18.Cau tao mai doc.Neu dien hinh cau tao mai ngoi.
1. Tam lop
Tam lop co the la ngoi, tam ton, tam fibroximang, tam betong, tam giay dau. Tac dung
chinh cua no la bao che va bao ve cho cac bo phan ben duoi dong thoi trang tri kien
truc cho ngoi nha.
2. He thong ket cau mang luc cua mai doc
Vat lieu che tao ket cau mang luc cua mai doc thuong lam bang go, thep, gach da
hoac betong cot thep duoi nhieu hinh thuc khac nhau: cau phong , vi keo hay bang cac
tam lap ghep.
*. Ket cau tuong thu hoi chiu luc :
Dung tuong ngang chiu luc xay thu hoi lam ket cau chiu luc chinh.
Tren tuong thu hoi gac xa go (don tay), tren xa go gac cau phong (ren, rui) hoac lat
van go va tren cau phong dat cac lito (me, lach) , cuoi cung la lop lop .
Vat lieu lam xa go : go hoac be tong cot thep.
Xa go duoc bo tri nhu dan cua san nha : o giua noc tren cung la xa go noc, o duoi
cung doc theo duoi mai la xa go mai dua. O cac vi tri dat xa go co cac mieng dem de
dam bao luc phan bo deu len dau tuong.
Vi tri cua xa go mai dua phu thuoc vao kich thuoc vuon ra khoi tuong cua mai
dua:
+ Khi mai dua ra < 50cm : dat truc tiep len tuong doc ngoai.
+ Khi mai dua ra > 50cm : tua tren cac dam cong xon duoc lien ket vao tuong
bang bulong neo giu .
Uu diem : ket cau don gian, kinh te.
Nhuoc diem: chieu rong cac gian bi han che (<= 4m) , neu can phai rong > 4m thi
nen dung ket cau vi keo, cau phong hoac dam.
*. Ket cau cau phong hay dam nghieng :
Cau phong la cac dam go duoc dat truc tiep len nhung dam go dem duoc dat doc
theo tuong ngoai .
Ap dung khi be ngang nha khong lon lam va giua nha co kha nang tao cac goi tua .
Co the lam mai 1 doc hoac 2 doc.
Tiet dien 80 x 100 - 80 x 150.
*. Vi keo :
- Mot so hinh thuc vi keo pho thong
Theo yeu cau cau tao ma vi keo co the lam bang go, thep, betong cot thep.Co
truong hop vi keo duoc lam bang go va thep, trong do thep chiu keo con go chiu nen
va uon.Vi keo thep va betong cot thep phu hop voi nhip nha lon, co yeu cau chiu lua
va do ben vung cao.
Theo hinh thuc co dan vi keo tam giac, hinh thang, hinh da giac. Khau do cua vi
keo co the chon tu 6-9m doi voi vi keo go, thep; 9-18m doi voi vi keo betong cot thep,
thep va >18m doi voi vi keo thep. Khi chon vi keo phai can cu vao chieu dai nhip, yeu
cau su dung cua phong oc, tai trong tac dung len dam, cac yeu cau ve tham my cung
nhu yeu cau ve tham my cung nhu yeu cau ve phong chay.
