertical load.
A third type of load arises from framing systems, which have fixed base columns. A streetlight or a flag poll is a common example of a fixed base column. When this type of column is subjected to wind loads, the foundation of such columns must be designed to resist the wind’s effort to overturn them. This overturning force is called a moment.
Engineers usually express the overturning moment as a “foot-kip”. As an example, assume that the wind load against the wall of the building creates an effective force of 2,000 pounds against the top of a 12′ column.
The resulting moment at the base would be an overturning force or moment of 24 -ft- kips (2,000 Pounds or 2 kips x 12 feet = 24 -ft- kips).
Load Transfer
Regardless of the type of load or where it is exerted on a rigid frame building, it is always transferred from part to part down to the foundation.
Assume, for example, a man standing on a roof of his metal building. His weight is directly on the panels, but the load is transmitted through the panels to the purlins, the closest purlins taking the greatest part of the load. The purlins transfer the load to the rafter, the rafter to the column, then the column to the foundation.
The load at the base of the column will be a vertical load and also a horizontal thrust or “side kick.” These horizontal thrusts can become very sizeable figures and must be taken into consideration when designing foundations for rigid frame buildings.
A wind load on the sidewall of the rigid frame structure may produce uplift on the main frame as well as horizontal thrusts.
The foundation must be designed to support not only vertical loads, but also the horizontal thrust.
Building Codes
Building codes are a set of minimum requirements for construction covering safety and serviceability. The safety requirements cover life, health, fire, and structural stability. Most areas have enforced codes governing construction in the community. They may be administered by a city, county, state, or by a combination of the three.
Building codes are necessary since their purpose is to benefit the public by helping eliminate unsafe design, poor construction practices, and unsightly buildings..
A community may originate and write its own codes, but generally they either adopt a recognized building code in its entirety, or modify it for its specific use.
International Building Code (IBC) Over the past several years the three national model building code bodies, SBCCI, BOCA, and ICBO have been working together to produce a single code to be used throughout the United States.
From a building design viewpoint, the IBC code has adopted new requirements for live, wind, snow, and seismic loads. The rules for applying and combining these loads are much more complex than in previous codes, and in many cases cause higher loads to be used for designing the building. This can result in higher costs for building foundations as well as for the pre engineered metal building structure.
There are new load maps in the code for wind, snow, and seismic loads. The wind load maps are based on 3-second gust wind loads, unlike the maps in the old codes that were based on sustained wind speeds. This means that the code specified wind speed for the whole country will be higher than before. Also, unlike some earlier codes, it is necessary to specify wind exposure categories and enclosure classifications.
The ground snow load maps in the new code is based on more recently accumulated data, but for most parts of the country the starting snow load values have not changed that much. However, there are new unbalanced snow load equations which drastically increase the roof snow load, especially for snow loads of 20 psf and greater.
The seismic provisions of the new code reflect the latest research for earthquake loads. The new seismic maps measures “Spectral Response Acceleration” for 0.2 and 1.0 seconds. This is a completely new approach to this problem. The IBC seismic equations and maps result in substantially higher imposed loads.
Over time, many areas have responded to unusual storms by increasing the base load to guard against future collapses. Many of the wind and snow load provisions of the new code were written in response to such events. Because of all these changes, you must make sure you confirm the exact loads and code with your local building department.
The snow provisions in the new code, for instance, may result in unbalanced loads because of the more than twice basic roof snow load, even with no high-low conditions. The minimum wind speed on the maps is now 85 mph, in lieu of the old 70 mph minimum that has been in effect for years.
Because of these changes, make sure to determine the values for the wind, snow, and seismic loads for a project only from the new maps. The majority of state and local jurisdictions seem to adopt newer codes and or change their values for any given area whenever they feel the need.
Codes are complicated and cover many phases of construction and differ from community to community. It is necessary that you become familiar with the codes that are applicable in your area. It is also advisable to discuss the code official’s interpretation of the codes. Interpretations of these codes can vary from official to official.
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Steel Design
Because of the various properties and characteristics of steel, many factors must be considered when designing both individual members and completed structures. Two organizations have published manuals that provide data and standards on which to base calculations for the design of steel:
AISC – The American Institute of Steel Construction was originated by steel fabricators and is generally concerned with hot rolled shapes and plates.
AISI – The American Iron and Steel Institute was originated by steel producers and is concerned with cold-formed steel structural members.
The manufacturer’s products, where applicable, are designed in accordance with AISI and AISC specifications. This is a mark of sound design and engineering practices, and contributes to the high quality of our products.