Earthquake proof walls with slits

Purpose: To improve the structure of earthquake proof walls which also serve as shielding walls in nuclear reactor buildings, etc. Constitution: In the earthquake proof walls adapted to increase the righdity in the prior art, since the flexural rigidity is large, the period of proper vibration of building is short and the seismic response of nuclear reactor buildings disposed on hard substrate rocks is increased. However, if slits are disposed to the earthquake proof walls, the shearing cross sectional area is inevitably reduced to render the shearing rigidity insufficient. Further, since radiation shielding function, etc. have to be maintained, usual slits can not be used. In view of the above, two vertical slits are formed with a predetermined gap in the present invention. The two slits control the rigidity and reduce the seismic response in accordance with the hardness of the substrate rocks on which buildings are installed. The transverse cross section of the slits are bent or curved to maintain the shielding function and the portion of the slits are reinforced with metal fixtures, etc. to prevent the reduction in the shearing rigidity. (Kamimura, M.)