Ventilation and COVID-19 transmission risks on board of Dutch governmental ships

The Dutch government (specifically the ‘Rijksrederij’, the governmental shipping company) owns a fleet of just under 100 ships that are equipped to service the internal waterways and parts of the North Sea. Think in this context of e.g. Coast Guard ships, ships that help to fight oil accidents or ships that maintain buoys. Just after the COVID-19 pandemic had started the ‘Rijksrederij’ decided that it was necessary to investigate to what extent the fleet might pose a risk for cross contamination of this new disease on board. This was approached with a specific focus on ventilation and the airborne route. The objective was to find out whether the most important spaces on board of the ships were adequately ventilated and to evaluate how ships can be made or kept ‘COVID-resistant’ as far as the airborne route is concerned. A sample of 16 ships of different types, most of them mechanically ventilated, were surveyed. This included a general inspection, an inspection of relevant HVAC system characteristics and measurements of e.g. air supply flows. Also, ships were equipped with monitors that measured CO2 concentration (e.g. in galleys and wheelhouses) that were left on board for at least one week. As reference for the supply flow measurement outcomes we used ISO 7547 guideline values and the Germanischer Lloyd ventilation requirements. On board of 6 of the 16 ships that were investigated we found serious problems with the fresh air supply and/or measured CO2 concentrations. On the positive side, the majority of the ships had ventilation capacities in line with the two reference standards, and almost all did not use central recirculation. We also found that many of the ships had adequate options, at room level, for individual control of both fresh air supply and temperature. The results of the study will be used to further improve ‘COVID safety’ on board of the whole fleet and to ameliorate future, new ships and their HVAC systems.Support AE+

Quidico Bay: Design Proposal for a Fishing Harbour in the bay of Quidico

Quidico is a small town, approximately 200 kilometer south of Concepcion. In the bay adjacent to Quidico town, a great number of local fishermen are active. In the current situation, high waves, a strong current and significant sediment transport hamper the effectiveness of the bay as fishing harbour. Also qualitative onshore facilities to support onshore activities of the fishermen, are absent. The Department of Ports of theMinistry of Public Works, developed a preliminary design proposal, to solve these problems. However, after consultation with the fishermen, this proposal was declared unsatisfactory. Therefore, an additional study is performed to develop a new integral design for the bay of Quidico. The desired design consists of onshore buildings, a paved support area, mooring facilities and breakwaters to create shelter for safe mooring of the fishing boats. Furthermore, these breakwaters shouldmitigate the problems related to sediment transport.To develop a new breakwater orientation and design, wave data is analysed. Waves coming from the south to south-west are most common, but not guiding due to the sheltering factor of IslandMocha, positioned in front of the coast. The guiding wave, which is coming from the north-west, is implemented in models of Delft3D to see what the new orientation of the breakwater should be. Based on the wave analysis, sediment transport analysis and modelling results, a new breakwater orientation is determined, that fulfills all requirements prescribed by the DoP. After defining this new orientation, the influence of the breakwater on sediment and waves is analysed. Due to the new orientation, a new design of the breakwater is made.The fishing harbour should offer the possibility for the fisherman to unload their goods and berth safely. The DoP proposed the construction of a mooring facility along the south-west shoreline of Quidico Bay. Two types of quay walls for the mooring facilities are proposed, a sheet pile wall and a concrete mass wall. For both types a preliminary design is developed, by making use of the 2D finite element software PLAXIS and hand calculations. The preferred mooring facility design mainly depends on the soil conditions at the specific location. From the boundary conditions it is concluded the bedrock is found at a depth of 60m, the soil above mainly consists of sand. Therefore the construction a sheet pile wall to serve as mooring facility, is recommended.In the initial design of the Department of Ports, six separate masonry buildings are proposed to accommodate the desired supporting facilities. These buildings cover a large area of the bay and will require a large paved supporting platform. To reduce this paved area, the DoP is interested in a more compact design, that includes all supporting facilities in one multi-storey building. In consultation with the DoP two different designs are developed; a three-storey steel building and a two-storey concrete building. A structural design is developed within the boundaries set by the functional design requirements. Next, a structural analysis is performed by making use of finite element software (ETABS) and a final design is obtained for both buildings. The concrete building is concluded to be the most suitable option for the DoP.Quick offloading of the boats and smooth transshipment of goods is hindered due to the lack of a good support area and access road. The DoP proposed a design for both pavements in the their preliminary study, but it was requested to evaluate different alternatives. Three different pavement technologies are proposed for the access road: surface treatment, asphalt and concrete slabs. For the pavement in the support area concrete slabs are the preferred solution. To achieve an optimal pavement design that fulfills all structural and serviceability requirements throughout the full design life, slab pavements with different dimensions and thicknesses are evaluated. In conclusion, short concrete slabs are the preferred pavement for both areas. Short slab pavement is an upcoming technology that has great advantages in terms of structural performance and costs.MP240Multidisciplinary Projec