Tiêu đề Module 02 Introduction to Reinforced Concrete Structures.pdf ✅

CHAPTER 1 INTRODUCTION Water Tower Place, Chicago, 74 stories, tallest concrete building in the United States. 1.1 STRUCTURAL CONCRETE The design of different structures is achieved by performing, in general, two main steps: (1) deter- mining the different forces acting on the structure using proper methods of structural analysis and (2) proportioning all structural members economically, considering the safety, stability, serviceabil- ity, and functionality of the structure. Structural concrete is one of the materials commonly used to design all types of buildings. Its two component materials, concrete and steel, work together to form structural members that can resist many types of loadings. The key to its performance lies in strengths that are complementary: Concrete resists compression and steel reinforcement resists tension forces. The term structural concrete indicates all types of concrete used in structural applications. Structural concrete may be plain, reinforced, prestressed, or partially prestressed concrete; in addi- tion, concrete is used in composite design. Composite design is used for any structural member, such as beams or columns, when the member contains a combination of concrete and steel shapes. 1.2 HISTORICAL BACKGROUND The first modern record of concrete is as early as 1760, when John Smeaton used it in Britain in the first lock on the river Calder [1]. The walls of the lock were made of stones filled in with 1
2 Chapter 1 Introduction concrete. In 1796, J. Parker discovered Roman natural cement, and 15 years later Vicat burned a mixture of clay and lime to produce cement. In 1824, Joseph Aspdin manufactured portland cement in Wakefield, Britain. It was called portland cement because when it hardened it resembled stone from the quarries of the Isle of Portland. In France, François Marte Le Brun built a concrete house in 1832 in Moissac in which he used concrete arches of 18-ft span. He used concrete to build a school in St. Aignan in 1834 and a church in Corbarièce in 1835. Joseph Louis Lambot [2] exhibited a small rowboat made of reinforced concrete at the Paris Exposition in 1854. In the same year, W. B. Wilkinson of England obtained a patent for a concrete floor reinforced by twisted cables. The Frenchman François Cignet obtained his first patent in 1855 for his system of iron bars, which were embedded in concrete floors and extended to the supports. One year later, he added nuts at the screw ends of the bars, and in 1869, he published a book describing the applications of reinforced concrete. Joseph Monier, who obtained his patent in Paris on July 16, 1867, was given credit for the invention of reinforced concrete [3]. He made garden tubs and pots of concrete reinforced with iron mesh, which he exhibited in Paris in 1867. In 1873, he registered a patent to use reinforced concrete in tanks and bridges, and four years later, he registered another patent to use it in beams and columns [1]. In the United States, Thaddeus Hyatt conducted flexural tests on 50 beams that contained iron bars as tension reinforcement and published the results in 1877. He found that both concrete and steel can be assumed to behave in a homogeneous manner for all practical purposes. This assumption was important for the design of reinforced concrete members using elastic theory. He used prefabricated slabs in his experiments and considered prefabricated units to be best cast in T-sections and placed side by side to form a floor slab. Hyatt is generally credited with developing the principles upon which the analysis and design of reinforced concrete are now based. A reinforced concrete house was built by W. E. Ward near Port Chester, New York, in 1875. It used reinforced concrete for walls, beams, slabs, and staircases. P. B. Write wrote in the American Architect and Building News in 1877 describing the applications of reinforced concrete in Ward’s house as a new method in building construction. E. L. Ransome, head of the Concrete Steel Company in San Francisco, used reinforced con- crete in 1879 and deformed bars for the first time in 1884. During 1889 to 1891, he built the two-story Leland Stanford Museum in San Francisco using reinforced concrete. He also built a reinforced concrete bridge in San Francisco. In 1900, after Ransome introduced the reinforced concrete skeleton, the thick wall system started to disappear in construction. He registered the skeleton type of structure in 1902 using spiral reinforcement in the columns, as was suggested by Armand Considére of France. A. N. Talbot, of the University of Illinois, and F. E. Turneaure and M. O. Withney, of the University of Wisconsin, conducted extensive tests on concrete to determine its behavior, compressive strength, and modulus of elasticity. In Germany, G. A. Wayass bought the French Monier patent in 1879 and published his book on Monier methods of construction in 1887. Rudolph Schuster bought the patent rights in Austria, and the name of Monier spread throughout Europe, which is the main reason for crediting Monier as the inventor of reinforced concrete. In 1900, the Ministry of Public Works in France called for a committee headed by Armand Considére, chief engineer of roads and bridges, to establish specifications for reinforced concrete, which were published in 1906. Reinforced concrete was further refined by introducing some precompression in the tension zone to decrease the excessive cracks. This refinement was the preliminary introduction of par- tial and full prestressing. In 1928, Eugene Freyssinet established the practical technique of using prestressed concrete [4].
1.3 Advantages and Disadvantages of Reinforced Concrete 3 The Barkwick House, a three-story concrete building built in 1905, Montreal, Canada. From 1915 to 1935, research was conducted on axially loaded columns and creep effects on concrete; in 1940, eccentrically loaded columns were investigated. Ultimate-strength design started to receive special attention, in addition to diagonal tension and prestressed concrete. The American Concrete Institute Code (ACI Code) specified the use of ultimate-strength design in 1963 and included this method in all later codes. The method is called in the current ACI code the strength design method. Building codes and specifications for the design of reinforced concrete structures are established in most countries, and research continues on developing new applications and more economical designs. 1.3 ADVANTAGES AND DISADVANTAGES OF REINFORCED CONCRETE Reinforced concrete, as a structural material, is widely used in many types of structures. It is com- petitive with steel if economically designed and executed. The advantages of reinforced concrete can be summarized as follows: 1. It has a relatively high compressive strength. 2. It has better resistance to fire than steel. 3. It has a long service life with low maintenance cost. 4. In some types of structures, such as dams, piers, and footings, it is the most economical structural material. 5. It can be cast to take the shape required, making it widely used in precast structural compo- nents. It yields rigid members with minimum apparent deflection.