Введение
Тип стали, используемой в строительстве
Type of steel used in construction
Конструкционная сталь – это категория стали, применяемая для изготовления строительных материалов различных форм. Многие элементы конструкционной стали имеют вид удлиненных балок с определенным профилем поперечного сечения. Формы, размеры, химический состав, механические свойства, такие как прочность, условия хранения и прочее, регулируются стандартами в большинстве индустриально развитых стран. Большинство элементов конструкционной стали, например балки, обладают высоким моментом инерции сечения, что означает их высокую жесткость по отношению к площади поперечного сечения и, следовательно, способность выдерживать большие нагрузки без чрезмерного прогиба.
Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, sizes, chemical composition, mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries. Most structural steel shapes, such as beams, have high second moments of area, which means they are very stiff in respect to their cross sectional area and thus can support a high load without excessive sagging.
Углеродистые стали
A36 – конструктивные формы и листы. A53 – конструкционные трубы и трубопроводы. A500 – конструкционные трубы и трубопроводы. A501 – конструкционные трубы и трубопроводы. A529 – конструктивные формы и листы. A1085 – конструкционные трубы и трубопроводы.
A36 – structural shapes and plate. A53 – structural pipe and tubing. A500 – structural pipe and tubing. A501 – structural pipe and tubing. A529 – structural shapes and plate. A1085 – structural pipe and tubing.
Противокоррозионные высокопрочные низколегированные стали
A243 – конструкционные профили и листы. A588 – конструкционные профили и листы.
A243 – structural shapes and plates. A588 – structural shapes and plates.
Слитые стали, затушенные и закаленные
A514 – конструкционные профили и листы. A517 – котлы и сосуды, работающие под давлением. Сталь Эглин – недорогие изделия для аэрокосмической отрасли и вооружений.
A514 – structural shapes and plates. A517 – boilers and pressure vessels. Eglin steel – Inexpensive aerospace and weaponry items.
Выбор идеального конструкционного материала
В большинстве строительных проектов требуется использование сотен различных материалов. Они варьируются от бетона различных марок, конструкционной стали, глины, раствора, керамики, древесины и так далее. С точки зрения несущего каркаса, материалы обычно состоят из конструкционной стали, бетона, каменной кладки и/или древесины, используя подходящую комбинацию для создания эффективной конструкции. Большинство коммерческих и промышленных зданий в основном строятся из конструкционной стали или железобетона. При проектировании конструкции инженер должен определить, какой материал или их комбинация наиболее подходит для данной задачи. При выборе строительного материала учитывается множество факторов. Стоимость обычно является определяющим, но также принимаются во внимание вес, прочность, технологичность, доступность (с учетом географического положения и рыночной конъюнктуры), экологичность и огнестойкость.
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before a final decision is made. Cost – The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form work. This refers to the lumber or framework necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time required. With steel being sold by weight, the structural designer must specify the lightest members possible while maintaining a safe structural design. Utilizing a large number of identical steel members rather that unique size or shape members also reduces cost. Strength/weight ratio – Construction materials are commonly categorized by their strength to weight ratio—or specific strength, which is the strength of a material divided by its density. These ratios indicate how useful the material is for its weight, which in turn indicates its cost and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression. Sustainability Primarily due to public image and government incentives, many construction companies and material vendors are having to focus efforts more on environmental friendliness. Sustainability has become an entirely new consideration for materials that will be in the environment for generations. A sustainable material minimally affects the environment upon installation and throughout its life cycle. Reinforced concrete and structural steel can be sustainable if used properly. Over 80% of structural steel members are fabricated from recycled metals, called A992 steel. This member material is cheaper and has a higher strength to weight ratio than previously used steel members (A36 grade). Concrete's material components are naturally occurring materials that are not harmful to the environment, and concrete can now be poured to be permeable, letting water flow through a paved surface to reduce the need for drainage or runoff infrastructure. Concrete can also be crushed and used as aggregate in future concrete applications, avoiding the use of land fill. Fire resistance One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of a fire and even resists the spreading of fire, as well as temperature changes. This makes concrete excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Constructability Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule friendly construction material. The tallest structures today (commonly called "skyscrapers" or high rise) are constructed using structural steel due to its constructability, as well as its high strength to weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength to weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low rise buildings, or those with several stories or less. Low rise buildings distribute much smaller loads than high rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.
Стоимость. Стоимость этих строительных материалов полностью зависит от географического расположения объекта и наличия материалов. Как и цена на бензин, цены на цемент, щебень, сталь и т.д. подвержены колебаниям. Примерно половина стоимости строительства железобетона приходится на опалубку – деревянные или металлические конструкции, необходимые для создания формы, в которую заливается бетон и удерживается до затвердевания. Высокая стоимость опалубки делает предварительно напряженный бетон привлекательным вариантом для проектировщиков благодаря снижению затрат и сроков строительства. Поскольку сталь продается по весу, конструктор должен выбирать элементы минимального веса, обеспечивая при этом надежность конструкции. Использование большого количества одинаковых стальных элементов вместо уникальных по размеру или форме также снижает стоимость.
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before a final decision is made. Cost – The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form work. This refers to the lumber or framework necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time required. With steel being sold by weight, the structural designer must specify the lightest members possible while maintaining a safe structural design. Utilizing a large number of identical steel members rather that unique size or shape members also reduces cost. Strength/weight ratio – Construction materials are commonly categorized by their strength to weight ratio—or specific strength, which is the strength of a material divided by its density. These ratios indicate how useful the material is for its weight, which in turn indicates its cost and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression. Sustainability Primarily due to public image and government incentives, many construction companies and material vendors are having to focus efforts more on environmental friendliness. Sustainability has become an entirely new consideration for materials that will be in the environment for generations. A sustainable material minimally affects the environment upon installation and throughout its life cycle. Reinforced concrete and structural steel can be sustainable if used properly. Over 80% of structural steel members are fabricated from recycled metals, called A992 steel. This member material is cheaper and has a higher strength to weight ratio than previously used steel members (A36 grade). Concrete's material components are naturally occurring materials that are not harmful to the environment, and concrete can now be poured to be permeable, letting water flow through a paved surface to reduce the need for drainage or runoff infrastructure. Concrete can also be crushed and used as aggregate in future concrete applications, avoiding the use of land fill. Fire resistance One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of a fire and even resists the spreading of fire, as well as temperature changes. This makes concrete excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Constructability Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule friendly construction material. The tallest structures today (commonly called "skyscrapers" or high rise) are constructed using structural steel due to its constructability, as well as its high strength to weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength to weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low rise buildings, or those with several stories or less. Low rise buildings distribute much smaller loads than high rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.
Соотношение прочности к весу. Строительные материалы обычно классифицируются по соотношению прочности к весу, или удельной прочности, которая определяется как прочность материала, деленная на его плотность. Эти показатели характеризуют эффективность использования материала с учетом его веса, что влияет на стоимость и простоту строительства. Бетон обычно в десять раз прочнее при сжатии, чем при растяжении, что обеспечивает более высокое соотношение прочности к весу при сжатии.
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before a final decision is made. Cost – The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form work. This refers to the lumber or framework necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time required. With steel being sold by weight, the structural designer must specify the lightest members possible while maintaining a safe structural design. Utilizing a large number of identical steel members rather that unique size or shape members also reduces cost. Strength/weight ratio – Construction materials are commonly categorized by their strength to weight ratio—or specific strength, which is the strength of a material divided by its density. These ratios indicate how useful the material is for its weight, which in turn indicates its cost and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression. Sustainability Primarily due to public image and government incentives, many construction companies and material vendors are having to focus efforts more on environmental friendliness. Sustainability has become an entirely new consideration for materials that will be in the environment for generations. A sustainable material minimally affects the environment upon installation and throughout its life cycle. Reinforced concrete and structural steel can be sustainable if used properly. Over 80% of structural steel members are fabricated from recycled metals, called A992 steel. This member material is cheaper and has a higher strength to weight ratio than previously used steel members (A36 grade). Concrete's material components are naturally occurring materials that are not harmful to the environment, and concrete can now be poured to be permeable, letting water flow through a paved surface to reduce the need for drainage or runoff infrastructure. Concrete can also be crushed and used as aggregate in future concrete applications, avoiding the use of land fill. Fire resistance One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of a fire and even resists the spreading of fire, as well as temperature changes. This makes concrete excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Constructability Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule friendly construction material. The tallest structures today (commonly called "skyscrapers" or high rise) are constructed using structural steel due to its constructability, as well as its high strength to weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength to weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low rise buildings, or those with several stories or less. Low rise buildings distribute much smaller loads than high rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.
Экологичность. В основном из-за имиджа и государственных стимулов многие строительные компании и поставщики материалов уделяют все больше внимания экологической безопасности. Экологичность стала важным фактором при выборе материалов, которые будут использоваться в окружающей среде на протяжении многих поколений. Экологичный материал оказывает минимальное воздействие на окружающую среду на этапах установки и в течение всего жизненного цикла. Железобетон и конструкционная сталь могут быть экологичными при правильном использовании. Более 80% конструкционных стальных элементов изготавливаются из переработанного металла, стали марки A992. Этот материал дешевле и имеет более высокое соотношение прочности к весу, чем сталь, использовавшаяся ранее (марка A36). Компоненты бетона – природные материалы, не наносящие вреда окружающей среде. Кроме того, бетон может быть изготовлен водопроницаемым, позволяя воде просачиваться через покрытие и снижая потребность в дренажной инфраструктуре. Бетон также можно измельчать и использовать в качестве заполнителя при производстве нового бетона, избегая захоронения отходов.
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before a final decision is made. Cost – The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form work. This refers to the lumber or framework necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time required. With steel being sold by weight, the structural designer must specify the lightest members possible while maintaining a safe structural design. Utilizing a large number of identical steel members rather that unique size or shape members also reduces cost. Strength/weight ratio – Construction materials are commonly categorized by their strength to weight ratio—or specific strength, which is the strength of a material divided by its density. These ratios indicate how useful the material is for its weight, which in turn indicates its cost and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression. Sustainability Primarily due to public image and government incentives, many construction companies and material vendors are having to focus efforts more on environmental friendliness. Sustainability has become an entirely new consideration for materials that will be in the environment for generations. A sustainable material minimally affects the environment upon installation and throughout its life cycle. Reinforced concrete and structural steel can be sustainable if used properly. Over 80% of structural steel members are fabricated from recycled metals, called A992 steel. This member material is cheaper and has a higher strength to weight ratio than previously used steel members (A36 grade). Concrete's material components are naturally occurring materials that are not harmful to the environment, and concrete can now be poured to be permeable, letting water flow through a paved surface to reduce the need for drainage or runoff infrastructure. Concrete can also be crushed and used as aggregate in future concrete applications, avoiding the use of land fill. Fire resistance One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of a fire and even resists the spreading of fire, as well as temperature changes. This makes concrete excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Constructability Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule friendly construction material. The tallest structures today (commonly called "skyscrapers" or high rise) are constructed using structural steel due to its constructability, as well as its high strength to weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength to weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low rise buildings, or those with several stories or less. Low rise buildings distribute much smaller loads than high rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.
Огнестойкость. Одной из самых серьезных опасностей для здания является пожар. Это особенно актуально в сухом, ветреном климате и для конструкций из дерева. При работе с конструкционной сталью необходимо учитывать специальные меры предосторожности, чтобы избежать опасной пожарной ситуации. Железобетон, как правило, не представляет угрозы при пожаре и даже препятствует распространению огня и изменению температуры. Это делает бетон отличным теплоизолятором, повышая экологичность здания за счет снижения энергозатрат на поддержание климата.
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before a final decision is made. Cost – The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form work. This refers to the lumber or framework necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time required. With steel being sold by weight, the structural designer must specify the lightest members possible while maintaining a safe structural design. Utilizing a large number of identical steel members rather that unique size or shape members also reduces cost. Strength/weight ratio – Construction materials are commonly categorized by their strength to weight ratio—or specific strength, which is the strength of a material divided by its density. These ratios indicate how useful the material is for its weight, which in turn indicates its cost and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression. Sustainability Primarily due to public image and government incentives, many construction companies and material vendors are having to focus efforts more on environmental friendliness. Sustainability has become an entirely new consideration for materials that will be in the environment for generations. A sustainable material minimally affects the environment upon installation and throughout its life cycle. Reinforced concrete and structural steel can be sustainable if used properly. Over 80% of structural steel members are fabricated from recycled metals, called A992 steel. This member material is cheaper and has a higher strength to weight ratio than previously used steel members (A36 grade). Concrete's material components are naturally occurring materials that are not harmful to the environment, and concrete can now be poured to be permeable, letting water flow through a paved surface to reduce the need for drainage or runoff infrastructure. Concrete can also be crushed and used as aggregate in future concrete applications, avoiding the use of land fill. Fire resistance One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of a fire and even resists the spreading of fire, as well as temperature changes. This makes concrete excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Constructability Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule friendly construction material. The tallest structures today (commonly called "skyscrapers" or high rise) are constructed using structural steel due to its constructability, as well as its high strength to weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength to weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low rise buildings, or those with several stories or less. Low rise buildings distribute much smaller loads than high rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.
Технологичность. Конструкционная сталь может быть изготовлена практически любой формы и соединяться болтами или сваркой. Монтаж конструкционной стали возможен сразу после доставки на строительную площадку, в то время как бетону требуется не менее 1–2 недель для затвердевания, прежде чем можно будет продолжить строительство, что делает сталь удобным материалом с точки зрения графика работ. Самые высокие здания в мире (так называемые небоскребы) обычно строятся из конструкционной стали благодаря ее технологичности и высокому соотношению прочности к весу. В то же время бетон, хотя и менее плотный, чем сталь, имеет значительно более низкое соотношение прочности к весу. Это связано с тем, что для поддержки той же нагрузки требуется больший объем бетонного элемента. Сталь, хотя и более плотная, требует меньшего количества материала для выдерживания нагрузки. Однако это преимущество становится незначительным для малоэтажных зданий, состоящих из нескольких этажей или меньше. Малоэтажные здания испытывают значительно меньшие нагрузки, чем высотные, что делает бетон экономически выгодным выбором. Это особенно верно для простых конструкций, таких как парковки или здания простой прямоугольной формы.
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before a final decision is made. Cost – The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form work. This refers to the lumber or framework necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time required. With steel being sold by weight, the structural designer must specify the lightest members possible while maintaining a safe structural design. Utilizing a large number of identical steel members rather that unique size or shape members also reduces cost. Strength/weight ratio – Construction materials are commonly categorized by their strength to weight ratio—or specific strength, which is the strength of a material divided by its density. These ratios indicate how useful the material is for its weight, which in turn indicates its cost and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression. Sustainability Primarily due to public image and government incentives, many construction companies and material vendors are having to focus efforts more on environmental friendliness. Sustainability has become an entirely new consideration for materials that will be in the environment for generations. A sustainable material minimally affects the environment upon installation and throughout its life cycle. Reinforced concrete and structural steel can be sustainable if used properly. Over 80% of structural steel members are fabricated from recycled metals, called A992 steel. This member material is cheaper and has a higher strength to weight ratio than previously used steel members (A36 grade). Concrete's material components are naturally occurring materials that are not harmful to the environment, and concrete can now be poured to be permeable, letting water flow through a paved surface to reduce the need for drainage or runoff infrastructure. Concrete can also be crushed and used as aggregate in future concrete applications, avoiding the use of land fill. Fire resistance One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of a fire and even resists the spreading of fire, as well as temperature changes. This makes concrete excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Constructability Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule friendly construction material. The tallest structures today (commonly called "skyscrapers" or high rise) are constructed using structural steel due to its constructability, as well as its high strength to weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength to weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low rise buildings, or those with several stories or less. Low rise buildings distribute much smaller loads than high rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.
Конструкционная сталь и железобетон не всегда выбираются исключительно из-за их идеальных характеристик для конкретной конструкции. Компании, как и проектировщики, стремятся получить прибыль от любого строительного проекта. Цена сырья (сталь, цемент, крупный и мелкий заполнитель, древесина для опалубки и т.д.) постоянно меняется. Если конструкция может быть построена из любого из этих материалов, то выбор, скорее всего, будет сделан в пользу более дешевого варианта. Важным фактором является также местоположение объекта. Ближайший завод по изготовлению стальных конструкций может находиться значительно дальше от строительной площадки, чем ближайший поставщик бетона. Высокая стоимость энергии и транспортировки также будет влиять на выбор материала. Все эти факторы будут учтены перед началом концептуального проектирования строительного объекта.
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel, clay, mortar, ceramics, wood, and so on. In terms of a load bearing structural frame, materials will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the primary controlling element; however, other considerations such as weight, strength, constructability, availability (with regards to geographic location as well as market availability), sustainability, and fire resistance will be taken into account before a final decision is made. Cost – The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form work. This refers to the lumber or framework necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time required. With steel being sold by weight, the structural designer must specify the lightest members possible while maintaining a safe structural design. Utilizing a large number of identical steel members rather that unique size or shape members also reduces cost. Strength/weight ratio – Construction materials are commonly categorized by their strength to weight ratio—or specific strength, which is the strength of a material divided by its density. These ratios indicate how useful the material is for its weight, which in turn indicates its cost and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression. Sustainability Primarily due to public image and government incentives, many construction companies and material vendors are having to focus efforts more on environmental friendliness. Sustainability has become an entirely new consideration for materials that will be in the environment for generations. A sustainable material minimally affects the environment upon installation and throughout its life cycle. Reinforced concrete and structural steel can be sustainable if used properly. Over 80% of structural steel members are fabricated from recycled metals, called A992 steel. This member material is cheaper and has a higher strength to weight ratio than previously used steel members (A36 grade). Concrete's material components are naturally occurring materials that are not harmful to the environment, and concrete can now be poured to be permeable, letting water flow through a paved surface to reduce the need for drainage or runoff infrastructure. Concrete can also be crushed and used as aggregate in future concrete applications, avoiding the use of land fill. Fire resistance One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of a fire and even resists the spreading of fire, as well as temperature changes. This makes concrete excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Constructability Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule friendly construction material. The tallest structures today (commonly called "skyscrapers" or high rise) are constructed using structural steel due to its constructability, as well as its high strength to weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength to weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low rise buildings, or those with several stories or less. Low rise buildings distribute much smaller loads than high rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape. Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.
Огнестойкость
Сталь теряет прочность при достаточном нагреве. Критическая температура стального элемента – это температура, при которой он не может безопасно выдерживать свою нагрузку. Строительные нормы и общепринятая практика в области строительного проектирования определяют различные критические температуры в зависимости от типа, конфигурации, ориентации и характеристик нагрузки конструктивного элемента. Критической температурой часто считается температура, при которой предел текучести снижается до 60% от предела текучести при комнатной температуре. Для определения предела огнестойкости стального элемента можно использовать общепринятые расчетные методы или провести огневое испытание, критическая температура в котором устанавливается стандартом, принятым уполномоченным органом, например, строительным кодексом. В Японии это ниже 400 °C. В Китае, Европе и Северной Америке (например, ASTM E 119) это примерно 1000–1300 °F (530–810 °C). Время, необходимое для достижения стальным элементом, подвергаемым испытанию, температуры, установленной в стандарте испытаний, определяет продолжительность огнестойкости. Передачу тепла стали можно замедлить с помощью огнезащитных материалов, тем самым ограничивая температуру стали. Распространенные методы огнезащиты стальных конструкций включают интумесцентные, эндотермические и гипсовые покрытия, а также гипсокартон, облицовку из кальциевого силиката и минераловатные теплоизоляционные маты. Бетонные конструкции зданий часто соответствуют требованиям к огнестойкости, поскольку толщина бетона над стальной арматурой обеспечивает достаточную огнестойкость. Однако бетон может растрескиваться, особенно при повышенном содержании влаги. Хотя дополнительная огнезащита не часто применяется к бетонным конструкциям зданий, она иногда используется в транспортных туннелях и в местах, где более вероятны пожары, связанные с углеводородным топливом, поскольку пожары горючих жидкостей выделяют больше тепла конструктивному элементу по сравнению с пожарами, связанными с обычными горючими материалами, в течение одного и того же периода времени. Материалы для огнезащиты стальных конструкций включают интумесцентные, эндотермические и гипсовые покрытия, а также гипсокартон, облицовку из кальциевого силиката и минеральную или высокотемпературную теплоизоляционную вату. Особое внимание уделяется соединениям, поскольку термическое расширение конструктивных элементов может снизить огнестойкость конструкций.
Steel loses strength when heated sufficiently. The critical temperature of a steel member is the temperature at which it cannot safely support its load. Building codes and structural engineering standard practice defines different critical temperatures depending on the structural element type, configuration, orientation, and loading characteristics. The critical temperature is often considered the temperature at which its yield stress has been reduced to 60% of the room temperature yield stress. In order to determine the fire resistance rating of a steel member, accepted calculations practice can be used, or a fire test can be performed, the critical temperature of which is set by the standard accepted to the Authority Having Jurisdiction, such as a building code. In Japan, this is below 400 °C. In China, Europe and North America (e. g., ASTM E 119), this is approximately 1000–1300 °F (530–810 °C). The time it takes for the steel element that is being tested to reach the temperature set by the test standard determines the duration of the fire resistance rating. Heat transfer to the steel can be slowed by the use of fireproofing materials, thus limiting steel temperature. Common fireproofing methods for structural steel include intumescent, endothermic, and plaster coatings as well as drywall, calcium silicate cladding, and mineral wool insulating blankets. Concrete building structures often meet code required fire resistance ratings, as the concrete thickness over the steel rebar provides sufficient fire resistance. However, concrete can be subject to spalling, particularly if it has an elevated moisture content. Although additional fireproofing is not often applied to concrete building structures, it is sometimes used in traffic tunnels and locations where a hydrocarbon fuel fire is more likely, as flammable liquid fires provides more heat to the structural element as compared to a fire involving ordinary combustibles during the same fire period. Structural steel fireproofing materials include intumescent, endothermic and plaster coatings as well as drywall, calcium silicate cladding, and mineral or high temperature insulation wool blankets. Attention is given to connections, as the thermal expansion of structural elements can compromise fire resistance rated assemblies.
Производство
Обычно заготовки отрезают по длине на ленточной пиле. Стрелочная сверлильная линия (сверлильная линия) давно зарекомендовала себя как незаменимый способ сверления отверстий и фрезерования пазов в балках, швеллерах и профилях HSS. Сверлильные линии с ЧПУ обычно оснащаются подающими конвейерами и датчиками положения для перемещения элемента в позицию для сверления, а также функцией зондирования для определения точного места, где необходимо сделать отверстие или прорезь. Для вырезания неправильной формы отверстий или неровных торцов на объемных (не листовых) элементах обычно используется резательная горелка. Окситопливные горелки – наиболее распространенная технология, варьирующаяся от простых ручных горелок до автоматических станков с ЧПУ, которые перемещают головку горелки вокруг металлоконструкции в соответствии с инструкциями по резке, запрограммированными в станок. Изготовление плоских листов производится на комплексе обработки листов, где лист укладывается на стационарный "стол", а различные режущие головки перемещаются по листу с помощью портальной системы или "моста". Режущие головки могут включать в себя пробойник, сверло или горелку.
Cutting workpieces to length is usually done with a bandsaw. A beam drill line (drill line) has long been considered an indispensable way to drill holes and mill slots into beams, channels and HSS elements. CNC beam drill lines are typically equipped with feed conveyors and position sensors to move the element into position for drilling, plus probing capability to determine the precise location where the hole or slot is to be cut. For cutting irregular openings or non uniform ends on dimensional (non plate) elements, a cutting torch is typically used. Oxy fuel torches are the most common technology and range from simple hand held torches to automated CNC coping machines that move the torch head around the structural element in accordance with cutting instructions programmed into the machine. Fabricating flat plate is performed on a plate processing center where the plate is laid flat on a stationary 'table' and different cutting heads traverse the plate from a gantry style arm or "bridge". The cutting heads can include a punch, drill or torch.