1 计算书
一.行车道板计算
如右图所示
恒载弯矩计算
(1)恒载集度(总想取1m 板宽计算)
沥青铺装:1g =0.05⨯1⨯23=1.15KN m 混凝土铺装:2g =0.1⨯1⨯24=2.4KN m 翼板:t=()0.560.150.180.60.15
1.72⨯++⨯=0.16m
3g =0.16⨯1⨯25=4.00KN m
板的恒载集度:g=1g +2g +3g =1.15+2.4+4.00=7.55KN m
(2)恒载弯矩
板的计算跨径:l =0l +t=1.72+0.16=1.88m 且<1.90m g M =21
8g l ⋅⋅=1
8⨯7.55⨯21.88=3.336KN m ⋅
3.活载弯矩计算
(1)汽车荷载为公路Ⅰ级,车辆荷载两后轮置于最不利位置
(2)公路22a b ⨯=0.2⨯0.6 经铺装层投45。扩散后得 122a a H =+=0.2+2⨯0.15=0.5m
122b b H =+=0.6+2⨯
0.15=0.9m
2 (3)板的有效宽度a
a =13l a +=0.5+1.88/3=1.127m 且23
l =2 1.88 1.2533m ⨯= 故a =1.253m <d(=1.4m) 即a =1.253m '1a a t =+=0.5+0.16=0.66m 且1 1.8833l =⨯=0.627m 'a =0.66m
10.9 1.881.3 1.30.092222b l C m ⎛⎫⎛⎫=--=--= ⎪ ⎪⎝⎭⎝⎭>0 故右侧车轮已经进到车板内 如图所示 '20.6620.090.84c a a c m =+=+⨯=
(4)荷载集度
①跨中车轮的荷载集度
114062.07322 1.2530.9
p p kN m a b ===⋅⋅⨯⨯ ②支点处车轮的荷载集度
''1140117.845220.660.9
p p kN m a b ===⋅⋅⨯⨯ ③C 点处车轮的荷载集度
''114092.593220.840.9
c p p kN m a b ===⋅⋅⨯⨯ (5)弯矩值计算 120.015462
c l c y l =⨯== 220.02344
2c
l c y l =⨯== 134240.3584
2
b l l y y l ⎛⎫- ⎪⎝⎭==⨯= ()()11225344=1 1.320.21826.284M A y A y A y A y KN m +⋅⋅+⋅+⋅+⋅=⨯=⋅汽μ
3
4.弯矩组合值
1.2 1.4+0.81.4g M M M M =+⨯⋅人汽
=1.2 3.336 1.426.2840=40.801KN m ⨯+⨯+⋅
板与梁肋高之比t 0.161=h 1.54
<则 跨中弯矩=0.5=20.4M M KN m ⋅中
支点弯矩=0.7=28.561M M KN m --⋅支
5.翼板配筋及强度复核
拟采用HRB335级钢筋φ12(外径13.5mm )钢筋弯矩采用30mm 。25C 混凝土11.5,280cd sd f MPa f MPa ==
(1)用基本公式法求。
设035,16035125s a m mm ==-=则h
4 6
022040.801100.22711.510000.3
cd M A f bh ⨯===⨯⨯ 查表得:00.261(0.56),0.864b ξξξ===<
6
20040.8011013490.864280125
S sd M A mm f h ξ⨯===⨯⨯ (2)选择布置钢筋
选取12φ12,则实际钢筋面积21357.2S A mm =混凝土保护层厚度30mm >d(=12mm)满足要求,故013.53036.7540mm 160401202
s s a mm a h mm =+===-=取,则有效高度 ()min 45/0.2440.2td sd f f ρ==%且不小于% 实际配筋率:01357.2 1.131000120
S A b h ρ===⋅⨯% 故:()min =1.130.244ρρ=%>% 满足配筋要求
(3)截面复核 钢筋净距:10002301213.570.7320011
n S mm mm -⨯-⨯==< 受压高度:()/0.011328011.50.2750.56sd cd b f f ξρξ=⋅=⨯÷==< 查结构设计原理表:00.238A = 则: ()220011.510001200.23839.41240.801cd M f b h A KN m M KN m μ=⋅⋅⋅=⨯⨯⨯=⋅=⋅< 故不满足要求,将选取14Ф12钢筋,2=1584mm S A 则()min 1584==1.320.2441000120
ρρ=⨯%>% 满足要求 10002301413.565.0420013
n S mm mm -⨯-⨯==<满足要求 ()/0.013228011.50.3210.56sd cd b f f ξρξ=⋅=⨯÷==< 则
()220011.510001200.26944.54640.801cd M f b h A KN m M μ=⋅⋅⋅=⨯⨯⨯=⋅=<故满足设计要求
5 二.主梁计算
(一)跨中截面荷载横向分布系数计算(偏心压力法求c m )
(1)求1号梁的跨中截面荷载横向分布系数
由于本桥各主梁横截面相等,梁数n=6梁间距1.9m 则:
()()()6222
2222222221234561 4.75 2.850.950.95 2.85 4.75i
i a a a a a a a ==+++++=+++-+-+-∑=63.1752m
211161
211661
1122.56250.52663.1751122.56250.190663.175i
i i
i a y n a a y n a ===+=+==-=-=-∑∑ 由结果绘制1号梁影响线:
计算y11, y16横向影响线的零点位置,设零点至1号梁的距离为X 则 5 1.9 6.9580.520.19
x x x ⨯-=⇒=
6 根据《桥规》规定,在横向影响线上确定荷载最不利位置对于汽车荷载车辆横向轮距为1.8m ,两列车轮的横向最小距离为1.3m 。车轮距人行道缘石最小距离为0.5m ,汽车人群荷载相应于各个荷载位置的横向影响线竖标值
,q r y y 则汽车荷载:()1110.52 6.208 4.408 3.108 1.3080.562226.958
cq q m y ==⋅⋅+++=∑ 人群荷载:10.5216.9580.250.5396.9582cr r m y ⎛⎫==⋅-+= ⎪⎝⎭
(2)号梁的横向分布系数
122161
262661
11 4.75 2.850.381663.17511 4.75 2.850.048663.175i
i i
i a a y n a a a y n a ==⋅⨯=+=+=⋅⨯=-=-=-∑∑ 2号梁影响线
计算零点位置 5 1.98.4370.3810.048
x x x ⨯-=⇒= 则汽车荷载:
()2110.3817.687 5.887 4.587 2.787 1.4870.3130.499228.437
cq q m y ==⋅⋅++++-=∑ 人群荷载:()2
0.3818.4370.50.250.3928.437cr r m y ==⋅+-=
7 (3)号梁的横向分布系数
133161
363661
11 4.750.950.238663.17511 4.750.950.095663.175i
i i
i a a y n a a a y n a ==⋅⨯=+=+=⋅⨯=-=-=∑∑ 3号梁影响线
计算零点位置
0.23815.8119.50.095
x x x =⇒=- 则汽车荷载:
()()3310.23815.06113.26111.96110.1618.8617.0610.499215.8110.23815.8110.50.250.24215.811cq cr m m =
⋅⋅+++++==⋅+-= (二)支点截面荷载横向分布系数计算(杠杆法)
(1)1号梁的影响线 汽车荷载:111.90.750.6051 1.9
q q y y -=⇒= 11110.6050.30322oq q m y ==⨯= 人群荷载:11 1.90.25 1.1321.9
or r m y +=== (2)2号梁的影响线 汽车荷载:12 1.9 1.81,0.0521.9q q y y -==