01/1903 Board of Public Works Minutes

Home Browse Search

rays 6 ane. 6iQnk The °E,ngineer filed a report of his investigations as to the condition of the condition of the Jefferson street bridge as recently ordered by the Board. The °re port °which was addressed to the Board is as follows; - Gentlemen; -Pursuant to your request, I have mule an exaruination of the Jefferson street bridge and submit the following report concerning this bridge. During the summer of 19019 a bride 'erector was employed by the'�City to examine all the bridges, the Jef _'erson bridge be ing t?� one at that tune of Spec ial interest, as se,reral of tiie adjustable lateral roils were loose aad there was in `consequenc considerable vibration of the trusse s. All the adjustable .parts were properly tightened and later the bridge was cleaned of rust and scale anti t?�- iron wor?� painted, and a new floor was put do%Arn, Thus puttin- the bridge in better condition thTan it had been for sever -al years. From an eXamination I made some ten days ago, I believe the bride is now practically in the same condition, allowing for wear, as when the above worm was complete This bridge was constr«cte;l in 7.881 bythe tit. `jernon Briclr,*e compalyiy and t17e ordinance providing for its constriz-tion( which is the only data that I have been able to fin(I; the plans and spec ifications apparently be ing lost or destroyed) , calls for a bridge "s80 f feet long-) each span of 100 feet. The bridge shall have a came ity of 80+ per ,sq. ft. eXc2 uding t-.se weight of the bridge, i.e. the live load zraas consi-tiered at 80=f� ,per sq. ft. with a factor of safety of 4. The material is wrot iron. I believe the bride is able to sustain this loading) with ;perhaps a slight dimi diminution of the factor of safety, oyling to the effects of rest and of>ternal influences. I deem it proper to call your attention to the fa^t that a bride designed uner present for City Brides would call for .., uniform loading of some twenty per cent s pec ifications greater than that use _i in this bridge and would require a c oncentr��ted loading; for tale floor system calling for greater strength of members than the uniform load would regiaire, The ma.Ximum load provided for may never come on the bridge; except during some extradori.n- ary event, but I would slzgest that the present loads should not be increased an,. under ordinary c ireumstan^es the bra. iUe should last for a number of years. Respectfully submitted, Alonzo J . ' iammond. San_�_ers-Egbert &. Co. avrarded tie contract for Oar, Lumber for Street Department. Remonstrance filed by property owner, on a�. Madison street against the proposed paving of said street. President.