Rat hiem de tai sU suy giam Wia nang chiu uon (M^) cua cau kien do tac nhan gay an mon, nhat la suy giam iWn cCia cau ki#n BTCT tiet dien chiKTdUdi ^nh hUdng cua an m 6 n. Ap lUc nay[r]
Trang 1Anh hLPang cua an mon den kha nang chju uon cua
dam be tong cot thep tiet dien c h i j t
Effect of corrosion on degradation offlexural strength inT-section reinforced concrete beams
Ngay nhan bai: 11/10/2014
Ngay sita bai: 8/11/2015
Ngay chap nhan dang: 10/12/2015
T O M T A T :
An mon cot th^p dildc xac dinh la mot
nguyen nhan quan trong dan den sd pha
huy ket cau be tong cdt thep (BTCT)
trong mdi trdtfng c6 tinh an m o n cao n h d
trong moi trddng b i l n Bai bao nay
n g h i l n cdu sii suy giam kha nang chiu
uon cua cau kien dSm b l tdng cdt thep c6
tilt diet dien chC T chiu anh hudng cua
tac nhan an mon Kit qua cua bai bao co
t h i l i m tdi H?u tham khao cho cac cdng
tac thiet ke, tham tra, kiem dinh cac ket
cSu lam viec trong moi tnfdng ven b i l n
Tii khoa: Kit c i u b l t6ng, an mon, kha
nang chiu u6n
ABSTRACT:
Corrosion of steel reinforcement is
identified as a significant cause of damage
in reinforced concrete structures exposed
to corrosive environment The paper
studies the flexural strength degradation
of T-section reinforced concrete beams
due to corrosion The results of the paper
can make reference to the design,
verification and inspection of reinforced
concrete structures in coastal
environments
Keywords: Reinforced concrete,
corrosion, flexural strength
D i o Ngpc T h i Ltfc
T n t d n g Dai hoc Bach Khoa - Dai hpc
Da N i n g
TrSn Dinh Manh Linh
Tnicfng Dai hpc K i l n Tnic Da Nang
1 G i t i t h i # u
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3],[ 5-7] Rat hiem de tai sU suy giam Wia nang chiu uon (M^) cua cau kien do tac nhan gay an mon, nhat la suy giam iWn cCia cau ki#n BTCT tiet dien chiKTdUdi ^nh hUdng cua an m 6 n Bai bao cua cau ki&n BTCT tiet dien chCt T difa tren tieu chuan ACI 318-11 c6 xet den sU suy g i ^ m lUc dinh giCfa be l o n g va cot thep d o an mon
2 M d h i n h t i n h kha nang d i [ u u o n (Mn) cilia cau ki#n BTCT co t i e t d i e n chiilT
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2.1 Ap lu'c an mdn (pcoi)
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Dao Ngoc The Lu'c, Tran Dinh Manh Linh
kinh ban dau cOa cot thep, ban kinh ngoSi ciia
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Ap lye an mon iJlng vdi trudng hop x>Xo [11]
p „ J ? ( , - p , R , + p a j , { r ) d r (2) 2.2 Life dinh giula be t d n g va cdt thep bi an
m d n Cae t h d n g sd hinh hoc eCia thanh cdt th^p
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diem A Ici d i l m cdch mat cdt t h ^ p m o t khodng
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(15)
Bdng 1 Tdnq h o p cac he thiJc cOa m d hinh h1nh tru t h a n h dav [11]
B i l n dang
vdng
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bj an mdn [10]
0 t r u d n g hap nay gia thiet rSng bien dang keo ciJa cdt t h e p Idn hon hoac b i n g b i l n dang
Idn nhat eua be t d n g bdng b i l n dang tai thdi diem b l t d n g d a t cudng d o chju nen (ei=&:o)
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source n o t found [8] vdi d la e h i l u cao lam
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Reference source n o t f o u n d (8]
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f o u n d [8]
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theo [81
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D i m bj phd hoai d o su t g t neo c o t thep T6ng li^c keo tde dung l i n cdt thep dupc tfnh theo edng thiic (23) [10]
T , = - c ^ 7 t d l , (23) Bien dang cOa cdt t h ^ p chiu keo Cs, b i l n
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4T,
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(24)
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thay t h i b i n g gid tri Oi, Oi va Pi dUOc Uy theo [4] Diem ddng luu y d ddy d d la gid trj e trong
la mdt gid trj chua biet De tfnh e, ban dau ta eho true trung hda d i qua mat dUdi cua ednh
K i l m tra n l u t o n g life nen t i c d u n g len b l t d n g
Trang 3hda d i qua ednh vd nguoc lai SiJrdung vdng lap
chpn c sao cho phuong trinh can bdng luc tren
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not found
3 K i t qui phan tich
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hinh se dupe so sdnh vdi thi nghiem eiia
Al-Sulaimani [1] Thi nghiem dupe thue hien tren
di^n 150x150 (mm), c h i l u dai d i m L=1000 m m
n^n Id 40 MPa VOng chiu keo eua t i l t dien ddm
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dai cua dam cd dudng kfnh dn, = 6 m m , cdch
nghiem trin bj cho dn m d n d cap dp khac nhau
trpng tdc dung tai t h d i diem dam be t d n g bi
phd hoai duae ghi nhan de tU do tinh dupc khd
qud xdc thue duoc the hien d Hinh 5 cho t h i y
nghiem
N h i m t h i y rd su dnh hudng cua an m d n
d i n cdu ki§n BTCT cd tiet dien ehUT, ta xet mdt
trudng h p p cu t h i mdt dam cd ede thdng sd
nhUsau: Cudng d d be t d n g fd = 30 MPa, cudng
dd cdt t h i p f, = 450 MPa, be rpng bung b = 300
h = 500 m m , chieu cao ednh h f - 100 m m , cdt
t h ^ p trong viing chiu keo 2(p18, trong viing
m m , c h i l u ddi doan neo cdt thep Li = 300 m m
D i m dupe k h i o sdt vdi khodng d p dd an mdn
hpp cd vd khdng ke den sU lam viee eua ednh
dupe t h i hi#n d Hinh 6 TU bieu d d d Hinh 6, ta
thay r i n g Ung vdi cap d p dn mdn tif 0% den
0.4%, tdc nhdn dn m d n dnh hudng tcJi Mo thdng
qua v i f c Idm suy gidm tiet dien edt thep ehiu
k t o Su dnh hudng nay Id khdng dang ke CTng
vdi cap d d an mdn tir 0.4% d i n 1%, tdc nhan dn
hudng nay ed tae ddng Idn den Mn, lam cho Mn suy gidm nhanh chdng va gay nguy h i l m cho
k i t c l u
Kinh 5 )Uc thuc mo hinh vcii Ihi nghiem cua Al-Sulaimani
4 K i t luan
Bdi bdo da xdy dung dupe md hinh tfnh kha ndng ehiu udn eua cau kien be tdng c5t t h i p cd hudng cua t i e nhdn an mdn d i n su hinh thanh phdt trien vet nut cung nhU sU suy g i l m luc
dupe x i c thifc vdi cac thf nghiem h\in cd Ket
Ung dung d l ddnh gia cdc cau ki^n vdi dieu ki^n Idm viec thuc te Tuy vdy, trong bdi bdo, do chua cd eac thf nghiem trdn dam chO t i l t dien
c h U T b j an mdn nen md hinh chi mdi dUOc xac dien chu nhat De tang them tinh tin cay cua nghiem k h i nang chiu udn tren cdc d i m tiet dien chor T bi an mdn de xdc t h i f c Qua sd lieu phdn tich, bai bdo da cho thay SI/ dnh hudng d i n g k l cua dn m d n den M„
tong va cdt thep Do dd can cd cac bien phap phong ngUa cac anh hudng nay nhutang chieu neo cdt thep ddi vdc cac dam be tdng cdt thep lam viec trong mdi trudng bien Tai lieu tliam khao [It Al-Sulaimani G I , Kaieemuiiah M., Basunbui I A, ,Rasheeduzzafar, "Influence of corrosion and craclung on bund hehautor and strength ot reinforced concrete members", ACI Structural loumal 87 (1990], pp 220-231 [2] Amleh L,Mira L, "Corrosion influerce on bond between steel aid concrete", ACI Struct J (1999) 96(3), pp 415-23
[3] Bong Seok Jatig,Byung Hwan Oh, "Effects of nc^-unitonn corrosion on the cracking and service iife of remforced concrete structures", Cement and Concrete Research (2010] 40,
pp 1441-1450 [4] Collins MP,Mitchell D, Prestressed concietestructuie, Prentice Hill, (1991)
[5] Coronelli D, "Corrosion cracking and bond strength modeling for corroded bars in reinforced concrete.", ACI StmctI (2002) 99(31, pp, 267-76,
15] E Chen.Christophei KY Leung, "finite element modeling of concrete cover cracking due to non-unifoim steel coiFosion", Engineering Fracture Mechanics (2015) 134, pp 61-78
(7] Fang C, iLindgren K, Chen L ,Zhu C, "Corrosion influence on bond in reinforced concrete", Cem Concr Res (2004) 34(ll),pp 2159-2157
|8] lame K Wighl,lame5 G MacGregor, Reiforced concrete - Mechanics and design, 6E, ed, Pearson Education, UpperSaddleRiuer, New leisey, (2012)
(9] Ottosen N S A, "A failure criterion for concrete", loumal of Engineering Mechanics Division, Proceedings of the American Society ofCivil Engineering (1977) 103, pp 527-535,
110) Sun-jin Han, DeuckHang Lee, Kang Su Kim, Soo-Yectfi Seo, luhyuk Moon,Paulo J,M Monteiro "Degradation offlenural strength In reinforced concrete members caused by steel corrosion" Construction and Building Materials 54 (2014), pp 572-583
[ H i Wang XH,Liu XL, "Modeling effects ot corrosion on cover cracking and bond in reinforced concrete", Mag Concr Res (2004) 56(4), pp
191-9-[12] Xiaohui Wang,Xila Liu, "Modeling bond strength of corroded reinforcement without stirrups" Cement andConcrelf Research34 (2004),pp,1331-1339
[13] V L Xu (1990), Expenmental study of anchorage
properties for deformed bars m concrete Department oiM
Engineering, Tsmghua University, Bei]ing,