Reso 2021-3217 - Laserfiche WebLink

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�� `�'��1A2,`'''�a'�� Additional Service Request. ��w eFay�'axra� To Lawrence Kline COMPANY Perkins + Will RE ASR-007 FROM Brad Malmsten DATE May 24, 2021 PROJECT NO. K18051.00 FEE TYPE Lump Sum SUB/PRASE No. CFD Study Cc Jose Bofill, Michelle Olender PRCT Sunny Isles Beach Pedestrian Bridge AME ASR DESCRIPTION Drainage Study with CFD Model ASR BACKGROUND & SCOPE Backaround The FOOT review team expressed concern about the potential for water to drain from the bridge structure onto the roadway below. Per FOOT SOG 10.13.13, "Drainage of the superstructure onto the roadway underneath is not allowed.' The bridge design includes gutters on both sides of the walking surface to carry any water away from the roadway below before draining to the ground. The bridge cladding is largely open but includes a curved solid surface above. the walkway to provide shade to occupants. Due to the curvature of the cladding and the openness on the sides of the bridge, the design intent is not for the roof structure to collect any water. Further, any water that does collect is expected to drain to the inside of the bridge, where gutters are provided. During the FOOT review process, the reviewers expressed concern that without a specific drainage system for the roof, there is a chance of rain water draining onto the. roadway underneath. The team agreed to study this through constructing a physical mock-up of a portion of the bridge and testing it for drainage. This proposal proved to cost prohibitive. As an alternative approach, we are proposing using a computer model to simulate the drainage process. Scope Thornton Tomasetti proposes the use of Computational Fluid Dynamics to model a section of the bridge to investigate the impingement of rain on the surface of the pedestrian bridge, and the associated run off. Computational Fluid Dynamics encapsulates a number of methods, both traditional mesh based and particle based Methods for simulating the flow of fluid within domain. Rain will collect initially on the bridge surface, causing a water film to develop, which will then flow across the bridge surface depending on the interaction between the wind force on the water film and gravity. Analysis methods in this work will consider both the incoming wind, rain and associated build up and run off and the associated interactions. This will necessitate a multiphase approach where both air and fluid are considered explicitly within one simulation. We will consider up to 3 incoming rain directions and up to 2 rain conditions (normal and torrential), and assess the buildup of water on the bridge surface and determineif any runoff is captured by the existing canopy (guttering) or Is forced down into the roadway. The intent of this analysis will be to confirm that rain water falling onto the top of the bridge will be collected by the bridge's drainage and guttering system, and to determine how much, if any, rain water falling on the top surface of the bridge should be expected to drip down.to the road below. If the study finds that rain water from the roof of the bridge does make it to the roadway, the study can then be used to help determine appropriate placement of additional guttering systems. Ij2