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64-450: The Minnesota Building is a thirteen-story office tower located on the corner of East 4th Street and Cedar Street in downtown St. Paul. It is built of reinforced concrete and has a polished Indiana Limestone facing. The structure's primary facades face the streets to the north and west, and have entrance bays flanked by commercial display window bays at the pedestrial level and vertical window shafts separated by limestone piers between

128-460: A four-story house at 72 rue Charles Michels in the suburbs of Paris. Coignet's descriptions of reinforcing concrete suggests that he did not do it for means of adding strength to the concrete but for keeping walls in monolithic construction from overturning. The, 1872–1873, Pippen building in Brooklyn stands as a testament to his technique. In 1854, English builder William B. Wilkinson reinforced

192-453: A major role in the evolution of concrete construction as a proven and studied science. Without Hyatt's work, more dangerous trial and error methods might have been depended on for the advancement in the technology. Joseph Monier , a 19th-century French gardener, was a pioneer in the development of structural, prefabricated and reinforced concrete, having been dissatisfied with the existing materials available for making durable flowerpots. He

256-419: A reduction in its durability. Corrosion and freeze/thaw cycles may damage poorly designed or constructed reinforced concrete. When rebar corrodes, the oxidation products ( rust ) expand and tends to flake, cracking the concrete and unbonding the rebar from the concrete. Typical mechanisms leading to durability problems are discussed below. Cracking of the concrete section is nearly impossible to prevent; however,

320-413: A short horizontal transom above the entry doors along with smaller wall lanterns. The tall pedestrian openings are crowned with terra cotta scrollwork. The opening facing the street corner also has a recessed corner shop entry. The two entrances are further defined by side piers and two piers directly above which are decorated with raised stone shafts stepping and terminating with floral motifs halfway up

384-576: A transition from Classical architecture to the Art Deco / Moderne design that gained wide popularity in downtown Saint Paul from the late 1920s through early 1940s. The building was followed by a small boom of notable Art Deco buildings in downtown St. Paul, including the Saint Paul City Hall and Ramsey County Courthouse , Saint Paul Women's City Club , Salvation Army Headquarters and First National Bank Building . Architecture critics had described

448-426: A well-chosen concrete mix will provide additional protection for many applications. Uncoated, low carbon/chromium rebar looks similar to standard carbon steel rebar due to its lack of a coating; its highly corrosion-resistant features are inherent in the steel microstructure. It can be identified by the unique ASTM specified mill marking on its smooth, dark charcoal finish. Epoxy-coated rebar can easily be identified by

512-515: Is a 1920 limestone, terra cotta , and brick commercial building in Saint Paul , Minnesota . Prior to the construction of the Hamm Building, the third Catholic cathedral of Saint Paul stood on the location until it was demolished in 1914. Construction of a new department store designed by Toltz, King & Day began shortly thereafter, but after the erection of the steel framework construction

576-658: Is a mixture of coarse (stone or brick chips) and fine (generally sand and/or crushed stone) aggregates with a paste of binder material (usually Portland cement ) and water. When cement is mixed with a small amount of water, it hydrates to form microscopic opaque crystal lattices encapsulating and locking the aggregate into a rigid shape. The aggregates used for making concrete should be free from harmful substances like organic impurities, silt, clay, lignite, etc. Typical concrete mixes have high resistance to compressive stresses (about 4,000 psi (28 MPa)); however, any appreciable tension ( e.g., due to bending ) will break

640-414: Is a narrow band of decorative, colored tile. The main entrance is recessed and displays two sets of brass plated doors flanked by wrought iron and glass display cases. Above the doors and cases is a band of cresting with a center metal plaque reading "MINNESOTA BUILDING". Above the cresting are five large transom windows, with the building address "46" painted in gold on the center window. The top of

704-528: Is coating them with zinc phosphate . Zinc phosphate slowly reacts with calcium cations and the hydroxyl anions present in the cement pore water and forms a stable hydroxyapatite layer. Penetrating sealants typically must be applied some time after curing. Sealants include paint, plastic foams, films and aluminum foil , felts or fabric mats sealed with tar, and layers of bentonite clay, sometimes used to seal roadbeds. Corrosion inhibitors , such as calcium nitrite [Ca(NO 2 ) 2 ], can also be added to

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768-495: Is located across the bay from San Francisco . Two years later, El Campanil survived the 1906 San Francisco earthquake without any damage, which helped build her reputation and launch her prolific career. The 1906 earthquake also changed the public's initial resistance to reinforced concrete as a building material, which had been criticized for its perceived dullness. In 1908, the San Francisco Board of Supervisors changed

832-541: Is one in which both the compressive and tensile zones reach yielding at the same imposed load on the beam, and the concrete will crush and the tensile steel will yield at the same time. This design criterion is however as risky as over-reinforced concrete, because failure is sudden as the concrete crushes at the same time of the tensile steel yields, which gives a very little warning of distress in tension failure. Steel-reinforced concrete moment-carrying elements should normally be designed to be under-reinforced so that users of

896-428: Is one in which the concrete element is only reinforced near the tensile face and the reinforcement, called tension steel, is designed to resist the tension. A doubly reinforced beam is the section in which besides the tensile reinforcement the concrete element is also reinforced near the compressive face to help the concrete resist compression and take stresses. The latter reinforcement is called compression steel. When

960-430: Is one in which the tension capacity of the tension steel is greater than the combined compression capacity of the concrete and the compression steel (over-reinforced at tensile face). So the "over-reinforced concrete" beam fails by crushing of the compressive-zone concrete and before the tension zone steel yields, which does not provide any warning before failure as the failure is instantaneous. A balanced-reinforced beam

1024-579: Is the theoretical failure point with a certain probability. It is stated under factored loads and factored resistances. Reinforced concrete structures are normally designed according to rules and regulations or recommendation of a code such as ACI-318, CEB, Eurocode 2 or the like. WSD, USD or LRFD methods are used in design of RC structural members. Analysis and design of RC members can be carried out by using linear or non-linear approaches. When applying safety factors, building codes normally propose linear approaches, but for some cases non-linear approaches. To see

1088-446: Is transferred from the concrete to the bar interface so as to change the tensile stress in the reinforcing bar along its length. This load transfer is achieved by means of bond (anchorage) and is idealized as a continuous stress field that develops in the vicinity of the steel-concrete interface. The reasons that the two different material components concrete and steel can work together are as follows: (1) Reinforcement can be well bonded to

1152-480: Is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion . Reinforcing schemes are generally designed to resist tensile stresses in particular regions of

1216-551: The Mississippi River . The building has a flat composition roof and an iron fire-escape on the southern facade. It is connected to the Saint Paul Skyway System through an adjacent building. The building was originally constructed with twelve stories, the thirteenth story was begun a soon as the building was completed in 1929 and completed in 1930. The thirteenth story is sheathed in the same limestone and repeats

1280-458: The United States , the most common methods of doing this are known as pre-tensioning and post-tensioning . For a strong, ductile and durable construction the reinforcement needs to have the following properties at least: François Coignet used iron-reinforced concrete as a technique for constructing building structures. In 1853, Coignet built the first iron reinforced concrete structure,

1344-462: The tensile strength of concrete was improved by the reinforcing. Before the 1870s, the use of concrete construction, though dating back to the Roman Empire , and having been reintroduced in the early 19th century, was not yet a proven scientific technology. Ernest L. Ransome , an English-born engineer, was an early innovator of reinforced concrete techniques at the end of the 19th century. Using

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1408-697: The 1890s, Wayss and his firm greatly contributed to the advancement of Monier's system of reinforcing, established it as a well-developed scientific technology. One of the first skyscrapers made with reinforced concrete was the 16-story Ingalls Building in Cincinnati, constructed in 1904. The first reinforced concrete building in Southern California was the Laughlin Annex in downtown Los Angeles , constructed in 1905. In 1906, 16 building permits were reportedly issued for reinforced concrete buildings in

1472-673: The City of Los Angeles, including the Temple Auditorium and 8-story Hayward Hotel. In 1906, a partial collapse of the Bixby Hotel in Long Beach killed 10 workers during construction when shoring was removed prematurely. That event spurred a scrutiny of concrete erection practices and building inspections. The structure was constructed of reinforced concrete frames with hollow clay tile ribbed flooring and hollow clay tile infill walls. That practice

1536-592: The English counties of Norfolk and Suffolk. In 1877, Thaddeus Hyatt , published a report entitled An Account of Some Experiments with Portland-Cement-Concrete Combined with Iron as a Building Material, with Reference to Economy of Metal in Construction and for Security against Fire in the Making of Roofs, Floors, and Walking Surfaces , in which he reported his experiments on the behaviour of reinforced concrete. His work played

1600-524: The Minnesota Building, which was his largest work. By the late 1990s, the demand for modern office space caused the building to fall out of favor with commercial renters, and it began to fall into disuse. As early as 2003, plans were proposed to turn the building into a residential building with limited, street level commercial space. It was purchased by Sand Companies in spring 2006, and in January 2010,

1664-695: The actual available length is inadequate for full development, special anchorages must be provided, such as cogs or hooks or mechanical end plates. The same concept applies to lap splice length mentioned in the codes where splices (overlapping) provided between two adjacent bars in order to maintain the required continuity of stress in the splice zone. In wet and cold climates, reinforced concrete for roads, bridges, parking structures and other structures that may be exposed to deicing salt may benefit from use of corrosion-resistant reinforcement such as uncoated, low carbon/chromium (micro composite), epoxy-coated, hot dip galvanized or stainless steel rebar. Good design and

1728-461: The actual bond stress varies along the length of a bar anchored in a zone of tension, current international codes of specifications use the concept of development length rather than bond stress. The main requirement for safety against bond failure is to provide a sufficient extension of the length of the bar beyond the point where the steel is required to develop its yield stress and this length must be at least equal to its development length. However, if

1792-399: The block, are defined by similar window placement, but with concrete floor banding between floors and common brick infill between windows; these facades also display "MINNESOTA BLDG." painted in large block letters between the twelfth and thirteenth window rows. The windows on the upper floors of the southern facade were altered in the latter quarter of the twentieth century to improve views of

1856-517: The building is considered "exceptional." The lobby has a decorative terrazzo floor, glazed terra cotta walls with various classical motifs, and iron chandeliers. The building exterior features a terra cotta façade manufactured in Chicago, with a custom "pulsichrome" finish. Small gargoyles top the parapets. Being in the heart of Saint Paul's theatre district, the Capitol Theatre was built into

1920-543: The chief reasons for the failure of reinforcement bars in concrete. The relative cross-sectional area of steel required for typical reinforced concrete is usually quite small and varies from 1% for most beams and slabs to 6% for some columns. Reinforcing bars are normally round in cross-section and vary in diameter. Reinforced concrete structures sometimes have provisions such as ventilated hollow cores to control their moisture & humidity. Distribution of concrete (in spite of reinforcement) strength characteristics along

1984-732: The city's building codes to allow wider use of reinforced concrete. In 1906, the National Association of Cement Users (NACU) published Standard No. 1 and, in 1910, the Standard Building Regulations for the Use of Reinforced Concrete . Many different types of structures and components of structures can be built using reinforced concrete elements including slabs , walls , beams , columns , foundations , frames and more. Reinforced concrete can be classified as precast or cast-in-place concrete . Designing and implementing

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2048-553: The classical style, such as the St. Paul Public Library (1917) and Hamm Building (1919). After the Hamm Building, no multistory office building was built in St. Paul until the Minnesota Building, itself the first high rise building in the city since World War I . The Minnesota Building was the idea of a consortium of developers interested in creating a higher business density in downtown. Lead developers Lincoln Hold and Development Company purchased

2112-422: The compression zone of a concrete is inadequate to resist the compressive moment (positive moment), extra reinforcement has to be provided if the architect limits the dimensions of the section. An under-reinforced beam is one in which the tension capacity of the tensile reinforcement is smaller than the combined compression capacity of the concrete and the compression steel (under-reinforced at tensile face). When

2176-541: The concrete resists compression and reinforcement " rebar " resists tension can be made into almost any shape and size for the construction industry. Three physical characteristics give reinforced concrete its special properties: As a rule of thumb, only to give an idea on orders of magnitude, steel is protected at pH above ~11 but starts to corrode below ~10 depending on steel characteristics and local physico-chemical conditions when concrete becomes carbonated. Carbonation of concrete along with chloride ingress are amongst

2240-412: The concrete roof and floors in the two-story house he was constructing. His positioning of the reinforcement demonstrated that, unlike his predecessors, he had knowledge of tensile stresses. Between 1869 and 1870, Henry Eton would design, and Messrs W & T Phillips of London construct the wrought iron reinforced Homersfield Bridge bridge, with a 50' (15.25 meter) span, over the river Waveney, between

2304-423: The concrete that might cause unacceptable cracking and/or structural failure. Modern reinforced concrete can contain varied reinforcing materials made of steel, polymers or alternate composite material in conjunction with rebar or not. Reinforced concrete may also be permanently stressed (concrete in compression, reinforcement in tension), so as to improve the behavior of the final structure under working loads. In

2368-416: The concrete, thus they can jointly resist external loads and deform. (2) The thermal expansion coefficients of concrete and steel are so close ( 1.0 × 10 to 1.5 × 10 for concrete and 1.2 × 10 for steel) that the thermal stress-induced damage to the bond between the two components can be prevented. (3) Concrete can protect the embedded steel from corrosion and high-temperature induced softening. Because

2432-453: The concrete, which occurs when compressive stresses exceed its strength, by yielding or failure of the rebar when bending or shear stresses exceed the strength of the reinforcement, or by bond failure between the concrete and the rebar. Carbonation, or neutralisation, is a chemical reaction between carbon dioxide in the air and calcium hydroxide and hydrated calcium silicate in the concrete. Hamm Building The Hamm Building

2496-403: The cross-section of vertical reinforced concrete elements is inhomogeneous. The reinforcement in a RC structure, such as a steel bar, has to undergo the same strain or deformation as the surrounding concrete in order to prevent discontinuity, slip or separation of the two materials under load. Maintaining composite action requires transfer of load between the concrete and steel. The direct stress

2560-399: The developer began construction on converting the building into 137 rental housing units, including some affordable units as well as 10,000 square feet (930 m) of commercial and office space The Minnesota Building was the first Art Deco building in downtown St. Paul. Originally designed in a conservative style, the building became more Moderne as it was being built. Its design reflects

2624-450: The entry recess is framed with decorative cream-colored terra cotta , which continues along the ceiling. In addition, the entrance has two large brass wall lanterns and, above the entrance, is a low-relief stone version of the Seal of Minnesota , flanked by two stylized eagles facing inward. The secondary entrance is similar to the main entrance, except the bay opening is not as tall and has only

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2688-403: The examples of a non-linear numerical simulation and calculation visit the references: Prestressing concrete is a technique that greatly increases the load-bearing strength of concrete beams. The reinforcing steel in the bottom part of the beam, which will be subjected to tensile forces when in service, is placed in tension before the concrete is poured around it. Once the concrete has hardened,

2752-481: The first Minnesota Club site in 1928 and razed it to the ground. Designed by St. Paul architect Charles A. Hauser, construction began in 1929 by the Fleisher-Greg Construction Company. Finished on November 1, 1929, the building cost an estimated $ 970,000, and was designed mainly for office suites for upscale business. The architect moved into the building's additional penthouse floor as soon as it

2816-557: The first concrete buildings constructed in the United States was a private home designed by William Ward , completed in 1876. The home was particularly designed to be fireproof. G. A. Wayss was a German civil engineer and a pioneer of the iron and steel concrete construction. In 1879, Wayss bought the German rights to Monier's patents and, in 1884, his firm, Wayss & Freytag , made the first commercial use of reinforced concrete. Up until

2880-645: The knowledge of reinforced concrete developed during the previous 50 years, Ransome improved nearly all the styles and techniques of the earlier inventors of reinforced concrete. Ransome's key innovation was to twist the reinforcing steel bar, thereby improving its bond with the concrete. Gaining increasing fame from his concrete constructed buildings, Ransome was able to build two of the first reinforced concrete bridges in North America. One of his bridges still stands on Shelter Island in New Yorks East End, One of

2944-811: The light green color of its epoxy coating. Hot dip galvanized rebar may be bright or dull gray depending on length of exposure, and stainless rebar exhibits a typical white metallic sheen that is readily distinguishable from carbon steel reinforcing bar. Reference ASTM standard specifications A1035/A1035M Standard Specification for Deformed and Plain Low-carbon, Chromium, Steel Bars for Concrete Reinforcement, A767 Standard Specification for Hot Dip Galvanized Reinforcing Bars, A775 Standard Specification for Epoxy Coated Steel Reinforcing Bars and A955 Standard Specification for Deformed and Plain Stainless Bars for Concrete Reinforcement. Another, cheaper way of protecting rebars

3008-438: The microscopic rigid lattice, resulting in cracking and separation of the concrete. For this reason, typical non-reinforced concrete must be well supported to prevent the development of tension. If a material with high strength in tension, such as steel , is placed in concrete, then the composite material, reinforced concrete, resists not only compression but also bending and other direct tensile actions. A composite section where

3072-656: The most efficient floor system is key to creating optimal building structures. Small changes in the design of a floor system can have significant impact on material costs, construction schedule, ultimate strength, operating costs, occupancy levels and end use of a building. Without reinforcement, constructing modern structures with concrete material would not be possible. When reinforced concrete elements are used in construction, these reinforced concrete elements exhibit basic behavior when subjected to external loads . Reinforced concrete elements may be subject to tension , compression , bending , shear , and/or torsion . Concrete

3136-448: The passivation of steel at the anodic oxidation sites. Nitrite is a much more active corrosion inhibitor than nitrate , which is a less powerful oxidizer of the divalent iron. A beam bends under bending moment , resulting in a small curvature. At the outer face (tensile face) of the curvature the concrete experiences tensile stress, while at the inner face (compressive face) it experiences compressive stress. A singly reinforced beam

3200-427: The piers above the parapet in stepped, zigzag finials . The spandrels between the buildings windows were cast in a geometric pattern and set flush with the piers, spreading the checkered motif downward across the entire facade. The building originally had double hung windows on the upper floors, however they were replaced in 1974 with metal-clad windows. The secondary facades, facing east and south internally in

3264-433: The reinforced concrete element is subject to increasing bending moment, the tension steel yields while the concrete does not reach its ultimate failure condition. As the tension steel yields and stretches, an "under-reinforced" concrete also yields in a ductile manner, exhibiting a large deformation and warning before its ultimate failure. In this case the yield stress of the steel governs the design. An over-reinforced beam

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3328-570: The second and thirteenth stories. At the pedestrian level, the East Fourth Street facade is symmetrical with the main building entrance flanked by display window bays and tall pedestrian openings on the outer corners. On the Cedar Street side the building's secondary entrance is flanked by three display window bays to either side. On both primary facades the base is sheathed with polished pink and gray marble . Directly above each bay opening

3392-581: The size and location of cracks can be limited and controlled by appropriate reinforcement, control joints, curing methodology and concrete mix design. Cracking can allow moisture to penetrate and corrode the reinforcement. This is a serviceability failure in limit state design . Cracking is normally the result of an inadequate quantity of rebar, or rebar spaced at too great a distance. The concrete cracks either under excess loading, or due to internal effects such as early thermal shrinkage while it cures. Ultimate failure leading to collapse can be caused by crushing

3456-468: The structure will receive warning of impending collapse. The characteristic strength is the strength of a material where less than 5% of the specimen shows lower strength. The design strength or nominal strength is the strength of a material, including a material-safety factor. The value of the safety factor generally ranges from 0.75 to 0.85 in Permissible stress design . The ultimate limit state

3520-455: The style used as "mild art deco" with features that are "very urbane." Reinforced concrete Reinforced concrete , also called ferroconcrete , is a composite material in which concrete 's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel reinforcing bars (known as rebar ) and

3584-454: The tension on the reinforcing steel is released, placing a built-in compressive force on the concrete. When loads are applied, the reinforcing steel takes on more stress and the compressive force in the concrete is reduced, but does not become a tensile force. Since the concrete is always under compression, it is less subject to cracking and failure. Reinforced concrete can fail due to inadequate strength, leading to mechanical failure, or due to

3648-408: The third story. An ornate terra cotta belt separates the second and third stories. Simple raised edge banding occurs in stone between the eleventh and twelfth stories. The building has no cornice ; it was one of the first buildings in the area to dispense with them. Above the twelfth story, the attic story, is a blind frieze of checkered stonework, terminating in a toothy crown formed by the rise of

3712-403: The water mix before pouring concrete. Generally, 1–2 wt. % of [Ca(NO 2 ) 2 ] with respect to cement weight is needed to prevent corrosion of the rebars. The nitrite anion is a mild oxidizer that oxidizes the soluble and mobile ferrous ions (Fe ) present at the surface of the corroding steel and causes them to precipitate as an insoluble ferric hydroxide (Fe(OH) 3 ). This causes

3776-479: The window pattern; the new roof did not feature the same toothy crown that was integrated into the facade of the thirteenth story. The state capital, St. Paul was most prosperous during the late 1800s and early 1900s, much of its downtown development occurred during that period. Construction in downtown St. Paul was slow in the early 1920s. Several significant buildings were constructed in the previous decade, though all commercial and public buildings relied heavily on

3840-602: Was delayed due to the outbreak of World War I . With the Archdiocese of Saint Paul having only leased the property to the builders, Archbishop John Ireland called St. Paul Saints owner John Norton asking for assistance in completing construction. Norton asked the Hamm family if they would continue the project. The Hamm family took over construction in 1919, with the project being finished in 1920. The six-story building became an office for Hamm's Brewery . The ornamentation of

3904-754: Was finished in 1930. The structure has 101,000 square feet (9,400 m) of interior floorspace. The building's architect, Charles A. Hausler , has several other buildings listed on the NRHP: St. Anthony Park Branch Library , Arlington Hills Library , Riverview Branch Library , also in Ramsey County, Minnesota , as well as the St. Mary's Church Non-Contiguous Historic District in Hague, North Dakota . Born in St. Paul in 1879, he apprenticed in Chicago with Louis Sullivan before returning to Minnesota being licensed in 1908. He

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3968-404: Was granted a patent for reinforcing concrete flowerpots by means of mixing a wire mesh and a mortar shell. In 1877, Monier was granted another patent for a more advanced technique of reinforcing concrete columns and girders, using iron rods placed in a grid pattern. Though Monier undoubtedly knew that reinforcing concrete would improve its inner cohesion, it is not clear whether he even knew how much

4032-675: Was named as St. Paul's first City Architect in 1914 and served for five terms before leaving in 1923 to serve eight terms in the Minnesota Senate . While city architect he drafted the city's first uniform building code in 1921, and designed numerous municipal buildings including the Beaux-Arts Carnegie libraries that were later placed on the NRHP. He returned to private practice while in the Minnesota Senate, and during that time designed

4096-422: Was strongly questioned by experts and recommendations for "pure" concrete construction were made, using reinforced concrete for the floors and walls as well as the frames. In April 1904, Julia Morgan , an American architect and engineer, who pioneered the aesthetic use of reinforced concrete, completed her first reinforced concrete structure, El Campanil, a 72-foot (22 m) bell tower at Mills College , which

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