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预应力混凝土简支T形梁桥(夹片锚具)一设计资料及构造布置
1、桥梁跨径及桥宽标准跨径40m(墩中心距离)主梁全长
39.98m计算跨径
39.00m桥面净空净
9.5+2×
0.75m=11m
2、设计荷载:汽车公路—级,人群
3.5KN/
3、设计时速80km/h
4、桥面宽度净(8+
0.5×n+1)+2×
0.75m(人行道)
5、桥面横坡
1.5%
6、环境桥址位于野外一般地区,Ⅰ类环境条件,年平均相对湿度75%;
7、施工方法主梁采用后张法,预留孔道采用预埋金属波纹管成型,两端同时张拉
8、预应力种类按A类预应力混凝土构件设计
3.材料及工艺混凝土主梁采用C50,桥面铺装用沥青混凝土预应力钢筋采用《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTGD62—2004)的
15.2钢绞线,每束六根,全梁配七束,=1860Mpa普通钢筋直径大于和等于12mm的采用HRB335钢筋,直径小于12mm的均用R235钢筋按后张法施工工艺要求制作主梁,采用内径70mm,外径77mm的预埋波纹管和夹片锚具
4.设计依据
(1)交通部颁《公路工程技术标准》(JTGB01—2003),简称《标准》
(2)交通部颁《公路桥涵设计通用规范》JTGD60--2004简称《桥规》3交通部颁《公路钢筋混凝土及预应力混凝土桥涵设计规范》JTGB62—20044基本计算数据见表一二横截面布置
1.主梁间距与主梁片数主梁间距通常应随梁高与跨径的增大而加宽为经济同时加宽翼板对提高主梁截面效率指标很有效故在许可条件下应适当加宽T梁翼板.本桥主梁翼板宽度为2750mm由于宽度较大为保证桥梁的整体受力性能桥面板采用现浇混凝土刚性接头因此主梁的工作截面有两种:预施应力运输吊装阶段的小截面和运营阶段的大截面.净-
9.5+2×
0.75m的桥宽采用四片主梁如图一所示.基本计算数据名称项目符号单位数据混凝土立方强度弹性模量轴心抗压标准强度轴心抗拉标准强度轴心抗压设计强度轴心抗压标准强度
503.
4532.
42.
6522.
41.83短暂状态容许压应力容许拉应力
20.
721.757持久状态标准荷载组合容许压应力容许主压应力短期效应组合容许拉应力容许主拉应力
16.
219.
4401.
5915.2钢绞线标准强度弹性模量抗拉设计强度最大控制应力186012601395持久状态应力标准荷载组合1209材料重度钢筋混凝土沥青混凝土钢绞线
25.
023.
078.5钢束与混凝土的弹性模量比无量纲
5.65注本示例考虑混凝土强度达到C45时开始张拉预应力钢束和分别表示钢束张拉时混凝土的抗压,抗拉标准强度,则=
29.6,=
2.512.主梁跨中截面尺寸拟订
(1)预应力混凝土简支梁桥的主梁高度与其跨径之比通常在1/15~1/25,标准设计中高跨比约在1/18~1/19当建筑高度不受限制时,增大梁高往往是较经济的方案,因为增大梁高可以节省预应力钢束用量,同时梁高加大一般只是腹板加高,而混凝土用量增加不多,综上所述,本桥梁取用2300mm的主梁高度是比较合适的
(2)主梁截面细部尺寸T梁翼板的厚度主要取决于桥面板承受车轮局部荷载的要求,要应考虑能否满足主梁受弯时上翼板受压的强度要求本算例预制T梁的翼板厚度取用150mm,翼板根部加厚到250mm以抵抗翼缘根部较大的弯矩在预应力混凝土梁中腹板内主拉应力较小,腹板厚度一般由布置预制孔管的构造决定,同时从腹板本身的稳定条件出发,腹板厚度不宜小于其高度的1/15本算例腹板厚度取210mm马蹄尺寸基本由布置预应力钢束的需要确定的,设计实践表明,马蹄__占截面__的10%~20%为合适本算例考虑到主梁需要配置较多的钢束,将钢束按三层布置,一层最多三束,同时还根据《公预规》
9.
4.9条对钢束净矩及预留管道的要求,初拟马蹄宽度为600mm,高度250mm,马蹄与腹板交接处作三角过渡,高度150mm,以减少局部应力按照以上拟订的外形尺寸,就可以绘出预制梁的跨中截面图(见图二)图2跨中截面尺寸图(尺寸单位mm)
(3)计算截面几何特征将主梁跨中截面划分成两个规则图形的小单元,截面几何特性列表计算见表二跨中截面几何特性计算表分块名称分块__()分块__形心至上缘距离()分块__对上缘的静矩()分块__自身惯矩()()分块__对截面形心的惯矩()()
(1)
(2)
(3)=
(1)*
(2)
(4)
(5)
(6)=
(1)*
(7)=
(4)+
(6)大毛截面翼板
41257.
530937.
577343.
7575.
4923507302.
9123584646.66三角承托
50018.
3339166.
52777.
77864.
6572090263.
82093041.578腹板399011043__0012003250-
27.
012910864.914914___.9下三角
292.
5200585003281.25-
117.
014004716.
9794007998.229马蹄
1500217.5326250187500-
134.
5127139410.
1527326910.
1510407.
586375471926711.52小毛截面翼板
25507.
5191254781288.952017___
1.
3820223673.38三角承托
50018.
3339166.
52777.
77878.
1173051132.
8453053910.623腹板399011043__0012003250-
13.
55732573.
97512735823.98下三角
292.
5200585003281.25-
103.
553136361.
2313139642.481马蹄
1500217.5326250187500-
121.
0521979653.
7522167153.
758832.
5851941.
561320204.21注大毛截面形心至上缘距离863754/
10407.5=
82.99小毛截面形心至上缘距离
851941.5/
8832.5=
96.46
(4)检验截面效率指标(希望在
0.5以上)上核心距下核心距截面效率指标
0.5表明以上初拟的主梁跨中截面是合理的三横截面沿跨长的变化如图一所示本设计主梁采用等高形式横截面的T梁翼板厚度沿跨长不变梁端部区段由于锚头集中力的作用而引起较大局部应力,也为布置锚具的需要,在距梁端1999mm的范围内将腹板加厚到与马蹄同宽马蹄部分为配合钢束弯起而从六分点附近开始向支点逐渐抬高,在马蹄抬高的同时腹板的宽度亦开始变化
(四)横隔梁的布置模型实验结果表明,在荷载作用处的主梁弯矩横向分布,当该处有横隔梁时比较均匀,否则直接在荷载作用下的主梁弯矩很大为减少对主梁设计起主要控制作用的跨中弯矩,在跨中设置一道中横隔梁当跨度较大时,应设置较多的横隔梁,本设计在桥跨中点和三分点,六分点,支点出设置七到横隔梁,其间距为
6.5m端横隔梁的高度与主梁同高,厚度为上部280mm,下部260mm,中横隔梁高度为2050mm,厚度为上部180mm,下部160mm,见图一二.主梁作用效应计算根据上述梁跨结构纵,横截面的布置,并通过可变作用下的梁桥荷载横向分布计算,可分别求得主梁控制截面的永久作用和最大可变作用效应,然后在进行主梁作用效应组合
(1)永久作用效应计算1.永久作用集度
(1)预制梁自重1跨中截面段主梁的自重2马蹄抬高与腹板变宽段梁的自重3支点段梁的自重4边主梁的横隔梁中横隔梁体积端横隔梁体积故半跨内横梁重力为5预制梁永久作用集度
(2)__永久作用1现浇T梁翼板集度2边梁现浇部分横隔梁一片中横隔梁体积一片端横隔梁体积故3铺装10cm混凝土铺装5cm沥青铺装若将桥面铺装均摊给四片主梁,则4栏杆一侧人行栏
1.52KN/m一侧防撞栏
4.99KN/m若将两侧人行栏,防撞栏均摊给四片主梁,则5边梁__永久作用集度
2.永久作用效应如图3所示,设x为计算截面离左支座的距离,并令主梁弯矩和剪力的计算公式分别为永久作用效应计算见表三1号梁永久作用效应作用效应跨中=
0.5四分点=
0.25支点=
0.0__弯矩
4973.
673730.250剪力
0255.
061510.12__弯矩
3779.
682834.760剪力
0193.
83387.66弯矩
8753.
366565.010剪力
0448.____
7.78
(2)可变作用效应计算(修正刚性梁法)1.冲击系数和车道折减系数按《桥规》
4.
3.2条规定,结构的冲击系数与结构的基频有关,因此首先要计算结构的基频简支梁桥的基频可采用下列公式估算其中根据本桥的基频,可计算出汽车荷载的冲击系数为按《桥规》
4.
3.1条,当车道大于两车道时,需进行车道折减,三车道折减22%,四车道折减33%,但折减后不得小于用两行车队布载的计算结构本算例按四车道设计,因此在计算可变作用效应时需进行车道折减2.计算主梁的荷载横向分布系数
(1)跨中的荷载横向分布系数如前所述,本例桥跨内设五道横隔梁,具可靠的横向__,且承重结构的长宽比为所以可按修正的刚性横梁法来绘制横向影响线和计算横向分布系数
①计算主梁抗扭惯矩对于T梁截面,抗扭惯矩可近似按下式计算式中——相应为单个矩形截面的宽度和高度——矩形截面抗扭刚度系数m——梁截面划分成单个矩形截面的个数对于跨中截面,翼缘板的换算平均厚度马蹄部分换算成平均厚度图四示出了的计算图示,的计算见表四图4计算图示(尺寸单位cm)计算表分块名称(cm)cm/翼缘板
①
27517.
215.9881/
34.66394腹板
②
180.
3218.___
0.
29814.97754马蹄
③
5532.
51.
69230.
20983.
9611213.6026
②计算抗扭修正系数对于本算例主梁的间距相同,并将主梁近似看成等截面,则得式中计算得=
0.90
③按修正的刚性横梁法计算横向影响线竖坐标值式中.计算所得的值列于表5内梁号
10.
57540.
44280.
34640.
25000.
15360.
05710.
03920.
44820.
37860.
31340.
25000.
18570.
12140.
057130.
34640.
31340.
28210.
25000.
21780.
18570.
153640.
25000.
25000.
25000.
25000.
25000.
25000.2500
④计算荷载横向分布系数1号梁的横向影响线和最不利荷载图式如图5所示图5跨中的横向分布系数计算图式(尺寸单位cm)可变作用双车道=1/2(
0.56+
0.420+
0.318+
0.178)=
0.728故取可变作用的横向分布系数为=
0.728
(2)支点截面的荷载横向分布系数如图6所示,按杠杆原理法绘制荷载横向分布系数影响线并进行布载,1号梁可变作用的横向分布系数可计算如下图6支点的横向分布系数计算图式(尺寸单位cm)可变作用(汽车)=
(3)横向分布系数汇总(见表6)一号梁可变作用横向分布系数表6可变作用类别公路—级
0.
7280.
423.车道荷载取值根据《桥规》
4.
3.1条,公路—级的均布荷载标准值和集中荷载标准值为=
10.5KN/m计算弯矩时=237KN计算剪力时=
2371.2=
284.4KN
4.可变作用效应在可变作用效应计算中,本算例对于横向分布系数的取值作如下考虑,支点处横向分布系数取,从支点至第一根横段梁,横向分布系数从直线过渡到,其余梁段取
(1)求跨中截面的最大弯矩和最大剪力计算跨中截面最大弯矩和最大剪力采用采用直接加载求可变作用效应,图7示出跨中截面作用效应计算图式,计算公式为图7跨中截面作用效应计算图式式中S——所求截面汽车标准荷载的弯矩和剪力;——车道均布荷载标准值;——车道集中荷载标准值;——影响线上同号区段的__;y——影响线上最大坐标值可变作用(汽车)标准效应=1/
20.72__.
7510.539-
0.
31906.
510.
51.083+
0.
72802379.75=
3159.1=1/
20.
728010.
50.
519.5-1/
20.
31906.
510.
50.0556+
0.
7280284.
40.5=
140.18KN可变作用(汽车)冲击效应M=
3159.
10.186=
587.59V=
140.
180.186=
26.07KN
(2)求四分点截面的最大弯矩和最大剪力图8为四分点截面作用效应的计算图式=1/
20.
72810.5____2539-1/2(
1.625+
0.5416)
0.
31906.
510.
50.7280237____25=
2344.06=1/
20.
728010.
50.
7529.25-1/
20.
31906.
510.
50.0556+
0.
7280284.
40.75=
238.52KN可变作用(汽车)冲击效应M=
2344.
060.186=
435.99V=
238.
520.186=
44.36KN
(3)求支点截面的最大剪力图10示出支点截面最大剪力计算图式图10支点截面剪力计算图式可变作用(汽车)效应=1/
210.
50.7280139-1/
210.
50.
3196.5(
0.9444+
0.0556)+
284.
40.
83330.7280=
310.78KN可变作用(汽车)冲击效应V=
310.
780.186=
57.81KN
(三)主梁作用效应组合本算例按《桥规》
4.
1.6~
4.
1.8条规定,根据可能同时出现的作用效应选择三种最不利效应组合,短期效应组合,标准效应组合和承载能力极限状态基本组合,见表7主梁作用效应组合表7序号荷载类别跨中截面四分点截面支点KNKNKN
(1)第__永久作用
4973.
6703730.
25255.
06510.12
(2)第__永久作用
3779.
6802837.
76193.
83387.66
(3)总永久作用=
(1)+
(2)
8753.
3606565.
01448.____
7.78
(4)可变作用公路—级
3159.
1140.
182344.
06238.
52310.78
(5)可变作用(汽车)冲击
587.
5926.
07435.
9944.
3657.81
(6)标准组合=
(3)+
(4)+
(5)
12500.
04166.
259345.
06731.
771266.37
(7)短期组合=
(3)+
10964.
7398.
1268205.
8615.
8541115.33
(8)极限组合=
15749.
398232.
6911770.
08934.
71593.36三预应力刚束的估算及其布置
(一)跨中截面钢束的估算和确定根据《公预规》规定,预应力梁应满足正常使用极限状态的应力要求和承载能力极限状态的强度要求,以下就跨中截面在各种作用效应组合下,分别按照上述要求对主梁所需的刚束数进行估算,并且按这些估算的钢束数的多少确定主梁的配束
1.按正常使用极限状态的应力要求估算钢束数对于简支梁带马蹄的T形截面,当截面混凝土不出现拉应力控制时,则得到钢束数n的估算公式式中——持久状态使用荷载产生的跨中弯矩标准组合值,按表7取用——与荷载有关的经验系数,对于公路—级,取用
0.6——一股
15.2钢绞线截__,一根钢绞线的截__是
1.4,故=
8.4在一中已计算出成桥后跨中截面=
145.20cm,=
48.7cm初估=15cm,则钢束偏心距为=-=
145.2-15=
130.2cm一号梁2按承载能力极限状态估算钢束数根据极限状态的应力计算图式,受压区混凝土达到极限强度,应力图式呈矩形,同时预应力钢束也达到设计强度则钢束数的估算公式为式中——承载能力极限状态的跨中最大弯矩,按表7取用——经验系数,一般采用
0.5~
0.7,本算例取
0.76——预应力钢绞线的设计强度,见表1,为1260MP计算得根据上述两种极限状态,取钢束数n=9
(二)预应力钢束的布置1跨中截面的钢束布置对于跨中截面,在保证布置预留管道构造要求的前提下,尽可能使钢束群重心的偏心距大些,本算例采用内径70mm,外径77mm的预埋铁皮波纹管,根据《公预规》
9.
1.1条规定,管道至梁底和梁侧净矩不应小于3cm及管道直径的1/2根据《公预规》
9.
4.9条规定,水平净矩不应小于4cm及管道直径的
0.6倍,在竖直方向可叠置根据以上规定,跨中截面的细部构造如图11a所示由此可直接得出钢束群重心至梁底的距离为a)b图11钢束布置图(尺寸单位cm)a)跨中截面b锚固截面对于锚固端截面,钢束布置通常考虑下述两个方面一是预应力钢束合力重心尽可能靠近截面形心,使截面均匀受压;二是考虑锚头布置的可能行,以满足张拉操作方便的要求按照上述锚头布置的“均匀”“分散”的原则,锚固端截面所布置的刚束如图11b所示钢束群重心至梁底距离为为验核上述布置的钢束群重心位置,需计算锚固端截面的几何特性图12示出计算图式,锚固端截面特性计算见表8所示钢束锚固截面几何特性计算表表8分块名称
(1)
(2)
(3)=
(1)+
(2)
(4)
(5)
(6)
(7)=
(4)+
(6)翼板
41757.
530937.
577343.
7577.32464807124725415三角承托
148.
2517.
173403.
95698.
0076.
31154150.
0431154848.043腹板
12900122.5158025049691875-
29.
0310871357.
6160563232.
6117273.
251614591.
4586443495.65其中故计算得.说明钢束群重心处于截面的核心范围内
2.钢束起弯角和线形的确定确定钢束起弯角时,既要照顾到因弯起所产生的竖向预剪力有足够的数量,又要考虑到由其增大而导致摩擦预应力损失不宜过大为此,本设计中将锚固端截面分成上、下两部分,如图所示,上部钢束的晚期较初定为,下部钢束弯起角定为为简化计算和施工,所有钢束布置的线型均选用两端为圆弧线中间再加一段直线,并且整根束道都布置在同一个竖直面内
3.钢束计算
(1)计算钢束起弯点至跨中的距离图13封锚端混凝土块尺寸图(尺寸单位cm)锚固点到支座中心线的水平距离为图14钢束计算图示(尺寸单位cm)钢束起弯点至跨中的距离表9钢束号钢束起弯高度(cm)N1N2N
331.
070.
99250.
12194133.
33503.
851477.24N4N5N
663.
370.
99250.
121984401028.
83947.35N
7146.
0150.
96590.
25884171.
421076.
22903.1N
8168.
3150.
96590.
25884808.
571244.
458726.8N
9184.
48150.
96590.
25885270.
8571364.
09599.11
(2)控制截面的钢束重心位置计算由图14所示的几何关系,得到计算公式为式中——钢束起弯后,在计算截面处钢束重心到梁底的距离;——计算截面处钢束的升高值;——钢束起弯前到梁底的距离;——钢束弯起半径计算各截面的钢束位置表10截面钢束号四分点N1N2N3钢筋尚未弯起99N4N5N
616.
716.7N
771.
94171.
420.
01720.
999850.
625799.6257N
8248.
24808.
570.
05160.
99866.
73216.
723.432N
9375.__
5270.
8750.
07130.
997513.
1728.
415.22支点N1N2N
3466.
764133.
330.
11290.
993626.
45935.45N4N5N
6996.
6584400.
11800.
993059.
0816.
775.78N
71040.
94171.
420.
24950.
9683132.
239141.23N
812184808.
570.
25320.
9674156.
7516.
7173.45N
91344.__
5270.
8750.
25510.
967173.
9428.
4202.34
(3)钢束长度计算一根钢束的长度为曲线长度、直线长度与两端工作长度之和,其中钢束的曲线长度可按圆弧半径与弯起角度进行计算通过每根钢束长度计算,就可得出一片主梁和一孔桥所需钢束的总长度,以利备料和施工计算结果如下表所示钢束长度计算表11钢束号钢束弯起角度曲线长度直线长度有效长度钢束预留长度钢束长度N1N2,N
34133.
337504.
731477.
243963.
941404103.94N4N5,N
6844071029.
68947.
353954.
061404094.06N
74171.
42151091.
52903.139__.
241404129.24N
84808.5715____.
84726.
93973.
481404113.48N
95270.
875151380.
97599.
113960.
161404100.
1636936.88
四、主梁截面几何特性在求得各验算截面的毛截面特性和钢束位置的基础上,计算主梁净截面和换算截面的__、惯性矩及梁截面分别对重心轴、上梗肋与下梗肋的静距,最后汇总成截面特性值总表,为各受力阶段的应力验算准备计算数据
4.1截面__及惯矩计算计算公式如下对于净截面(4.1)截__(
4.2)截面惯矩取用预制梁截面(翼板宽度)计算对于换算截面截__(
4.3)截面惯矩(
7.4)取用主梁截面()计算上面式中、——分别为混凝土毛截面__和惯矩;、——分别为一根管道截__和钢束截__;、——分别为净截面和换算截面重心到主梁上缘的距离;——分__重心到主梁上缘的距离;——计算__内所含的管道(钢束)数;——钢束与混凝土的弹性模量比值;得
4.2截面静距计算图7-1示出对重心轴静距的计算图式,计算过程见表4-1图7-1静距计算式(尺寸单位mm)跨中截面__和惯性矩计算表表7-1特性分类截面分块名称分块__分块__重心至上缘距离分块__对上缘静距全截面重心到上缘距离分块__的自身惯矩208cm净截面毛截面818563.
3518461.
759.3532652107-
3.9512770629332561扣管道__-
309.
25164.93-
51004.6-
105.58-
3447251.
97875.7546745732652107-
3319545.9210cm换算截面毛截面
818563.
3518461.
766.
84326521073.
54793.334945456混凝土接缝
28719659.
84100263.1钢束换算__
227.
85164.9351004-
98.
092192292.
58440.
85569661.
7326521072293348.9计算数据跨中截面对重心轴静距计算表表7-2分块名称及序号净截面换算截面静距类别及符号分块__分块至全截面重心距离对净轴静距(cm3)静距类别及符号分块__(cm3)翼板
①翼缘部分对净轴静距
263252.35139521翼缘部分对净轴静距
226059.
84159174.4三角承托
②
9504235062.
568849.
5147034.5肋部
③
48047.
352272848054.
84826323.2∑201879232532下三角
④马蹄部分对净轴静距
22590.
6520396.25马蹄部分对换轴静距
22583.1618711马蹄
⑤
1250108.
15135187.
51250100.66____25肋部
⑥
30088.
152644530080.6624198管道或钢束-
309.
25105.58-
32650.
62227.
8598.
0922349.8∑
149378191083.8翼板
①净轴以上净__对净轴静距139251换轴以上换算__对换轴静距
159174.4三角承托
②
3990047034.5肋部
③
3391.
533.
91535224.
21336.
836.
4544675.9∑
214375.
2250884.8翼板
①换轴以上换算__对换轴静距13952净轴以上净__对净轴静距
159174.4三角承托
②
3990047034.5肋部
③
1336.
9125.
9334663.
2118737.16544___.86∑
213814.
2250323.
767.3截面几何特性汇总其他截面均采用同样方法计算,结果均列于表7-3中主梁截面特性值总表表7-3名称符号单位截面跨中四分点支点混凝土净截面净__
8440.
858440.
8511731.6净惯矩
29332561.12983372___41347净轴到截面上缘距离
59.
3559.
7361.83净轴到截面下缘距离
120.
65120.
27112.17截面抵抗矩上缘
494230.2499476569679下缘
243121248056.23444__对净轴静距翼缘部分__
201879202785236614.5净轴以上__
214375.2225293284641换轴以上__
213814.2214795283996马蹄部分__149378149572钢束群重心要净轴距离
105.
58102.
4131.64混凝土换算截面换算__
8440.
858440.
8512183.85换算惯矩
34945455.
9346327423914048.5换轴到截面上缘距离
66.
8466.
4272.92换轴到截面下缘距离
113.
16113.
58107.08截面抵抗矩上缘
522823521340536765.6下缘308815304919365536对换轴静距翼缘部分__232532231267259282净轴以上__250324249786319058换轴以上__250885249987298875马蹄部分__19108418__42钢束群重心到换轴距离
98.
0996.
2226.55钢束群重心到截面下缘距离
15.
0717.
3680.538主梁截面几何特性根据《公预规》
6.
2.1规定,当计算主梁截面应力和确定钢束的控制应力时,应计算预应力损失值后张法梁的预应力损失包括(钢束与管道壁的摩擦损失,锚具变形、钢束回缩引起的损失,分批张拉混凝土弹性压缩引起的损失)和后期预应力损失(钢绞线应力松弛、混凝土收缩和徐变引起的损失),而梁内钢束的锚固应力和有效应力(永存应力)分别等于张拉应力扣除相应阶段的预应力损失预应力损失值因梁截面位置不同而有差异,以四分点截面(既有直线束,又有曲线束通过)说明各项应力损失
8.1预应力钢束与管道壁之间的摩擦引起的预应力损失按《公预规》
6.
2.2条规定,计算公式为(
8.1)式中——张拉钢束时锚下的控制应力;根据《公预规》
6.
1.3条规定,对于钢绞线取张拉控制应力为——钢束与管道壁的摩擦系数,对于预埋波纹管取;——从张拉端到计算截面曲线管道部分切线的夹角之和(rad);——管道每米局部偏差对摩擦的影响系数,取;——从张拉端到计算截面的管道长度(m),可近似取其在纵轴上的投影长度,当四分点为计算截面时,四分点截面管道摩擦损失计算表表8-1钢束号N1(N2)
70.
12220.
02447.
570.
0113550.
035760.
035142.14N3(N4)
70.
12220.
02447.
540.
011310.
035710.
035142.14N
514.
10.
2460.
04927.
560.
011340.
060540.
058770.44N
612.
040.
210.
0427.
490.
0112350.
060440.0___
70.32N
710.
790.
1880.
03767.
420.01___
0.
048740.
047657.1跨中截面管道摩擦损失计算表表8-2钢束号N1(N2)
70.
12220.
024414.
8230.
022230.
04660.
045563.47N3(N4)
70.
12220.
024414.
7860.
022220.
04660.
045563.47N
5150.
2620.
52414.
8060.
02220.
07460.
0719100.3N
6150.
2620.
52414.
7390.
02210.
07450.
0719100.3N
7150.
2620.
52414.
6720.
0220.
07450.
0719100.
38.2由锚具变形、钢束回缩引起的预应力损失按《公预规》
6.
2.3条,对曲线预应力筋,在计算锚具变形、钢束回缩引起的预应力损失时,应考虑锚固后反向摩擦的影响根据《公预规》附录D,的计算公式如下(
8.2)式中——锚具变形、钢束回缩值(mm),按《公预规》
6.
2.3条采用;对于夹片锚具——单位长度由管道摩擦引起的预应力损失,按下列公式计算(
8.3)其中——张拉端锚下控制应力,此设计中为1395MPa,——预应力钢筋扣除沿途摩擦损失后锚固端应力,即跨中截面扣除后的钢筋应力,——张拉端至锚固端距离张拉端锚下预应力损失(
8.4)在反摩擦影响长度内,距张拉端处的锚具变形、钢筋回缩损失(
8.5)在反摩擦影响长度外,锚具变形、钢筋回缩损失:.四分点截面的计算结果见表8-3四分点截面的计算表表8-3钢束号影响长度锚固端距张拉端距离N1(N2)
0.
004281816530141.
567573.
276.7N3(N4)
0.
004292516510141.
747536.
377.04N
50.
006774313172178.
467556.
476.08N
60.
00680513112178.4574__.
476.52N
70.
00683613083178.
877422.
477.39为你提供优秀的毕业论文参考资料,请您删除以下内容,O∩_∩O谢谢!!!2__nypeopleh__ethesamemixedfeelingswhenplanningatripduringGoldenWeek.Withheapsoftimetheseven-dayChinese为你提供优秀的毕业论文设计参考资料,请您删除一下内容,O∩_∩O谢谢!!!NationalDayholidaycouldbethebestoccasiontoenjoyadestination.Howeveritcanalsobetheeasiestwaytoruinhowyoufeelaboutapla__andyou__ybecomemorefatiguedaftertheholidayduetobattlingthelargecrowds.Duringpeakseasonadreamaboutapla__canturntonight__rewithoutcarefulplanningespeciallyifyoutr__elwithchildrenandolderpeople.AsmostChinesepeoplewilltaketheholidaytovisitdomestictouristdestinationscrowdsandbusytrafficareinevitableatmostpla__s.Alsotobeexpectedareincreasingtransportandaccommodationpri__swiththepossibilitythattherewillbenorooms__ailable.Itisalsocommonthatyou ll waitinthelineforonehourtogetaticketandanothertwohoursatthesitetoonlyseeatinybitofthepla__duetothecrowds.Lastyear428milliontouriststr__eledinChinaovertheweek-longholidayinOctober.Tr__elingduringthisperiodisa__tterthatneedsthoroughpreparation.IfyouareshortontimetoplantheupcomingGoldenWeekit__ynotbeabadideato__oidsomeofthemostcrowdedpla__sfornow.Thereisalwaysapla__sofascinatingthateveryoneyearnsfor.Arxanisapla__likethis.ThebeautyofArxaniseverlastingregardlessofthechangingoffourseasons.Bestowedbynatureitsspectacularseasonallandscapeandmountainsarejustbeyondword.Arxanisacrucialdestinationfortherecommendedtr__ellingrouteChinaInnerMongoliaArxan—Hailar—__nzhouli.ItisalsothejointofthefourprairiesacrosstheSino-Mongolianborderwherepeoplegr__itatetowardstheexoticatmospheremixedwithChineseRussianandMongoliaelements.AsahistoricsitefortheYitianBattleArxanstillembo___sthespiritofGenghisKhan.WalkingintoArxanyouwillbea__zedbyakaleidoscopeofgorgeouscolorsalltheyearround--theSpringazaleasbloomingredinthesnowtheSummerseaw__eringblueinthebreezetheAutumnle__espaintedinyellowcoveringvolcanictra__sandtheWinterwoodsshiningwhiteonthevastalpinesnowscape.HingganLeagueArxancityissituatedinthefareasternareaofInnerMongoliaAutonomousRegion.ItsfullnameHarenArxanmeanshotholywaterintheMongolianlanguage.Arxanisatouri__cityinthenorthernfrontierwithablendoflargeforestgrandprairiesvastsnowfieldhe__enlakeclusterthermiumaswellasvolcaniccluster.Itisarareanduniqueecotouri__basefilledwithhealthysunshinecleanairandunspoiledgreen. Nestledclosetothecountryslargestvirginforestandknownforitsspringandecologicalenviro__entArxanis__rveledatby__nytouristsasthepurestlandonearth. YoucannotmissouttheAutumnofArxan.Itisdefinitelythebestwithbrightly-coloreds__neryfullofemotions. AutumninthenorthernpartofthecountrycomesearlierthantheSouth.ASeptemberrainfollowedbythefootprintsofAutumnbringsmorecolorstotheon__emeraldgreenmountainandbloominggrassland. Shutterbugsflocktoseeforthemselvesthe__rvelofsplendidcolorsaroundthemountainsandwaters__nyofwhomh__etr__elalongdistan__andevencamphereonlytocaptureamomentofthenaturewonder. Thesilverbirchturnsgoldenwhilethelarchisstillproudlygreen.Youwillfindyourselfdrownedintheintoxicatingredofthewildfruitsaswellastheglamourofflowersinfullblown.Andyourheartwillbelingeringonthewoodsasitstimeforthewildfruitstoripe.ThepicturesqueArxaninAutumnisindeedafairylandonlyexistsinadreamthatsatisfiesallyourfantasies.Ifit rainshe__ilyonSaturdaynightsomeelderlyChinesewillsayitisbecauseZhinuortheWe__ing__idiscryingonthedayshemetherhu__andNiulangortheCowherdontheMilkyWay.MostChineserememberbeingtoldthisro__ntictragedywhentheywerechildrenonQixiortheSeventhNightFestivalwhichfallsontheseventhdayoftheseventhlunarmonthwhichisusuallyinearlyAugust.ThisyearitfallsonSaturdayAugust
2.FolkloreStoryAsthestorygoeson__therewasacowherdNiulangwholivedwithhiselderbrotherandsister-in-law.Butshedislikedandabusedhimandtheboywasfor__dtole__ehomewithonlyanoldcowforcompany.Thecowhoweverwasaformergodwhohadviolatedimperialrulesandwassenttoearthinbovineform.OnedaythecowledNiulangtoalakewherefairiestookabathonearth.AmongthemwasZhinuthemostbeautifulfairyandaskilledseamstress.Thetwofellinloveatfirstsightandweresoon__rried.TheyhadasonanddaughterandtheirhappylifewasheldupasanexampleforhundredsofyearsinChina.YetintheeyesoftheJadeEmperortheSupremeDeityinTaoi____rriagebetweenamortalandfairywasstrictlyforbidden.Heorderedthehe__entrooptocatchZhinuback.NiulanggrewdesperatewhenhediscoveredZhinuhadbeentakenbacktohe__en.DrivenbyNiulangsmiserythecowtoldhimtoturnitshideintoapairofshoesafterit___d.The__gicshoeswhiskedNiulangwhocarriedhistwochildreninbasketsstrungfromashoulderpoleoffonachaseaftertheempress.ThepursuitenragedtheempresswhotookherhairpinandslasheditacrosstheskycreatingtheMilkyWaywhichseparatedhu__andfromwife.Butallwasnotlostas__gpiesmovedbytheirloveanddevotionformedabridgeacrosstheMilkyWaytoreunitethefamily.EventheJadeEmperorwastouchedandallowedNiulangandZhinutomeeton__ayearontheseventhnightoftheseventhmonth.ThisishowQixicametobe.Thefestivalcanbetra__dbacktotheHanDynasty206BC-AD
220.Traditionallypeoplewouldlookupattheskyandfindabrightstarinthecons____ationAquilaaswellasthestarVegawhichareidentifiedasNiulangandZhinu.ThetwostarsshineonoppositesidesoftheMilkyWay.CustomsInbygonedaysQixiwasnotonlyaspecialdayforloversbutalsoforgirls.ItisalsoknownastheBeggingforSkillsFestivalorDaughtersFestival.InthisdaygirlswillthrowasewingneedleintoabowlfullofwateronthenightofQixiasatestofembroideryskills.Iftheneedlefloatsontopofthewaterinsteadofsinkingitprovesthegirlisaskilledembroiders.Singlewomenalsoprayforfindingagoodhu__andinthefuture.Andthenewly__rriedwomenpraytobecomepregnantquickly.TraditiontransformedThelovestoryofNiulangandZhinuandtheQixiFestivalh__ebeenhandeddownforgenerations.Yettheseancienttraditionsandcustomsareslowlydyingout.__nymodernChineseparticularlyyoungstersseemtoknowmoreaboutStValentinesDayonFebruary14characterizedbybouquetsofroseschocolatesandro__nticcandlelightdinnersthantheydoabouttheirhome-growndayforlovers.EvenQixiisnowadaysreferredtoastheChineseValentinesDay.MoreandmoreyoungChinesepeoplebeginto__lebratethisdayinaverysimilarwayasthatinwesterncountries.Fewerpeoplethaneverwillgazeatthehe__ensonSaturdaytopickoutthetwostarsshiningbrightoneithersideoftheMilkyWaythatisifpeopleevenknowonwhichdayQixifalls.TherearereadyremindersdottedaboutintheformofbigadssayingSalesonChineseValentinesDay!inshopshotelsandrestaurants.Butfewyoungwomenwill__rkthefestivalwiththeirboyfriendsortakepartintraditionalactivitiestoprayforcleverness.Alarge-scaleofexhibitionontheSilkRoadopenedtothepublicintheNationalMuseumonThursday.Theexhibitiondisplaysmorethan400treasuresfromShaanxiprovin__Gansuprovin__and14otherregions.ItislargestscaleexhibitionthatshowsthehistoryoftheSilkRoadinre__ntyears.As APEC isgoingoninBei___gtheexhibitaimstoshowtheworldthisbrilliantsectionofhistory.TheSilkRoadisaseriesoftradeandculturaltran__issionroutesthatwere__ntraltoculturalinteractionthroughregionsoftheAsiancontinent.ItconnectedtheWestandEastbylinkingtradersmerchantspilgrimsmonkssol___rsno__dsandurbandwellersfromChinaandIndiatotheMediterraneanSeaduringvariousperiodsoftime.Imetmydearhubbyin2009thesecondyearIwasinmyschoolanditwasthefirstyearwhenhecamehere.Webecamecolleagues.Andtherewasnothingspecialhappeningduringthatyear.Hewasjustakindandhumblebrothergraduatedfromthesamecollegeasme.Butwedidnotknoweachothertillhebecamemycolleagueandhisoffi__deskwasjustinfrontofme.Therewasonlyaglassbetweenus.Soactuallywecouldseeeachotherwhenwebothlookup.Butitisnotthe__inreasonthatreallydrawsusclose.Howwebecomeclosetoeachotherwassomethingseemsquitenatural.Wewentouttoplaybadmintonwithothercolleaguesandwesometimeschattedforawhile.Heisa__noffewwordsbutsomehowsometimeswillsaysomethingreallyhumorous.ThenonedaytomygreatsurpriseIfoundapotofbeautifulfloweronmydesk.ItwasjusttheflowerIhadtalkedaboutwithmycolleaguetheotherdayandIthoughtitwasherwhoputtheflowerthere.Butthetruthisnot.Itwasthehumbleguysittinginfrontofme.Hejustsimplysaid”wellIcaughtsightofthisflowerandthoughtthatit’sbeautifulandyou__ylikeit”.IwonderwhyIwasmovedbecauseofthese______wordsandpresent.__ybeitisthesin__rityandthetrueselfthatimpressme.Ithankedhimandsomecolleagueswalkedpastmydeskwouldappreciatethebeautifulflowerandtheynoti__dthatsomethingro__n__happenedthere.Thenlateronthereweresomelittlesurpriseson__inawhile.On__therewassomethingwrongwithmydrawerandIhadcomplainedaboutitunconsciously.Andhefixeditforme.Thentheotherdayhepla__dseveralpinkdiamondrosesbesidetheflowerwithapie__ofpapersaying”IloveyoumorethanIcansay!Diamondstandsfor__rriagerosestandforlove.Ihopeyouareminebecomemywife.YouaretheonlygirlwhoIreallywanttospendtherestofmylifetostandby.”Althoughthereweresomegram__rerrorsbutIgotwhathemeant.Hemeantsoclearandsodirect. AndactuallyIac__ptedhimsomedaysearlier.Iwasjustwaitingforhimtobreakthei__.Sofinallythecommoninterestsandthecommonunderstandingbroughtustogether.Somepeoplesaytherelationshipandthefeelingwillchangeaftergettinghitched.Youwillfindthatloveisnolongerstrongandthereisalwayslackofpassionandwhat’sworseyou__yfindout__nybadhabitsofyourpartnerwhichneverappearwhenyouarefirstinlovebeforethe__rriage.Itseemsthat__nyfaultsturnupafteryoutrulylivingtogetherandseeeachother’sfa__themomentyouopenyoureyesintheearlymorning.Butafteralmost4yearsfromnowIdonotfeelanynegativechangeinourrelationship.DuringalltheseyearsweknoweachotherbetterandwebecomemoretolerantabouteachotherandIrealizethatifyoureallyloveapersonyouwillac__pthisimperfect.Andwhatisthequalificationofagoodhu__andOn__Iwaschattingwithmycolleagueaboutthisissue.AndoneofthequalificationsIthoughtwasthathemustbeagoodcook.Buttomysurprisemycolleaguesaidthatagoodhu__andmustbesomeonewho__kesbigmoney.What__deherthinksowasquitebeyondme.__ybeIamnotsophisticatedenoughandwhatIwantisjust______lifestyle.Themostenjoyablethingisthatwegotothe__rkettobuyvegetablesandotherdailystuffsifwebothh__etime.__ybeheisahouseboundhu__andandIlovehousebound__n.AndthereisanotherreasonwhyWelovegoingtothe__rket.Thatisbecausewesometimeswillgetsomesurprises.Thesurpriseiss__inglittlefishwhicharedissertedbythefishmongers.Becausethesefishareswellfish.Thenwewillcollectthemandsetthemfreeintotheriver.Swellfisharelovelycreature.Whentheylooklikealittlesub__rinewhentheyareswimminginthewaterandlooklikeameatballwhenyouholdtheminyourhand.Andiftheyarescaredtheywillswellandlooklikealittleball.Everytimeweseethemswimawayandwefeeltheirhappinessofreturninghomeandthisalso__keuscherishlife.__ybesomewillconsiderthesebeh__iorassomethingchildish.Wellthatisfinewithus.Welovedoingthesetogetherandfeelhappythatiswhatitisallabout.Mydearhubbyisakindhearted__nandheloveani__lsjustasIdo.Iamluckytoh__esomeonewhocanbebothmyinti__tedsoul__teandmyforeverfriend.。