Major maintenance work on two movable bridges in Heerenveen

Witteveen+Bos was commissioned to prepare functional specifications for major maintenance work to be performed on two movable bridges in the Dutch town Heerenveen. Not all the required design, construction and maintenance documentation was available. By performing inspections and drawing on the specialised knowledge and skills of Witteveen+Bos consultants, we were able to prepare the functional specifications.

Performed in phases

The work was performed in phases. The first phase involved inspecting the civil and mechanical engineering components to obtain a clear picture of the current situation, and on that basis defining the scope of the major maintenance work for 2018. In 2020, the Heerenveen municipal authority plans to replace the electrical installations of the Zijlroede Bridge and Boarne Bridge to comply with CE marking requirements under the Machinery Directive (Directive 2006/42/EC). For this purpose, a risk inventory and evaluation was performed to gain insight into the safety risks and how they can be addressed.

In addition, calculations were carried out to determine the current load class of the two bridges. The municipal authority now knows the maximum axle loads and maximum total loads that can be supported by the bridges, which enables it to put up the required traffic signs.

In the second phase, the scope of the contract was fully elaborated into a set of partially functional (i.e. descriptive) and partially solution-oriented (i.e. prescriptive) specifications. Operational and environmental requirements were also included. This phase was completed by drawing up a cost estimate in accordance with the Standard System for Costs Projection (SSK) and preparing a health and safety plan.