ããå±é¢æ¿ååé¢æ¿çéªç®
ããå±é¢ææéç¨ååé¢æ¿,檩æ¡é´è·ä¸º0.9M,
ãã设计活è·è½½0.75KN/M2, æè½½0.2KN/M2ï¼ åºæ¬é£å2.59 KN/M2ï¼
ããéç¨830åPUå泡æ¿,æ¿å0.426mm, æªé¢å½¢ç¶å尺寸è§:
ããWx=4.02Cm3=4020mm3 Ix=7.98Cm4=79800mm4
ããåæ:
ãã(1) å
å计ç®: ååé¢æ¿éç¨å波线è·è½½
ããqx1=0.75KN/m2 x1mx1.5=1.125KN/m qx2=2.59KN/m2 x1mx1.5=3.885KN/m qx=0.2KN/m2x1m x1.35=0.27KN/m
ããq=1.125KN/m+3.885KN/m+0.27KN/m=5.28KN/m æç®æ¯æ¢è®¡ç®ååé¢æ¿è·¨ä¸æå¤§å¼¯è· Mmax=1/8qL2
ãã=1/8 x 5.28KN/M x( 0.9m)2=0.594KN.M
ãã(2) æªé¢å ä½ç¹æ§
ããç±830åPUå泡æ¿,æ¿å0.426mmå¾ç¥: Wx=4.02Cm3=4020mm3 δ=Mmax/Wx
ãã=0.594kN.M/4020mm3
ãã=0.594x103x1x103mm/4020 mm3
ãã=147.76N/mm2<[w]=215N/mm2 满足è¦æ± (3) 强度éªç® (a) æ£åºåéªç® δ= Mmax/Wx
ãã=0.594KN.M/79800mm3=74.436N/mm2<[w]=215N/mm2 满足è¦æ± (b) åªåºåéªç® Vmax=1/2qL
ãã=1/2 x 5.28KN/m x 0.9m=2.376KN (c) è
¹æ¿æ大åªåºå: δ=V/âht
ãã= 2.376KN x 103/( 2 x25mm x 0.5mm) =2.376 x 103 / (2 x 25 x 0.5)
ãã=95.04N/mm2 < [ f ]=120N/mm2 满足è¦æ± (4) é¢åº¦éªç®
ããæåè·¨ç®æ¯æ¿è®¡ç®è·¨ä¸æ大æ 度 Wmax=5qxL4 / 384EIx
ãã=5 x 0.27KN/N /1.4 x 0.9M x 1012 / (384 x 2.06 x 105 x79800 mm4) =0.13mm < [w] = L/300 = 3.4mm 满足è¦æ± éè¿ä»¥ä¸è®¡ç®,å¯ç¥æ»¡è¶³è®¾è®¡è¦æ±.
温馨提示:答案为网友推荐,仅供参考