预应力空心板1
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①根据等面积和等惯性矩,将空心板转化成工字形截面,如下图:
截面几何特性如下:
25551cmA 4610227.6cmI 35
10311.1cmW
②荷载:
mKNmKNqmKNmKNqmKNmKNqmKNqmKNmNq/2.620.104925A/52/14.430.55126A/62/98.224.11.0/24/8/2.624.1/5000353433221灌缝灌缝自重:
自重:
面层荷载:
线荷载:
均部荷载:
荷载组合如下:
标准值:mKNqqqqqqk/23.3454321
设计值:mKNqqqqqq/916.43)(2.1)(4.154321
准永久值:mKNqqqqqqq/13.27)()(5.054321
mKNlqMmKNqlMmKNlqMqqkk37.1641
8
1
92.2656
8
1
92.2070
8
1
2
2
2
KNqlV076.48321
③钢筋数量估算
⑴预应力钢筋估算
根据构件在荷载效应标准组合下规定:
tkpcckf
其中 WMkck WeNANppcpcpc
则 WeAfWMNptkkpc1 mmap8.146 则ppahe2
代入得NNpc610056.3
lconpcpNA
张拉控制应力取0.72/1302mmNfptk 预应力损失取20%
则22934mmAp, 选2.1522s,23058mmAp。
⑵非预应力钢筋估算
另40sa 9100h
Mxhxbffc)2(
0
'
得05.50hmmxb
0'yppyfcsfAfxbfA
满足最小配筋率,取126,2678mmAs
④承载力验算
⑴正截面验算:
mmap8.146
mmas40
mmfAfAafAafAayspypsysppypps111.141
mmahhps889.808173.1319500
6''6
10407.310264.4ffcsyppyhbfAfAf
,属第二类截面
mmbfhbbfAfAfxcffcsyppy448.220'
MmKNxhbxfhhhbbfMcfffcu31012)2()(
00
'
截面抗弯承载力满足要
求。
⑵斜截面计算:
495.13.36595.1182950
b
h
w
,属于厚腹梁
VKNbhfcc31.1696889.8083.3651.2325.025.0
0
,满足要求。
VKNbhfot930.3907.0
mmmmhfbhfVsAyvtsv/43.0889.80821025.139093048307625.17.0200
选用双肢箍。s200@8
⑤抗裂性验算
⑴截面几何特征:
797.51045.3102652.51045.31095.1452451
c
S
E
c
p
E
E
E
E
E
2
1022574700559000mmAAAmmAAApEn
sEn
⑵预应力损失:
选用夹片式锚具,a=5mm
MPaElasl31.441095.122000551
选用橡胶管0014.0
MPaeexconl49.39)11(1302)11(0308.02
MPafconptkconl55.32)5.0(125.04
NANplconp6.3725255)(
2.3281pe
99.151yIeNANppnppc 0033.02
n
sp
A
AA
MPafcupcl67.11815128035'5
则:MPal8.83 MPal02.235
⑶正截面抗裂度验算:
(拉)压MPayIeNANMPayIeNANyyyAAyAyAeNANMPafpnpnppcpnpnppcsnpnslplconsnslpnplconpnplconpptkcon269.2)(942.134754352.328659.32510263.313027.0'556
二级构件要求为:0cpccqtkpckf
MPaWMMPaWMqcqkck52.1210311.11037.16418.1510311.11092.20708686
则64.2858.1tkpcckf
0
pccq
正截面抗裂满足要求。
⑷斜截面抗裂度验算:
二级构件混凝土主拉应力规定:tktpf95.0
其中 2222yxyxtp
梁横截面中间剪应力最大,MPabISVk79.110227.63.3658443468010076.4831030
MPaANnpx83.5
则tktpfMPa95.051.0 斜截面抗裂满足要求
⑥施工阶段验算:
二级构件截面边缘混凝土法向应力应符合下列要求:
ckcc
tkct
ff8.02
其中28.52269.2'tkpcctf
92.258.0942.13tkpcccf
满足要求
⑦挠度验算
⑴荷载作用下构件的挠度
BlMfkl21485
其中IEBc85.0
141041026.1810227.61045.385.0B
mmfl18.571026.18220001092.207048514261
⑵预应力产生的反拱
BleNfppl822
a:标准组合下的反拱值:
141026.1885.0IEBc
NNNpp6.3725255
mmeepp2.3281
mmfl51.401026.188220002.3286.37252551422
mmmmfffll67.36600/2200067.1651.4018.5721
b:预应力长期影响下的反拱值:
14
1067.945.0IEB
c
NNNpp3263000
mmeepp659.3252
mmfl48.661067.9822000659.32532630001422
mmmmfffll67.36600/220003.948.6618.5721
⑧局部受压验算
端部锚具布置如下:
计算面积如下如:
⑴端部受压截面尺寸验算
232400mmAl 272000mmAb
56.283307242lnlAA
49.13240072000lblAA
KNAFpconl130383413022.12.1
lclcFKNAf131656.283301.2349.135.135.1ln 满足要求
⑵局部受压承载力验算
端部配有4片8方格焊接网片,间距mms50,如下
lcorAmmA236000200180
054.13240036000lcorcorAA
间接钢筋的体积配筋率
042.050360002003.5041803.504222111sAlAnlAncorssv
KNAffycorvclc135256.28330)210054.1042.021.2349.1(9.0)2(9.0ln
KNFl1303
满足要求
配筋如下:
中部 端部