# data[].attributes.headline
Steel posts are often enclosed in fire-resisting terra-cotta or in concrete. This restrains them from twisting under extreme heat. same

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Steel posts are often enclosed in fire-resisting terra-cotta or in concrete. This restrains them from twisting under extreme heat. same

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A steel framework is joined together by bolting, riveting, or welding. A new method permits the pieces to be joined by fasteners that interlock and are sealed by the blows of a hammer.  same

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A steel framework is joined together by bolting, riveting, or welding. A new method permits the pieces to be joined by fasteners that interlock and are sealed by the blows of a hammer.  same

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A skyscraper is constructed with a steel skeleton framework that supports the weight of the entire building. same

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A skyscraper is constructed with a steel skeleton framework that supports the weight of the entire building. same

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Foundation soil may also be made rigid by packing it down with heavy machines or by flowing grout, a watery concrete, into voids and spaces in the soil.  http://school.eb.com/levels/middle/article/273396

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Foundation soil may also be made rigid by packing it down with heavy machines or by flowing grout, a watery concrete, into voids and spaces in the soil.  http://school.eb.com/levels/middle/article/273396

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Extensive studies of soil mechanics must be made before foundations are laid for skyscrapers. Facts about the ground are determined by drilling or boring holes for soil samples and by transmitting sound waves and electric currents through the soil. http://school.eb.com/levels/middle/article/273396

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 The basic steps are: 1) ask: identify needs and constraints, 2) research the problem, 3) imagine: develop possible solutions, 4) plan: select a promising solution, 5) create: build a prototype, 6) test and evaluate prototype, 7) improve: redesign as needed. https://www.teachengineering.org/activities/view/ucd_straw_tower_activity1

# data[].attributes.subject
 The basic steps are: 1) ask: identify needs and constraints, 2) research the problem, 3) imagine: develop possible solutions, 4) plan: select a promising solution, 5) create: build a prototype, 6) test and evaluate prototype, 7) improve: redesign as needed. https://www.teachengineering.org/activities/view/ucd_straw_tower_activity1

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mathematics concepts to solve problems that improve the built world, including the design of buildings, bridges and other structures.  https://www.teachengineering.org/activities/view/ucd_straw_tower_activity1

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mathematics concepts to solve problems that improve the built world, including the design of buildings, bridges and other structures.  https://www.teachengineering.org/activities/view/ucd_straw_tower_activity1

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Roofs serve to protect against rain, snow, sunlight, wind, and extremes of temperature. They have been constructed in a wide variety of forms and are classified according to shape. Among the most common are gable, hip, gambrel, shed, mansard, and flat roofs. same

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Roofs serve to protect against rain, snow, sunlight, wind, and extremes of temperature. They have been constructed in a wide variety of forms and are classified according to shape. Among the most common are gable, hip, gambrel, shed, mansard, and flat roofs. same

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The framing for a one-story or two-story structure may be constructed from 2-inch by 4-inch pieces of lumber, called 2-by-4s. Heavier lumber is used for load-bearing joist headers over windows and doors, stair stringers, roof rafters, floor joists, and other supporting structures.  same

# data[].attributes.subject
The framing for a one-story or two-story structure may be constructed from 2-inch by 4-inch pieces of lumber, called 2-by-4s. Heavier lumber is used for load-bearing joist headers over windows and doors, stair stringers, roof rafters, floor joists, and other supporting structures.  same

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In some houses, the supporting joists and girders may be of steel, usually by beams.  same

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In some houses, the supporting joists and girders may be of steel, usually by beams.  same

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After the concrete has hardened, lengths of lumber, called sills, are fastened to the bolts, anchoring a house to its foundation.  same

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After the concrete has hardened, lengths of lumber, called sills, are fastened to the bolts, anchoring a house to its foundation.  same

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When concrete is used for foundation walls, it is poured into forms placed on top of the footings. The forms are then secured to the footing by fitting them into a narrow slot along the length of the footing. The footings and foundation walls are sometimes poured in one operation, and steel reinforcing rods are included to strengthen the walls. 

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When concrete is used for foundation walls, it is poured into forms placed on top of the footings. The forms are then secured to the footing by fitting them into a narrow slot along the length of the footing. The footings and foundation walls are sometimes poured in one operation, and steel reinforcing rods are included to strengthen the walls. 

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same cite

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First, concrete footings are poured into forms. A footing must extend below the frost line of the ground so that frost will not cause it to heave and crack. The width and thickness of the footing are determined by the weight of the building and the nature of the soil. same webcite

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First, concrete footings are poured into forms. A footing must extend below the frost line of the ground so that frost will not cause it to heave and crack. The width and thickness of the footing are determined by the weight of the building and the nature of the soil. same webcite

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Foundations are usually made of cement blocks, cinder blocks, or poured concrete. They must be properly laid to keep them from sinking, shifting, cracking, or allowing excessive moisture to enter and possibly damage the completed structure. http://school.eb.com/levels/middle/article/273396

# data[].attributes.subject
Foundations are usually made of cement blocks, cinder blocks, or poured concrete. They must be properly laid to keep them from sinking, shifting, cracking, or allowing excessive moisture to enter and possibly damage the completed structure. http://school.eb.com/levels/middle/article/273396

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 standard-frame, lumber construction. Apartments and condominiums are often constructed of brick, concrete, or masonry.  http://school.eb.com/levels/middle/article/273396

# data[].attributes.subject
 standard-frame, lumber construction. Apartments and condominiums are often constructed of brick, concrete, or masonry.  http://school.eb.com/levels/middle/article/273396

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2,722 feet gives it the undisputed and well-recognized status as the tallest man-made structure in the world. http://school.eb.com/levels/middle/article/273396