Ferry Street Bridge Ooverload Analysis, Sydney, NS


Project Description

In January 2014 Total Transport and Rigging (TTR) engaged Harbourside Engineering Consultants (HEC) to complete an analysis of the Ferry Street Bridge in Sydney Nova Scotia to determine the requirements for the transport of a large transformer across the structure that was destined for the Lingan Power Plant. The transformer was shipped by rail to Sydney, loaded onto a heavy load self-propelled transporter to traverse the Ferry Street Bridge and then reloaded onto the train to complete the final leg by rail. The requirement to cross the highway structure was to by-pass an adjacent rail line culvert that could not support the rail car loads from the large transformer.

Based on information provided by TTR, the 140 tonne transformer was to be loaded onto a Self-Propelled transporter that contained 11 axles, each spaced 1500 mm c/c with a total gross weight of 181 tonnes (unit and transporter). The hydraulic systems of the trailed ensured that each of the axles were loaded equally.

HEC obtained the Issued for Construction drawings of the Ferry Street Bridge from NS Lands (the owner) to facilitate the desk top review the structure. The bridge is a 35 meter single span bridge with 5-NEBT 1800 prestressed girders, complete with a 225 mm composite concrete deck, fully integral piled abutments, 8.9 meter long cantilevered wingwalls and 250 mm thick reinforced concrete approach slabs. The bridge was recently constructed in 2011-2012 and the condition of the structure was described as new. The desk-top analysis undertaken by HEC confirmed the ultimate limit strength for the one-time overload condition on the bridge. The analysis of the structure concentrated on several bridge components, including: the reinforced concrete approach slabs, reinforced concrete bridge deck, the composite precast prestressed concrete girders, the abutment piles and integral abutment caps.

It was determined that the capacity of the structure was sufficient to support the transporter vehicle for the crossing. A variety of operational constraints were stipulated by HEC so as control the loading and load distribution of the structure such as:  limiting the crossing speed to minimize dynamic loading, positing of the transporter on the structure during the crossing to optimize load distribution, closing the structure to all other traffic during the crossing and visual inspection of the structure before and after the crossing to confirm its condition.

Client: Total Transport & Rigging Inc.

Year: 2014

Role: Overload Transport Analysis