Pyrmont Bridge has a number of discrete components: the masonry and concrete abutments and retaining walls and embanked approaches, faced with sandstone; the timber Allan truss side spans; the stone pivot and rest piers; and the central steel swing span.
In later years the bridge deck was resurfaced with asphalt.
Following the closure of Pyrmont Bridge to vehicular traffic the eastern approach was demolished to make way for the Western Distributor. A pedestrian bridge was constructed over the distributor to link Pyrmont Bridge to Market Street.
In 1987 a section of the monorail track was constructed across the Pyrmont Bridge.
Further works at the eastern end of the bridge, in 1996, included the introduction of a pair of escalators and a set of stairs to the Cockle Bay promenade.
Pyrmont Bridge is maintained in a sound condition.
The old Pyrmont Bridge (1857) crossing Darling Harbour was purchased by the Government in 1884 for (Pounds)49,600, after the tolls were abolished. In 1891 competitive designs were invited for a new bridge on the south side of the old structure, but due to the economic depression no further action was taken until 1894, when, after prolonged inquiry and the consideration of about twenty six schemes, the Parliamentary Standing Committee on Public Works decided in favour of a design for a steel bridge with a swing span of 54 feet, affording two 70-foot clear fairways, submitted by the Public Works Department (PWD).
The foundations stone of the new bridge was laid by the Hon. E.W. O'Sullivan, State Minister for Works, on 6 September, 1899; and the bridge opened for traffic on 28 June 1902, by his Excellency Vice-Admiral Sir Harry Holdsworth Rawson, K.C.B., Governor of New South Wales.
Powered by electricity from the Ultimo Powerhouse, the swing bridge could be opened and closed in 45 seconds. Percy Allan, PWD Engineer-in-Chief of bridge design, designed over 550 bridges in NSW.
In 1981 the bridge was permanently closed to traffic and the Government ordered the bridge to be demolished, but later revoked this decision. In 1984 the Darling Harbour Authority was formed with the task of redeveloping Darling Harbour. The Pyrmont Bridge was restored, with the swing span in full working order, and incorporated as a pedestrian bridge in the redevelopment of Darling Harbour. A section of the Monorail was built across the bridge at this time. The Pyrmont Bridge was re-opened to pedestrian traffic in 1988.
Following the end of the monorail's 25 yeasr of operation in July 2013, the Sydney Harbour Foreshore Authority began discussing plans to give teh bridge a facelift to coincide with Darling Harbour's $2.5b redevelopment. "It is anticipated that the monorail infrastructure will be removed from the bridge by the end of 2013" said SHFA's spokesman. The SHFA will commission a design brief to look at options for future enhancements including furniture, lighting and pop-up cafes. "Pyrmont Bridge will remain open and accessible to the public...Any future use proposals must not impact on the bridge's surviving historic fabric, or its technological significance, or prevent the continued use as an open swing span bridge" (Gorman, 2013).
The NSW Government will invest in a $23m renewal of heritage-listed Pyrmont Bridge. The project is part of a $73m commitment over the next four years to protect heritage assets along Sydney Harbour foreshore. The projets include $15m to replace ferry wharves in Cockle Bay and $20m to refurbish public spaces at Campbell's Cove at the Rocks and Darling Harbour. Minister for Finance, Services and Property, Dominic Perrottet made the announcement. He said that foreshore renewal was part of Property NSW's broader responsibility for preserving heritage across the state. 'Property NSW is working with the OEH and the Greater Sydney Commission on a proposal to designate The Rocks a heritage precinct'. (Inner West Courier, 10/5/16).
Property NSW CEO Brett Newman announced in 2018 a remediation project, will be undetaken in stages over the next five years, which will include replacing deteriorated timber sections within the bridge pier and truss sections to maintain its structural integrity. The works will cost $23m, part of a wider $73m state government restoration project to protect and enhance heritage assets along the Sydney Harbour foreshore. A spokeswoman said the projects were funded from the divestment of government-owned assets. The first stage of works will restore the timber pier sets below the bridge and is expected to be completed by the end of 2019. Pyrmont Bridge will remain open during the works (Sydney Central n/ppr., 16/5/18, 16).