|
Voided biaxial slabs are reinforced concrete slabs in which voids reduce the amount of concrete. While concrete has been used for thousands of years, the use of reinforced concrete is usually attributed to Joseph-Louis Lambot in 1848. Joseph Monier, a French gardener, patented a design for reinforced garden tubs in 1868, and later patented reinforced concrete beams and posts for railway and road guardrails. The main obstacle with concrete constructions, in case of horizontal slabs, is the high weight, which limits the span. For this reason major developments of reinforced concrete have focused on enhancing the span, either by reducing the weight or overcoming concrete's natural weakness in tension. An early example is the Pantheon in Rome, build 125 AD. Although not reinforced, coffers were used to reduce the weight. ==Biaxial slabs== Focus has been on biaxial slabs and ways to reduce the weight. Several methods have been introduced during the last decades, but with very limited success, due to major problems with shear capacity and fire resistance as well as impractical execution. For decades, several attempts have been made to create biaxial slabs with hollow cavities in order to reduce the weight. Most attempts have consisted of laying blocks of a less heavy material like expanded polystyrene between the bottom and top reinforcement, while other types included waffle slabs and grid slabs. Of these types, only waffle slabs can be regarded to have a certain use in the market. But the use will always be very limited due to reduced resistances towards shear, local punching and fire. The idea of placing large blocks of light material in the slab suffers from the same flaws, which is why the use of these systems has never gained acceptance and they are only used in a limited number of projects in Spanish-speaking countries. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Voided biaxial slab」の詳細全文を読む スポンサード リンク
|