Abstract: A thermal shock resistant porous sound absorbing body having high durability in which the prior drawbacks of sound absorbing bodies have been obviated, is produced by sintering a mixture comprising 100 parts by volume of ceramic particles having a bulk density of 1.2-2.0 kg/l, a grain size of 0.3-4.0 mm, a thermal expansion coefficient of less than 70.times.10.sup.-7 /.degree. C. and a fire resistant temperature of higher than 1,000.degree. C. and 4-18 parts by volume of an inorganic binder having a melting temperature of lower than that of the ceramic particles and a thermal expansion coefficient of lower than that of the ceramic particles, and further a sizing agent.

Abstract: A structure for decreasing low frequency air vibrations, comprising a sound insulating floor, sound insulating sidewalls and a sound absorbing ceiling arranged so as to form an air chamber below and separate from the underside of an elevated road or railway bridge's traversed surface, thereby forming a space between the sound absorbing ceiling and the elevated bridge. The structure is very effective for decreasing the low frequency air vibration emanating from the structure of the elevated bridge and the low frequency air vibrations transmitted from the structural supports of the elevated bridge.