The Brattleboro daily reformer. (Brattleboro, Vt.) 1913-1955, 1920-07-20
LITTLE CHANCE TO
IMPROVE BRIDGE
oN
Engineer Reports on Ex-
animation of West Riv-
er Structure W.
ALL MEMBERS NOW
STRESSED TO LIMIT
Could Be Made Much Safer and Serv-
iceable for Some Time if it Gould Be
Strengthened UP and Thoroughly
Braced, Report Says.

Clerk A. d. Wyatt of the board OF
selectmen has lust received from State
Engineer H NJ. Mcintosh of Montpelier
a copy of the report of Engineer Jasper
o. Draffin on the strength and carrying
capacity of the wooden bridge over West
river at Brattleboro, based on notes
taken by Prof A. f. Winslow and an
examination of the bridge by Dr. Dratfin
The report covers six typewriter pages
of letter paper and covers much technical
ground that would not be of interest to
the general reader, but in a nutshell Mr..
Draffin does not see much possibility OF
permanent improvement.
The bridge is combination of the lat
ticed-truss and arch types. The arch is
practically Independent of the truss, be-
ing connected to the truss work at
comparatively few places. The load is
carried to the arches by means of vertical
iron rods which pass through beams
placed cross-wise under the trusses; as
the truss defects under its own load and
that of traffic, the detection carries loau
to the arch. At present there Is con-
siderable lateral detection of the struc-
ture and tipping of the top in down
stream direction.
| During his examination of the bridge
| Mr.. Draffin stood on one of the arches.
near the top, while a trnckload OF gravel
passed over, and he says there was a
4 very perceptible swaying of the whole
4 structure" The wind load is consider
able, he says, and as the portal braclng -
/ almost negligible the wind load is very
| important factor. The effect OF tins ls
shown by the way in which both ends OF
/ the bridge have tipped downstream.
! In order to have the bridge stiff and
able to resist the wind load, large be-
cause of the length of the bridge, there
| should be good system of braeing be-
tween the two upper chords, also suffi-
cient bracing between the chords and the
web or inclined members. "There is a
large amount of bracing between the
chords the engineer reports, "but it does
not appear to be very effective; it is not
connected rigidly enough"
/ Engineer Draffin summarizes his re-
port as follows: "The bridge appears to
be top heavy, and it lacks rigidity, es-
peeially as regards braeing. Because of
its length the dead load stresses constf-
tute the greater part of the stresses in
the bridge. Both upper and lower chords
J are stressed to their allowable limits by
dead, wind and snow loads alone and the
upper chord by dead load, wind load and
Z a six and one fourth ton truck. The
;. stringers are not stressed to the limit by
: a six and one-fourth ton truck, but as
7 the tabulated stresses make no allowance
for impact it does not seem advisable to
2 recommend a heavier loading as allow
5 able because if impact were considered
: the stresses would reach the allowable
: limit The arch is stressed beyond its
r allowable limit by any combination OF
(. loads and as the effect of high stresses
: in the arch is to cause sidewise bending
4 the condition of the bridge confirms the
: analysis.
"Since practically all members of ths
bridge are stressed to or beyond the
2 limit by the dead load and six and one
fourth ton truck it would not appear that
e the expenditure of large sum for re
pairs would be justified. If the bridge
were strengthened up and thoroughly
braced it would be much safer and would
give service for some time, but on account
of the present condition of the bridge
) the type, and the small amount of head
room available for bracing it does not
seem to me to offer much, possibility o.
e permanent improvement.