KHOAHOC-CdNGNGHe -So 4/2016
Ung xu* cof hoc cua khe co gian
bang vat lieu asphalt d a n hoi dtfdfi tac dung cua tai trong banh xe va thay doi nhiet do
• TS. NGUYEN HflU THUAN
• ThS. N G U Y I N THACH BJCH
• ThS. N G U Y I N M A N H HAI Trudng Dgi hge Giao thdng v$n tdi
T6m tat: Bdi bdo phdn tich cdc tfng xit cd hgc cua khe co gian bing vgt Uiu asphalt ddn hii dudi tde dgng eua hogt til vd thay dil nhi$t di mdi trudng. Trong dd, phUdng phdp phan tCr hdu hgn (PTHH) dugc sCr dgng di md hinh hda kit eiu; md hinh vgt li$u ddn-nhdt ddo dutfc sCr dtfng. Til trgng tde dgng cUa hogt tdi dUtfc phan tich d diiu kign tfnh va ding, tde dtfng cua ehuyin vl ctfdng bdc diu dam do thay dil nhigt dg cung dUtfc xit den trong md hinh tfnh toan.
Trgng thdi tfng suit, biin dgng cua kit cau dUtfc phdn tich di tim ra edc W tri bat igl trong kit du.
Tii khoa: Asphalt, khe co gidn, ddn hoi, tai trgng, nhi$t di.
Abstract: T/i/s paper presents the study for mechanical behavior of Bridge Asphalt Plug Joints (APJ) under the effect of load and temperature. Finite element method (FEM) is used to model the structure; model of viseoeiastic material is used. Load effect Is analyzed in static and dynamic conditions. Stress state, deformation of the structure is analyzed to find out the location of the structural disadvantage.
Finally a number of experiments were performed to verify the calculation results In this paper.
Keywords: Asphalt, expansion joints, elastic, load, temperature.
1. Dgt vin d l
Khe eo gidn APJ la logi khe eo gian lien bing vdt Iteu asphalt dan hdi (asphalt plug joints -APJ).
Day Id logi khe dupe sQ dung rdng rai tQ Idu trdn the gidi eho ede eau nhjp nhd va nhjp trung blnh do edc uu dilm ehfnh vd ndi trdi sau: (i) Khai thde rat dm thudn khdng xung kfch; (ii) tuydt ddi kin nude; (ill) thi cdng nhanh, de lap ddt vd cd t h i khai thde ngay sau khi thi cdng.
6 Vidt Nam, khe co gian APJ mdi dupc dua vdo sQ dgng trong vdi nam gan ddy, chfl y l u 6 giai dogn thQ nghidm. Cau thdnh cfla khe APJ gdm 4 logi vdt lidu ehfnh la: Chit k i t dfnh asphalt (gde bl- tum, polymer biln tfnh), cdt lidu cQng thd ft/khong
d p phdi (diu hgt), xdp ddo ehju nhiet va thep tam mg kem. Khe APJ cd nhilu Qu diem, tuy nhien d l dp dgng rdng rai 6 Vidt Nam can tien hanh thi edng thfl nghidm, ede nghidn cQu de dg bdo Qng xQ^efla kit elu dudi tde ddng bdn ngoai, dg bdo tudi thp, dd bin cfla kit eau, tQ dd cd ed sd thiet ke phu hpp. Hidn nay d Viet Nam cung nhg tren the gidi cd rat it cac nghidn cQu ndy, do vdy, vide nghidn cQu Qng xii efla khe dQdi tac dung cfla tdi trpng vd thay ddi nhiet dp Id can thilL
Cde loai khe cd bdn tren thj trQdng hien nay deu nhdp khiu tron gdi tQ nQdc ngodi nhu khe Feba (Anh), khe APJ-150 (My).
a) - Mat cit ngang; b) - Phii cinh
Hinh 1.1: Cau tgo khe co gidn ddn hii APJ-150 Tuy theo d u tao cfla Idp phfl mat eau vd chilu ddi nhjp md cd t h i bd trf kfch thude vd d u tgo cfla khe co gidn APJ d l ddm bdo ehuyen vj vd phu hpp vdi Idp phfl mdt d u . Tuy nhien, kich thude thudng sfl dung cho ehilu rdng Id 500 - 750mm vd ehieu day Id 50 - 100mm [3],
2. Tfnh toan khe APJ dUdi tac dung cfla hoat tdi va chuyen vj cUdnc| bQc
Khe CO gian APJ ed nhidu uu diem, tuy nhidn nhUde diem cfla nd Id tudi thp khdng Idn vd phu thude nhieu vdo cdng nghd thi cdng eung nhu kilm sodt, Iga chon vdt lieu diu vdo. Tudi thp thgc t l thgdng dgpc ghi nhdn nhd hon tuli thp dg kiln cfla nd (6 - 7 ndm). Vide tudi thp thip trong tfigc te la nguydn nhdn chfnh Idm edn trd viee Qng dgng rdng rdi hdn logi khe co gidn ndy tren the gidi [4], Trong thgc t l , hien cd rit ft ede nghien cUu de tfnh todn, md phong edc Qng xQ cd hpe efla khe nay dQdi cdc tde dong efla cde nhdn td ben ngodi gay hQ hdng ehung. Nghien cQu tQdng ddi todn dien v l khe APJ dQpe thgc hidn lan dau tgi My bdi
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KHOA Hpc-CONG N G H I
Bramel et al nam 1999 [5] (Hinh 2.2) vd sau do cfla Parti et al.2002 [6] tai cac nude EU. Ca hai nghien cQu ndy deu nham md phdng, du kien Qng xfl ed hoe eua khe APJ dudi tde dpng cfla tdi trpng va nliiet dd, tQ dd dUa ra edc de xud't thiet k l de cdi thien tudi thp vd dp ben eua khe APJ.
Hinh 2.1: Khe co gidn APJ chiu tde dgng cua hogt tai xe
Hinh 2.2: Md hinh vgt ligu vd md hinh PTHH cho khe APJ [5]
Trong thuc t l , khe co gian APJ chiu tde ddng efla nhilu ylu td nhQ: Tdi trpng xe, thay ddi nhiet dp mdi trQdng (gay ra ehuyen vj diu dam, gdy ehuyin vj cUdng bQc eho khe), do tae ddng eua khf hdu, dn mdn,.. Cdc dgng hu hdng thudng thdy cfla khe co gian logi ndy thudng ed hai dang: NQt vd lun Idn.
Tuy nhidn, trong tfnh todn khe co gian APJ, 2 nhdn td cd bdn Id tai trpng cfla banh xe len khe vd thay ddi nhidt dd thudng dupc xet den (Hinh 2.3). Trong do, tdi trpng bdnh xe tde ddng len khe thdng qua tdi trpng thang dQng vd nam ngang (trupt) trdn didn tieh tilp xuc efla banh xe vdi mat khe. Tdi trpng ndy di dpng qua khe trong thdi gian ngan (phu thupc vao tde dp xe chgy).
Trong nghidn cQu nay, ehung tdi trinh bdy md hinh tfnh todn khe co gian APJ dudi tde dung eua tdi trpng cua bdnh xe vd chuyen vj cudng bQc gid djnh. PhUdng phap PTHH da dupc sfl dung de xdy dgng md htnh tfnh toan 2D. Mpt khe co gidn APJ vdi kfch thudc thdng thudng: 500 x 100mm (mgt cat ngang) da dupe sQ dung. Tdi trpng banh xe dupc md phdng dUdi hai thanh phan: LQc phdn bd thang dQng ddi deu (p) quy ddi tQ iQc tdp trung bdnh xe P = 38KN vd lge trUdt (q) quy ddi tQ Q = 6KN trdn be mat rdng 300mm efla khe co gian [5]. Vdt lidu si!f dgng d l che tao mdu dupe lam tQ cdc thdnh phin nhga polymer bien tfnh, dd dam cfla hdng Thomal Joint (Anh) [3]. Md hinh vat lidu Viseoeiastic, trong phan mem ANSYS dUdc sQ dyng de md hinh hda vdt lieu nay. Cdc dQ lidu dudng cong Qng suit bien dgng efla vdt lieu (thf nghidm marshall) dupe sQ dung d l hieu chinh md hinh hda vgt lieu APJ trong phin mem tfnh toan.
Anh hudng cua thay ddi nhidt dp dupc xet den trong md hinh tinh toan ndy thdrig qua ehuyen
vi ngang gia djnh cfla d i u dam len khe APJ, c = 2,5(mm).
Dieu kien bidn cfla md hinh tfnh toan nhg trong Hinh 2.2. khe APJ dUdc gia thiet la tiep xue vdi cac*
mat tuydt ddi cQng (dudi day vd hai mat ben).
mnra^
Hinh 2.3: Sd do tai trgng tinh todn Idn khe APJ va diiu kien bien chju tai trgng xe vd nhi$t dd thay doi
^
Hinh 2.4: DUdng eong md hinh vdt ii$u trong phuong phip PTHH
PhQdng phap PTHH dupe sQ dgng de mo phdng Qng xQ cd hpe cfla khe APJ dudi tde dung cfla lge thing dQng vd igc trUdt gdy ra do banh xe chgy qua khe. Phan tQ Solid 2D dan-deo, phi tuyen dd dUdc sQ dgng eho vung vat lieu khe APJ.
Ldp be tdng nhga hai ben khe APJ, ldp be t6ng;{i mang dudi day khe dUdc gid thiet Id khdng bien dang, chuyen vj (thgc t l Id rd't nho), tuyet ddi cilng, l-ilnh 2.5a the hidn trudng bien dgng va iJng suit cfla khe APJ dudi tae dung cfla bdnh xe. TDy theo vj trf efla bdnh xe ma trudng bien dgng vi*
Qng suat cfla khe co gian APJ se thay ddi. Troni;
md hinh tfnh toan nay, hieu Qng gdy ra trong khs APJ dudi dnh hudng diddng efla tdi trpng banhw, cung dUde tinh toan. Trong do, tdi trpng banh xe (quy ve tdi trong phan bd thang dQng va luc ck) dupc md hinh Id di dong vdi van tde tUdng dUdng vdi tde dp di ehuyen cua xe. Van td'e 50km/ti dupc sQ dgng trong md phong. Trong chilu rflng 500mm eua khe APJ, tai trpng bdnh xe di don^
qua trong khodng thdi gian 36,Ops. Hinh 2.5b the hien dUdng thay ddi gid trj Qng suit Idn nhd't trong khe APJ theo thdi gian bdnh xe ehay qua. Trong dd, CO the thay gid trj ldn nhit Qng suat trong khe APJ dgt dupe tgi thdi diem bdnh xe d giQa chi^u rpng khe (thdi gian t = 18ps).
a) - Trtfdng dng suat, biin dgng cOa khe APJ do tii trong binh xe;
b) - C/ng suit Idn nhit trong khe APJ theo tm gian banh xe ehgy qua
Hinh 2.5 52
K H O A H O C - C 6 N G N G H |
3. LJTng xii cua khe dUdi tac dgng cDa tdi trpng lap
Mpt nghidn eQu v l Qng xQ eua khe APJ dQdi tde dgng efla tdi trpng ldp da dUdc thgc hien. Mot mdu hdn hpp APJ da dupe md phdng d l danh gia, du bao dnh hUdng eua tdi trpng lap den lun tfch luy tren b l mdt (vet han lun banh xe). K i t qud tfnh toan sau do da dUdc so sdnh vdi edc k i t qud thf nghidm.
Mdu honhppAPJed kich thQde320x260x5mm [7], mpt sd thdng sd efla bdnh xe di ddng nhu trong Bing 3.1:
Bang 3.1
So 4/2016
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)2D]i26(bi5 Tigng Iirong b t o h M t N )
700
'^'^IT"
SO
°r
i<a (tiigt/phuU
"
lip (cycle)
20 « »
- Md hinh hda
Tifdng ta nhif phan tren, trong nghien CLJU n&y, SL( dung phan nnem Ansys 6i mo ph6ng t&i trpng ISp, kfch thudc l<St cSu duoc md hinh nhu Bing 3.1. VIb hinh vat lieu tUdng tu nhu phan 2. B i i u kien bi6n m6 hinh lida nhu Hinh 3.1. T4i trpng l^p dupc m6 hinh hda tudng dUdng vdi thdng so trong Bing 3.1. Trong dd, de ddn giin, coi &\ trpng banh xe di dpng phan b6 deu tren dien tfch tiep xuc ciia b4nh xe vdi mat h6n hpp APJ. Mpt h4m tiii trpng trpng ph^n mem dupc sii dyng de md phfing t&i trpng lap vdi gia trj va budc dat t&l tudng dudng vdi tSc dd cDa banh xe di ddng. Chu ky cua tJi trpng lap diipc sit dyng vdi gia tri 20.000 (vdng ISp).
M6 hinh v j t lieu: SD dyng md hinh vSt Ii6u ORNL trpng phan mim tinh tdan, vdi cac tham sd' vat li$u tham khic til nghien cCtu cCia Musharraf Zaman [10]: n = 0.8; m = 0,45; A = 3,25.
4=Ui[(m + lH"l'*' (1) Bdnh xe diddng
"1
— J f l?.
• Thi nghidm
Thi nghiem vet hSn lun banh xe dUdc thuc hiSn vdi may Wheel tracking, tai Phdng Thi nghiem TrUdng Bai hpc GTVT, cic thdng sS cOa may thf nghiem vdi banh xe di dpng cho trong Bing 3.1.
Thi nghiem dupc thuc hiSn trong dilu ki^n nhiet dd phdng d l so sinh vdi ket qui trdng md hinh tlrih toan. Hai miu hBn hpp APJ dupc che tad va s& dung chd nghien cijfu niy, v i t lieu SLf dung la nhya polyme biln tinh v i da d i u hat kich thudc 20mm [7].
Hinh 3.1: Sd dd thi nghidm miu APJ dudi tic dung cua tii tr<>ng lip
Hinh 3.2: Biiu ki$n biin cua mo hinh tinh toin (mit bing)
Hinh 3.3: Thiet bi thi nghidm v$t han idn binh xe
- Kit qui
Hinh 3.4 t h i hien k i t q u i v l trudng Cfng suat, biln dang cCia mau APJ trcng md hinh ttnh toin.
Hinh 3.5thi hien ket qua v0t hin lun binh xe sau thf nghidm. Ket qui sd sanh giOa hai phUdng phap dupc t^ng hpp trdng bieu do Hinh 3.6. Kit qui cho thiy sU phii hpp tUOng ddi t i t giOa k i t q u i thi nghiem v i md ph6ng.
a) - Chia ladi phin til; b) - Bien dang tich lOy do tai trong lap: c) - Tnidng ting suit
Hinh 3.4: Kit qui mo hinh hoa bang phudng phip PTHH (m^t nia kit ciu)
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KHOA H O C - C d N G NGHg
Hinh 3.5: V$t hiffi lun banh xe sau thi nghigm mki
Hinh 3.6: So sdnh kit qua thi nghigm va md phdng
4. K i t lugn va k i e n n g h j
Nghidn cQu da tdp trung vdo Qng xQ cua vat lidu APJ dudi tde dgng efla tdi trpng bdnh xe vd thay ddi nhidt d d . M6 hinh vgt hgu phi tuyen, dieu kidn bidn, md hinh tdi trpng, chuyen vi cudng bQc... da dQde iga ehpn phfl hpp vdi sg lam vide efla k i t e l u trong thgc t l . Hidu Qng cfla tdi trpng bdnh xe eung nhu tinh chat di ddng efla nd cung dUdc md hinh hda trong md hinh tinh todn.
K i t qud tfnh todn trong md hinh dd sQ dgng mdt sd k i t qud thf nghidm d i u vdo (ch? tieu ky thudt efla vdt li^u thanh p h i n , dudng cong Qng s u i t b i l n dgng cfla vdt ligu thanh p h i m APJ).
Ddc bidt, nghidn cQu eung dUa ra mot s d k i t qud v l Qng xii efla hdn hpp APJ dudi tde dgng efla tdi trpng l$p. Cde k i t qud md hinh hda dg bao cung da dUdc so sdnh vdi k i t qud thf nghiem vet han lun bdnh xe. K i t qud eho thay s g tUdng thfch giQa hai phQdng phdp nghidn cQu.
Tuy nhidn, 0 l tdi e i n tiep tgc nghien cQu thdm d l hodn thign md hinh tfnh todn nhU: Nghien cQu, xde djnh mpt sd tham sd ve vat lieu de edi thidn md hinh vdt lieu, md hinh dieu kien bidn, tdi trpng... phfl hdp hdn vdi sg ldm vide eua k i t cau thgc t l ; nghidn cQu dnh hudng cfla thay doi ty le, thdnh p h i n vdt lidu nhu nhga k i t dfnh, edt lieu dd... efla hdn hpp APJ d i n Qng xQ ed hpc cfla nd.
Ngodi ra, vide nghien eQu Qng xQ eua khe APJ dQdi tde dgng eua cde tde nhdn khde nhg khf hdu (dd I m , nhidt d d , dnh sang...) cung e i n phdi dupe d l cdp trong cdc nghien cQu tiep theo.
Tdi l l # u t h a m k h d o
[1]. PGS. N g u y l n T h i Minh NghTa (2000), Gido ti\r\h-Ting ludn eiu", NXB. GTVT.
[2]. Tieu c h u i n T C V N (2014), Khe co giin len
Asphalt - Tieu chuin thiit ki thi cdng vd nghidm thu (du thdo l i n 4).
[3]. Khe co gian Idn Asphanit Thorma Joint - Tidu chuin cd sd thi edng vd nghi$m thu, TCCS 01:2015/Thalotec.,JSC, 2015.
[4]. Alexander J . Austerman (2004), Evaluation of Asphaltic Expansion Joints.
[5]. Philip Park (May/June 2010), Behavior of Bridge Asphalt Plug Joints under Thermal and Traffic Loads. Journal of Bridge Engineering, Vol.
15, No. 3, pp. 250-259.
[6]. Moon, Kyoung-tae Park, Philip-Park, Sang-yeol, A Study on Analysis Method of Asphalt Plug Joint using FEM.
[7]. N g u y i n HQu T h u a n , N g u y i n Mgnh Hdi, Bfli Tien T h d n h , N g u y i n T u i n Binh (11/2015), iJng dung khe co gian bang v$t lidu ddn hSi d)o cdng trinh ciu nhip nhd vi trung binh d Viet Nam, Tgp chf GTVT.
[8]. N g u y i n HQu T h u a n , N g u y i n Mgnh HSi, Bui T i l n Thanh, Nguydn T u i n Blnh, Ngd Vdn Minh (10/2015), iJng dijng khe co gian Thorma Jolntcua hang ENNIS-FLINT trong sda chQa thay thi khe CO gian du dtfdng d td, Hdi thdo khoa hpc, TP. Hd Npi, T P . Hd Chf Minh.
[9]. Quy dinh ky thuit phtfdng phip thd d^ siu v$t han lun binh xe cOa bd tdng nhtfa xic dmh bang thiet bi Wheel tracking, 2014 •
N g a y n h d n b a i : 7/3/2016 N g a y c h i p n h d n d a n g : 15/3/2016 NgUdi p h d n b i $ n : T S . Ho X u d n Nam
T S . Le Ba A n h
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