85-1三铰拱的支座反力和内力 支座反力与同跨度同荷载对应简支梁比较 b ∑ M,=0 Pai+ pa HA ,242=02=PP+)v二 ∑x=0H1=H=H P ∑M。=0 C P P VAL-P d-H f=0 C H B MC=H,f=0…H=1§5-1 三铰拱的支座反力和内力 一、支座反力 与同跨度同荷载对应简支梁比较 P2 HA VA VB P1 HB VA  VB  P1 P2 a1 a2 b1 b2 x x d D VA H P1 d c l1 f y f  M = V = ( + ) = l B 0 A Pb Pb VA VA 1 1 1 2 2   M = V = ( + ) = l A 0 B Pa P a VB VB 1 1 1 2 2   x = 0 HA = HB = H  MC = 0 V l P d H f A  1 − 1  −  = 0 M H f H M f C  C  −  = 0  = l l1 l2 c c