20.Cau tao thang bo be tong cot thep do tai cho

1.Dac diem

a)uu diem:Cau thang btct toan khoi co do cung va do on dinh cao,khong bi han che boi tieu chuan hoa,hinh thuc da dang thoa man moi yeu cau tham my cua kien truc.Ap dung trong ct dan dung = be tong cot thep va co yeu cau dac biet ve tao hinh tham my.

b)nhuoc diem:Ton cot pha,toc do thi cong va dua vao sd cham

2.He thong ket cau chiu luc

a.)Cau thang hinh thuc ban:

Than thang la 1 ban phang,ban chiu toan bo tac dung len cau thang,ban tua len tuong hoac tua tren dam do chieu nghi va chieu toi.Hinh thuc ket cau nay thich hop nhip cau thang nho<=4,5m va hep <=1,5m,chiu tai trong tuong doi nho.

b.)Cau thang hinh thuc ban dam.

Ket cau chiu luc co 2 phan:Ban va Dam nghieng

Cung co the cau tao ban va bac thang thanh 1 khoi,luc nay bac thang giong nhu 1 dam nho tua tren dam nghieng,dam nghieng tua len dam chieu nghi.Quan he giua ban,bac va dam nghieng co may truong hop sau:

-Ban,bac o phia tren dam,ve phuong dien chiu luc,ket cau hop ly,nhung dam lo xuong phia duoi nhieu.

-Ban,bac dat o phia dam,tran phang,dep,de lam ve sinh.

-Ban,bac dat o giua dam:Tuy tinh hinh cu the,moi chan thang co the bo tri 1 dam chiu ban bac:dam chiu 1 dau,dau kia cua bac ke vao tuong,hoac theo ket cau congxon 1 hoac 2 dam dat o giua ban bac.