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hlr. h9at! Wraadru,�; I'.E. <br />C3ctober I5, 20dQ <br />Page 3 of 4 <br />stizaekure wilt cantinue to deteriarate, with the core of the deferioraiidn oecurr4ng <br />at the deck spall under tk�e southboa�ad lanes. �ased upon nomeal deterivra�ion <br />�e�els, we antieipate ��is structure will be eansidered Structurally lieficient in the <br />next few years. <br />The existang i�ri�ge aiso do�s not pro�ide th� necessary width to allaw two-way <br />�ehicular traff c and the des�red shared-use ��i�ycle ��d gedestrian} path alang <br />QId Snelling A�enue, Either a separaie structure w€ruld be required for the pat.�, <br />or an unsafe condition constricting the �ehicies and pedesirians onta the existiazg <br />width that wc�ul� ztot rneet Mnll�'ClT State A�d standards. <br />S#�uciure l�ecamr�endation <br />Bas� upan t�e condition of the exis�i�g bridge, the narrow dec�c width, and tl�e <br />desire tt� add a trail along this aTignmen�, we recamme�� �,t�se City ca�sider <br />replacing this bridge as part af �e C)ld Snelling A�enue irnprc�Vements. A <br />repiacement stn�cture wQuld ac�ommQdate the laading capacity of a. two-lane <br />roadrvay and a rr�ulti-use trail and wauld be canstn.ictec� ta MnfUDT State Aid <br />Standards. `T�te structure ty�e vvill l�kely l�e a eulvert. This type of s�.ruct�re <br />w[�rald a�law the rcr2tdrxay and tra.i� to sp�� ��er t3�e drai�age channel and a <br />cuivert is i}se masi cost effeetive str�etua-e type. Culve�ts are alsa � very lnw <br />maintenance siracture wher� cor�structed corr�etly. <br />In review af tbe existing hydra�lics, we ass�me t�ai we will n.eed ta gro�vid� a <br />similar waterway apeniug as the existing b�idge sa tlaa� base fland elevatior�s are <br />not signi�cantiy af�ecte�. Based u�acan ihe Fload �nsuranee StFic�y, the Jr�sephine <br />Lake Discharge Channel has a 1 aa-year ( l% ann�al ch�n�e) flaod ele�atian �f <br />880.� irrunediately upsiream of the O�d Snellin� �r��ige, and 879.9 immediately <br />dawnstream. The low chard on the existing b�icige is S$fi.12, approximatety 6- <br />feei aba�e the flood ele�atian. <br />Basec� �tpon tize sutvey of the exisiing channel, t�e waterway a�ening is <br />apprnximate�y 20-feet tan� and 2 feet high. We aa�ti�ipate two 1+Qx4 box culverts <br />will pra�ide �he req�ired waterway �pe��ag, and allaw fc�r a i-faoi freei��ard ta <br />the Iow-ci�ord. The }aax �ralVe�s a�-e est�rnated to ha�e a total lers�th af 9�-feet, to <br />�rro�ide the roadway and trail sectit�� acrQss the channel with ihe a�ticipated <br />reca�ery ze�nes. <br />During preliminary and final design af t�e stnact�re, a detail�ec� hydraulic analysis <br />will r�eed t� be �ernducted. The �ulvert sizin� antncipated �� this repvrt wouid be <br />fin�lized during �his phase af the project. We har�e canser�ati�vedy assumed ihat <br />the wa�erway area provided by th,e Gul�ert wcauid need to clasely resemble what <br />is provided lay the existing bridge. This vvi�i provide a conser�ati�e cost estimate <br />for t�e structure. <br />Since the cul�ert cons�nzc#�on would have impacts on the surrounding weflands, <br />flc�odplain, and floodway, several perrriits would be required. These permits <br />include: <br />